[0001] This invention relates to phosphating metal surfaces.
[0002] Japanese Patent Publications (unexamined) No. 107784/1980 and No. 152183/1980 (both
in the name Nippon Paint Co. Ltd.) disclose phosphating methods for treating iron-based
metal surfaces which are particularly suitable for treating manufactured products
having complicated surfaces, such as automobile bodies. The phosphating methods are
in use commercially in the automotive industry for pre-treating automobile bodies
prior to cationic electrocoating, which is a coating process now used extensively
in this industry. The phosphating method of Japanese Patent Publication No. 107784/1980
is carried out by first subjecting the metal surface to a dipping treatment with an
acidic aqueous solution containing 0.5 to 1.5 g/I of zinc ion, 5 to 30 g/I of phosphate
ion, and 0.01 to 0.2 g/I of nitrite ion and/or 0.05 to 2 g/I of m-nitrobenzenesulfonate
ion at a bath temperature of 40° to 70°C for 15 seconds or more, followed by spraying
with the above-mentioned solution for 2 seconds or more. The method of Japanese Patent
Publication No. 152183/1980 comprises spraying onto the metal surface an acidic aqueous
solution containing 0.4 to 1.0 g/I of zinc ion, 5 to 40 g/I of phosphate ion, 0.01
to 0.2 g/I of nitrite ion and 2.0 to 5.0 g/I of chlorate ion at 40° to 70°C for 40
seconds or more.
[0003] Recently, in the automotive industry, with the aim of further improving corrosion-resistance
after the application of a siccative coating, steel components which are plated on
one surface only with zinc or a zinc alloy have come to be used as materials for automobile
bodies. When the processes of these Japanese Patent Publications are applied to such
materials (i.e. to metal components having both iron-based metal surfaces and zinc-based
metal surfaces), the iron-based surfaces are provided with a phosphate coating film
having a low film thickness with uniform and dense cubic or plate-like crystals, as
well as excellent adhesion and corrosion-resistance. Such a phosphate coating on the
iron-based surface is suitable as a substrate for cationic electrocoating. However,
in the case of the phosphate coating film formed on the zinc-based surfaces, the resistance
to salt water spraying after the application of a cationic electrocoating thereto
is insufficient, and secondary adhesion (tested by immersion of the surface bearing
the film with cross-hatched scratches in warm water) after the sequence cationic electrocoating-intermediate
coating-top coating is greatly inferior to that on the iron-based surfaces.
[0004] In addition to these Japanese Patent Publications, the following references disclose
phosphating compositions for metal surfaces:
[0005] U.S. Patent 3,338,755 (Jenkins et al) discloses a process for phosphating metal surfaces
with a phosphating solution containing zinc, manganese, phosphate, nitrate, and nitrite,
as essential ingredients, in stated proportions.
[0006] German Patent 29 31 693 (Fosfa-Col) discloses a phosphating process using a solution
containing zinc, manganese, phosphate, nitrate, and chlorate ions in stated gram-atom
relationships.
[0007] However, none of the above proposed phosphating methods has succeeded in giving satisfactory
results, especially with the above-mentioned combination of substrate materials.
[0008] Japanese Patent J50139-039 (JA 197511) discloses a conversion coating solution containing
manganese ions for the treatment of zinc surfaces. However, this prior art solution
contains from 3 to 20 g/I of zinc ions, which results in a conversion coating having
leaf-like crystals on iron-based surfaces. Such leaf-like crystals are unsuitable
as a substrate for cationic electrocoating. Hence, the solutions of this patent are
unsuitable for treating both zinc-based and iron-based surfaces.
[0009] EP-A-0 018 841 discloses a coating composition for forming a zinc phosphate coating
on a metal surface, which composition comprises an acidic, aqueous solution containing
about 0.4 to about 1 g/I of zinc, about 5 to about 40 g/I of phosphate, and about
0.01 to about 0.2 g/I of nitrite. The specification states that there are applications
where advantages can be realized by applying the composition utilizing intermittent
spraying, and that for these applications, the composition includes also about 2 to
about 5 g/I of chlorate. The specification states also that the aqueous coating solution
may contain, in addition to the aforementioned ingredients, one or more of: nickel,
cobalt, calcium and manganese ions, and one or more of nitrate, chloride and complex
fluoride ions.
