FR2504156A1 - PASSIVATION PRODUCT SOLUTION HAVING CHROMIC ASPECT AND METHOD OF USE - Google Patents

Abstract

AQUEOUS ACID SOLUTION AND PROCESS FOR TREATING METAL SURFACES, ESPECIALLY ZINC AND ZINC ALLOYS, PROVIDING THEM WITH IMPROVED CORROSION RESISTANCE; THE SOLUTION CONTAINS EFFECTIVE AMOUNTS: A) OF HYDROGEN IONS TO PROVIDE A PH OF ABOUT 1.5 TO ABOUT 2.2; B) AN OXIDANT; C) AT LEAST ONE OF THE IRON, COBALT, NICKEL, MOLYBDENE, MANGANESE, ALUMINUM, LANTHAN, MIXTURES OF LANTHANIDES OR CERIUM, OR THEIR MIXTURES, OR, IN PLACE OF C), OF IRON AND COBALT IONS, THE SOLUTION MAY ALSO INCORPORATE: D) CHROME IONS, SENSITIVELY ALL IN THE TRIVALENT STATE, AND IRON IONS IN COMBINATION WITH AN ADDITIONAL METAL FROM C) OR CERIUM IONS, OR A), B), C) AND D) AND F), A COMPOUND OF SILICATE SOLUBLE IN THE BATH AND COMPATIBLE WITH IT, OR A), B), C) AND D) AND G), A MIXTURE OF 1-HYDROXYETHYLIDENE-1,1-DIPHOSPHONIC ACID AND CITRIC ACID, OR MIXTURES OF A), B), C) AND D) WITH 2 (OR MORE) OF E), F) AND G), THE SOLUTION MAY ALSO CONTAIN HALOGENIDE IONS AND A WETTING AGENT.

Description

1.

  The present invention relates to passiva-

  metal surfaces to give the appearance of a

passivation chrome.

  To date, a large number of aqueous solutions containing chromium have been used for

  surface treatment of zinc, zinc alloy, cadmium

  mium, cadmium alloy and aluminum to improve

  their corrosion resistance and

  the appearance of these surfaces by giving a coating

  yellow or bright blue, the latter resembling a

  These treatment solutions originally contained

  chromium in the hexavalent state and in recent years

  the chromium component was present as a mixture of the hexavalent and trivalent forms, the toxicity

  reduced trivalent chromium and the simplicity and efficiency of

  increased effluent treatment of residual effluents

  trivalent chromium resulted in greater use of

  commercialization of passiva-

  in which the chromium constituent is substantially

  totally in the trivalent state These solutions have been found to be

  Passivation conditions prior to trivalent chromium were

  somewhat less effective than passive solutions.

  traditional hexavalent chromium to provide good corrosion resistance to zinc surfaces

2 2504156

  and alloy of zinc, cadmium, cadmium alloy, and aluminum, aluminum alloy, magnesium and

  of magnesium alloy, and it was therefore necessary to

  to further improve trivalent chromium passivation solutions and processes.

  The excellent corrosion protection provided

  denies by hexavalent chromium passivation solutions

  is usually associated with a film of passiva-

  The light yellow iridescent (or shimmery) color that has been recognized and implemented in ASTM standards Classically, trivalent chromium passivation product films have a light blue to a light blue color and are

  protection against corrosion less than the film of pas-

  yellow sivation with hexavalent chromium This problem has been

  aggravated by a shift from conventional

  cyanide cadmium and zinc to electrolytic acidic and alkaline electroless coating baths that do not contain cyanide that produce metal deposits that are not as receptive to

  chromium passivation products.

  Typically among the compositions and the

  methods of the prior art, for treating

  metal faces, there are those described in US Pat. Nos. 2,393,663, 2,559,878, 3,090,710 and 3,553,034; No. 3,755,018, No. 3,795,549, No. 3,880,772, No.

  3,932,198, No. 4,126,490, No. 4,171,231, British Patents

  Nos. 586,517 and 1,461,244, and the patent application

German Published 2 526 832.

  According to its broadest aspect, the present invention

  provides an aqueous acid solution useful in the

  treatment of metal substrates receivers for

  providing a passivation podu t film comprising A) hydrogen ions to provide an acidic acid; B) an oxidizer; and

  C) at least one of iron, cobalt, nickel, molybdenum, manganese

  ganesis, aluminum, lanthanum, mixture of lanthanide or

  or their mixtures in an amount effective to confer

  better corrosion resistance to the treated substrate.

2504156 '

  The present invention is particularly applicable

  but not limited to the treatment of electrolytic

  Alkaline and acidic cyanide-free cadmium and zinc ticks to impart improved corrosion resistance Particularly satisfactory results are obtained on decorative electrolytic zinc and cadmium deposits of the gloss and semi-gloss types, although advantageous effects are also obtained on zinc and zinc alloy substrates, such as galvanized substrates, zinc die-castings and substrates composed of cadmium or alloys

  of cadmium predominantly formed of cadmium.

  While the present invention in its various aspects,

  as described here, is particularly applicable to the treatment

  surfaces of zinc and zinc alloy, it has been observed that

  that advantageous results are also obtained in the

  treatment of aluminum surfaces, aluminum alloy

  nium, magnesium and magnesium alloy, to form

  a film or coating of passivation product in

  sequence, the present invention in its broad sense

  than the treatment of metal surfaces which are recep-

  these vis-à-vis the formation of a product film pas-

  when brought into contact with the solution of the present invention according to parameters and methods

described.

  According to the aspects of the process of this

  vention, surfaces of zinc, cadmium, zinc alloy, cadmium alloy, aluminum and magnesium

  are brought into contact with the aqueous solution of

  acid, at a temperature ranging from about 41 C to about

  WC 66 for a period of time typically ranging from about 10 seconds to about 1 minute to form the

  desired film of passivation product.

  A treatment bath formulation according to the various aspects of the present invention which are described in detail below may be applied to a substrate to be treated by spraying, dipping, flooding or the like for a period of time sufficient to form the

4 2504156

  desired film of passivation product

  treatment is controlled in a temperature range of about 41 C to about 66 WC, an interval

  a temperature of about 21 C to about 320 C being preferred.

  Temperatures above about 321 C tend to cause rapid loss of peroxide oxidants when used, while temperatures below about 210 ° C reduce bath activity requiring high temperatures.

  longer contact times to get a movie

  the passivation process having the same thickness or the same

  intensity of color than can be obtained at

  tures in short time intervals Ty-

  only about 20 or 30 seconds

  at about 1 minute are satisfactory,

  tact of about 30 seconds being ordinarily preferred.

  According to a first aspect of the present invention there is provided a passivation solution which does not contain chromium ions and is effective in conferring resistance to

  corrosion on zinc, cadmium and aluminum surfaces

  as well as the surfaces of their alloys.

  This aspect of the present invention provides a solution and a method of treatment that are effective

  to selectively confer a film of passiva-

  bright yellow or bright blue, with surfaces of zinc, zinc alloy, cadmium, cadmium alloy, aluminum and magnesium, which provides improved resistance to corrosion. The present invention is further characterized by a process that is simple to control and

  to put into operation Onnleent and that works in a way ef-

Fiscal and economical.

