Note: Descriptions are shown in the official language in which they were submitted.
CA 02665044 2013-11-07
1
LAYER SYSTEM WITH AT LEAST
ONE MIXED CRYSTAL LAYER OF A POLYOXIDE
This invention relates to a PVD layer system for the coating of workpieces and
to a method for
producing a corresponding coating system. The invention further relates to
workpieces coated
with a layer system according to the invention.
Prior Art
EP 0513862 and US 5,310,607 (Balzers) describe an (A1,Cr)203 hard-metal layer,
a tool coated
with it and a process for producing that layer whereby, from a crucible
serving as the anode for a
low voltage arc (LVA) discharge, Al and Cr powder are jointly vaporized and
tools are coated in
an Ar/O, atmosphere at about 500 C. That layer exhibits intrinsic compressive
stress and consists
essentially of mixed crystals with a Cr content in excess of 5%, its
thermodynamic stability
enhanced by a high aluminum content, its abrasion resistance enhanced by an
increased chromium
content. While on the basis of a purported 202 line the layer is referred to
as a modified
a-aluminum oxide (corundum) with a shift reflecting the chromium content, all
other corundum
lines are missing in the analyses performed. Their described advantages
notwithstanding, these
layers have failed to establish themselves as an industrial standard since due
to their insulating
properties their production by the stated LVA process causes process-related
problems in
continuous operation.
The three documents mentioned below describe ways to circumvent these process-
related
problems by the deposition of an at least adequately conductive layer of a
ternary nitride followed
by an oxidation step. All three documents, however, aim at providing an oxide
layer or dispersion
in a corundum structure to serve as a base for the epitaxial growth of an a-
aluminum oxide layer.
The latter is produced by an unbalanced magnetron sputter (UBMS) process in an
Ar/02
atmosphere with extensive process monitoring, using a plasma emission monitor
(PEM), in order
to keep the Al sputtering targets in a transitional range between a
contaminated, i.e. oxidic, and a
metallic surface.
CA 02665044 2013-11-07
2
US 6,767,627 and JP No. 2002-53946 (Kobe) describe a layer system and a method
for producing
an a-aluminum oxide containing layer system. As a first step, by way of
example, a TiAlN and an
AlCrN hard layer are applied, followed by the oxidation of at least the
surface of the AlCrN hard
layer, the result being a corundum-like lattice structure, with a lattice
constant of between 0.4779
and 0.5 nm, as an intermediate layer on which the a-aluminum oxide layer (a =
0.47587 nm) is
deposited. The authors claim to be able even at temperatures between 300 and
500 C to produce
layers of a corundum structure by employing an ALP process with a subsequent
oxidation step,
followed by the UBMS of aluminum oxide. Also, as an alternative, they describe
aluminum oxide
layers deposited on Cr203, (A1,Cr)203, and (Fe,Cr)903 intermediate layers
which also were
produced by UBMS in an A1/02 atmosphere. In addition, making reference to JP5-
206326 published
August 13, 1993, the authors mention the inadequate suitability of (A1,Cr)203
layers for the processing of
steels due to the reaction of chromium on the surface of the layer with the
iron of the material being treated.
In contrast thereto, inventors of the same applicant acknowledge in the more
recent US 2005 005
8850 (Kobe) that these techniques do in fact require temperatures of 650 C to
800 C since no
oxidation takes place if the temperature is too low. Yet they only describe
examples at
temperatures of 700 and 750 C and lay claim to a method whereby at least the
oxidation step or
the deposition of the aluminum oxide film takes place at a temperature of 700
C and above.
Preferably, they say, both process steps are carried out at the same
temperature. The inventors
further describe the additional application of a preferably Ti-containing
diffusion barrier such as
TiN, TiC, TiCN, among others, in order to prevent the harmful diffusion of the
oxygen through the
oxide layer into the substrate, which would occur at these high temperatures.
WO 2004 097 062 (Kobe) as well sees a need for improvement on the invention
described in JP No.
2002-53946. The starting point in this case is an attempt whereby, as in JP No
2002-53946, CrN is
oxidized at 750 C whereupon, at the same temperature, aluminum oxide is
deposited by a
PEM-monitored sputter process in an Ar/02 atmosphere. While this does result
in crystalline
layers, these become increasingly coarse-grained and thus excessively rough
with the progressive
augmentation of the layer thickness. WO 2004 097 062 tries to solve that
problem with a method
whereby the growth of the aluminum oxide crystals is interrupted either at
periodic intervals by
thin oxide layers of different metal oxides which also grow with a corundum
structure, such as
CA 02665044 2009-03-31
WO 2008/043606 PCT/EP2007/059196
3
Cr203, Fe2 03 (A1CO203, (A1Fe)203, or at least by the periodic dispersion of
such oxides. The layer
regions encompassing those other metal oxides are supposed to be held at less
than 10 and
preferably even less then 2%. It would appear, however, that the long coating
times involved in
producing these layers, about 5 hours for 2 are hardly practical for
industrial processes.
A publication by Ashenford [Surface and Coatings Technology 116-119 (1999),
699-704]
describes the growing of aluminum oxide of a corundum structure and chromium
oxide of an
eskolaite structure in a temperature range between 300 C and 500 C. The
eskolaite structure of the
chromium oxide is similar to the corundum structure of the aluminum oxide,
albeit with somewhat
modified lattice parameters. The objective of the tests, performed with an MBE
system in the
UHV range, was to use chromium oxide of a corundum structure as a
crystallization base for
growing the corundum high temperature phase of the aluminum oxide. In the
process the oxygen is
excited by the plasma, the metals are vaporized separately by elemental
sources so disposed that
the material flows reach the substrate at the same time. In the temperature
range explored, between
300 and 500 C, steel substrates permitted the deposition of amorphous aluminum
oxide only,
whereas, largely independent of the pretreatment of the steel substrates,
chromium oxide grows as
a polycrystalline layer with an eskolaite structure. Still, it was not
possible to produce a pure
a-aluminum oxide even on eskolaite layers since in that temperature range, at
an aluminum
concentration of 35 at% and up, the crystalline structure flips into amorphous
aluminum oxide
within just e few atom layers. The practical results were then confirmed by
simulated calculations
using a semi-empirical model, predicting a destabilization of the a-aluminum
oxide by oxygen
defects in favor of a x-modification.
EP 0 744 473 B1 describes a sputter process which for substrate temperatures
below 700 C
provides a layer that consists of an a- and 7-phase of the aluminum oxide and
is completely
crystalline but exhibits high compressive stress of at least 1 GPa. The
intermediate layers between
the tool and the aluminum oxide layer are said to be metal compounds with 0, N
and C.
To summarize, it can be said that, in terms of producing oxides with a
corundum structure using
PVD processes, prior art has for more than 10 years endeavored to come up with
a-aluminum
oxide layers that can match the layer long successfully obtained with CVD but
without the
CA 02665044 2009-03-31
WO 2008/043606 PCT/EP2007/059196
4
drawbacks inherent in the CVD process. The techniques applied, however, are so
complex,
error-prone and cumbersome that to this day there has only been one
manufacturer that offers an
amorphous aluminum oxide layer but still no crystalline and especially no a-
aluminum oxide
layers for tool-coating purposes. For similar reasons there are still no other
pure oxide layers
available, in particular thick oxide layers, even though it is evident from
the available gamut of
oxynitrides, oxycarbonitrides, etc. that in the tool market there is a great
demand for
thermochemically resistant coatings
Definitions
The term thermally stable, for the purpose of this invention, defines layers
which, exposed to air
within a temperature range from room temperature to at least 900 C, preferably
1000 C and
especially 1100 C, reveal no changes in their crystal structure, hence no
significant changes in
their x-ray diffraction pattern and thus in their lattice parameters. Layers
of this type, if they
exhibit a corresponding basic hardness of at least 1500 HV but preferably at
least 1800 HV, are of
particular interest for tools exposed to high thermal stress, since no phase
conversion processes are
to be expected during the machining cycle, and because they offer clearly
superior thermal
hardness compared to other layers.