[0010] EP-A-0 060 716 discloses a process for phosphating an iron- or zinc-based metal surface
comprising subjecting the metal surface to a dipping treatment in an acidic aqueous
solution characterized in that the solution contains:
(a) from 0.5 to 1.5 g/I of zinc ion;
(b) from 5 to 30 g/l of phosphate ion;
(c) from 0.6 to 3 g/I of manganese ion; and
(d) a conversion coating accelerator.
[0011] The specification states that the conversion coating accelerator is preferably at
least one of the following:
(i) from 0.01 to 0.2 g/I, preferably 0.04 to 0.15 g/l, of nitrite ion;
(ii) from 0.05 to 2 g/I, preferably 0.1 to 1.5 g/I, of m-nitrobenzene-sulphonate ion;
and
(iii) from 0.5 to 5 g/I, preferably 1 to 4 g/I, of hydrogen peroxide (based on 100%
H202).
[0012] The specification states also that optionally the acidic aqueous solution may also
contain one or more of the following:
(e) from 0.1 to 4 g/I, preferably 0.3 to 2 g/l, of nickel ion;
(f) from 1 to 10 g/I, preferably 2 to 8 g/I, of nitrate ion; and
(g) from 0.05 to 2 g/I, preferably 0.2 to 1.5 g/l, of chlorate ion.
[0013] The present inventors have surprisingly found that by the inclusion of defined quantities
of manganese ion in certain acidic aqueous phosphating solutions, very satisfactory
results can be attained when the resulting solutions are applied by spraying more
than once. The inventors have further found that the amounts of chlorate ion can be
markedly lower than those of known compositions.
[0014] Accordingly, the present invention provides an improved phosphating method for metal
surfaces, which is particularly suitable for treating metal surfaces, such as those
of car bodies, which have both iron-based surfaces and zinc-based surfaces. The method
is especially advantageous for forming phosphate coating films suitable for electrocoating,
particularly cationic electrocoating.
[0015] Accordingly, the invention provides a process for phosphating an iron- or zinc-based
metal surface comprising contacting the metal surface with an acidic aqueous solution
containing:
(a) from 0.1 to 2.0 g/l, preferably 0.5 to 1.5 g/I, and more preferably 0.7 to 1.2
g/I, of zinc ion;
(b) from 5 to 30 g/I, preferably 10 to 20 g/l, of phosphate ion;
(c) from 0.2 to 3 g/l, preferably 0.6 to 3 g/l, and more preferably 0.8 to 2 g/l,
of manganese ion;
(d) as conversion coating accelerator from 0.01 to 0.2 g/l, preferably 0.04 to 0.15
g/l, of nitrite ion; and
(e) from 0.05 to 1.9 g/I of chlorate ion, in which process the contact is by spraying
the metal surface with the solution more than once. Additional conversion coating
accelerator can also be present, in particular at least one of-the following:
(i) from 0.05 to 2 g/I, preferably 0.1 to 1.5 g/I, of m-nitrobenzene-sulfonate ion;
and
(ii) from 0.5 to 5 g/l, preferably 1 to 4 g/I, of hydrogen peroxide (based on 100%
H2021.
[0016] The solution can be formed by a method comprising diluting with water a concentrate
which comprises:
a. at least 25 g/I of zinc ion;
b. from 2.5 to 300 parts by weight of phosphate ion;
c. from 0.1 to 30 parts by weight of manganese ion; and optionally
d. from 0.05 to 40 parts by weight of nickel ion; the parts by weight being per 1
part by weight of zinc ion.
[0017] Using the present phosphating process, there can be produced a metal substrate having
an iron- or zinc-based surface, which surface is coated with a zinc phosphate conversion
coating which contains from 1 to 20%, preferably 2 to 15%, especially 2 to 7%, by
weight of manganese, and which coating has a non-leaf-like crystal structure on iron-based
surfaces.
[0018] In a particular, preferred, embodiment, the solution contains 0.1 to 0.4 g/I of zinc
ion. In another particular, preferred, embodiment, the solution contains 1.6 to 2.0
g/I of zinc ion. In another particular, preferred, embodiment, the solution contains
0.2 to 0.5 g/I of manganese ion.
[0019] Optionally, the present acidic aqueous solution may also contain one or more of the
following:
(f) from 0.1 to 4 g/l, preferably 0.3 to 2 g/I, of nickel ion;
(g) from 1 to 10 g/I, preferably 2 to 8 g/l, of nitrate ion.
