Note: Descriptions are shown in the official language in which they were submitted.
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Describtion
AQUEOUS PHOSPHATING COMPOSITION AND PROCESS FOR METAL SURFACES
Field of the invention
This invention relates to a treatment composition, more particularly a liquid
solution in water, that forms a zinc phosphate-type conversion coating on
metal surfaces
and to a method for treating metal surfaces with such a treatment composition.
The
s invention is particularly effective when applied to iron and steel, but in
addition it can
also be applied to a variety of surfaces that are constituted of zinc or an
alloy thereof
andlor aluminum or an alloy thereof, such alloys containing at least 55 atomic
percent
of zinc or of aluminum.
Description of Related P,rt
,o Zinc phosphate treatments are carried out in order to impart corrosion
resistance
to metals such as iron and steel, as an undercoating for painting operations,
and to pro-
vide lubrication in forging and wire drawing operations. This treatment is
carried out by
bringing the workpiece into contact with the treatment composition, often
called a "bath"
hereinafter, even though not necessarily contacted by immersion of the metal
substrates
,s in it, for a sufficient period of time at an appropriate temperature.
Spraying and/or
dipping are typically employed to effect this contact. The overall process
generally
proceeds through the following steps.
(1) Cleaning
(2) Surface conditioning
zo (3) Phosphate conversion treatment
(4) Post-treatment
A water rinse is t~ipically used between each of these steps and the next
succes-
sive one of these steps, except between steps (2) and (3), in order to avoid
dragging
material from an upstream step into a downstream step.
zs Cleaning step (1) is carried out in order to remove grease and other
contamin-
ants adhering to the workpiece and thereby provide for the smooth execution of
the
downstream steps. An alkaline cleaner is typically used in this cleaning step.
In the surface conditioning step (2), the workpiece is typically brought into
con-
tact with a treatment bath that contains colloidal titanium. This treatment
results in a
so substantial acceleration of the film-forming reactions during the phosphate
conversion
treatment and in this manner makes possible the formation of a uniform, fine,
and dense
conversion coating in a short period of time. The use of phosphate coatings as
paint-
base coatings on automotive components requires high-quality phosphate
coatings that
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must exhibit paint adherence and corrosion resistance, and the surface
conditioning step
has been considered essential for the production of coatings of this type.
Phosphate conversion treatment step (3) is run using a variety of treatment
bath
compositions and treatment conditions whose particular selection will depend
on the
s specific objective. As an example, in the case of paint-base coating
treatments for auto-
motive components, the ingredients present in a zinc phosphate-type treatment
bath wilt
be phosphate ions, zinc ions, and other metal ions (e.g., nickel, manganese),
and each
of these components will provide specific properties to the final film. Other
components
typically present in baths of this type are nitrate, nitrite, chlorate,
fluoroborate, and fluoro-
,o silicate. A lowering of the treatment temperature has been pursued over the
last few
years, and at present these treatments are run at temperatures of 40 °C
to 50 °C for
treatment times of about 1.5 to 3 minutes. The treatment is often carried out
by dipping.
Post-treatment step (4) is carried out, for example, in order to improve the
corro-
sion resistance and paint adherence. A treatment bath, either containing
hexavalent
,s chromium or chromium-free, is used as the post-treatment agent. This step
may be
omitted depending on the particular objective or application.
The high-quality zinc phosphate-type conversion films used as paint-base coat-
ings on iron and steel can be evaluated through (1) the appearance of the
conversion
coating, (2) the coating weight, and (3) the P/(P + H) ratio as defined below.
zo The following characteristics are essential, or if so stated, preferred,
for rating
as "good" the appearance of a conversion coating: The conversion coating must
be free
of defects such as rust) blue color, and thin or incomplete coverage, and in
addition is
preferably a columnar and/or nodular crystalline coating whose crystals are
preferably
microcrystalfine, with sizes from about 1 to 5 micrometres (hereinafter
usually abbreviat-
is ed as "um").