The term stress-free refers to layers which in test procedures, described in
more detail below, have
exhibited minor if any compressive or tensile stress. Consequently, a shift
for instance of the
interplanar spacing or the lattice constant of (A1Cr)203 layers, established
through a linear
interpolation between the lattice constants of the binary compounds a-A1203
and a-Cr203, will
provide a direct indication of the Al and, respectively, Cr content of the
layer (Vegard's Law).
This is in contrast to the PVD methods described for instance in EP 0513662
and EP 0744473. The
layers discussed in these documents, grown with mechanical bias due to the
inclusion of inert-gas
atoms, direct-current bias or for other reasons exhibit high intrinsic
compressive stress in excess of
one GPa, which in the case of thicker layers often leads to spalling.
By comparison, CVD layers are usually subject to tensile stress as a result of
the different thermal
expansion coefficients of the layer and the base material during the cooling-
off of the high
deposition temperatures that are typical of the process. For example,
according to US 2004202877
the deposition of a-A1203 requires temperatures of between 950 and 1050 C.
Apart from the
CA 02665044 2009-03-31
WO 2008/043606 PC T/EP2007/059196
additional problem of an unavoidable concentration of undesirable
decomposition products (such
as halogens) from the deposition process, this constitutes the main drawback
of the CVD coating
process, since such stress leads to fissuration, for instance ridge cracks,
making these layers less
than suitable for machining processes such as jump cutting.
The term polyoxides refers to compounds of at least two or more metals with an
oxide. It also
refers to the oxides of one or more metals which additionally contain one or
several semiconductor
elements such as B or Si. Examples of such oxides include the cubic double or
polyoxides of
aluminum, known as spinels. This present invention, however, relates to oxides
with a
corundum-type isomorphous a-aluminum oxide structure composed of (Melt,
Me2,)203, where
Mel and Me2 each contain at least one of the elements Al, Cr, Fe, Li, Mg, Mn,
Ti, Sb or V and
where the Mel elements differ from the Me2 elements.
Measuring Methodology
To permit a better comparison, the following will briefly discuss individual
methods and
equipment used in determining specific layer characteristics.
X-ray Diffraction Analyses
For the analysis of the XRD spectra and the lattice constants calculated on
the basis of the latter,
the equipment employed was a D8 X-ray diffractometer by Bruker-AXS, with a
Goebel mirror, a
Soller slit and an energy-dispersive detector.
The simple 0-20 measurement was performed in a Bragg-Brentano geometry with Cu-
ka radiation,
no grazing incidence.
Angular range: 20 to 900, with rotating substrate.
Test duration: With a dwell time of 4 s per 0.010 the test duration was 7 h 46
min (for 70 ).
Measuring the Intrinsic Stress of the Layers
One method applied to measure the intrinsic stress of the layers was the
Stoney bending strip
method using hard metal sticks (L=2r=20mm, Ds=0.5 mm, E=210 GPa, v=0.29) and
calculating
the intrinsic stress with the following formula:
CA 02665044 2013-11-07
6
Es * I)!
= *f
3*L2 *df
where Es ... Young Module of the substrate, Ds ... total thickness of the
substrate, df ... layer
thickness, f ... deflection, and L ... free bar length.
Another method applied was the bending disk method, with the intrinsic stress
calculated with the
following formula:
Es Ds2 * 8
= _________
(1 ¨ vs) 6 * L2 * df
where L=2r=20mm, D=0.5 mm, E=210 GPa, v=0.29.
Moreover, the deviation, determined by x-ray diffractometry, of the measuring
points of a
polyoxide from the straight line determined by applying Vegard's Law provides
an indication of
the intrinsic stress patterns in a composite layer system.
Overview
It is the objective of this invention to offer improvements over the drawbacks
of prior art,
described in detail above, and to provide a layer system that lends itself
well to high-temperature
applications and contains at least one thermally stable oxidic layer, as well
as workpieces, in
particular tools and components, protected by said layer system. Another
objective consists of a
method for producing the layer system in such fashion that a simple and
reliably reproducible
coating of workpieces and an adjustment of the properties of the layer system
to varying
applications is possible.
This objective is achieved with a PVD layer system for the coating of
workpieces, comprising at
least one mixed-crystal layer of a polyoxide having the following composition:
(Mel 1,Me2),)203
CA 02665044 2015-10-16
7
where Mel and Me2 each include at least one of the elements Al, Cr, Fe, Li,
Mg, Mn, Nb, Ti, Sb
or V, with the elements of Mel differing from those of Me2 and the crystal
lattice of the mixed-
crystal layer having a corundum structure which in a spectrum of the mixed-
crystal layer,
measured by x-ray diffractometry or electron diffraction, is characterized by
at least three,
preferably four and especially five lines associated with the corundum
structure. In one
embodiment the mixed-crystal layer of a multi-oxide comprises areas of the at
least one element.
Especially well suited are layer systems in which Mel is aluminum and Me2
consists of at least
one of the elements Cr, Fe, Li, Mg, Mn, Nb, Ti, Sb or V while 0.2 < x < 0.98,
preferably
0.3 < x < 0.95. In this case, particular significance is attributed to
aluminum as the element
enhancing oxidation resistance as well as high-temperature hardness. Too high
an aluminum
content, however, has been found to pose a problem especially in producing the
layers since,
particularly at low coating temperatures, these layers form progressively
smaller crystallites with a
correspondingly diminished reflection intensity in the x-ray diffractogram.
For growing the layer in as undisturbed and stress-free a manner as possible,
the concentration of
halogens and inert gas in the mixed-crystal layer should in any event be less
than 2%. This can be
achieved by operating the sources with a process gas that consists of a
minimum of 80%,
preferably 90% and ideally even 100% of oxygen. The inert gas content in the
mixed-crystal layer
can then be limited to a maximum or 0.1 at%, preferably a maximum of 0.05 at%
and/or the
halogen content can be limited to a maximum of 0.5 at% and preferably to a
maximum of 0.1 at%,
or, in a best-case scenario, the mixed-crystal layer can preferably be
produced essentially free of
any inert gas and halogens.
The mixed-crystal layer can be built up in different ways. For example, the
layer can be produced
as a single or a multi-stratum layer from at least two different,
alternatingly deposited polyoxides.
Alternatively, a polyoxide can be deposited in an alternating sequence with
another oxide.
Polyoxides that have been found to be particularly resistant to high
temperatures are those
produced by arc vaporization or sputtering of aluminum/chromium and
aluminum/vanadium
alloys. Other oxides with good high-temperature resistance characteristics and
suitable for
alternating coating with polyoxides include Hf02, Ta205, Ti02, Zr02, and y-
A1203, but especially
oxides with a corundum structure such as Cr203, V203, Fe203, FeTiO3, Ti203,
MgTiO2 and, of
course, especially a-A1203.
CA 02665044 2009-03-31
WO 2008/043606 PCT/EP2007/059196
8
In generating the layer system it was found to be desirable to minimize any
stress in the
mixed-crystal layer so as to permit the deposition even of thick layers that
are needed especially
for high-speed lathe work on metals. If the layer system is to feature
additional characteristics such
as a specific intrinsic stress pattern for the machining of hardened steels,
particular antifriction
qualities for improved chip removal or for use on sliding elements, enhanced
adhesion to different
substrates, or the like, such properties can be attained for instance by
selecting appropriate
intermediate layers between the substrate and the mixed-crystal layer,
consisting of at least one
bonding and/or hard-metal layer, or by providing the mixed-crystal layer with
one or several cover
layers.