[0020] The chlorate concentration in the present solution is preferably 0.2 to 1.5 g/I.
[0021] The present process is carried out preferably at a temperature of from 40° to 70°C,
especially 45° to 60°C, and preferably for a contact time of at least 5 seconds, more
preferably at least 15 seconds, especially 30 to 180 seconds, and most preferably
30 to 120 seconds, as hereinafter discussed. The period of spray treatment is generally
at least 5 seconds. It should be noted that at temperatures below about 40°C coatings
can be formed, but the coating is sparse, coating formation is relatively slow and
longer times are required to form satisfactory coatings. At temperatures above 70°C,
the conversion coating accelerators begin to decompose at an unacceptable rate, changing
the composition of the solution and resulting in an unacceptable conversion coating;
also, precipitates begin to form in the bath.
[0022] Following the present treatment, the phosphated metal surface(s) are then usually
coated with a siccative coating by a known electrocoating process, preferably by the
cationic electrocoating process.
[0023] The term "iron- or zinc-based metal surface" as used herein means iron-based surfaces,
iron alloy-based surfaces, zinc-based surfaces, and zinc alloy-based surfaces. Zinc-based
and zinc alloy-based surfaces include, for example, zinc plated steel plate formed
by hot dipping, alloyed zinc plated steel plate formed by hot dipping, zinc plated
steel plate formed by electroplating, and alloyed zinc plated steel plate formed by
electroplating.
[0024] An important advantage of the present invention is that surfaces of metal components,
such as car bodies, that contain both iron-based surfaces and zinc-based surfaces
can be treated by the process of the invention with excellent results. In fact, the
process of the invention produces better conversion coatings than are obtainable with
conventional dip or spray treating processes, and the amount of etching of the metal
surfaces during the present process is only 2/3 to 4/5 that of conventional processes,
so that both the quantity of chemicals used in the process as well as sludge formation
is only from 2/3 to 4/5 that of conventional processes. The present process is equally
applicable to the treatment of a single metal surface of a type described above.
[0025] The metal surface to be phosphated is preferably first degreased by dipping in and/or
spraying with a known alkaline degreasing agent at 50° to 60°C for a few minutes;
washed with tap water; dipped in and/or sprayed with a known surface conditioner at
room temperature for 10 to 30 seconds; and the thus treated metal surface then contacted
with the acidic aqueous solution of the invention at 40° to 70°C for at least 5 seconds.
Finally, the thus treated metal surface is preferably washed with tap water and then
with deionized water. An acidic final chromate rinse can be employed before the rinse
with deionized water.
[0026] In the present spraying procedure, the acidic aqueous solution contains
(a") from 0.1 to 2.0 g/I, preferably 0.5 to 1.5 g/I, and more preferably 0.7 to 1.2
g/I, of the zinc ion;
(b") from 5 to 30 g/l, preferably 10 to 20 g/l, of the phosphate ion; and
(c") from 0.2 to 3 g/l, preferably 0.6 to 3 g/I, of the manganese ion.
[0027] The ranges can be adjusted depending on the intended objects, materials and conditions
used. However, when the amount of zinc ion is less than 0.1 g/l, an even phosphate
film will seldom form on an iron-based surface, and a partially blue-coloured film
is formed. On the other hand, when the amount of zinc ion is in excess of 2.0 g/I,
then the film tends to be in the form of leaf-like crystals and deficient in secondary
adhesion, which renders it unsuitable as a substrate for cationic electrocoating.
When the amount of phosphate ion in the solution is less than about 5 g/l, an uneven
film results, whereas when the amount of phosphate ion exceeds 30 g/I, no further
improvement in the phosphate film is realized and hence, the use of greater quantities
of phosphate is uneconomical. When the amount of manganese ion is less than about
0.2 g/l, the manganese content in the film formed on the zinc-based surface is insufficient,
resulting in inadequate adhesivity of the siccative coating film to the phosphate
conversion coating after cationic electrocoating. When the amount of manganese ion
exceeds 3 g/l, no further improvement in the phosphate coating is realized and hence,
use of a greater quantity is uneconomical. Furthermore, spot rusting of iron-based
surfaces will increase. With respect to the nitrite conversion coating accelerator,
when its amount is less than 0.01 g/l, the conversion coating on iron-based surfaces
is inadequate, forming yellow rust, etc. When the amount of the nitrite accelerator
exceeds 0.2 g/l, a blue-coloured uneven film is formed on iron-based surfaces.