  The advantages of the first aspect of the present invention are attained according to the aspects and compositions

  by providing an aqueous acidic treatment solution

  as the essential constituent of hydrogen ions, preferably to provide a solution pH of about 1.2 to about 2.5 which can be suitably introduced by

  mineral acids such as sulfuric acid, nitric acid,

  2504156 i that or hydrochloric acid; an oxidant, hydrogen peroxide

  itself being preferred, preferably present in

  from about 1 to about 20 g / l, iron and cobalt ions

  in an amount effective to confer increased resistance

  The reaction medium is treated with corrosion and is preferably present in an amount of about 0.02 to about 1 g / l to form a light blue or bright passivation product film. The treatment solution contains an oxidant in an amount effective to activate the metal surface and form a film of passivation product thereon, and

  iron and cobalt ions present in an amount effective to

  tive the bath and to give an initial hardness

  the passivation product film The processing solution

  optionally additionally contains cerium ions present in an amount effective to further activate the bath and to promote the formation of a clear film of light yellow passivation product.

  treatment solution may optionally contain

  have halide ions comprising fluoride, chloride and bromide ions, to increase the hardness of the passivation product film and one or more agents

  compatible anchorage, preferably in small quantities

  to achieve effective contact with the treated substrate.

you.

  Iron and cobalt ions are suitably introduced

  in the bath by means of salts compatible with the

  bath and soluble in the bath comprising the salts

  sulphates, nitrates or halides.

  concentration of iron and cobalt ions combined to obtain

  appropriate activation of the treatment bath is controlled

  in a range of about 0.02 to about 1 g / l of

  in a range of about 0.1 to about 0.2 g / l.

  The iron and cobalt ions individually are present in an amount of from about 0.01 to about 0.5 g / l, with individual amounts of about 0.05 to about 0.1 g / l being preferred.

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6.

  When you want a film of passiva-

  With a light yellow appearance, the treatment bath also contains cerium ions present in an amount effective to further activate the bath and to impart a light yellowish color, preferably an iridescent light yellow color, to the passivation product film on the surface. treated substrate Cerium ions can be introduced in the form of any soluble cerium salt

  in the bath and compatible with the bath comprising the

  cerium fate (Ce (504) 24H20); salts consisting of

  such as cerous chloride (Ce C 13 6 H 20); or salts consisting of nitrate such as cerium nitrate (Ce (NO 3) 5 H 20), (Ce (NO 3) 3 (OH) 3 H 20) Ordinarily, at least some of the cerium ions are introduced into the bath in the tetravalent state to impart the characteristic yellow color of the tetravalent cerium ion to the passivation product film Some oxidants such as hydrogen peroxide serve as a reducing agent under the predominant acidic conditions in the working bath mass and reduce

  some of the tetravalent cerium ions in the trivalent state.

  However, the oxidants such as hydrogen peroxide come from a state of reducing agent to a state of oxidizing agent at the interface of the treated substrate as a result of the predominant upper H at the interface and oxidize at least a part trivalent cerium ions to the tetravalent state, these ions being coded in the film, and give the characteristic yellow color. Therefore, when oxidants such as hydrogen peroxide are used, all the cerium ions can, if Desirably, they are initially introduced into the working bath in the trivalent state, part of which is oxidized in the tetravalent state at the interface of the substrate.

  passivation product film usually contains a

  a mixture of trivalent and tetravalent cerium compounds, and the intensity of the yellow color of the film is imposed by the

  Concentration of tetravalent cerium fluos present.

  The cerium ions, in addition to imparting a light yellow color to the passivation product film, also improve the corrosion resistance of the treated substrate. The cerium sulfate compound, due to solubility difficulties, is preferably added to the bath. under the

  form of an acid solution such as an acid solution

  diluted sulfuric acid containing cerium sulphate

under in.

  The concentration of cerium ions in the working bath can range from about 0.5 to about 10 g / l, with concentrations of about 1.0 to about 4.0 g / l being preferred. Concentration of cerium ions is partly influenced by the importance of the desired yellow coating and higher concentrations of cerium ions produce corresponding increases in the yellow color of the

passivation product film.

  As a result of cost considerations, the cerium ions are preferably introduced as a commercially available mixture of earth salts.

  rare metals in the series of lanthanides which

  hold cerium compounds as the main component.

  One of these commercially available materials is a

  cerous chloride solution containing about 46% of

  This C 3 d 6 H 20 predominates The solution of unreacted chloride comes from a rare earth oxide concentrate (RTO) sold by Molycorp, Inc., of White Plains, New York under the product code 5310 containing a minimum of 99% of total OTR o This O 2 is in proportion of 96%, The 23 is in proportion of 2.7%, Nd 203 is in proportion of 1% and Pr 601 l is in proportion of 0, 3% One

  ceric sulfate solution is available in the commercial

  at the same source containing about 42% solids o Ce (SO 4) 29 H predominates and is also prepared from

  of product code 5310 containing other

  rare earths in similar quantities of

  your. The working bath according to this first aspect of the

  The present invention can suitably be prepared in

  bending a concentrate containing the active constituents to

8 2504156

  with the exception of cerium ions and the oxidant which is adapted to be diluted with water to which the cerium ions, if used, and the oxidant are separately added to form a bath suitable for the constituents in the concentration range In a similar way, the reinstatement

  provision of bathing on a continuous or intermittent basis

  tent can be obtained by using a concentrate of

  except for the cerium ions and the oxidant, which are individually added separately to the working bath Typically, a bath make-up concentrate may contain about 0.5 to about 50 g / l of iron ions and cobalt, halide ions up to about 20 g / 1 and

  a suitable surfactant product in an amount up to

  at about 5 g / l, if used. Such a make-up concentrate is adapted to be diluted with about 96% by volume of water to which cerium ions, if used, and an oxidant are added to produce a working bath

  containing the active constituents in the specific ranges

  The oxidant such as hydrogen peroxide, for example, is separately introduced into the bath preferably in a commercially available form, containing from about 35 to about 40.degree.

% by volume of hydrogen peroxide.

  As indicated previously, the low solubility of cerium sulphate makes it desirable to introduce this constituent into the working bath in the form of a

  aqueous acid solution Normally, the use of sulphate

  cerium fate at the necessary high concentrations

  to form a concentrate with the active constituents

  other than the peroxide component causes the

  cipitation of the cerium compound Even when the cerium is

  introduced as a salt formed of halide or ni-

  the presence of sulphate ions in the concentrated emulsion

  fold introduced by the other constituents causes precipitation.

  As a result, the cerium concentrate is pre-

  formed as a separate addition component

  and may include aqueous acid solutions of chlorine

2504156 X

9.

  cerous or ceric sulphate with a concentration of

  cerium ion ranging from about 200 to about 320 g / l and about 60 to 100 g / l, respectively

  cerium may be properly composed of the materials

  previously described commercially available res, available from Molycorp, Inc.