The hard-metal layer or cover layer preferably contains at least one of the
metals of subgroups IV,
V and VI of the periodic system, or Al, Si, Fe, Co, Ni, Co, Y, La or of such
metal compounds of
these elements with N, C, 0, B, or mixtures thereof, compounds with N or CN
being preferred.
Compounds found to be particularly suitable for the hard-metal layer include
TiN, TiCN, AlTiNi
AlTiCN, AlCrN and AlCrCN, while the compounds that are especially suitable for
the cover layer
include AlCrN, AlCrCN, Cr203 or A1203, and in particular y-A1203 or a-A1203.
Much like the
mixed-crystal layer, the intermediate and/or the hard-metal layer may comprise
several strata. The
layer system may also be built up as a multilayer structure with an
alternating intermediate and
mixed-crystal layer or alternating cover layer and mixed-crystal layer.
The mixed crystals with a corundum structure can be produced employing arc
processes without or
with a specially configured, small vertical magnetic field, by pulse-
superposed arc processes, as
well as by general methods such as arc or sputter processes where high-current
pulses are fed to the
material sources such as arc vaporizers or sputter sources or are superimposed
on the DC base
mode. This permits operation in the contaminated state, or alloying on the
target, as long as certain
prerequisites, explained in more detail below, are observed.
In connection with the arc processes employed for producing the layer system
according to the
invention and in particular for producing the oxidic mixed-crystal layer,
please refer to the
following patent applications by the same claimant which in teims of the
methodology represent
CA 02665044 2009-03-31
WO 2008/043606 PCT/EP2007/059196
9
the latest state of the art: WO 2006099758, WO 2006/099760 as well as CH
01166/06. All of the
processes were implemented using a Balzers RCS coating system.
To produce mixed crystals with a corundum structure it is important that in
each process the target
is an alloy target, because otherwise, as explained below, it will not be
possible at deposition
temperatures below 650 C to deposit an oxidic mixed-crystal layer with a
corundum structure. In
the interest of an as simple as possible reproducible process, the process
parameters should be
selected so that the metal composition of the mixed-crystal layer, scaled to
the total metal content,
will not differ for the respective constituent metals by more than 10%,
preferably 5% and
especially 3% from the concentrations in the metal composition of the target.
This is attainable for
instance by observing the parameters indicated in the experiment examples, by
selecting a rather
low substrate bias of perhaps less than 100 V so as to prevent dissociation by
an edge effect etc.
Those skilled in the art can adjust and vary these parameters depending on the
alloying system, for
instance if there is a need to achieve a very high compressive stress.
Arc processes in which no magnetic field is applied to the target surface, or
only a small external
magnetic field extending in a direction essentially perpendicular to the
target surface, are generally
suitable for producing polyoxides according to this invention. If a magnetic
field with a vertical
component B, is applied, it will be desirable to set the radial or surface-
parallel component Br over
most but at least not less then 70% and preferably 90% of the target surface
at a value smaller than
B,. The vertical component B, is set between 3 and 50 Gauss but preferably
between 5 and 25
Gauss. This type of magnetic field can be generated for instance by means of a
magnet system
consisting of at least one axially polarized coil whose geometry fairly
matches the target
circumference. The coil plane may be positioned at the level of the target
surface or preferably
behind and parallel to the latter. The processes described below, employing
pulsed sources, lend
themselves well to arc processes using sources that have such weak magnetic
fields or even no
magnetic field.
The following pulse source processes for producing in particular thermally
stable mixed-crystal
layers of polyoxides with a corundum-type crystal lattice involve the
simultaneous feeding of at
least one arc source with a direct current and a pulsed or alternating
current. A first electrode of an
CA 02665044 2009-03-31
WO 2008/043606
PCT/EP2007/059196
= 10
arc or sputter source, in the form of an alloy target, and a second electrode
serve to deposit a layer
on the workpiece, the source simultaneously being fed a direct current or DC
voltage as well as a
pulsed or alternating current or a pulsed or alternating AC voltage. The
composition of the alloy
target is essentially the same as that of the mixed-crystal layer. The
preferred pulse frequency is in
a range from 1 kHz to 200 kHz. The pulse current supply may also be operated
at some other
pulse-width ratio or with pulse separations.
The second electrode may be either separated from the arc source or constitute
the anode of the arc
source, with the first and the second electrodes connected to and powered by a
single pulse current
supply. If the second electrode does not serve as the anode of the arc source,
the arc source can be
connected to and operated with one of the following material sources via the
pulse current supply:
Another arc vaporizing source that is itself connected to a DC power supply;
- A cathode of a sputter source, in particular a magnetron source, also
connected to a
power supply, especially to a DC power supply;
- A vaporizing crucible that doubles as the anode of a low voltage arc
vaporizer.
The DC power supply delivers a base current in a manner whereby the plasma
discharge is
maintained essentially without interruption at least at the arc vaporizer
sources but preferably at all
sources.
It is desirable to decouple the DC power supply and the pulse current supply
by means of an
electric decoupling filter that preferably contains at least one blocking
diode. The coating process
can take place at temperatures below 650 C and preferably below 550 C.
In this case the polyoxide layers grow with a corundum-like structure in spite
of the relatively low
coating temperature and the bonding or intermediate layer that may be
positioned underneath them
perhaps as a cubic metal nitride or carbonitride layer, which is surprising
given the fact that in
earlier experiments in which layers were produced through simultaneous vapor
deposition on
workpieces using elemental aluminum and chromium targets in an oxygen
atmosphere only
CA 02665044 2009-03-31
WO 2008/043606 PCT/EP2007/059196
11
amorphous layers such as (A11_Crx)203 were attainable. This was even the case
when the coating
range of the sources was set in overlapping fashion. Only when alloy targets
are used is it possible,
already at relatively low process temperatures, to deposit polyoxides with a
crystalline and
especially corundum structure. It is also necessary to ensure that enough
oxygen is available at the
target, which is why a high oxygen content of at least 80% and preferably 90%
is selected for the
process gas or, as in the following Example #1), only oxygen is used as the
process gas. During the
arc process the target surface is immediately coated with a thin,
nonconductive layer. In the
opinion of the inventors, the growth of a crystalline layer and especially one
with a corundum
structure, which used to be possible at much higher temperatures only, at a
lower temperature can
be attributed to the formation of polyoxides on the target surface which
evaporate during the
process, initially form growth nuclei on the workpiece and ultimately
participate in the build-up of
the layer. There are several reasons pointing to this growth mechanism. For
one, the temperatures
generated on the target surface by the arc are within the melting point of the
alloy, which in the
presence of a sufficiently high oxygen concentration establishes a good basis
for the formation of
high-temperature-stable corundum-like polyoxide structures. For another, as
mentioned above, the
simultaneous vaporization of elemental aluminum and chromium targets failed to
produce mixed
crystals. Similar results were obtained with oxide layers produced by a
sputter process. For
example, in experiments analogous to those per US 6,767,627 the inventors
authoring this patent
application produced aluminum oxide and aluminum-chromium oxide layers in a
temperature
range between 400 and 650 C by sputtering, although crystalline aluminum oxide
or
aluminum-chromium oxide layers having a corundum structure could not be
established. Nor were
attempts using alloy targets successful, which may be due to the absence in a
typical sputter
process of a thermal excitation on the substrate surface, and to the fact that
the target surface does
not sputter compounds but atoms only.
While at this juncture there is no factual proof, for instance by a
spectrographic analysis, of such a
formation mechanism, and while other mechanisms are perhaps a factor in this,
it can nevertheless
be stated that this present invention makes it possible for the first time to
produce polyoxides with
a distinctly verified corundum lattice structure at a coating temperature of
between 450 and 600 C.
