CUTTING BLADES MADE OF OR COATED WITH AN AMORPHOUS METAL

NO TRANSLATION AVAILABLE

English Abstract

A B S T R A C T
Metal alloys in an amorphous state are
employed in the fabrication of cutting implements such
as razor blades or knives. The implement may be formed
from the amorphous metal or a coating of the amorphous
metal may be applied. Such products may be formed from
a ribbon of the amorphous metal alloy which has been
prepared by quenching the molten metal or by coating the
amorphous metal alloy on a suitable substrate such as
by a sputtering procedure or vapor, chemical or electro-
deposition of the alloy on the substrate.

Claims

The embodiments of the invention in which an
exclusive property or privilege is claimed are defined as
follows:
1. A cutting implement comprising a metal which
is at least 50% amorphous, characterized in that the metal
has the composition MaXb, where M is at least one element
selected from the group consisting of Ni, Fe, Co, Cr and V,
X is at least one element selected from the group consisting
of P, B, C, Si, Al, Sb, Sn, In, Ge and Be, a ranges from 65
atomic percent to 90 atomic percent and b ranges from 10
atomic percent to 35 atomic percent.
2. The cutting implement of claim 1 in which
a ranges from about 73 atomic percent to 84 atomic percent
and b ranges from about 16 atomic percent to 27 atomic percent.
3. A cutting implement according to claim 1
wherein up to one-third of M is replaced by Mo, Mn, Ti, W
and/or Cu.
4. The cutting implement of claim 1 in the form
of a razor blade.
5. A cutting implement having deposited thereon
a metal film which is at least 50% amorphous, characterized
in that the metal has the composition MaXb, wherein M is at
least one element selected from the group consisting of Ni,
Fe, Co, Cr and V, X is at least one element selected from
the group consisting of P, B, C, Si, Al, Sb, Sn, In, Ge and
Be, a ranges from 65 atomic percent to 90 atomic percent
and b ranges from 10 atomic percent to 35 atomic percent.
6. The cutting implement of claim 5 in which
a ranges from about 73 atomic percent to 84 atomic percent
and b ranges from about 16 atomic percent to 27 atomic
percent.



7. A cutting implement according to claim 5
wherein up to one third of M is replaced by Mo, Mn, Ti, W
and/or Cu.
8. The cutting implement of claim 5 in the
form of a razor blade.
9. The cutting implement of claim 5 in which

the metal film ranges from about 50 .ANG. to 300 .ANG. in thickness.
10. A process of preparing a metal cutting
implement comprising the steps
(a) quenching a molten metal under conditions
producing a metal strip which is at least 50% amorphous,
the metal strip having a composition represented by MaXb,
wherein M is at least one element selected from the group
consisting of nickel, iron, cobalt, chromium and vanadium,
X is at least one element selected from the group consisting
of phosphorous, boron, carbon, silicon, aluminum, antimony,
tin, indium, germanium and beryllium, a ranges from 65 to
90 atomic percent and b ranges from 10 to 35 atomic percent;
(b) forming the metal strip to a desired
implement form; and
(c) sharpening a cutting edge on said implement.
11. The process of claim 10 in which up to one-
third of M is at least one element selected from the group
consisting of molybdenum, manganese, titanium, tungsten and
copper.
12. In a method of fabricating a metal cutting
implement, the improvement comprising depositing on a metal
substrate a metal film which is at least 50% amorphous, the
metal film having a composition represented by MaXb, wherein
M is at least one element selected from the group consisting
of nickel, iron, cobalt, chromium and vanadium, X is at least
one element selected from the group consisting of phosphorous,