The mass of the coating formed divided by the area of the surface being
coated,
a value also denoted as "coating weight" hereinafter, as a general rule is
preferably from
about 1 to 3 grams per square meter (hereinafter usually abbreviated as
"glm2").
The P/(P + H) ratio is calculated from the immediately following equation:
so P/(P + H) ratio = Ip/(Ip + Ih) ,
where Ih represents the X-ray diffraction intensity from the (020) surface of
hopeite (zinc
phosphate) and Ip represents the X-ray diffraction intensity from the (100)
surface of
phosphophyllite (zinc iron phosphate) or one of its analogs in which
manganese, nickel,
cobalt, calcium, magnesium, copper and/or the like cations that were dissolved
in the
ss phosphating solution can replace some or all of the iron cations in
phosphophyllite itself.
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The P/(P + H) ratio is vvidely recognized as a characterizing value for the
zinc phos-
phate-type films used as paint-base coatings on iron and steel. P/(P + H)
values of 0.8
to 1 are generally considered to provide good conversion coatings for paint-
base coat-
ings.
s A coating solution taught in Japanese Patent Application Laid Open (Kokai or
Unexamined) Number Hei 1-123080 (123,080/1989) uses hydroxylamine sulfate
(HAS)
as an accelerator. Thc: intent in this case is through the use of this
accelerator to
change the film morphology from platelet structures to columnar and/or nodular
structures over a broad range of zinc concentrations. While Ni and Mn are
mentioned
,o as general supplementary ions, neither the Detailed Description nor the
Examples
provide an explanation of how their quantity of addition should be determined.
This
reference also describes a relatively large number of other patents in which
hydroxyl-
amine sulfate is added to zinc phosphate solutions and in addition describes
patents in
which oxidizing agent is present, including United States Patent Nos.
2,743,204 and
,s 2,298,280.
Japanese Patent Application Laid Open Number Hei 1-123080 also teaches
treatment of the metal surface with a colloidal titanium-containing surface
conditioner
prior to conversion treatiment.
The hydroxylamine source is taught to be added to the conversion bath taught
zo in Japanese Patent Appli~,~,ation Laid Open Number Hei 1-123080 in order to
broaden the
permissible range of zinc concentrations in the bath at which the desired
conversion
coatings can be obtained. in this reference the zinc concentration range is
expressed
by the zinc/phosphate ions ratio. The zinclphosphate ions weight ratio is no
more than
0.27 while the concentration of the zinc itself is from 0.02 to 0.2 weight %,
which is
is equivalent to about 0.2 to 2 grams per liter of total composition
(hereinafter usually ab-
breviated as "gIL").
A phosphate conversion treatment bath taught in Japanese Patent Application
Laid Open (Kokai or Unexamined) Number Hei 5-195245 (195,245/1993)contains hy-
droxylamine (HAS), nickel ions, and manganese ions. This reference also
teaches sur-
so face conditioning with a colloidal titanium-containing bath prior to
conversion treatment.
Japanese Patent Application Laid Open Number Hei 5-195245 teaches nickel
ions and manganese ions as essential components in its treatment bath and also
stipu
lates about 1125 to 1/10 as a more desirable range for the zinc ions/phosphate
ions
weight ratio for the treat~rent bath of Japanese Patent Application Laid Open
(Kokai or
35 Unexamined) Number Hei 1-123080. The nickel ions content in this case is
specified
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as from 0.02 to 0.15 weight % and the manganese ions content is specified as
from 0.02
to 0.15 weight %. Also specified is a zinc ions/(manganese ions + nickel ions)
weight
ratio of about 1/1.5 to 110.5.
The phosphate conversion treatment bath taught in Japanese Patent Application
Laid Open (Kokai or Unexamined) Number Hei 5-195246 (195,246/1993) uses a
combi-
nation of simple and complex fluoride, a chefating agent for iron, phosphate
ions, a hy-
droxyfamine source, and an oxidizing agent selected from water-soluble
aromatic organ-
is nitro compounds, molybdic acid salts, and tungstic acid. This bath can
efficiently form
a highly corrosion-resistant phosphate conversion coating on a variety of
metal surfaces
,o without requiring the use of the divalent and higher valent metal ions used
in the prior
art.