[0028] The present contact of the metal surface with the coating solution, a plurality of
times can be by intermittent spraying of the metal surface. For example, the coating
solution can be applied by intermittent spray where the metal substrate is sprayed
for about 5 to about 30 seconds, then allowed to stand without any coating application
for about 5 to about 30 seconds, and then sprayed for at least 5 seconds, with a total
spray time of at least 40 seconds. This cycle can be carried out once, twice or three
times.
[0029] Of course, the above-mentioned treating times and treating sequences can be changed
according to the composition of the metal substrate to be treated and the treating
solution and conditions to be used.
[0030] For the spray applications, the coating solution is conveniently applied at a spraying
pressure of from about 0.5 to about 2 kg/cm
2.
[0031] Irrespective of the particular application means and contacting solution used, the
resulting phosphate film present on the zinc-based surface should preferably contain
from about 1.0 to about 20% by weight, more preferably from about 2 to about 18% by
weight, and most preferably from about 5 to about 18% by weight of manganese ion,
which is very important for the subsequent cationic electrocoating. The zinc ion is
usually present in from about 28 to about 45% by weight, preferably about 28 to about
40% by weight. When nickel ion is used in the solution, then from about 0.3 to about
4% by weight, preferably about 0.5 to about 4% by weight of nickel is usually present
in the coating. The remainder of the coating is usually phosphate and water, except
for quantities of other ions such as sodium, calcium and magnesium, which usually
total less than 1% by weight. It has also been found that as the content of manganese
in the bath increases, increased manganese coating results. However, increasing the
manganese level of the coating above the ranges given above does not improve coating
quality.
[0032] As examples of sources of zinc ions for use in the invention, one or more of the
following can be employed: zinc oxide, zinc carbonate, and zinc nitrate. As examples
of sources of phosphate ions, one or more of the following can be used: sodium phosphate,
zinc phosphate, and manganese phosphate. As examples of sources of manganese ions,
one or more of the following can be employed: manganese carbonate, manganese nitrate,
manganese chloride, and manganese phosphate. As examples of sources of nitrite conversion
coating accelerator, sodium nitrite or ammonium nitrite can be employed. As examples
of sources of chlorate ions, chloric acid, sodium chlorate or ammonium chlorate can
be employed. With respect to the optional ingredients that can be present in the acidic
aqueous solution, the addition of nickel ion to the manganese-containing composition
results in further improvement in the performance of the phosphate conversion coating,
so that the adhesion and the corrosion-resistance of the film produced by cationic
electrocoating are also further improved.
[0033] As sources of the optional ingredients, nickel carbonate, nickel nitrate, nickel
chloride, nickel phosphate, etc. can be used for nickel ions; sodium nitrate, ammonium
nitrate, zinc nitrate, manganese nitrate, nickel nitrate, etc. for nitrate ions; and
sodium m-nitrobenzene-sulfonate or hydrogen peroxide for additional conversion coating
accelerators.
[0034] The acidic aqueous treating solutions are conveniently prepared by diluting an aqueous
concentrate which contains a number of the solution ingredients in proper weight ratios,
and then adding other ingredients as needed to prepare the treating solutions. The
concentrates are advantageously formulated to contain zinc ion, phosphate ion and
manganese ion, and optionally nickel ion, in a weight proportion of
0.1 to 2: 5 to 30: 0.2 to 3: 0.1 to 4.
[0035] The concentrates are preferably formulated to contain at least about 25 g/I, and
more preferably from about 50 g/I to 130 g/l, of zinc ion.
[0036] The phosphated metal surface is preferably rinsed and electrocoated.
[0037] The invention is illustrated by the following Example XXV. Comparative Examples I-XXIV
and XXVI-XXXI are presented for purposes of comparison.
Comparative Examples I-XIV
[0038] The treating process used, which is common to all of these Examples, is given below,
with the aqueous coating compositions of each Example being set forth in Table 1,
while the metal treated and the test results obtained following the phosphate treatment
are given in Table 2.