To further increase the thermal excitation on the target surface, individual
experiments were
CA 02665044 2009-03-31
WO 2008/043606 PCT/EP2007/059196
12
conducted with uncooled or with heated targets, vaporizing material in an
oxygen atmosphere on
the nearly red-hot target surface. Even layers produced in that fashion
exhibit a corundum-like
lattice. At the same time, the rising discharge voltages in these processes
point to an increased
plasma impedance which is attributable to the increased electron emission of
glowing surfaces in
combination with an elevated vapor pressure of the target material, further
intensified by the
pulsation of the source current.
Another way to produce oxide layers according to this invention is through the
operation of a
high-power discharge with at least one source. This is attainable for instance
by operating the pulse
current source or pulse voltage supply with pulse slopes that are generated at
least in the range
from 0.02 V/ns to 2.0 \Tins, preferably in the range from 0.1 Vins to 1.0
V/ns. The currents applied
are at a level of at least 20 A but preferably equal to or greater than 60 A,
with voltages between 60
and 800 V, preferably between 100 and 400 V above or in addition to the
voltage and current of the
simultaneous DC discharge. These voltage spike pulses can be generated for
instance by means of
one or several capacitor cascades which, apart from a few other advantages,
also makes it possible
to alleviate the load on the basic power supply. Preferably, however, the
pulse generator is
connected between two simultaneously DC-powered arc sources. Surprisingly, by
applying the
spike impulses in the arc process, it is possible to increase the voltage at
the source over several p.s
as a function of the magnitude of the voltage signal applied, whereas pulses
with a flatter slope will
result in an increased source current, as would be expected.
Initial experiments have shown that with these high-current discharges it is
also possible to
produce from sputter sources with alloy targets oxidic polyoxides with
corundum, eskolaite or
comparable hexagonal crystal structures, which can presumably be ascribed to
the increased
energy density on the target surface and the concomitant large temperature
increase, so that here as
well the use of uncooled or heated targets, described above, could prove
beneficial. For processes
of that nature the high-power discharge exhibits similar characteristics for
both high-power arcing
and high-power sputtering, corresponding to the anomalous glow discharge
pattern known from
Townsend's current-voltage diagram. The convergence on that range occurs from
mutually
opposite sides, one being the arc discharge of the arc technique (low voltage,
high current), the
other being the glow discharge of the sputter process (medium voltage, low
current).
CA 02665044 2009-03-31
WO 2008/043606 PCT/EP2007/059196
13
Approaching the stage of an anomalous glow discharge from the high-current
side, i.e. the "arc
side", will in any event require measures aimed at increasing the impedance of
the plasma or of the
target surface (see above). As stated, this can be accomplished by the
superposition of spike pulses,
by heating the target surface or by a combination of these measures.
Another way to increase the plasma impedance is to pulse the magnetic field of
the source. This
can be accomplished by means of the pulse current of the source which, either
entirely or as a
partial current, is passed through a magnetic system composed of an axially
polarized coil as
described above. In this case, in adaptation to the high current peaks, cooled
coils with a small
number of turns (I to 5) can be used if necessary.
From the above explanations and the experiments described below it will be
evident that layer
systems according to this invention are in general superbly suited to tool
applications. These layer
systems can thus be advantageously applied on such tools as milling cutters,
drills, gear cutting
tools, interchangeable cutting inserts, cut-off tools and broaches made of
different metals such as
cold work steel and hot forming tool steel, HSS steel as well as sintered
materials such as powder
metallurgical (PM) steel, hard metal (HM), cermets, cubic boronitride (CBN),
silicon hard (SiC)
and silicon nitride (SiN). They lend themselves particularly well, however, to
tool applications
involving high machining temperatures or cutting speeds as for instance in
lathe work, high-speed
milling and the like which, apart from abrasion resistance, are subject to
highly demanding
requirements in terms of thermochemical stability of the hard-metal layer.
Nowadays, these tools
use primarily CVD-coated interchangeable inserts, often with coatings between
10 and 40 um
thick. In view of their above-described properties, the layers according to
the invention constitute a
preferred application for coated interchangeable inserts, with particular
emphasis on
interchangeable inserts made of PM steel, hard metal, cermet, CBN, SiC, SiN
sintered metals, or
interchangeable inserts precoated with a polycrystalline diamond layer.
While the emphasis of the work performed in connection with this invention was
primarily
focused on the development of protective layers for metal-cutting tools, it is
of course possible to
use these layers to advantage in other fields as well. For example, they can
be assumed to be quite
CA 02665044 2009-03-31
WO 2008/043606 PCT/EP2007/059196
14
suitable for tools used in various hot-forming processes, for instance in the
precision forging and
swaging or die-casting of metals and alloys. Given their high chemical
resistance these layers can
also be used on tools for plastics processing such as injection and
compression molding equipment
for producing preformed components.
Other application possibilities exist in the realm of parts and components
coating, for instance of
heat-exposed components of combustion engines, including fuel injection
nozzles, piston rings,
tappets, turbine blades and similarly stress-exposed parts. In these cases as
well, much like those
discussed above and at least in areas exposed to wear, the following base
materials can be
employed: Cold work steel, HSS steel, PM steel, HM, cermet or CBN-sintered
metals.
Even for thermally stable sensor layers, layers can be deposited by the method
according to the
invention, such as piezoelectric and ferroelectric materials and all the way
to quaternary
superconductive oxide layers. It will be understood that these layers are not
limited to any
particular substrate structure and that in this context their application is
indicated especially in
connection with silicon-based MEMS.
CA 02665044 2009-03-31
WO 2008/043606 PCT/EP2007/059196
Examples and Figures
The following explains this invention solely with the aid of examples and with
reference to the
exemplary figures which illustrate the following:
Fig. 1 X-ray spectra of (Al i_xCrx)203 layers;
Fig. 2 Lattice parameters of (Ali_xCrx)203 layers;
Fig. 3 Temperature pattern of the lattice parameters;
Fig 4 Oxidation pattern of a TiAlN layer;
Fig. 5 Oxidation pattern of a TiCN layer;
Fig. 6 Oxidation pattern of a TiCN / (Ali_xCrx)203 layer;
Fig. 7 Detail of a (Ali_xCrx)203 layer.
The example per test #1), described below in more detail, covers a complete
coating cycle
according to the invention, employing a weak, essentially vertical magnetic
field in the area of the
target surface.
The workpieces were placed in appropriately provided double- or triple-
rotatable holders, the
holders were positioned in the vacuum processing chamber, whereupon the vacuum
chamber was
pumped down to a pressure of about 10-4 mbar.
For generating the process temperature, supported by radiation heaters, a low
voltage arc (LVA)
plasma was ignited between a baffle-separated cathode chamber housing a hot
cathode and the
anodic workpieces in an argon-hydrogen atmosphere.
The following heating parameters were selected:
Discharge current (LVA) 250 A
Argon flow 50 sccm
CA 02665044 2009-03-31
=
WO 2008/043606 PCT/EP2007/059196
16
Hydrogen flow 300 sccm
Process pressure 1.4x10-2 mbar
Substrate temperature approx. 550 C
Process duration 45 min
Those skilled in the art will be familiar with possible alternatives. As a
matter of preference the
substrate was connected as the anode for the low voltage arc and in addition
preferably pulsed in
unipolar or bipolar fashion.
As the next process step, the etching was initiated by activating the low
voltage arc between the
filament end the auxiliary anode. Here as well, a DC-, pulsed DC- or AC-
operated MF or RF
power supply can be connected between the workpieces and ground. By
preference, however, a
negative bias voltage was applied to the workpieces.