This treatment bath may also contain a colloidal titanium compound, in which
case conversion treatment and surface conditioning can be carried out in a
single step.
The laid-open patent applications cited above make no statements regarding
,s omission of the surface conditioning step, and in fact state that inclusion
of a surface
conditioning step is desirable. Moreover, as a result of our own
investigations we have
found that the conversion treatment baths of Japanese Patent Application Laid
Open
(Kokai or Unexamined) Numbers Hei 1-123080 and Hei 5-195246, while able to
produce
conversion coatings even in the absence of a surface conditioning step, are
inadequate
zo in this case to the task of producing the high-quality conversion coatings
applicable as
paint-base coatings.
Problems to Be Solved by the Invention
The present invention provides a treatment bath that can form a high-quality
phosphate coating on metal surfaces with or without the execution of a surface
condi-
zs tinning step. The present invention also provides a method for treating
metal surfaces.
Surface conditioning with a colloidal titanium-containing treatment bath has
until
now been essential, for example, in the case of phosphate treatments tasked
with the
formation of high-quality conversion coatings as typified by the paint-base
coatings for
automotive steel sheet. The introduction of a conversion treatment bath that
can form
so high-quality conversion coatings even in the absence of a surface
conditioning step will
permit the pursuit of conversion treatment facilities that require less space
and will offer
the advantage of rendering unnecessary the work inputs associated with
management
of the surface conditioning bath.
In addition, the present invention specifically provides a method that even in
the
ss absence of a surface conditioning step can form high-quality zinc phosphate
coatings,
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most importantly on artiicles that must exhibit corrosion resistance and for
which adhe-
sion must be generated between a paint film, rubber, or plastic and a surtace
of iron or
steel. The zinc phosphate coating afforded by the present invention can not
only be
used as a paint-base coating, but can also be used as an adhesion-base
coating, for ex-
ample, in the adhesion of resin films or rubbers to an iron or steel surface.
Summary of the Inventi~~n
It has been discovered that high-quality zinc phosphate conversion coatings
can
be produced on a stable basis, without having to resort to the use of a
surface condition-
ing step through the use: of hydroxylamine in combination with poiycarboxylic
acids) or
,o salts) thereof and/or starch phosphate or by maintaining both a suitable
concentration
for the zinc ions and an upper limit on the ratio of zinc ions to phosphate
ions present
in the conversion treatment bath.
Detailed Description of vhe Invention and of Preferred Embodiments
A preferable cornposition according to a first embodiment of the invention is
an
,s aqueous zinc phosphate. solution that contains phosphate ions at from 5 to
50 gIL, zinc
ions at from 0.2 to 10, or preferably from 2.0 to 10, g/L, a hydroxylamine
source in a
quantity that provides hydroxylamine at from 0.5 to 4.0 gIL, and 0.01 to 5.0
g/L of at
least one selection from the group consisting of polycarboxylic acids, salts
thereof, and
starch phosphate.
zo The hydroxylamine source is believed to increase the conversion reactivity
of the
phosphate treatment solution. Thus, the hydroxylamine source is a component
that
makes possible omission of the surface conditioning step. The chemical nature
of the
hydroxylamine source added to the coating treatment solution according to the
present
invention is not critical and may be, for example, a salt or complex salt of
hydroxylamine.
zs Specific preferred exarnples are the phosphate, nitrate, and sulfate salts
of hydrox-
ylamine and mixtures thereof.
In the present invention the hydroxyiamine quantities are reported in terms of
the
stoichiometric equivalent of hydroxyiamine as calculated from the addition of
the hydrox-
ylamine source. For the example of hydroxylamine sulfate as the hydroxylamine
source,
so the addition of 10 g/L of hydroxylamine sulfate provides 4.0 g/L
hydroxylamine. The hy-
droxylamine source is preferably added so as to give from 0.5 to 4.0 grams of
hydroxyla-
mine per liter. Concentrations below this range are without adequate effect
and thus re-
sult in poor coating in the absence of a surface conditioning treatment.