[0039] Samples of all four metal surfaces specified in Table 2 were treated simultaneously
according to the following procedure:
(a) degreasing, using an alkaline degreasing agent (Nippon Paint Co., "Ridoline SD200",
2% by weight) which was sprayed on the metal surfaces at 60°C for 1 minute, followed
by dipping in the solution for 2 minutes;
(b) the metal surfaces were then washed with tap water at room temperature for 15
seconds;
(c) the metal surfaces were next dipped into a surface conditioner (Nippon Paint Co.,
"Fixodine 5N5", 0.1% by weight) at room temperature for 15 seconds;
(d) the metal surfaces were then dipped into the acidic aqueous solution specified
in Table 1 at 52°C for 120 seconds;
(e) the metal surfaces were washed with tap water at room temperature for 15 seconds;
(f) the metal surfaces were then dipped into deionized water at room temperature for
15 seconds;
(g) the surfaces were then dried in hot air at 100°C for 10 minutes. At this stage,
the appearance and film weight of the treated metal surfaces was determined, with
the results set forth in Table 2; and
(h) a cationic electrocoating material (Nippon Paint Co., "Power Top U-30 Dark Gray")
was coated to 20 pm thickness onto the treated metal surfaces (voltage 180 V, treatment
time 3 minutes), followed by baking at 180°C for 30 minutes. One sample of each electrocoated
plate so obtained was subjected to the brine spray test.
[0040] A second sample of each electrocoated plate so obtained was coated with an intermediate
coating material (Nippon Paint Co., "Orga T0778 Gray") to 30 pm thickness, followed
by baking at 140°C for 20 minutes, and a top coating material (Nippon Paint Co., "Orga
T0626 Margaret White") in 40 um thickness was then applied, followed by baking as
above. Accordingly, coated plates with a total of 3 coatings and 3 bakings were obtained.
The coated plates were subjected to the adhesion test, and with the cold rolled steel
plate, to the spot rusting test.
[0041] The testing procedures referred to above are described below:
(A) Brine spraying test (JIS-Z-2871): Cross-cuts were made on an electrocoated plate;
5% brine was sprayed thereon for 500 hours (zinc plated steel plate) or 1000 hours
(cold rolled steel plate).
(B) Adhesion test: After dipping a coated plate in deionized water at 50°C for 10
days, grids (100 squares) were made at 1 mm intervals or at 2 mm intervals using a
sharp cutter; an adhesive tape was attached to each surface; and the number of squares
of coating film that remained on the plate after the removal of the adhesive tape
was counted.
(C) Spot rusting test: A coated plate was set at a 15 degree angle to the horizontal
plane, and an arrow with a cone shaped head with a 90 degree vertical angle, made
of alloyed steel (material quality, JIS-G-4404, hardness Hv 700 or higher) weighing
1.00 g and 14.0 mm in total length was dropped repeatedly from a distance of 150 cm,
until 25 scratches were made on the coated surface. Subsequently, the coated plate
was subjected to 4 cycles of testing, each cycle consisting of first, the brine spray
test (JIS-Z-2871, 24 hours), second, a moisture test (temperature of 40°C, relative
humidity 85%,120 hours), and third, standing at room temperature (24 hours). Test
results are shown in Table 2.
[0042] In Table 2 above, the brine spray and spot rusting results each indicate average
values (mm) of the largest diameter of blisters and rust spots, respectively.
Example XXV and Comparative Examples XV-XXIV and XXVI-XXXI
[0043] The treating process used, which is common to all of these Examples, is given below,
with the aqueous coating composition of each Example being set forth in Table 3, while
the metal treated and the test results obtained following the phosphate treatment
are given in Table 4.
[0044] Samples of all four metal surfaces specified in Table 4 were treated simultaneously
according to the following procedure:
(a) degreasing, using an alkaline degreasing agent (Nippon Paint Co., "Ridoline S102",
2% by weight) which was sprayed on the metal surfaces at 60°C for 2 minutes;
(b) the metal surfaces were then washed with tap water at room temperature for 15
seconds;
(c) the metal surfaces were then sprayed with the acidic aqueous solution specified
in Table 3 at 52°C for 120 seconds, (in Ex. XXV, first sprayed for 15 seconds, spraying
discontinued for 15 seconds, and again sprayed for 105 seconds) spraying pressure
-0.8 kg/cm2 (gauge pressure);
(d) the metal surfaces were washed with tap water at room temperature for 15 seconds;
(e) the metal surfaces were then dipped into deionized water at room temperature for
15 seconds;
(f) the surfaces were then dried in hot air at 100°C for 10 minutes. At this stage,
the appearance and film weight of the treated metal surfaces were determined, with
the results set forth in Table 4; and
(g) a cationic electrocoating material (Nippon Paint Co., "Power Top U-30 Dark Gray")
was coated to 20 µtm thickness onto the treated metal surfaces (voltage 180 V, treatment
time 3 minutes), followed by baking at 180°C for 30 minutes. One sample of each electrocoated
plate so obtained was subjected to the brine spray test.