The following etching parameters were selected:
Argon flow 60 sccm
Process pressure 2.4x10-3 mbar
Discharge current LVA 150 A
Substrate temperature approx. 500 C
Process duration 45 min
Bias 200-250 V
The next process step consisted in the coating of the substrate with an A1Cr0
layer and a TiAlN
intermediate layer. If higher ionization is needed, all coating processes can
be assisted by means of
the low voltage arc plasma.
For the deposition of the TiAlN intermediate layer the following parameters
were selected:
Argon flow 0 sccm (no argon added)
Nitrogen flow Pressure-regulated to 3 Pa
CA 02665044 2013-11-07
17
Process pressure 3x10-2 mbar
DC source current TiAl 200 A
Coil current of the source
magnetic field (lVIAG 6) 1 A
DC substrate bias U = -40 V
Substrate temperature approx. 550 C
Process duration 120 min
For the transition of about 15 min to the actual functional layer, the AICr
arc sources with a DC
source current of 200 A were added, with the positive pole of the DC source
connected to the
annular anode of the source and to ground. During that step a DC substrate
bias of -40 V was
applied to the substrate. 5 minutes after activation of the A1Cr(50/50)
targets the oxygen inflow
was started and was then ramped up within 10 min from 50 to 1000 sccm. At the
same time the
TiA1(50/50) targets were switched off and the N2 was reduced back to approx.
100 sccm. Just
before the introduction of oxygen the substrate bias was switched from DC to
bipolar pulses and
increased to U = -60 V. That completed the intermediate layer and the
transition to the functional
layer. The targets were powder-metallurgically produced targets.
Alternatively, melt-metallurgical
targets may be used as well. To reduce spattering, monophase targets as
described in DE 19522331
(published January 4, 1996) may be used.
The coating of the substrate with the actual functional layer took place in
pure oxygen. Since
aluminum oxide constitutes an insulating layer, either a pulsed or an AC bias
supply was used.
The key functional-layer parameters were selected as follows:
Oxygen flow 1000 sccm
Process pressure 2.6x10-2 mbar
DC source current, AlCr 200 A
Coil current of the source
magnetic field (MAG 6) 0.5 A, which generated on the target surface a
weak,
essentially vertical field of approx. 2 mT (20 Gs).
CA 02665044 2009-03-31
=
WO 2008/043606
PCT/EP2007/059196
18
Substrate bias U = 60 V (bipolar, 36 s negative, 4 us
positive)
Substrate temperature approx. 550 C
Process duration 60 to 120 min
The process described yielded well-bonded, hard layers. Comparison tests of
the layer on
lathe-work and milling tools revealed an edge life significantly improved over
traditional TiAlN
layers, although the surface roughness was clearly higher than the roughness
values of optimized
pure TiAlN layers.
The experiment examples #2 to #22 shown in Table 1 refer to simple layer
systems according to
the invention, each consisting of a double oxide layer of the (Ali_xCrx)203
type produced at a
coating temperature of between 450 and 600 C. The remaining parameters were
identical to the
parameters described above for producing the functional layer. The
stoichiometric component of
the layer composition was measured by Rutherford backscattering spectrometry
(RBS). The
largest deviation from the target alloy composition shown in column 2 was
encountered in
experiments #10 to #12, with a deviation of 3.5 percentage points at a 70/30
Al/Cr ratio. The metal
components of the layer are scaled to the total metal content of the oxide. In
terms of the
stoichiometry of the oxygen, however, there were somewhat greater deviations
of up to over 8%.
All layers nevertheless exhibited a clearly corundum-like lattice structure.
Preferably, therefore,
layers produced according to the invention should have an oxygen-related
stoichiometry shortage
of 0 to 10% since even with an oxygen deficit of as much as 15% the desired
lattice structure will
be obtained.
Fig. 1 A to C show typical corundum structures of (Al i_xCrx)203 layers
produced at 550 C in
accordance with the invention, with targets of varying alloys as indicated in
experiments #18
(Al/Cr=25/75), #14 (50/50) and #3 (70/30). The measurements and analyses were
obtained by
x-ray diffractometry with the parameter selections described in more detail
under Measuring
Methodology, above. In the illustration any correction for background noise
was dispensed with.
Lattice parameters can be determined by other means as well, such as electron
diffraction
spectrometry. Due to the decreasing layer thickness from Fig. lA to 1C, from
3.1 to 1.5 um, there
is a strong increase of the unmarked substrate lines relative to the marked
layer lines of the
CA 02665044 2009-03-31
=
WO 2008/043606
PCT/EP2007/059196
19
corundum structure. But even in spectrum C, the linear presentation of the Y-
axis notwithstanding,
7 lines can still be clearly associated with the corundum lattice. The
remaining lines belong to the
base hard-metal material (WC/Co alloy). Of course, for an unambiguous
association of the crystal
lattice and the determination of the lattice constants, at least 3 and
preferably 4 to 5 lines should be
clearly identifiable.
The crystal structure of the layers is compact-grained, in large measure with
an average crystallite
size of less than 0.2 pm. Only in cases of large chromium content and at
coating temperatures of
650 C were crystallite sizes found to be between 0.1 and 0.2 gm.
For the experiments #2 to #22, Fig. 2 shows the lattice constants a (solid
line) and c (dashed line)
of the (Al1_xCrx)203 crystal lattice plotted above the stoichiometric chromium
content and
comparing them with the dotted straight lines determined by three values DB1
to DB3 from the
ICDD (International Center for Diffraction Data), applying Vegard's Law. Over
the entire
concentration range the maximum deviation from the ideal Vegard's straight
line is 0.7 to 0.8%.
Measurements taken on other polyoxide layers showed similar results, with
deviations for the
parameters indicated amounting to a maximum of 1%. This suggests very low
intrinsic stress in the
mixed-crystal layer, which is why, in contrast to many other PVD layers, it is
possible to deposit
these layers with a greater layer thickness for instance between 10 and 30 gm,
in some cases even
up to 40 pm, with good bonding qualities. Larger stress patterns in the layer
were obtained only by
applying greater substrate voltages (>150) and/or by using an Ar/02, mixture
of the process gas
with a high Ar component. Since for many applications it is especially the
rnultilayer systems,
described in more detail below, that are well suited, it is possible within a
wide range to adjust,
where necessary, the layer stress values by selecting perhaps a multistratum
intermediate layer
and/or cover layer between the workpiece and the mixed-crystal layer. For
example, this allows for
the selection of higher intrinsic compressive stress values to increase the
hardness of the layer for
hard-metal machining processes. For industrial applications involving a high
level of abrasive
wear, thick layer systems with layers more than 10 or 20 gm thick can be
produced economically,
with the mixed-crystal layer preferably having a thickness of more than 5 and
especially more than
8 pm.
CA 02665044 2009-03-31
WO 2008/043606 PCT/EP2007/059196
Parallel tests were performed on mixed-crystal layers 2 pm thick, employing
the methods
described above (Stoney's bending strip method and the bending disk method).
The layer stress
values measured ranged from stress-free to minor compressive and tensile
stress values less than
or equal to 0.5 GPa. However, thicker PVD layers can still be deposited with
layers exhibiting a
somewhat higher layer stress of about 0.8 GPa. Another possibility consists in
a sequence of thin
layers (< 1 pm) deposited with alternating tensile and compressive stress,
constituting a multilayer
system.
As shown in Table 2, experiment #2, the temperature and oxidation resistance
of the corundum
structure of the deposited (Ali_xCrx)203 layers was tested by heating coated
hard metal test objects
with an elevated Co content to a temperature of 10000 and 1100 C over a period
of 50 minutes,
then holding them there for 30 minutes and finally cooling them to 300 C over
a time span of 50
minutes. Once cooled to room temperature, the lattice constants were
reevaluated. According to
the phase diagram [W. Sitte, Mater.Sci.Monogr., 28A, React. Solids 451-456,
1985] referred to in
Phase Equilibria Diagrams Volume XII Oxides published by the American Ceramic
Society, there
is a miscibility gap in the range between about 5 and 70% aluminum, i.e.