Values in excess
of 4.0 g/L have a pronounced tendency to produce such defects as blue color.
ss Addition of the polycarboxylic acid and/or salt thereof or starch phosphate
to the
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zinc phosphate treatment solution supports and facilitates the production of
high-quality
zinc phosphate conversion coatings by controlling the weight of the conversion
coating
and inhibiting coarsening of the crystals in the conversion coating. However,
an addition
in excess of 5 gIL has the contrary effect of inhibiting the conversion
reactivity. Polycar-
boxylic acid refers to compounds that contain at least two carboxyl moieties
in each
molecule and in the context of the present invention also encompasses
hydroxycarbox-
ylic acids that contain one or more hydroxyl moieties in addition to at least
two carboxyl
moieties. Typical examples of the subject pofycarboxylic acids are citric
acid, tartaric
acid, succinic acid, ethylenediaminetetraacetic acid, and nitrilotriacetic
acid, with the first
,o three of these constituting a preferred group and citric acid most
preferred. Their salts
are exemplified by the sodium, potassium, ammonium, and iron ammonium salts.
A composition according to a second preferred embodiment of the invention is
an aqueous zinc phosphate solution that contains phosphate ions at a
concentration
from 7.5 to 50 gIL, zinc ions at a concentration from 2 to 10 g/L, and a
hydroxylamine
,s source in a quantity that provides hydroxylamine at a concentration from
0.5 to 4.0 g/L
and in which the zinc ions/phosphate ions weight ratio is not more than 0.27.
The use
of this treatment solution at temperatures of 40 °C to 50 °C for
treatment times of at
least 1 minute produces high-quality zinc phosphate coatings consisting mainly
of nodu-
lar andlor columnar zinc iron phosphate crystals. Either dipping or spraying
can be used
zo as the treatment methodology.
At least 7.5 gIL of phosphate ions are required to avoid too high a zinc to
phos-
phate ions ratio with even the minimum concentration of zinc suitable for this
embod-
invent. While a conversion coating is produced at phosphate ions values in
excess of
50 g/L, such levels are uneconomical due to the increased reagent consumption,
for ex-
zs ample, by drag out.
Suitable zinc ions concentrations for this second preferred embodiment are
from
2 to 10 g/L. While a conversion coating can be obtained at zinc ions
concentrations
below 2 gIL even in the absence of a surface conditioning step, the coverage
by such
coatings has a pronounced tendency to be thin or incomplete. Zinc ions
concentrations
so in excess of 10 g/L cause the weight of the resulting conversion film to be
too large,
making it unsatisfactory as a high quality paint-base coating.
The type of hydroxylamine source and its content range are the same as in the
first preferred specific embodiment. The zinc ions/phosphate ions weight ratio
should
be at or below 0.27. Precipitation occurs in the conversion treatment bath at
values in
s5 excess of 0.27; this not only impairs the stability of the treatment bath
but also prevents
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the production of normal conversion coatings.
The aqueous zinc phosphate solutions of the first and second preferred embodi-
ments may also contain ferrous ions. The presence of ferrous ions improves the
conver-
sion treatment activity. However, since ferrous ions are supplied by the
etching of an
s iron or steel workpiecE: by the canversion treatment solution itself,
ferrous ions are
typically present to soma degree even in the absence of any deliberate
addition of them
to the treatment bath.
At least one selection from the following may be added in order to obtain addi-
tional improvements in the conversion treatment activity and/or additional
improvements
,o in the quality of the conversion coating: nickel ions, manganese ions,
nitrate ions,
fluorine (as a chemical compound of fluorine), and complex fluoride ions.