boron, carbon, silicon, aluminum, antimony, tin, indium,

11

germanium and beryllium, a ranges from 65 to 90 atomic
percent and b ranges from 10 to 35 atomic percent.
13. The method of claim 12 wherein the metal
film is deposited on the sharpened metal substrate.
14. The method of claim 12 wherein the metal
substrate is sharpened after the metal film is deposited.
15. The method of claim 12 for fabricating a
metal cutting implement wherein the metal film is vacuum
deposited onto the metal substrate to a thickness of about
50 .ANG. to 300 .ANG. .
16. The method of claim 12 for fabricating
a metal cutting implement wherein the metal film is
electrodeposited onto the metal substrate.
17. The method of claim 12 in which up to
one-third of M is at least one element selected from the
group consisting of molybdenum, manganese, titanium,
tungsten and copper.
18. A cutting implement comprising a metal
which is at least 50% amorphous, characterized in that the
metal has the composition MaXb, where M is at least one
element selected from the group consisting of Ni, Fe, Co,
Cr, and V, up to about one-third of which may be replaced
by alloying elements normally used in steels, X is at least
one element selected from the group consisting of P, B, C,
Si, Al, Sb, Sn, In, Ge and Be, a ranges from 65 atomic
percent to 90 atomic percent and b ranges from 10 atomic
percent to 35 atomic percent.
19. A cutting implement having deposited
thereon a metal film which is at least 50% amorphous,
characterized in that the metal has the composition MaXb,
where M is at least one element selected from the group

12

consisting of Ni, Fe, Co, Cr, and V, up to about one-third
of which may be replaced by alloying elements normally used
in steels, X is at least one element selected from the
group consisting of P, B, C, Si, Al, Sb, Sn, In, Ge and Be,
a ranges from 65 atomic percent to 90 atomic percent and
b ranges from 10 atomic percent to 35 atomic percent.
20. The cutting implement of claim 18 in which
up to about one-third of M is replaced by at least one
element selected from the group consisting of molybdenum,
manganese, titanium, tungsten and copper.
21. The cutting implement of claim 19 in which
up to about one-third of M is replaced by at least one
element selected from the group consisting of molybdenum,
manganese, titanium, tungsten and copper.

13

Description

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CUTTING BI~DES MADE OF OR . COATED WITH AN AMORPHOUS METAL
Description of Prior Art
The production of cutting implements by sharpening a piece Of
metal is an ancient art. Typically, the implement is fabricated
from a crystalline metal which is formed to the desired shape and
an edge is then ground to a reduced thickness.
It is recognized that the properties and hence usefulness of
the blade are determined by, the form of the edge and by the
properties of the substance from which the blade is produced;
these properties generally depend upon the processing of the
metal as well as upon its chemical composition.
Scientific investigations have demonstrated that it is
possible to obtain solid amorphous metals for certain alloy
compositions, and as used herein, the term Namorphous" contem-
plates "solid amorphous". An amorphous substance generally
characterizes a noncrystalliné or glassy substance~ In dis-
tinguishing an amorphous substance from a crystalline substance,
diffraction measurements are generally suitably employed.
Brief Description of the Drawing
Fig. 1 illustrates the diffraction intensity of an amorphous
Fe40Ni40P14B6 metal.
Fig. 2 illustrates the diffracted intensity of the crystal-
line metal of FE40Ni40Pl4B6-
Fig. 3 is an x-ray diffraction pattern for a partially
crystalline metal alloy of Ni77P14B6A13
An amorphous metal produces a diffraction profile which
varies slowly with the diffraction angle and is qualitatively
similar to the diffraction profile of a liquid or ordinary winds~
glass. For example, Fig. 1 is the first peak of the diffracted
intensity I as a function of the diffraction angle 2~ for amor-
phous Fe40Ni40P14B6 as obtained from an x-ray diffractometer
with MoK ~ radiation. Such a pattern is typical for amorphous