(Al0.o5-0.7Crxo.95-0.30)203
for temperatures up to about 1150 C, which would predict a segregation of the
(Ali _xCrx)203
mixed crystal into A1903 and Cr203 and an (Ali_xCrx)203 mixed crystal of some
other composition.
From that diagram it is also evident that with the process according to this
invention it is possible
to shift the thermodynamic formation temperature for (Al 1_xCrx)203 mixed-
crystal layers from
1200 C to between 450 and 600 C. Surprisingly it was also found that the
mixed-crystal layers
produced by this method according to the invention experience only minimal
changes in their
lattice constants as a result of the glow process and that there is no
segregation into their binary
components. The maximum deviation, shown in Fig. 3, of the value of the
lattice parameters a and
of the red hot sample, measured after the coating process at room temperature,
is about 0.064%
while the maximum deviation of value c is 0.34%. For various other polyoxides
as well, the
measurements revealed an extraordinary thermal stability of the layer with a
minor deviation of the
lattice constants by 1 to 2% at the most.
Fig. 4 and 5 show the results of oxidation experiments on known layer systems
based on an REM
fracture pattern of a TiA1N and a TiCN layer, heated to 900 C as described
above and then glowed
CA 02665044 2009-03-31
WO 2008/043606 PCT/EP2007/059196
21
at that temperature for 30 minutes in an oxygen atmosphere. In a range of over
200 nm the TiAlN
layer reveals a distinct alteration of its surface structure. An outer layer,
consisting essentially of
aluminum oxide and having a thickness of between 130 and 140 nm, is followed
by a porous
aluminum-depleted layer with a thickness of between 154 and 182 nm. Much
poorer yet is the
oxidation pattern of the TiCN layer in Fig. 5 which, subjected to the same
treatment, has oxidized
right down to the base material and reveals an incipient layer separation on
the right side in the
illustration. The layer is coarse-grained and no longer features the columnar
structure of the
original TiCN layer.
Fig. 6 and Fig. 7 show the results of identical oxidation experiments on a
TiCN layer protected by
an (A10.7Cro.3)203 layer, about 1 gm thick, according to this invention. Fig.
6 is a 50,000 x
magnification of the layer composite. The known columnar structure of the TiCN
layer and the
slightly finer-grown crystalline (AloaCro.3)903 layer are clearly
recognizable. The crystallite size
of the aluminum/chromium oxide layer can be further refined by using targets
with a higher Al
content. Fig. 7 is a 150,000 x magnification of the layer composite, with the
TiCN layer still visible
only at the bottom edge of the image. Compared to the layers in Fig. 4 and
Fig. 5 the reaction zone
of the (A10.5Cr0.5)203 layer with a height H2 of maximally 32 nm is
substantially narrower, having
a dense structure without detectable pores. A series of comparison experiments
with different
mixed-crystal layers according to the invention revealed that, unlike other,
prior-art, oxide layers,
they protect the intermediate layers underneath, thus giving the entire layer
system excellent
thermal and oxidation resistance. It is generally possible to use for this
purpose all inventive
mixed-crystal layers which in the oxidation test described do not form
reaction zones larger than
100 nm. The preferred mixed-crystal layers are those with reaction zones
between 0 and 50 nm.
The hardness values of the (A10.5Cro.5)203 layers were determined to be about
2000 HV50.
Measurements performed on other polyoxides such as (A10.5110.3Cro.2)203, or
(A10.6Tio.4)203,
(V0.5Cr0.5)203, (A102Cro.8)203, on their part yielded values between 1200 and
2500 Ky.
Tables 3 to 6 list additional multilayer implementations of the layer system
according to the
invention. Process parameters for producing AlCr0 and AlCrON mixed-crystal
layers on a
4-source coating system (RCS) are shown in Table 7 while corresponding process
parameters for
CA 02665044 2009-03-31
WO 2008/043606 PCT/EP2007/059196
22
producing individual strata for various support layers are shown in Table 8.
The experiments #23 to #60 in Tables 3 and 4 refer to layer systems in which
the oxidic
mixed-crystal layer is of a corundum structure throughout and is mostly formed
as a monolayer.
Only in experiments #25, #29 and #31 in the mixed-crystal layer formed from
two consecutive
individual strata of different chemical compositions. In experiment #29 the
only difference
between the mixed-crystal layers is their different Al/Cr ratio.
The experiments #61 to #107 in Tables 5 and 7 refer to layer systems in which
the mixed-crystal
layer is composed of 5 to as many as 100 very thin layers measuring between 50
nm and 1 gm. In
these cases, there may be alternating oxidic mixed-crystal layers of a
corundum structure with
different chemical compositions and corresponding mixed-crystal layers with
different layer
systems.
In comparison experiments on various turning and milling tools, the layers
used in experiments
#23, #24 and #61 to #82 proved clearly superior in turning and milling
applications over
conventional layer systems such as TiAlN, TiN/TiA1N and AlCrN. Even when
compared to CVD
layers, tool edge life improvements were achieved in milling and in some
turning applications.
Although, as stated above, analyses and tests have already been conducted on a
substantial number
of different layer systems, those skilled in the art will use conventional
measures, where necessary,
to adapt certain characteristics of the invention's layer system to specific
requirements. For
example, one may consider adding further elements to individual or all layers
of the system but in
particular to the mixed-crystal layer. Elements known to improve for instance
the heat resistance at
least of nitridic layers include Zr, Y, La or Ce.
.
.
WO 2008/043606 PCT/EP2007/059196
_
23
Table 1.
Exp. No. Target Depos'n Glow Stoichiometric
Cr / Lattice Constants d
[Mr] Temp. Temp Component (Cr+ Al)
[pm]
[ C] i*Ci
_ Cr Al 0 a
c c/a
DB1- A1203 0.00 2.00 3.00 0.00
4.75870 12.99290 2.7303
D82- 90/10 0.20 1.80 3.00 0.10
4.78550 13.05900 2.7289
2 70/30 560 - 0.59 1.41 3 0.30
4.85234 13.26296 2.7333
3 70/30 550 0.60 1.40 2.80
0.30 4.85610 13.24587 2.7277 1.5
-
'
4 70/30 600 - 0.61 1.39 3.00 0.31
4.84603 13.23092 2.7303 3.3
70/30 550 - 0.62 1.38 2.75 0.31 4.85610 13.24587 2.7277
3.0
6 70/30 550 - 0.64 1.36 3.1 0.32
4.85610 13.24587 2.7277 3.1
_
7 70/30 550 0.63 1.37 2.90 0.32
4.85612 13.23089 2.7246 2.9
8 70/30 550 - 0.67 1.33 2.8 0.34
4.88443 13.15461 2.6932 2.7
9 70/30 550 - 0.68 1.32 2.95
0.34 4.86815 13.15461 2.7022 n
70/30 650 0.67 1.33 3 0.34 4.85610 13.24567 2.7277 1.9
-
0
11 70/30 650 0.67 1.33 2.95
0.34 4.84804 13.23103 2.7292 2.5
N)
-
c7,
12 70/30 550 0.67 1.33 2.85
0.34 4.83993 13.24192 2.7360 2.5
-
in
13 50/50 500 1.01 0.99 2.80
0.51 4.89218 13.32858 2.7245 4.1 0
-
Fi.