[0045] A second sample of each electrocoated plate so obtained was coated with an intermediate
coating material (Nippon Paint Co. "Orga T0778 Gray") to 30 µm thickness, followed
by baking at 140°C for 20 minutes, and a top coating material (Nippon Paint Co., "Orga
T0626 Margaret White") in 40 Ilm thickness was then applied, followed by baking as
above. Accordingly, coated plates with a total of 3 coatings and 3 bakings were obtained.
The coated plates were subjected to the adhesion test, and with the cold rolled steel
plate, to the spot rusting test.
[0046] The testing procedures referred to above are described below:
(A) Brine spraying test (JIS-Z-2871): Cross-cuts were made on an electrocoated plate;
5% brine was sprayed thereon for 500 hours (zinc plated steel plate) or 1000 hours
(cold rolled steel plate).
(B) Adhesion test: After dipping a coated plate in deionized water at 50°C for 10
days, grids (100 squares) were made at 1 mm intervals or at 2 mm intervals using a
sharp cutter; an adhesive tape was attached to each surface; and the number of squares
of coating film that remained on the plate after the removal of the adhesive tape
was counted.
(C) Spot rusting test: A coated plate was set at a 15 degree angle to the horizontal
plane, and an arrow with a cone shaped head with a 90 degree vertical angle, made
of alloyed steel (material JIS-G-4404, hardness Hv 700 or higher) weighing 1.00 g
and 14.0 mm in total length was dropped repeatedly from a distance of 150 cm, until
25 scratches were made on the coated surface. Subsequently, the coated plate was subjected
to 4 cycles of testing, each cycle consisting of first, the brine spray test (JIS-Z-2871,
24 hours), second, a moisture test (temperature of 40°C, relative humidity 85%, 120
hours), and third, standing at room temperature (24 hours). After testing, the average
value (mm) of the largest diameter of rust spots and blisters was obtained, with the
results shown in Table 4.
(D) Determination of Mn in coating: A phosphated plate was dipped in a 5% aqueous
chromic acid solution (75°C) for 5 minutes, and the weight of the conversion coating
was calculated from the weight difference of the plate before and after this treatment.
Next, the amount of manganese dissolved out and contained in the aqueous chromic acid
was determined by the atomic-absorption method, and manganese in the conversion coating
was calculated therefrom.
Mn(%) in the conversion coating=WM/Wcx100 (%)
WC=Wl-W2/S
WM=A.M/S
wherein
W, stands for weight (g) of plate before chromic acid treatment;
W2 stands for weight (g) of plate after chromic acid treatment;
S is surface area (m2) of plate;
Wc is the coating weight per square metre (g/m2);
A stands for volume (1) of chromic acid solution used;
M stands for amount of Mn determined by atomic-absorption method (g/I); and
WM stands for amount of Mn in unit area (m2) of coating.
1. Ein Verfahren zur Phosphatisierung von Metalloberflächen auf Eisen- oder Zinkbasis,
wobei die Metalloberfläche mit einer säurehaltigen wässrigen Lösung in Kontakt kommt,
die folgende Komponenten enthält:
a) 0,1 bis 2,0 g/I Zinkionen
b) 5 bis 30 g/I Phosphationen
c) 0,2 bis 3 g/I Manganionen
d) 0,01 bis 0,2 g/I Nitritionen als Konversionsbeschleuniger für die Oberflächenvergütung
und
e) 0,05 bis 1,9 g/I Chlorationen,
wobei das Verfahren dadurch gekennzeichnet ist, dass der Kontakt mit der Metalloberfläche
durch das mehrmalige Aufsprühen der Lösung erfolgt.