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metals. On the other hand, Fig. 2 represents the diffracted
intensity I as a function of the diffraction angle 2e for poly-
crystalline Fe40Ni40P14B6 over the same range of 2~- This more
rapidly varying intensity is typical of crystalline materials.
These amorphous metals are in a metastable state. Upon
heating to a sufficiently high temperature, they crystalline with
the evolution of a heat of crystallization and the diffraction
profile changes from one having the glassy or amorphous charac-
teristics to one having crystalline characteristics.
Additionally, suitably employed transmission electron
micrography and electron diffraction can be used to distinguish
between the amorphous and the crystalline state.
It is possible to produce a metal which is a two-phase
mixture of the amorphous and the crystalline state; the relative
proportions can vary from totally crystalline to totally amor-
phous. An amorphous metal, as employed herein, refers to a
metal which is primarily amorphous but may have a small
fraction of the material present as included crystallites.
For a suitable composition, proper processing will
produce a metal in the amorphous state. One typical procedure
is to cause the molten alloy to be spread thinly in contact with
a solid metal substrate such as copper or aluminum so that the
molten metal looses its heat to the substrate.
When the alloy is spread to a thickness of ~ 0.002",
cooling rates of the order of 106C/sec are achieved. See,
for example, R.C. Ruhl, Mat. Sci. ~ Eng. 1, 313 (1967), which
discusses the dependence of cooling rates upon the conditions of
processing the molten metal. For an alloy of proper composition
and for a sufficiently high cooling rate, such a process pro-
duces an amorphous metal. Any process which provides a suitably

high cooling rate can be used. Illustrative examples of proce-
dures which can be used to make the amorphous metals are the



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109ie74

rotating double rolls described by H~S. Chen and C.E. Miller,
Rev. Sci. Instrum. 41, 1237 (1970) and the rotating cylinder
technique described by R. Pond, Jr. and R. Maddin, Trans. Met.
Soc., AIME 245, 2475 (1969).
Alternatively, a deposition techniquè can be used to
produce an amorphous metal. Two such techniques are vapor depo-
sition and sputtering. In vapor deposition, the metal to be
deposited is placed in a high vacuum and is heated to a tempera-
ture such that its vapor pressure is at least 10 2 mm Hg; this
vapor is then condensed to the solid state on sufficiently cold
surfaces exposed to the vapor. In sputtering, the metal to be
deposited and the substrate upon which it is to be deposited
are placed in a partial vacuum, usually of the order of one
mm Hg. A high potential is applied between an electrode and
the metal to be deposited, and the gaseous ions created by
the high potential strike the surface of the metal with an
energy sufficient to cause atoms from the metal to enter the
vapor phase; these atoms then condense to the solid state
on surfaces exposed to the vapor. Both the vapor deposition
and the sputtering techniques are described in detail in Hand-
book of Thin Film Technology, L.I. Maissel and R. Glang,
McGraw Hill, 1970~ Similarly, chemical (electro-less) or
electro-deposition of a suitable alloy composition from a
solution can also lead to an amorphous alloy.
Summary of the Invention
The invention has as its primary object the provision
of cutting implements which are composed of, or are coated with,
an amorphous metal.
Additional objects and advantages will be apparent
from the specification and claims.
One class of cutting implements which is of particular
interest is that typified by safety razor blades. A strip or

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sheet of an amorphous metal with a thickness of about 0.001" to
0.005" can be sharpened so as to produce a razor blade. Further
treatment such as the sputtering on of a crystalling or amor-
phous metal coating or the application of a fluorocarbon
coating may be used to produce the finished blade.
We have discovered that amorphous metals are exception-
ally well-suited to use for razor blades since compositions
with high as-formed hardness, ductibility, a high elastic
limit and good corrosion resistance can be selected. Addition-
ally, these amorphous metals are more homogeneous than common
crystalline materials for the dimensions characteristic of the
sharpened edge of a razor blade. Greater hardness and better
corrosion resistance than the stainless steel blades now in use
can be achieved.
Strips from which the blades are made can be obtained
by any of various techniques. Most suitable is the quenching
from the melt of a continuous strip by, for example, using a
pair of rotating rolls or by squirting the molten metal onto
the outside of a rapidly rotating cylinder.
Additionally, razor blades can be produced which
consist of sharpened crystalline metal or amorphous metal
blades with an amorphous metal film deposited on top of the
edge, for example, by sputtering.
Further, a blade can be produced by sharpening after
the amorphous metal coating has been applied to a crystalline
substrate, by sputtering or vapor deposition, for example.
Cutting blades such as common knives can be produced
with an amorphous metal coating applied, for example, by
sputtering or electro-deposition so as to improve the proper-
ties of the surface.
Cutting blades other than razor blades can also be
produced by sharpening an amorphous metal strip or sheet.