14 50/50 550 - 1.04 0.96 2.95 0.52
4.88403 13.31746 2.7267 1.9
50/50 600 - 1.06 0.94 2.95
0.53 4.87996 13.33965 2.7336 3.5 iv
16 25/75 600 1.52 0.48 2.85
0.76 4.92028 13.44988 2.7336 0
-
0
17 25/75 500 1.54 0.46 2.8
0.77 4.92464 13.43581 2.7283 4.5
q3.
-
i
18 25/75 550 . 1.53 0.47 2.8
0.77 4.92053 13.44655 2.7327 3.1 0
u.)
19 1/100 550 2.00 0.00 2.80 1.00
4.95876 13.58287 2.7392
-
21 1/100 450 = 2.00 0.00 2.85
1.00 4.97116 13.58280 2.7323 2.0 H
22 1/100 500 _ 2.00 0.00 2.75 1.00
4.97116 13.59412 2.7346 1.7
083- Cr303 2.00 0.00 3.00 1.00
4.95876 13.59420 2.7415
Table 2.
Exp. Target Depos'n Glow
No. [MCI Temp.
Temp Lattice Constants
[ C] i C] a
C c/a
2 70/30 550 RT - - - - 4.85030
13.24484 2.7307
2 70/30 550 1000 - - - - 4.85339
13.22837 2.7256
2 70/30 550 1100 ' -- -
- 4.84727 13.20028 2.7232
Test objects: Hard metal
.
.
=
WO 2008/043606 PCT/EP2007/059196
_
24
Table 3.
Intermediate Layer Mixed-Crystal Layer Monolayer Cover Layer
Bonding Layer Hard Metal Layer Corundum Structure
Other Oxide Layer DS1 DS2
Exp. No. [(Mel Me2)X] d [pm] [(Mel Me2)X] d [pm] [(Mel
Me2)X) d [pm] [(Mel Me2)X] D [pm] [(Mel Me2)X] d [pm) [(Mel
Me2)X] d [pm]
23 TiN 0.2 TiAIN 3.0 (AI.5Cr.6)203
3.0 we we wo
24 wo TIAIN 3.0 (A1.5Cr.5)203
3.0 wo we we
25 TiN 0.3 TiAIN 4.0 (AI.5Cr.5)203 2.0
(A1,7Cr.3)203 1.0
26 TiN 0.4 TiCN 6.0 (A1.65Cr.35)203 5.0
27 TiN 8.0 (A1.65Cr.15)203 8.0
28 TiCN 8.0 (AI.7Cr.3)203 6.0
29 TiN 0.5 TiAIN 3.0 (A1.7Cr.3)203
3.0 (Al, Cr, Zr02 1.0 TrN 0.5
Zr)203+z
30 TiN 0.3 TIC 4.0 (AI.7Cr.3)203
2.0 n
31 TiN 0.4 TiAIN 2.0 (A1.7Fe.3)203 4.0
(Al, Cr)203 2.0 AlCrN 0.5 o
32 TiN (AI.6Fe.4)203
5.0 AlCrN 2.0 "
o)
o)
33 TiN TiCN 8.0 (AI.6Fe.4)203
4.0 in
o
34 T1CN 8.0 (Al.iFe.9)203
4.0 .i.
Fi.
35 wo TiAIN 3.0 (Al.1Fe.3)203
5.0 iv
o
36 wo we (AI.5Fe.5)203
8.0 o
q3.
1
37 we wo (AI.5Fe.5)203
8.0 AlCrN 3.0 o
u.)
1
38 TiN 0.3 wo (AI.5V.5)203
5.0 TiN 0.3 u.)
H
39 VN 0.4 VCN 4.0 (AI.5V.5)203
6.0 AIVN 1.0
40 VN 0.4 Cr203 10.0
AIVN 1.0 -
41 CrN 0.5 CrC 4.0 Cr203 3.0
CrN 2.0
42 CrN 0.5 CrCN 6.0 Cr203 4.0
CrN 1.0
43 CrN 0.5 we Cr203 4.0
CrN 2.0
44 CrN 0.5 wo Cr203 5.0
-
45 AlCrN 0.3 wo (A1.2Cr.6)203
4.0 AlCrN 1.0
.
.
-
WO 2008/043606 PCT/EP2007/059196
_
Table 4.
Intermediate Layer Mixed-Crystal Layer Monolayer Cover Layer
Bonding Layer Hard Metal Layer Corundum Structure
Other Oxide Layer DS1 DS2
Exp. No. [(Mel Me2)X1 _ d [01] [(Mel me2)X] d Wm) [(Mel
me2)Xg d [pm] [(Mel Me2)X] D [pm) [(Mel Me2)X] d [pm]
[(Mel Me2)X] d [I-Irll]
46 CrN 0.3 AICION 5.0 (A1.02Cr.38)20.3
3.0 wo wo
47 CrN 0.5 AlCrN 3.0 (A1,05Cr.95)203
3.0 (AI.7Cr.3)203 1.0 CrN 2.0
48 AlCrN 0.5 AlCrON 5.0 (A1.05Cr.95)203
3.0
49 TiN 0,8 TiAIN 4.0 (A1.5110203
4.0 TIN 1.0
50 we TiAIN 6.0 (At5Ti.5)203 2.0
51 TIN 0.3 TiCN 8.0 (A1.719.3)203 4.0
52 wo TiAIN 3.0 (Al, Mg, 11)203
3.0
53 TiN 0.5 AlMgTIN 6.0 (Al, Mg, Ti)203
4.0 0
54 TIN 5.0 (Al, Mg, Ti)203
3.0 TiN 2.0 o
I\)
55 TIN 0.3 (Al, Mg,Ti)ON 5.0 (Al, Mg, Ti)203
2.0 o)
o)
in
56 AlCrN 0.2 (Al, Mg, Ti)ON 1.0
(Al, Mg, Ti)203 6.0 0
11.
57 TiN 1.0 (Al, Fe, Ti)203
5.0 TIN 0.5 11.
N.)
58 TiN 1.0 TiCN 6.0 (Al, Fe, Ti)203
2.0 TIN 1.0 o
o
59 TiN 1.0 TiAIN 4.0 (Al, Fe, Ti)203
4.0 ko
o1
,.
60 TiCN 4.0 (Al, Fe, Ti)203
2.0 us.)
(1.....)
H
=
WO 2008/043606 PCT/EP2007/059196
= .
26
_
Table 5
Intermediate Layer Mixed-Crystal Layer as Multi-layer
Cover Layer
Bonding Layer Hard Metal Layer Corundum
Structure Other Multi-layer No.MLs DS1 DS2
Exp. [(Mel Me2)X] d [pm) [(Mel Me2)X] d [pm] [(Mel
Me2)X) d [pm] [(Mel Me2)X] I d [pm] [(Mel Me2)X] d [pm]
[(Mel Me2)X] d [pm]
No. .
61 TiN 0.2 TiAIN 3.0 (AI.65Cr35)203 0.100 AlCrN
0.100 -- 50.0 -- AlCrN -- 0.5
62 wo TiAIN 2.0 (A1.65Cr.3.5)203 0.500 AlCrN_
0.500 10.0
63 TIN 0.3 TiAIN 3.0 (A1,55Cr.35)203 0.100 AICrN
0.050 -- 100.0 -- AlCrN -- 0.2
64 TiN 0.3 TiAIN 4.0 (AI.65Cr.35)203 , 0.050 AlCrN
0.050 100.0
65 TiN 0.3 TiAIN 3.0 (A1,65Cr.35)203 0.190 Zr02
0.390 -- 10.0 -- ZrN -- 1.0
66 TIN 0.3 -MAIN 6.0 (AI.65Cr.35)203 0.200 Ta205
0.100 -- 30.0 -- TaN -- 0.5
67 TIN 0.3 -RAIN 3.0 (AI.55Cr.35)203 0.200 Nb205
0.500 -- 10.0 -- NbN -- 1.0
68 TIN 0.3 TiAIN 4.0 (A1.65Cr3.5)203 0.200 V203
0.100 50.0 n
69 TIN 0.3 TiAIN 3.0 (AI.65Cr.35)203 0.200
(A1.8Cr.2)203 0.050 30.0 AlCrN 0.2 o
I\)
70 TiN 0.3 TiAIN 2.0 (A1.6,5Cr.35)203 0.200 (Al, V)203
0.050 30.0 AIVN 0.2 m
m
in
71 TiN 0.3 TIAIN 2.0 (AI.5Cr.5)203 0.100 TiAIN
0.100 50.0 o
11.