The concentrations of the ferrous ions, nickel ions, manganese ions, nitrate
ions,
fluorine, and complex fluoride ions are preferably in the range from 0.01 to 5
g/L.
In a preferred method for replenishing the reagents, the treatment bath is
,s supplied with a replenisher composition comprising an aqueous solution
containing zinc
ions, phosphate ions, ;and hydroxyfamine source in which the total
concentration of
these species is at least 15 weight %.
The invention may be further appreciated by consideration of the non-limiting
working examples and comparison examples shown below.
zo The next following tests were carried out in order to demonstrate the
advantage
ous effects of the present invention in its first preferred embodiment as
described above.
The test substrates were cold-rolled steel panels with a thickness of 0.8
millimet
er, a unit hereinafter usually abbreviated in either singular or plural as
"mm", and major
dimensions of 70 mm X 150 mm. Conversion treatment was carried out using the
con
zs version treatment solutions reported in Table 1 and the properties of the
resulting coat
ings were tested. Conversion-treated test panels were also painted as
described below
in order to test the painting performance.
Process steps
(1) Degreasing.
3o Degreasing was carried out using FINECLEANER~ L4460 alkaline degreaser
from Nihon Parkerizing Co.) Ltd. The conditions were as follows: 43 °C,
120
seconds, spray.
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Table 1
CompositionConcentration
f in
g/L
in
the
Composition
of:
-
or: PO4 Hydrox-Zn+2Ni+zMO+Z Fe+z Fluor-Other Additional
3 ylamineIonsIonsIons Ions ine Solute If
Ions Aoy
Example I 5 2 2 0 0 0 0 Ferric ammonium
1 citrate 2.0
Example 15 2 2 I 0 0.01 0.2 Ferric ammonium
2 citrate 2.0
Example 20 4 5 1 0.5 0.01 0.2 Ferric ammonium
3 citrate 2.0
Example 15 2 2 1 0 0.01 0.2 Sodium tartrate
4 2.0
Example 15 2 2 1 0 0.01 0.2 Sodium succinate
2.0
Example 15 2 2 1 0 0.01 0.2 Starch phosphate
6 1.0
Example 15 2 2 1 0.5 0.01 0.2 Citric acid 2.0
7
Comp. 16 0 2 1 0 0.01 0.2 -
Ex. 1
Comp. 15 0.4 2 1 0 0.01 0.2 Starch phosphate
Ex. 2 1.0
Comp. 15 5 2 1 0 0.01 0.2 Starch phosphate
Ex. 3 1.0
Comp. 15 2 2 0 0 0.01 0.2 -
Ex. 4
Com . 15 2 2 1 0 0.01 0.2 -
Ex. 5
Abbreviation and Other Notes for Table 1 et sea.
"Comp. Ex." means "Comparison Example".
Hydroxylamine was supplied to the bath by addition of hydroxylamine sulfate,
i.e., (NH20H)2 ~ H2S04.
Fluorine was supplied to the bath by addition of hydrofluoric acid, i.e., HF.
(2) Water rinse (tap water).
The conditions were as follows: ambient temperature (i.e. from 18 to 25
°C), 30
seconds, spray.
(3) Zinc phosphate conversion treatment.
s Treatment compositions were those reported in Table 1. The process
conditions
were as follows: 43 °C, 120 seconds, dipping.
(4) Water rinse (tap water).
The process conditions were as follows: ambient temperature, 30 seconds,
spray.
(5) Rinse with deionized water with a specific electrical conductivity of not
more than
0.2 microSiemens per centimeter. The process conditions were as follows:
ambient temperature, 20 seconds, spray.
(6) Draining and drying.
The process conditions were as follows: 110 °C air, 180 seconds.