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Further, a sandwich construction where the amorphous metal is
held between two layers of a softer material could be used to
make blades.
It has been found that metal alloys which are partially
amorphous can sometimes also have the desirable properties
of high hardness, high strength, high elastic limit, and
ductility which can be obtained with the fully amorphous
state. These alloys may be a mixture of the amorphous and
crystalline states because of several possible reasons. The
composition may be one which for obtainable ~uench rates or
deposition parameters does not give a totally amorphous
substance, or a relatively low quench rate may have been
employed, or part of the sample may have been recrystallized
upon a heat treatment of the sample. A typical x-ray
diffraction pattern for such an amorphous-crystalline mixture
is shown in Fig. 3. It is a superposition or summation of
an amorphous pattern and a crystalline pattern. Resolving the
two patterns and measuring the relative integrated intensities
indicates the approximate relative percentages of the two
structures. Additionally, transmission electron micrography
and diffraction can also be used to estimate the percent of
each phase. Further, the measured heat of crystallization
will be proportional to the fraction that is amorphous.
The articles described above can be made from such an
amorphous-crystalline mixture where the crystalline fraction
is less than 50%.
Description of the Preferred Embodiments
. _
In accordance with the invention, an amorphous metal strip
can be sharpened to form razor blades of excellent edge
characteristics: high resistance to mechanical damage and

superior corrosion resistance. In production, for example, an
amorphous metal strip which is 0.002" thick and about 1/4" wide


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can be sharpened at one edge and then cut into lengths of
about 1.75". Alternatively, strips of greater width can be
sharpened on both edges.
Strips of many different alloy compositions can be used
for razor blades. The preferred alloys will consist of primar-
ily iron, nickel, cobalt, chromium, vanadium and mixtures
thereof. Alloys of particular interest contemplated by the
invention are those having the general formula MaXb wherein M
may be any combination of Ni, Fe, Co, Cr and/or V, X will
be elements such as P, B, C, Si, Al, Sb, Sn, In, Ge and/or Be
and "a" and "b" represent atomic percent in which "a" will
generally range from 90 to 65 atomic percent and "b" will
range from 10 to 35 atomic percent. Preferably, "a" will
vary from about 84 to about 73 atomic percent while "b" will
vary from about 16 to about 27 atomic percent.
Examples of some of the preferred compositions include
Ni P16B6A13; Ni50Fe28pl4B6Al2; cr24Fe24Ni3o 14 4 2 2


Fe38cr38pl5c4B~2Al3; Fe40NI4opl4B6; and Fe30 20 28 14 6 2
The alloying elements normally used in steels, such as
Mo, Mn, Ti, W and Cu, can also be included in these compositions
as a partial replacement for any of the metals Ni-Fe-Cr-Co-V.
In replacing the latter with the former, preferably not more
than about one-third of the latter metals in atomic percent is
replaced with the former.
An alternate embodiment of the invention resides in
coating a metal substrate with an amorphous metal layer such as
by the sputtering of a thin film (about 50 to 300A thick) of
metal which is at least 50~ amorphous onto the edge of an already
sharpened amorphous or crystalline razor blade. The general


compositions of such coating alloys are essentially those
listed above in connection with the amorphous strips.