  The treatment bath contains hydro-

  gene, preferably in quantity to provide a p H of

  1.2 to about 2.5, a pH range of about 1.5 to about 2.0 being preferred.

  working up to the desired range of p H can be obtained

  naked by a large number of mineral acids and organic acids.

  such as sulfuric acid, nitric acid, hydrochloric acid, formic acid, acetic acid, or propionic acid, including sulfuric acid.

  and nitric acid are preferred. The presence of sulphuric

  In the bath, it has proved advantageous to obtain the desired passivation of the substrate and can be introduced by the addition of sulfuric acid or sulphate salts of the other constituents of the bath. 15 g / l,

  concentrations of from about 0.5 to about 5 g / l being

ferred.

  The treatment bath also contains one or more

  oxidizers that are compatible with the bath, including peroxides including hydrogen peroxide and

  metal peroxides, such as metal peroxides,

  hugs are preferred The hydrogen peroxide itself quality

  of about 25% to about 60% in volume.

  peroxide is the preferred material.

  xydes that can be employed include zinc peroxide In addition, ammonium persulfates and metals

  alkalis have also been found effective as oxidants.

  The concentration of the oxidant or mixture of oxy-

  is controlled to obtain the desired surface appearance

  Typically, the concentration of the oxidant can range from about 1 to about 20 g / l,

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  from about 3 to about 7 g / l being preferred,

  on a basis of effectiveness equivalent in weight per

compared to hydrogen peroxide.

  As an optional but preferred component, the bath may contain halide ions comprising ions

  chlorine, bromine and fluoride, which have been found to

  the hardness of the passivation product film on the

  treated substrate Halide ions or their mixtures can

  suitably be introduced using any of the alkali metal and ammonium salts, as well as

  than salts of the metal ions indicated above.

  The concentration of the total halide component in the bath can normally be up to about 8 grams per liter, from about 0.1 to about 2.5 grams per liter.

being typical.

  In the second, the fourth and the fifth

  of the present invention, it may be preferred that the concentration of the total halide component in the bath normally ranges up to about 2 grams per liter,

  concentrations of from about 0.1 to about 0.5 g / l being typical

  c. In addition to the foregoing, the use of a small, effective amount of a large number of bath-compatible wetting agents also provides advantageous results in the nature of the product film.

  passivation deposited When used, the agent of wet-

  can be present at concentrations up to about 1 d / l of concentrations of about 50 to about

mg / i being preferred.

  Wetting agents suitable for use in

  in the treatment bath include sulfonylurea

  the aliphatic fluorocarbons available from the so-called 3 M company under the trade name Fluorad, such as, for example, the product called Pluorad FC 98, which is a wetting agent that does not form foam, and its use at around 100 mg / l in the working bath improves the color and hardness of the passivation product film.

  second class of suitable wetting agents is

  derived from the sulfonated derivatives of succinates An example of this class is provided by the product called Aerosol

  MA-80 which is the dihexyl ester of the sodium salt of

  of sulfosuccinic acid and is commercially available from the so-called American Cyanamid Company. A third class of suitable wetting agents is formed by the

  naphthalene sulfonates which are (linear) naphthalene

  talenesulfonates such as the product Petro BA, by

  example, available to the so-called Petrochemical Compa-

  ny. According to the second aspect of the present invention there is provided a solution and a treatment method which are effective to impart improved corrosion resistance to surfaces of zinc, zinc alloy, cadmium and cadmium alloy, as well as aluminum and

  magnesium, and to give the desired surface finish

  table that can range from a bright glossy appearance to a

  light blue, this process being simple to control

  and to put into operation, and its operation

  being effective and dynamic This aspect, together with the

  number three to number seven of the present invention,

  all use trivalent chromium ions.

  The advantages of the second aspect of the present invention are achieved according to the aspects of the compositions

  by providing an aqueous acidic treatment solution

  having as essential constituents chromium ions, all being substantially present in the trivalent state, preferably at a concentration of about 0.05 grams per liter (g / l) to saturation, preferably hydrogen ions to provide a p H of the solution of about 1.5 to about 2.2 that can be suitably introduced

  with mineral acids such as sulfuric acid,

  nitric acid, or hydrochloric acid, an oxidant, the hydrogen peroxide itself being preferred, preferably present in an amount of about 1 to about 20 g / l, and iron ions

  preferably present in an amount of from about 0.05 to about

12.

  0.5 g / l, for example in the combined ferric state with

  be with at least one additional metal ion chosen

* in the group consisting of cobalt, nickel, molyb-

  dein, manganese, lanthanide, lanthanide mixture and mixtures thereof in an amount effective to provide increased corrosion resistance to the treated substrate and to activate the bath and the formation of a passivation product film at room temperature. chrome appearance on the substrate

  As mentioned for the first aspect of the preface

  invention, the solution may furthermore contain

  Optional halide ion to impart hardness

  initial coating, as well as a wetting agent.

  In this second aspect of the present invention,

  whereas it is applicable in the same way as the first

  aspect, in the case of electrolytic coatings de-

  zinc coatings, another reinforcement of the appearance of these substrates in addition to the resistance to the conferred corrosion is obtained by the film of passivation product, which goes from a light blue glossy appearance to a bright glossy appearance

  resembling that of a chrome 8 t depot.

  The treatment solution contains an oxidant

  in an amount effective to activate the trivalent chromium

  to form a chromate film on the metal surface

  metallics, iron ions present in the working bath in the ferric state at a concentration of about 0.05

  at about 0.5 grams per liter, and at least one metal ion

  that additional selected in the group consisting of co-

  balt, nickel, molybdenum, manganese, lanthanum and

  mixtures present in an amount effective to confer

  a complete initial hardness to the chromate film

latineux.

  Trivalent chromium ions can be introduced

  in the form of any bath-soluble and bath-compatible salt such as chromium sulphate (Cr 2 (SO 4) 3), chromium alum (K Cr (SQ 4) 224 H 20 ), chromium chloride (Cr C 13), chromium bromide (Cr Br 3), chromium fluoride (Cr F 3), or chromium nitrate (Cr (NO 3) 3) Trivalent chromium ions can also be

13 2504156

  introduced by reducing a solution containing hexavalent chromium ions employing a suitable reducing agent of any of the types well known in the art to effect substantially complete stoichiometric reduction of all hexavalent chromium to the trivalent state . The concentration of trivalent chromium ions in

  the treatment solution can range from as low as

  about 0.05 g / l to saturation, quantities of

  About 0.2 to 2 g / l are preferred. Typically, the working bath contains about 0.5 to about 1 g / l.

of trivalent chromium ions.

  The treatment solution further contains iron ions, preferably present in an amount of from about 0.05 to about 0.5 g / l, with concentrations ranging from about 0.1 to about 0.2 g / l being preferred. Iron ions in the

  baths are predominantly in the ferri-

  as a result of the presence of bath oxidants although they may be added in the ferrous form As in the case of chromium ions, the iron ions may be added to the bath in the form of any soluble iron salt in the bath and compatible with the bath, such as sulphate

  iron and ammonium, ferric sulphate, ferric nitrate,

  In the foregoing, ferric sulfate forms the preferred material for economic reasons, and because the use of this salt also introduces the desired sulfate ions into the solution.

  In addition to iron ions, the bath also contains

  at least one additional metal ion selected from the group consisting of cobalt, nickel, molybdenum, manganese, lanthanum, and mixtures thereof.

  metal ions above that metal ion mixtures

  are suitably introduced, as in the case of iron ions, by means of bath-soluble and bath-compatible metal salts, including salts of sulphates, nitrates, or halides.