,s Paintin
(1) Electropainting was carried out using GT-10BT"" cationic electropaint from
Kansai Paint Kabushiki Kaisha. The conditions were as follows:
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bath temperature: 28 °C
voltage: .200 volts
current application time: 180 seconds
coating thickness: 20 Nm
s bake: 170 °C, 20 minutes residence
(2) An intermediate coating was applied using TP-65 8160T"" melamine-alkyd
paint
from Kansai Paint Kabushiki Kaisha. The conditions were as follows:
coating thickness: 40 Nm
bake: 140 °C, 20 minutes residence
,o (3) A top coating was applied using NE06000 D40T"" melamine-alkyd paint
from
Kansai Paint Kabushiki Kaisha. The conditions were as follows:
coating thickness: 40 Nm
bake: 140 °C, 20 minutes residence
Methods for evaluating the conversion coatin4s .
,s (1 ) Appearance of the coating.
The appearance was visually evaluated.
(2) Coating weight.
This was calculatE:d from the weight difference before and after stripping
with an
aqueous solution containing 50 gll. of Cr03 .
zo (3) Size of the coating crystals and coating morphology.
The coating morphology was inspected and the crystal size was measured (unit:
Nm) using a sc~snning electron microscope from Nippon Denshi Kabushiki
Kaisha.
(4) The PI(P + H) ratio.
zs The diffraction intensities from the (100) surface of phosphophyllite and
the (020)
surtace of hopeite were measured using a Geiger Flex 2028 X-ray diffraction in-
strument from Ril3aku Denki Kabushiki Kaisha.
Methods for evaluatin4 the painted panels
(1 ) Paint adherence testing (Secondary, water-resistance, adhesion testing)
3o The test panel, after processing up to and including electropainting, was
dipped
in deionized water at 40 °C for 240 hours. The test panel was then
withdrawn
from the water and a 100 unit checkerboard pattern was scribed on the panel
with a sharp cutter down to the steel basis metal: 11 parallel lines were
first
scribed on a 1-mm interval and another 11 parallel lines also on a 1-mm
interval
ss were then scribed perpendicular to the first set. The pattern was peeled
with
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cellophane tape and the number of squares that were at least 50 % peeled was
counted.
(2) Saltwater spray testing
Using a sharp cutter a cross was scribed down to the steel basis metal in the
test
s panel after it had been processed up to and including electropainting. The
test
panel was then subjected to 5 % saltwater spray testing (according to Japanese
Industrial Standard Z-2371 ) for 1,000 hours. The reported value is the width
in
mm of the blistering in the paint film produced along the scratch, taking both
sides into account.
,o (3) Outdoor exposure with saltwater supplement
Using a sharp cutler, a cross was scribed down to the steel basis metal in the
test panel after it had been processed up to and including top coating. The
panel was then exposed outdoors for 3 months in Hiratsuka, Kanagawa Prefec-
ture, Japan. The panel was sprinkled with 5 % saltwater once a week during the
,s exposure period. The reported value is the width in mm of the blistering in
the
paint film produced along the scratch, taking both sides into account.
Results from the evaluations of the conversion-treated panels
Table 2 reports the results from the evaluations of the conversion-treated
panels
and the painted panels.
Table 2
Test ResultConversionCoating CoatingCrys-P/(P+H)Paint Salt- Outdoor
for: AppearanceMorphol-Weight,tal Ratio - water Exposure
ogy g/m2 Size, Loss, Spray,with
~cm % of mm Salt
Squares Water,
mm
Example Excellent Nodular 2.6 2 0.95 0 1.5 0.4
1 -
3
Example Excellent Nodular 2.4 2 0.94 0 1.4 0.3
2 -
3
Example Excellent Nodular 2.4 2 0.95 0 1.3 0.3
3 -
3
Example Excellent Nodular 2.5 2 0.95 0 1.3 0.3
4 -
3
Example Excellent Nodular 2.5 2 0.94 0 1.3 0.4
-
3
Example Excellent Nodular 2.5 2 0.96 0 1.4 0.3
6 -
3
Example Excellent Nodular 2.5 2 0.94 0 1.3 0.3
7 -
3
Comp. No CoatingNo Crystals- - - 75 2.9 2.5
Ex. 1
Comp. No CoatingNo Crystals- - - 70 3.6 2.3
Ex. 2
Comp. Blue ColorNo Crystals- - - 30 3 2.4
Ex. 3
Comp. Excellent Nodular 2.9 3 0.95 0 2 0.6
Ex. 4 -
4
Com . Excellent Nodular 2.9 3 0.95 0 1.8 0.5
Ex. 5 -
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The results in Table 2 show that the present invention provided good results
for the
conversion coating on al! criteria: conversion appearance, coating weight,
size of coating
crystals, morphology of the coating crystals, and P/(P + H) ratio. The results
in Table
2 also confirm that the present invention provided an excellent paintability
even in the
s absence of a surface conditioning step.