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Preferred coating compositions are, for example, cr8opl5s5;
60 20; Cr65NiloP15Si10 and Cr77Pl3B5si5.
Still another em~odiment resides in the deposition of
an amorphous coating of the generaI compositions listed above on
various articles of cutlery. For example, a composition such
as Ni80P20 can be eIectro-deposited onto a formed utensil such
as a knife or instead a composition such as Cr60NI20P15B5 can
be sputtered thereon.
The invention will be further described by reference to
the following specific examples. It should be understood,
however, that although these examples may describe in detail
certain preferred operating conditions andjor materials and/or
proportions, they are provided primarily for purposes of
illustration and the invention, in its broader aspects, is not
limited thereto. Parts expressed are parts by atomic percent
unless otherwise stated.
Example 1
A molten alloy of composition Ni48Fe30P14B6A12 at a
temperature of 1050C. is quenched to the amorphous state by
using the rotating double roll apparatus described by Chen and
Miller in Rev. Sci. Instrum. 41, 1237 (1970). An argon pressure
of 8 psi is used to squirt the molten metal through a 0.010"
hole in the bottom of a fused silica tube into the nip of the
two inch diameter, three inch long double rolls which are at
room temperature and rotating at about 1400 rpm. A force of
about 100 lbs. is applied so as to push the rolls towards each
other. The molten metal is thus quenched to a 0.002" thick
ribbon of amorphous metal of the same composition. The edge
of the ribbon is sheared off so as to provide a straight edge
and a cutting edge is ground and honed on the sheared edge of
the strip in a manner conventionally used to sharpen razor




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blades. In sharpening, care is taken such that any part of
the metal strip does not reach a temperature above 340C. The
strips are cut to the desired length for individual blades.
The blade may be suitably employed at this juncture. However,
the blade may be further processed after shapening such as by
the deposition of an amorphous or crystalline metal film of
about 150~ on the cutting edge. This coating may be applied
by sputtering or vapor deposition, as described in the afore-
mentioned Maissel and Glang text. A fluorocarbon coating may
also be applied such as disclosed in U.S. Patent 3,071,856 -
care again being taken to avoid excess temperature which
would cause crystallization of the amorphous metal.
Example 2
A 0.004" thick strip of stainless steel is ground and
honed to produce a razor blade with a conventionally shaped
edge. An alloy of composition Cr78P14B5Si3 is sputtered onto
the edge of the blade which is kept at a temperature below
100C. in the manner described in Chapter 4 of the Maissel and
Glang text, so as to produce a metal film of this alloy
composition which is more than 50~ amorphous and has an average
thickness of 200 ~ on the edge of the blade. A fluorocarbon
coating in the manner disclosed in Example 3 of U.S. Patent
3,071,856 is applied to the blade.
A similar procedure was followed for a 0.002" thick
blade of amorphous Ni50Fe28P14B6A12.
Y' 58 il8P14B6Si4 is sputtered onto other
ground stainless steel and amorphous Ni50Fe28P14B6A12 blades
which are then coated with a fluorocarbon.
Examples 3-8
Following the procedure of Example 1, amorphous strips

suitable for forming of razor blades are prepared from the

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alloys shown in Table I. Some examples, as indicated, are
coated.
TABLE

Coating
Example Alloys (atomic %) (if any
3 Fe39Ni3gPl6B4si2
4 Fe39Ni39Pl6B4si2 Cr80P15B5 (sput*ered)
Fe30Ni2ocr28pl4B6Al2 Cr65Niloplssilo

(sputtered) and there-
after coated with poly-
tetrafluoroalkylene

6 Fe3gcr3gP15C4B2 3 Cr OP B (sputtered)
an~ thereafter coated
with polytetrafluoro-
ethylene
7 Ni Pl6B6silAl2 Cr OP B5 (sputtered)
an~ thereafter coated
with polytetrafluoro-
ethylene
8 Cr40co36pl4B6Al4 Cr (sputtered)
Example 9
A stainless steel knife with a high polish is cleaned
by washing with trichloroethylene and dried. An amorphous
film of Cr80P15B5 is sputtered on the entire blade. The film
thickness is 1000 A. A relatively tough and durable mar-
resistant coating is produced.