250 '415614.

  lanthanum ions are preferably introduced.

  not in the form of the pure lanthanum compound, but in the form of a mixture of rare earth metal salts of the lanthanide series (hereinafter referred to as "lanthanide mixture") which contains

  of lanthanum as predominant constituents.

  The commercially available lanthanide mixture which is suitable for use in the practice of the present invention is lanthanum-rare earth chloride, product code 5240, available from Molycorp Inc. of White Plains, New York. This product has the general formula TRC 13 6 H 20 and is available as a solution containing approximately 55 to 60% by weight of solids The solution is prepared from a concentrate of terrestrial oxide (OTR) containing at least 46% by weight of total OTR comprising approximately 60% of lanthanum oxide (La 203), 21.5% of neodymium oxide (Nd 203),% of cerium oxide (Ce O 2), 7, 5% praseodymium oxide

(Pr 6011) and 1% residual OTR.

  The presence of these other rare earth metals in the solution does not appear to have any deleterious effect at low concentrations, where they are present and may further contribute to the activation of the treatment solution for

  form the passivation product film.

  The concentration of the additional metal ions

  for the proper activation of the treatment bath

  is controlled to provide a concentration ranging from

  0.02 to about 1 g / l, concentrations of

  0.1 to about 0.2 g / l being preferred.

  The working bath according to this second aspect of the

  The present invention can suitably be prepared in

  bending a concentrate containing the active constituents with the exception of the oxidant which is adapted to be diluted

  with water, to form a bath containing the constituents

  killing in the desired concentration range so

  similar, the replenishment of the bath on a

  tinue or intermittent can be obtained by using a

2504156

  concentrated active constituents with the exception of oxy-

  which is added separately to the operating bath.

  Typically, a booster concentrate may contain about 10 to about 30 g / l of chromium ions, about 0.5 to about 10 g / l of iron ions, about 5 to about 50 g / l of

  least one additional metal ion of the group is

  cobalt, nickel, molybdenum, manganese, lanthanum, mixture of lanthanides or mixtures thereof, halide ions up to about 20 g / l and a suitable surfactant in an amount up to about This auxiliary concentrate is adapted to be diluted with about 98.5% by volume of water to produce a working or working bath containing the active constituents included in the ranges.

  The oxidant such as hydrogen peroxide, for example

  ple, is introduced separately in the bath preferably

  in a commercially available form containing approximately

  35 to 40% by volume of hydrogen peroxide.

  According to the third aspect of the present invention,

  a solution and a treatment method which are effective in conferring a clear film of

  from light yellow passivation to zinc surfaces, alloyed

  zinc, cadmium, cadmium alloy, aluminum and magnesium which provides improved resistance to

  corrosion approaching or comparable to that obtained

  using conventional passivation solutions

  Hexavalent chromium The present invention is still

  characterized by a process which is simple to control and put into operation and whose operation

is efficient and economical.

  The advantages of the third aspect of the present invention are achieved according to the aspects and compositions

  by providing an aqueous acidic treatment solution

  holding as essential constituents, chromium ions,

  being all substantially present in the trivalent state of pre-

  at a concentration of about 0.05 grams per liter

  (g / l) until saturation, hydrogen ions of

16 2504156

  to provide a solution of about 1.2 to about 2.5, which may be suitably introduced by mineral acids such as sulfuric acid, nitric acid or hydrochloric acid; an oxidant, the oxygenated water itself being preferred, preferably present in an amount of about 1 to about 20 g / l, and cerium ions present in an amount effective to activate the bath and the formation of a film of passivation product

  with a light yellow chrome appearance on the treated substrate.

  In addition to cerium ions in the treatment solution

  In addition, the solution may contain more

  cultured and preferable, an additional metal ion selected from the group consisting of iron, cobalt,

  nickel, molybdenum, manganese, lanthanum,

  lanthanides, as well as their mixtures, to provide

  Another embodiment of the bath and other formation of passivation product film. As mentioned for the first aspects of the present invention, the solution

  can also optionally contain

  fittings to impart hardness to the coating in addition to a small amount of a wetting agent

  cerium can be introduced with the treatment solution

  in this third aspect of the present invention in the same manner as described for the first aspect of the present invention.

of the present invention.

  In addition to cerium ions, the bath may additionally optionally and preferably contain at least one

  additional metal ion selected from the group

  iron, cobalt, nickel, molybdenum, manganese

  lanthanum, mixtures of lanthanides, as well as

  mixtures These metal ions can be introduced

  in the treatment solution in this third

  pect of the present invention in the same way as that

  already described for the second aspect.

  The working bath according to this third aspect of the present invention can be suitably prepared by employing a concentrate containing the active ingredients at 17.

  with the exception of cerium ions and the oxidant, which is suitable

  to be diluted with water, to which the cerium ions and the oxidant are separately added to form a bath containing the constituents in the desired concentration range. Similarly, the replenishment of the

  bathing on a continuous or intermittent basis may be

  held using a concentrate and active constituents with the exception of cerium ions and oxidant which are

  individually added separately to the working bath.

  Typically, a booster concentrate may contain about 10 to about 80 g / l of chromium ions, about 0.5 to about

  approximately 50 g / l of additional metal ions from the group

  pe consisting of iron, cobalt, nickel, molybdenum, manganese, lanthanum, mixtures of lanthanides, or mixtures thereof, halide ions up to about g / l and a suitable surfactant in quantity

  up to about 5 g / l if used.

  Centered booster is suitable for being diluted with approximately

  96% by volume of water, to which cerium ions and an oxy-

  are added to produce a working bath containing

  active constituents in the specified ranges.

  Oxidant, such as hydrogen peroxide for example, is separated

  introduced into the bath preferably in a commercially available form containing about 35 to 40%

volume of oxygenated water.

  As previously indicated, the low solubility

  cerium sulphate makes it desirable to introduce this component into the working bath in the form of a

  aqueous acid solution Normally, the use of sulfa

  cerium at the high concentrations necessary to formulate

  concentrate with the remaining active constituents

  the peroxide component causes the precipitation of the cerium compound. Even when the cerium is introduced in the form of salts consisting of halide or nitrate;

  the presence of sulphate ions in the concentrate used

  produced by the other constituents causes a precipita-

  Accordingly, the cerium concentrate is preferably

18 2504156

  formed as a separate additive component, and may comprise aqueous acid solutions of cerous chloride or ceric sulfate, having a cerium ion concentration of about 200 to about 320 g / l and about 60 to 100 g / l, These cerium concentrates may suitably be composed of commercially available materials previously described available from Molycorp, Inc.

  According to the fourth aspect of the present invention,

  a solution and a treatment method which are effective in providing improved corrosion resistance to surfaces of zinc, zinc alloy, cadmium and cadmium alloy, and aluminum are provided.

  and magnesium, and to impart a surface finish

  desirable, which can range from a bright glossy appearance to a

  light blue glossy pect to a yellow iridescent appearance, which produces a film of passivation product of clarity and

  improved initial hardness, this process being simple to

  tr 8 ler and put in operation and its operation

being efficient and economical.