2. Ein Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass die Behandlung mittels
ein bis drei intermittierenden Aufsprühzyklen erfolgt, wobei jeder Zyklus durch einen
Sprühvorgang von 5 bis 30 Sekunden Dauer, einer nachfolgenden Pause von 5 bis 30 Sekunden
Dauer und einem abschliessenden Sprühvorgang von wenigsten 5 Sekunden Dauer gekennzeichnet
ist und der ganze Sprühvorgang bei jedem Zyklus wenigstens 40 Sekunden dauert.
3. Ein Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass der Kontakt
mit der Metalloberfläche mittels Aufsprühen einer Lösung mit folgenden Komponenten
erfolgt:
a) 0,5 bis 2 g/I Zinkionen
b) 10 bis 20 g/I Phosphationen
c) 0,6 bis 3 g/I Manganionen
d) 0,01 bis 0,2 g/I Nitritionen als Konversionsbeschleuniger für die Oberflächenvergütung
und
e) 0,05 bis 1,9 g/I Chlorationen.
4. Ein Verfahren nach Anspruch 3, dadurch gekennzeichnet, dass die Lösung 0,5 bis
1,5 g/I Zinkionen enthält.
5. Ein Verfahren nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass
die Lösung ebenfalls 0,1 bis 4 g/I Nickelionen enthält.
6. Ein Verfahren nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass
die Lösung ebenfalls 1 bis 10 g/I Nitritionen enthält.
7. Ein Verfahren nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass
die Temperatur zwischen 40 und 70°C beträgt.
8. Ein Verfahren nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass
das zu behandelnde Metall sowohl Oberflächen auf Eisen- als auch Zinkbasis aufweisen
kann.
9. Ein Verfahren nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass
die phosphatisierte Metalloberfläche gewaschen und elektrochemisch beschichtet wird.
1. Un procédé de phosphatation de surface métallique à base de fer ou de zinc, par
mise en contact de cette dernière avec une solution acide aqueuse contenant:
a) de 0,1 à 2,0 g/I d'ion zinc
b) de 5 à 30 g/I d'ion phosphate
c) de 0,2 à 3 g/I d'ion manganèse,
d) de 0,01 à 0,2 g/I d'ion nitrate à titre d'accélérateur de revêtement de conversion;
et
e) de 0,05 à 1,9 g/l d'ion chlorate,
lequel procédé est caractérisé par le fait que la mise en contact s'effectue par plusieurs
pulvérisations de la solution sur la surface métalliques.
2. Un procédé conforme à la revendication 1, caractérisé par le fait que le traitement
est constitué d'un à trois cycles de pulvérisation intermittents, chacun comprenant
une première pulvérisation d'une durée de 5 à 30 seconds, suivie de pulvérisations
discontinues d'une durée de 5 à 30 secondes, suivi d'un cycle de pulvérisation final
de 5 secondes au moins, la durée total de traitement pour chacun des cycles étant
au moins de 40 secondes.
3. Un procédé conforme à la revendication 1 ou 2, caractérisé par le fait que le traitement
a lieu par pulvérisation, sur la surface métallique, d'une solution contenant:
a) de 0,5 à 2 g/I d'ion zinc
b) de 10 à 20 g/I d'ion phosphate
c) de 0,6 à 3 g/I d'ion manganèse
d) de 0,01 à 0,2 g/I d'ion nitrate à titre d'accélérateur de revêtement de conversion;
et
e) de 0,05 à 1,9 g/I d'ion chlorate.
4. Un procédé conforme à la revendication 3, caractérisé par le fait que la solution
contient de 0,5 à 1,5 g/I d'ion zinc.
5. Un procédé conforme à l'une des revendications précédentes, caractérisé par le
fait que la solution contient également de 0,1 à 4 g/I d'ion nickel.
6. Un procédé conforme à l'une des revendications précédentes, caractérisé par le
fait que la solution contient également de 0,1 à 10 g/I d'ion nitrate.
7. Un procédé conforme à l'une des revendications précédentes, caractérisé par le
fait que la température est comprise entre 40 et 70°C.
8. Un procédé conforme à l'une des revendications précédentes, caractérisé par le
fait que la surface métallique traitée inclut à la fois une surface à base de fer
et une surface à base de zinc.
9. Un procédé conforme à l'une des revendications précédentes, caractérisé par le
fait que la surface métallique phosphatée est rincée et électroplaquée.