72 TiN 0.2 TiCN 6.0 (AI.5Cr.5)203 0.100
0.100 0.100 , 50.0 -- AlCrN -- 0.5 -- 11.
N.)
73 wo TiCN 3.0 ((AI.5Cr.5)203 0.500 AlCrN
0.500 10.0 o
o
74 TIN 0.3 TiCN 12.0 (A1.5C(5)203 0.100 AlCrN
0.050 100.0 AlCrN 0.2 ko
i
o
75 TIN 0.3 TiCN 8.0 (AI.5Cr.5)203 0.050 AlCrN
0.500 100.0 u..)
Lai
76 TIN 0.3 TiCN 4.0 (AI.5Cr.5)203 0.100 Zr02
0.300 -- 10.0 -- ZrN -- 1.0
77 TiN 0.3 TiCN 3.0 (AI.5Cr,5)203 0.200 Ta205
0.100 -- 30.0 -- TaN -- 0.5
78 TiN 0.3 TiCN 6.0 (Al.4Cr.5)203 0.200 Nb205
0.500 -- 10.0 -- NbN -- 1.0
79 TiN 0.3 TICN 3.0 (AI.4Cr.6)203 0.200 V203
0.100 50.0
80 TIN 0.3 TiCN 2.0 (AI.4Cr.6)203 0.200 (Al,
Cr.)203 -- 0.050 -- 30.0 -- AlCrN -- 0.2
81 TIN 0.3 TiCN 3.0 (AI.4Cr.6)203 0.200 (Al,
Zr)203 -- 0.050 -- 30.0 -- AlZrN -- 0.2
82 TiN 0.3 TIC 4.0 (Al.4Cr.6)203 . 0.100 AlCrN
0.050 100.0 TiN 0.2
83 TiN 0.5 TiAIN 3.0 (A1.4Cr.6)203 0.300 (Al,
Zr, Cr)203,4 0.300 ZrN 1.0 ZrN 0.5
84 TiN 0.4 TiAIN 2.0 (AI.7Cr.3)203 0.200 (Al,
Cr.)203 -- 0.200 -- 10.0 -- AlCrN -- 0.5
85 TiN 0.3 wo (AI.6V.4)203 0.200
AIVN 0.100 TiN 0.3
86 VN 0.4 VCN 4.0 (AI.5V.4)203 0.200 (Al.
Cr,)203 0.100
,
WO 2008/043606 PCT/EP2007/059196
27
Table 6
Intermediate Layer Mixed-Crystal Layer as Multi-layer
Cover Layer
Bonding Layer Hard Metal Layer Corundum Structure
Other Multi-layer No.MLs DS1 DS2
Exp. Nr. [(Mel Me2)X] d [pm] [(Mel Me2)X] d [pm] [(Mel Me2)X]
d [pm] [(Mel Me2)X] D [pm] [(Mel Me2)X] d [pm] [(Mel Me2)X] d [pm]
87 CrN 0.5 CrC 4.0 Cr203 0.200 CrN
0.300 5.0 CrN 2.0
88 CrN 0.5 CrCN 6.0 Cr2O3 0.200 (AI 650..35)203
0.100 10.0 CrN 1.0
89 CrN 0.5 wo Cr203 1.000 (AI.65Cr.35)203
0.500 5.0
90 CrN 0.5 wo Cr203 0.050 (AI.55Cr.35)203
0.050 200.0
91 CrN 0.5 wo Cr203 0.050 CrN
0.050 100.0
92 AlCrN 0.3 wo (A1.55Cr.35)203 0.100
CrN 0.400 8.0 AlCrN 1.0
93 CrN 0.3 AlCrON 5.0 (AI 5Cr.5)203 0.200
(A13Cr.3)203 0.100 10.0
94 CrN 0.5 AtC rN 3.0 (AI.5Cr5)203 1.000
(A1.7Cr.3)203 0.500 5.0 CrN 0.5 CrN 2.0 n
95 AlCrN 0.5 AlCrON 5.0 (A1,5Cr.5)203 0.050
(A1.7Cr.3)203 0.050 200.0 o
n.)
96 TiN 0.8 TiAIN 4.0 (AI.5T1 5)203 0.100
TIAIN 0.200 30.0 TIN 1.0 (33
(33
in
97 wo TiAIN 6.0 (AI ITi.9)203 0.050
TiAIN 0.300 10.0 o
11.
11.
98 TiN 0.3 TiCN 8.0 (Al.1T1.3)203 0.200
(AI.7Cr.3)203 0.100 20.0
I\)
99 wo TiAIN 3.0 (Al, Mg, 11)203 0.100
0.100 0.100 40.0 o
o
ko
100 TiN 0.5 AlMgTIN 6.0 (Al, Mg, Ti)203 0.500
AlCrN 0.500 12.0
o1
101 TiN 5.0 (Al, Mg, Ti)203 0.100
AlCrN 0.050 50.0 u..)
Lai
102 TiN 0.3 (Al, Mg, Ti)ON 5.0 (Al, Mg, Ti)203
0.050 AlCrN 0.050 30.0 H
103 AlCrN 0.2 (Al, Mg, Ti)ON 1.0 (Al, Mg, 11)203
0.100 (AI.65Cr.35)203 0.300 15.0
104 TIN 1.0 (Al, Fe, Ti)203 0.200
Nb205 0.500 20.0 TiN 0.5
105 TiN 1.0 TiCN 6.0 (Al, Fe, Ti)203 0.200
V203 0.100 20.0 TiN 1.0
106 TiN 1.0 TiAIN 4.0 (Al, Fe, Ti)203 0.200
(AI.65Cr.35)203 0.100 10.0
107 TiCN 4.0 (Al, Fe, Ti)203 0.200
(Al, Me)203 0.050 15.0
, CA 02665044 2009-03-31
,
WO 2008/043606 PCT/EP2007/059196
28
Table 7.
Material I-Source 1 . I-S. 2 I-S. 3 I-S. 4 U-bias bp
02 N2 P T
[A] [A] [Al [A] [V] [sccm]
[scorn] [Pa] [ C]
AlCr0 200 200 -60 1000 --
2.6 550 C
AlCrO-AlCrN
-- 200 -- 200 -60 1000
1000 2.6 550 C
Multilayer
Coil current of the source magnetic system 0.5 to 1 A
Table 8.
_
Material , I-Source 1 I-S. 2 I-S. 3 I-S. 4 U-bias DC Ar
C2H2 N2 p T
[A] [Al [A] [A] [V] [scorn] [sccm] [sccm] [Pa] [
C]
TIAIN 200 -- 200 -- -40 -- Pressure
3 550 C
regulated
TiN 180 -- 180 -- -100 -- Pressure
0.8 550 C
regulated
TiCN 190 -- _ 190 -- -100 420 15-125
500-150 2.5 -2.0 550 C
_
AlCrN 200 -- 200 -- -100 -- 1000
2.6 550 C
AlMeN 140 -- 140 -- -80 -- 800
0.8 500 C
AlMeCN 220 --Pressure 220 -- -120 300 10-
150 2.5 600 C
regulated
-
Coil current of the source magnetic system 0.1 to 2 A