  The advantages of the fourth aspect of the present invention are achieved according to the aspects and compositions

  by providing an aqueous acidic treatment solution

  holding as essential constituents, chromium ions, all

  being substantially present in the trivalent state of preference

  this at a concentration of about 0.05 grams per liter (g / l)

  until saturation (and which can be introduced

  indicated for the second and the third aspect), preferably hydrogen ions to provide a p H of solution

  from about 1.2 to about 2.5 which may be suitable

  introduced by mineral acids such as sulfuric acid, nitric acid or hydrochloric acid, a

  oxidant, the hydrogen peroxide itself being preferred, preferably

  present in an amount of from about 1 to about 20 g / l,

  soluble organic carboxylic acid in the bath and

  with the bath present in an amount effective to

  initial hardness and clarity in the film

  passivation agent, said organic acid having the formula 19. Expanded (OH) to R (COOH) b or: a is an integer of 0 to 6; b is an integer of 1 to 3; and

  R represents an alkyl, alkenyl or aryl group;

  the container of 1 to 6 carbon atoms; as well as its bath-soluble and bath-compatible salts, and at least one additional metal ion selected from the group consisting of iron,

  cobalt, nickel, molybdenum, manganese,

  thane, cerium and lanthanide mixtures, as well as

  of their mixtures, present in an effective quantity for the

  the bath and the formation of a film of passive product

  appearance with the desired appearance on the substrate.

  Processed by desirably imparting initial hardness to the gelatinous chromate film As mentioned for the foregoing aspects of the present invention, the solution may optionally additionally contain

  halide ions to impart additional hardness

  In this fourth aspect of the present invention, while it is applicable in the same manner as the first aspect of the present invention, it is applicable to the coating as well as a wetting agent.

  in the case of electrolytic coatings of decorative zinc

  tif, another reinforcement of the appearance of these substrates

  in addition to the corrosion resistance conferred is obtained

  naked by the film of passivation product which goes from a bright glossy aspect to a shining light blue, simulating that of a deposit of chxcoe or alternatively, a light yellow aspect simulating that obtained by the use of chromium solutions hexavalent of the prior art, In addition, the bath contains moreover at least one

  additional metal ion selected from the group

  iron, cobalt, nickel, molybdenum, manganese

  lanthanum, mixtures of lanthanides and

  rium, as well as their mixtures Metallic ions

  where metal ion mixtures are suitable.

20.

  introduced into the bath by means of metal salts

  bath-soluble and bath-compatible salts, comprising salts of sulfates, nitrates, or halides, indicated for the second and third exemplary embodiments, and those materials which are as indicated for these aspects; , can be used and are

  desirably used in this aspect of the pre-

this invention.

  The concentration of the additional metal ions

  other than cerium ions for the activation of

  propriety of the treatment bath to produce an appearance

  clear to bright blue is controlled to provide a concentration

  ranging from about 0.02 to about 1 g / l,

  concentrations of from about 0.1 to about 0.2 g / l being

  While these metal ions can be used

  at concentrations above 1 g / l, such as up to 10 g / l, the use of these higher concentrations even in the absence of cerium ions tends to produce dull films with a rather yellow hue. that clear films

  This is why these concentra-

  Higher levels are undesirable from the aspect point of view.

  Another essential constituent of the improved bath

  of the present invention comprises a carboxylic acid

  organic material or its salt having the structural formula, as previously presented, present in an amount effective to impart increased clarity and initial hardness to the deposited gelatin chromate film. The unexpected improvement in clarity of the film is particularly pronounced.

  in the case of light yellow iridescent films produced

  firing solutions containing cerium ion The particular concentration or concentration range of a lightness / hardness agent will vary proportionally

  molecular weight of the particular acid and / or metal salt

  used, with higher concentrations being required

  for equivalent efficiency when the average molecular weight

  of the additive agent increases the concentration of

  to obtain optimum clarification and hardness 21.

  is also imposed to a certain extent by the concentration

  tion of the other metal ions present in the bath, higher concentrations being used when the metal ion concentrations increase. Generally, the organic carboxylic acid additive agent or its metal salts may be employed in an amount of about 0, 05 up to about 4.0 g / l, concentrations

  from about 0.1 to about 1.0 g / l being ordinarily preferred.

  Rees. The additive can be introduced as an acid

  organic or in the form of any salt

  soluble in the bath and compatible with the bath comprising the alkali metal salts, the ammonium salts and the salts of the various additional metal ions

  In the bath For economic reasons, the organic acid

  that is usually introduced in the form of an acid or

  in the form of its sodium or potassium salt.

  In the field of the structural formula as previously discussed, organic carboxylic acids which have been found to be particularly suitable include malonic, maleic, succinic, gluconic, tartaric and citric acids, including salts of

  succinate and / or succinic acid have been shown to be particularly

effective.

  The working bath according to this fourth aspect of the present invention may suitably be prepared by employing a concentrate containing the active ingredients of the present invention.

  the exception of oxidant and cerium ions, if used

  lise, which is adapted to be diluted with water to form

  sea a bath containing constituents in the range of

  desired concentration In a similar way, the reappro-

  viewing the bath on a continuous or intermittent basis

  can be obtained by using a concentrate of

  Active killing agents with the exception of oxidizing agent and cerium ions, if used, which is added separately to the working bath Typically, a makeup concentrate of the bath may contain about 10 to about 80 g / l of ion chromium, about 22. 1.0 to about 80 g / l of the organic carboxylic acid additive agent and / or its salt, about 5 to about g / l of at least one additional metal ion of the

  group consisting of iron, cobalt, nickel, molyb-

  diene, manganese, lanthanum, mixtures of lanthanides, or mixtures thereof and halide

  about 5 g / 1, if used. Such a concentrate of

  point is suitable to be diluted with approximately 98% in volume

  me of water in order to produce a working bath containing

  active constituents in the specified ranges Oxygen

  such as hydrogen peroxide, for example, is separately

  introduced into the bath, preferably in a form

  with about 35 to 40% of

  The cerium ions, when employed, are preferably introduced in the form of an acidic aqueous solution of cerous chloride, or ceric sulfate, having a cerium ion concentration of about 200 to about

  320 g / l and about 60 to about 100 g / l, respectively.

  These cerium concentrates may be suitably

  commercially available materials, described above,

  According to the fifth aspect of the present invention there is provided a treatment solution which aims at reducing the severity of a problem of oxidative loss associated with the bath of the prior art. improvements have been made in trivalent chromium passivation product compositions and methods to produce

  acceptable passivation product films in the

  a continuing problem associated with these baths was the relatively rapid loss of

  peroxide, particularly oxygenated water, which is

  These baths of the prior art are also required as a necessary component of the bath to obtain passivation product acceptable films.

  relatively fast increase of p H requiring

  careful control and addition of acid to maintain the level of p H in the optimum operating gamoe

2504 155

23.

  progressive loss of the peroxide oxidant, particulate

  Oxygenated water is partly due to the presence of metal activating ions present in the solution, as well as contamination metal ions such as zinc or cadmium, for example introduced by the dissolution of the solution. metal from treated substrates that tend

  to catalyze a decomposition of the oxidant formed from

  The progressive loss of oxidant of the peroxide type is

* produced not only during treatment but also during

  the rest of the bath all night and during weekends when the installation is stopped Typically,

  a fresh working bath containing 3% by volume of a

  35% hydrogen peroxide, resting overnight,

  about 0.1% by volume per hour of the hydrogen peroxide oxidizer, while a used solution containing about 2 to about 10 grams per liter of zinc ions

  contamination will suffer a loss of oxygenated water at a rate

  so high that about 0.4 t in volume per hour It appears that

  from the foregoing that careful monitoring

  of the composition of the working bath and a replenish-

  Frequently, the peroxide oxidant is required to maintain optimum bath efficiency, which is not

  only expensive but also takes time.