The remaining following tests were carried out in order to demonstrate the
advantageous effects of the present invention in its second preferred
embodiment as
described above. Except for the phosphate conversion coating compositions
used,
these tests were performed in the same manner as those described above and on
the
,o same type of substrates. The conversion coating treatment solutions used
are de-
scribed in Table 3 and the test results are described in Table 4.
Table 3
CompositionConcentration (Zinc lons):(Phosphate
for: in
g/L
in
the
Composition
of:
_3 +2 +z +z +z Ions) Ratio by
P04 Hy- Zn Ni Mn Fe FluorineWeight
Ions droxyt-IonsIonsIons Ions
amine
Exam le 17 1.2 4 0 0 0 0 0.24
8
Exam le 17 1.2 4 0 0 0.01 0.2 0.24
9
Exam le 20 1.2 5 l 0 0.01 0.2 0.25
Exam le 25 2.8 5 1 0 0.01 0.2 0.2
11
Exam le 15 1.2 2 l 0 0.01 0.2 0.13
12
Exam le 30 I.2 7 l 0 0.01 0.2 0.23
13
Exam le 20 1.2 S l 0.5 0.01 0.2 0.25
14
Com . 17 0.4 4 0 0 0.01 0.2 0.24
Ex. 6
Com . 35 4.8 8 l 0 0.01 0.2 0.23
Ex. 7
Com . 1 ~ 1.2 1 l 0 0.01 0.2 0.07
Ex. 8
Com . 40 1.2 11 l 0 0.01 0.2 0.28
Ex.9
Comp. 15 4.8 3 l 0 0.01 0.2 0.2
Ex. 10
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Table 4
Test ResultConvey-Coating CoatingCrys-P/(P+H)Paint Salt- Outdoor
for: sion MorphologyWeight,tal Ratio - water Exposure
Ap- g/m2 Size, Loss, Spray,with
pearance um % of mm Salt Water,
Squares mm
Exam le ExcellentNodular 3 4 0.95 0 2 0.5
8 -
5
Exam le ExcellentNodular 2.9 3 0.94 0 1.8 0.4
9 -
4
Exam le ExcellentNodular 2.9 3 0.96 0 1.5 0.4
-
4
Exam le ExcellentNodular 3 4 0.94 0 2.1 0.4
11 -
5
Exam le ExcellentNodular 3 3 0.97 0 1.8 0.5
12 -
4
Exam le ExcellentNodular 3 3 0.94 0 1.9 0.4
13 -
4
Exam le ExcellentNodular 2.8 3 0.95 0 1.8 0.3
14 -
4
Com . No CoatinNo Crystals- - - 70 4.5 2.5
Ex. 6
Comp. ExcellentNodular 12 10 0.94 10 2.5 0.7
Ex. 7 to -
Leaflet 11
Comp. IncompleteNodular 1.4 5 0.95 5 3 0.6
Ex. 8 Coatin -
6
Comp. ExcellentNodular 10.7 9 0.93 40 3.8 0.8
Ex. 9 to -
Leaflet 10
Comp. Blue No Crystals- - - 36 4.3 2.2
Ex. Color
10
Benefits of the Invention
The results reported in Tables 1 to 4 confirm that the present invention
provides
high-quality conversion coatings even in the absence of a surface conditioning
treat-
ment.
12