  Thus, this fifth aspect of the present invention

  intended to provide a solution and a method of

  which are effective in conferring resistance

  corrosive to zinc surfaces, alloy

  zinc, cadmium and cadmium alloy, as well as aluminum

  minium and magnesium, and to impart a desirable finish

  surface that can range from a clear glossy appearance to

  a light blue glossy appearance to an iridescent aspect

  which produces a film of passivation product

  both an improvement in corrosion resistance, hardness, durability, clarity and hardness

  which provides a stable treatment solution

  against a rapid loss of oxidant consisting of peroxygen

  of and against a rapid increase of p H, the process being simple to control and put into operation and 24.

  its operation being efficient and economical.

  The advantages of the fifth aspect of the present invention are achieved according to the aspects of the compositions

  by providing an aqueous acidic treatment solution

  holding as essential constituents, chromium ions, all

  being substantially present in the trivalent state, preferably

  at a concentration of about 0.05 grams per liter (g / l) to saturation (and which may be introduced as indicated for aspects number two to number four),

  hydrogen ions preferably to provide a p H in so-

  from about 1.2 to about 2.5 which may be suitable

  nally introduced by mineral acids such as

  sulfuric acid, nitric acid, hydrochloric acid or

  analogous, an oxidant, the hydrogen peroxide itself being preferred

  which is preferably present in an amount of from about 1 to about g / l, a stabilizing additive comprising a mixture of

  1-hydroxyethylidene-1,1-diphosphonic acid and

  of citric acid and their soluble salts in the bath and

  baths present in an amount effective to reduce the loss of the peroxide oxidant and to stabilize the pH of the working bath, and at least one additional metal ion selected from the group consisting of iron, cobalt, nickel, imlybdenum, manganese, aluminum

  lanthanides, mixtures of lanthanides, and cerium, and

  if any of their mixtures, present in an effective amount for

  activate the bath and the formation of a product film of pas-

  sivation with a chrome aspect having the desired appearance on the

  treaty treated As mentioned for previous aspects

  of the present invention, the solution may contain

  optional halide ion to impart

  additional hardness to the coating and optionally

  An anchor agent may also incorporate a

  soluble in the bath and compatible with the

  bath, present in an effective amount to confer a

  increased corrosion resistance and hardness of the passivation product film, for example in an amount of about

  0.01 to about 5 g / l calculated as SiO 2, as

  25. in relation to the sixth aspect below

  can also incorporate an organic carboxylic acid

  bath-soluble and bath-soluble, present in an amount effective to further impart initial hardness and clarity to the passivation product film, such as

  indicated in relation to the fourth aspect above.

  In this fifth aspect of the present invention,

  tion, while it is applicable in the same way as the first aspect in the case of a decorative electrolytic coating of zinc, another reinforcement of the appearance of

  these substrates, in addition to the corrosion resistance

  is obtained by the film of passivation product which goes from a light glossy appearance to a light blue glossy appearance simulating that of a chromium deposit or, alternatively, a pale yellow clear appearance simulating that obtained

  by the use of hexavalent chromium of the

térieure.

  Another essential constituent of the milking bath

  according to the fifth aspect of the present invention is

  the stabilizing agent comprising a mixture of acid 1-

  hydroxy ethylidene-11-diphosphonic acid and citric acid as well as their soluble salts in the bath-and compatible with the bath The combination of the constituents of acids

  diphosphonic and citric acid appears to provide syner-

  because it not only reduces the decomposition

  the rate of loss of the peroxide type oxidizer, but also that it stabilizes the pH of the working bath by preventing a rapid increase as it had been

  previously the case with step-processing solutions

  trivalent chromium sivation of the type of the prior art

  Typically, the two constituents of stabilizers

  are added in acid form or in the form of

  alkali metal salts or ammonium salts, A material

  commercially available suitable for use in

  is sold under the trade name Dequest

  2010 by the so-called Monsanto Chemical Company and

  1-hydroxyethylidene-1,1-diphosphonate is used.

26.

  The component of diphosphonic acid or di-

  phosphonate may be present in the working bath in

  from about 0.05 to about 3 g / l,

  From about 0.1 to about 0.5 g / l being preferred. The citric acid or citrate component may be present in the working bath in an amount of from about 0.1 to about 10 g / l. , amounts from about 0.5 to about

1.5 g / l being preferred.

  An optional but preferred component of the treatment bath comprises a silicate compound present in an amount effective to provide improved corrosion protection and improved film hardness.

  passivation product formed on the treated substrates.

  The silicates to be used and the amounts by which they must be employed are indicated in more detail below.

  below in relation to the sixth aspect of the

present invention.

  In addition, the bath still contains at least one additional metal ion selected from the group consisting of iron, cobalt, nickel, molybdenum,

  manganese, aluminum, lanthanum, mixtures of lanthan-

  The preceding metal ions or mixtures of the metal ions are suitably introduced into the bath by means of bath-soluble and compatible metal salts in the bath.

  the bath comprising sulphates, nitrates, or ha-

  saline fittings, as indicated for aspects number two to number four, and these materials as they are

  previously mentioned for these aspects can be used

  and are preferably used in these aspects of

the present invention.

  Previous metal ions or their combinations

  With the exception of cerium ions, which are used to produce a clear to light blue passivation product film When a yarn of iridescent yellow passivation product

  clear is desired, cerium ions are used, preferably

  in combination with one or more of the other ions 27.

  metal to produce a film of passiva-

  whose appearance simulates the films of passiva-

  previously obtained by employing hexavalent chromium passivation solutions which have been recognized and implemented in ASTM standards due to their characteristic color and excellent resistance to associated corrosion.

  be introduced in the manner indicated above in relation to

  with aspects number one, three and four.

  The concentration of the additional metal ions

  other than cerium ions for the appropriate activation

  requested from the treatment bath to produce an

  clear to light blue must be controlled in the indi-

  in relation to the fourth aspect of this

vention.

  When the working bath must contain an organic carboxylic acid or its salt as indicated in relation

  with the fourth aspect of the present invention, teaching

  However, it has been found that the presence of a silicate compound in the

  work as indicated below in relation to the

  aspect of the present invention contributed to a

  improved clarity of the passivation product film; in con-

  sequence, the use of the carboxylic acid addition agent

  organic boxyl is not usually necessary

  when a silicate compound is used in the bath.

  The working bath according to this fifth aspect of the present invention can suitably be prepared by employing a concentrate containing the active ingredients of the present invention.

  the exception of the oxidant and cerium ions, if used

  which is adapted to be diluted with water to form a bath containing the constituents in the desired concentration range.

  replenishment of the bath on a continuous or inter-

  may be obtained by using a concentrate of the active constituents with the exception of the oxidant and cerium ions, if used, which is added separately to the working bath.

  bath may contain about 10 to about 80 g / i of chromium ions.

  approximately 5 to about 50 g / i of at least one metal ion

  than the group consisting of iron, cobalt, nickel, molybdenum, manganese, aluminum, lanthanide, mixtures of lanthanides, or mixtures thereof, halide ions in an amount of up to about g / l, about 5 to about 30 g / l of a silicate compound, if used, calculated as SiO 2; and a surfactant in an amount of up to about 5 g / l if used. Such a make-up concentrate is adapted to be diluted with about 98% by volume of water to produce a working bath containing the same. active constituents in the specified ranges Oxidizer such as hydrogen peroxide, by

  example, is introduced separately into the bath preferably

  this in a commercially available form containing

  35 to 40% by volume of hydrogen peroxide. Cerium ions, when used, are preferably introduced in the form of an aqueous acid solution of cerous chloride or of

  ceric sulfate having a concentration of cerium ions of

  These cerium concentrates may be suitably made from the commercially available materials described above, available from Molycorp, Inc.

  Previous trivalent chromium concentrate con-

  metal ions and acidic components in combination with a mineral silicate compound tends to form precipitates during prolonged storage as a result of the high concentrations and acidic conditions present. As a result, these previous concentrates are

  normally diluted with water, shortly after

  parate Qn to provide a working bath containing the active constituents in the desired concentrations concentrates with substantially improved stability and duration

  extended storage can be provided by the user.

  of organic silicates, as shown below in relation to the sixth aspect and in combination with trivalent chromium ions and, optionally, halide ions and a wetting agent. These stable concentrations typically contain about 10 at about 80 g / l of trivalent chromium ions, about 5 to about

  g / i of a quaternary calcium azmonium silicate

  Sio 2, halide ions in an amount of up to about 50 g / l and a surfactant in an amount of up to about 5 g / l. This stable concentrate is suitable for use in connection with a second concentrate containing the acidic components, the ions

  additional metal in an amount of approximately 5 to

  50 g / l, up to 80 g / l of the organic carboxylic acid

  and / or salt as an additive agent if used

  This second concentrate may also optionally contain some or all of the halides and wetting compounds if not used in the process.

  first trivalent chromium concentrate.

  In the preparation of such a chromium concentrate

  trivalent / silicate, the organic silicate is first di-

  read with water to the desired concentration range, after which the trivalent chromium component is added with the optional halide and wetting agent, if

  An organic silicate compound is used.

  especially suitable in the trade includes a product called Quram 220 available to the so-called company

  Emery Industries which comprises a quaternary amine silicate

  nary. Diphosphonic acid and citric acid and / or

  diphosphonate and citrate as an additive to

  bilization can be incorporated into any of

  previous concentrates comprising the concentrate of

  in the amount needed to obtain the concentration

  In the alternative, the stabilizing additive can be prepared in the form of

  a separate aqueous concentrate, containing about 30 to about

  170 g / l of the diphosphonic compound / diphosphonate

  The reaction was carried out with about 160 to about 500 g / l of the citric acid / citrate acid compound and added separately to the working bath to provide the desired working concentration within the limits specified above, and typically 4-5 g / l of

  Stabilization concentrate According to a pre-

  the stabilizing additive is incorporated directly into the chromium-containing concentrate, the cerium ion concentrate in the case of a yellow passivation product process, or in the second concentrate used in connection with the organic silicate concentrate. amount of about 3

  about 17 g / l of diphosphonic acid / diphosphonic compound

  phonate and about 16 to about 50 g / l citric acid /

consists of citrate.

  As indicated above for number aspects

  one to number four, the treatment bath can be applied

  substrate in a number of ways and the process conditions described for these aspects can be

  used and desirably, should be used

  for this fifth aspect of the present invention.

  At the conclusion of the passivation treatment, the substrate is extracted from the treatment solution and dried,

  for example, by circulating warm air Ordinary-

  These passive substrates, particularly

  processed while they are supported on a

  working maul, are characterized by the fact that they

  have a uniform film of passivation product on their sur-

  faces requiring no further treatment In the case of small workpieces that are mass treated, or

  such as in a rotary barrel, a number of

  tain damage, for example, scratches, may occur in the passivation product film during

  treatment and it is therefore desirable to submit these

  these to be machined to a silicate rinse post-treatment (as indicated below as a seventh aspect of the present invention) for sealing all surface defects,

  thus significantly improving the protection against

  erosion of the parts treated in barrel.

  When such an optional silicate rinse treatment after passivation is employed, the substrate 31.

  after the passivation treatment is preferably

  at least one or more rinsing steps with

  water usually at room temperature to remove

  to the residual solution of the passivation product of their surfaces, after which the substrates are brought into contact with the rinsing solution after the treatment with

  silicate according to the teachings given below,

  lation with the seventh aspect of the present invention.

  According to the sixth aspect of the present invention,

  A treatment solution is provided which aims to reduce the severity of a problem of damage to the passivation product of the passivated workpieces during the subsequent treatment. Thus, while improvements have been made to the passivation product compositions. to trivalent chromium and commercially acceptable passivation product film production methods, it has been found that such films as initially formed in some cases initially lacked sufficient hardness to permit the handling of substrates at other times.

  stages of work without the product film of passiva-

  In addition, it has also been found that these chromium passivation product compositions

  trivalent and the processes of their production are translated into

  in some cases for lack of resistance to

  corrosion, durability and optimum longevity and

  In this sixth aspect of the present invention, there is provided a process solution and a process for imparting improved resistance to the film. corrosion on surfaces of zinc, zinc alloy, cadmium and cadmium alloy, as well as on surfaces

  aluminum and magnesium, and to provide a surface finish

  this desirable which can range from a bright glossy appearance to a bright blue-blue appearance to an iridescent appearance

  yellow, which produces a film of passivation product with

  improved corrosion resistance, better hardness and longer life, improved clarity and initial hardness, this process being simple to control and

  to put into operation, the functioning being effi-

and economic.

  The advantages of the sixth aspect of the present invention are achieved according to the compositions by providing an aqueous acid treatment solution containing, as

  essential components, chromium ions, all of which are sen-

  present in the trivalent state, preferably at least one

  concentration of about 0.05 grams per liter (g / l)

  saturation (and which can be introduced as indicated for aspects number two to number five),

  preferably hydrogen ions to provide a pH of

  from about 1.2 to about 2.5 that can be

  introduced by mineral acids such as

  sulfuric acid, nitric acid or hydrochloric acid,

  an oxidant, the hydrogen peroxide itself being preferred, preferably

  present in an amount of about 1 to about 20 g / J, a bath-soluble silicate compound compatible with the bath present in an amount effective to impart

  better resistance to corrosion and a greater degree of

  to the passivation product film (preferably

  in an amount of about 0.01 to about 5 g / l calculated

  in the form of Si O 2), and at least one additional metal ion

  chosen from the group consisting of iron, co-

  balt, nickel, molybdenum, manganese, aluminum, lanthanum, mixtures of lanthanides and cerium, and

  mixtures, present in quantities

  worm the bath and form a passivation product film

  chromium having the desired appearance on the treated substrate Com-

  mentioned to me for the earlier aspects of this

  invention, the solution may optionally contain

  have halide ions to impart additional purity

  to the coating, and optionally an agent

  It may also incorporate a car-

  Boxylic organic soluble in the bath and compatible with the bath in quantity to confer even more 33.

  initial hardness and clarity to the pass product film

  vation. In this sixth aspect of the present invention,

  whereas it is applicable in the same way as the first

  In the case of decorative electrolytic coatings of zinc, another aspect of reinforcing the appearance of these substrates, in addition to the corrosion resistance conferred, is obtained by the film of passivation product which goes from one aspect to another. bright gloss with bright blue appearance

  simulating that of a chromium deposit or as a varian-

  a light yellow appearance simulating that obtained by the use

  tion of hexavalent chromium solutions of the prior art.

  Another essential constituent of the treatment bath

  according to the sixth aspect of the present invention is

  the silicate compound present in an amount

  wear improved corrosion protection and better hardness to the formed passivation product film

  on the treated substrate The silicate compound may comprise

  an organic or mineral silicate compound which is soluble in the bath and compatible with the bath, as well as their

  mixtures, which are preferably present in

0.01 to about 5 g / l calculated as SiO 2, concentrations of about 0.1 to about 0.5 g / l

  being preferred When inorganic silicates are used

  However, concentrations above about 2 g / l in the working bath are undesirable due to the tendency of the silicate to form fine flocculent precipitates with the metal ions present in the bath in the baths.

  acidic conditions, which contributes to the instability

  On the other hand, organic silicates supplied

  improved bath stability and are preferred for

  the formation of replenishment concentrates and

  As a result of improved stability and prolonged storage time, inorganic silicates which can be used in the practice of the present invention include

  alkali metal and ammonium silicates, among

  For economic reasons, sodium silicate (Na 20 x SiO 2 (x = 2-4)) and potassium silicate (K 20 y Si O 2 (y = 3-5) are preferred. Organic silicates which can also be used satisfactorily include quaternary ammonium silicates which contain the

  tetramethylammonium silicate, silicate, disilicate

  cate and phenyltrimethylammonium trisilicate and

  silicate and benzyltrimethylammonium disilicate.

  These silicates satisfying the purpose of the present invention

  may be expressed by the following general formula:

te: ROR ': x Si O 2: YH 20

  o R represents a quaternary radical substituted by four

  groups selected from the groups consist of

  alkyl, alkylene, alkanol, aryl, alkyl,

  R, or mixtures thereof, R 'represents R or a hydrogen atom;

  x is equal to 1 to 3, and y to 0 to 15.

  These organic silicates soluble in water

  taking their synthesis and characterization are more fully described in the literature, as in the article by Merrill and Spencer, "Some Quaternary Ammonium Silicates," published in the Journal of Physical and Colloid

  Chemistry, 55, 187 (1951) Similar silicates com-

  taking their typical syntheses are described in the

  American vet only 3 939.548, to which reference is also made

for other details.

  In addition, the bath still contains at least one

  additional metal ion selected from the group

  iron, cobalt, nickel, molybdenum, manganese

  ganesis, aluminum, lanthanum, mixtures of lanthani-

  cerium and their mixtures.

  previous metallics or mixtures of metal ions are suitably introduced into the bath by means of salts

  soluble in the bath and compatible with this

  including sulphates, nitrates, and halo-

  saline creatures, as indicated for aspects number two 35.

  number five, and these materials, as indi-

  above for these aspects, can and should be used desirably in these aspects of

present invention.

  Previous metal ions or their combinations with the exception of cerium ions are used to produce a clear blue passivation product film.

  when an iridescent passivation product film

  no clear is desired, we use cerium ions, pre-

  in combination with one or more other ions

  in order to produce a film of passive product.

  whose appearance simulates the product films of pas-

  light yellow sivation previously obtained by employing hexavalent chromium passivation solutions which have been recognized and implemented in ASTM standards by

  their characteristic color and their excellent

  resistance to the associated corrosion Cerium ions can

  may be introduced in the manner described above in

  tion with aspects number one, number three, number

four and five.

  The concentration of the additional metal ions

  other than the cerium ions for an ap-

  ownership of the treatment bath to produce an appearance

  bright blue must be controlled in the

  in relation to aspects number four and number

five of the present invention.

  When the working bath must contain an organic carboxylic acid or its salt as indicated in

  aspects number four and number five of the present invention.

  The lessons given here must be followed.

  It has been unexpectedly found that the presence of the silicate compound in the working bath according to this

  sixth aspect of the present invention also contributes to

  improved clarity of the passivation film and in particular

  consequence, the use of the addition agent

  Organic carboxylic acid is not essential when a silicate is present in the bath according to this aspect of the 36.

  present invention, although it may be desirable.

  The working bath according to this sixth aspect of the present invention can suitably be prepared by employing a concentrate containing active components with the exception of the oxidant and cerium ions, if used, which is adapted to be diluted. with water to form a bath containing the constituents in the range of

  desired concentration In a similar way, the

  Bathing on an intermittent or continuous basis can be obtained by using a concentrate of the active constituents, with the exception of oxy (dant and cerium ions, if

  they are used, which are added separately to the working bath.

  Typically, a bath make-up concentrate can

  hold about 10 to about 80 g / l of chromium ions, about 5 to about 30 g / l of the silicate compound calculated as

  of Si O 2, from about 5 to about 50 g / l of at least one metal ion.

  additional steel of the group consisting of iron, cobalt, nickel, molybdenum, manganese, aluminum,

  of lanthanides, mixtures of lanthanides, or their

  ges, halide ions in quantities up to about 50

  g / l and a suitable surfactant product in

  only about 5 g / l if it is used. Such a concentrate of

  point is suitable for dilution with about 98 t in volume

  The oxidant, such as hydrogen peroxide, for example, is separately introduced into the bath, preferably in a commercially available form containing about 10% of water. 35 to 40% by volume of hydrogen peroxide. The cerium ions, when employed, are preferably introduced in the form of an acidic aqueous solution of cerous chloride or ceric sulfate having a cerium ion concentration of about 200 to about 320 g / l and about 60 to about 100 g / l, respectively, These cerium concentrates may be the commercially available materials previously described available from Molycorp, Inc. 37.

  The previous concentrate of trivalent chromium con-

  the silicate compound, the metal ions and the

  acidic components tends to form precipitates

  As a result, these previous concentrates are normally diluted with water shortly after preparation to provide

  a working bath containing the active constituents

  In addition, it has been discovered according to this sixth aspect of the present invention that concentrates with substantially improved stability and shelf life.

  prolonged storage can be obtained through the use of

  organic silicates of the types previously

  combined with trivalent chromium ions and, optionally, halide ions and an

  These stable concentrates contain

  Preferably, about 10 to about 80 g / l of trivalent chromium ions, about 5 to about 50 g / l of organic quaternary ammonium silicate calculated as SiO 2, halide ions up to about 50 g / 1 and a surfactant product

  in an amount of up to about 5 g / l This concentrated concentrate

  ble is suitable for hearth used in connection with a second

  concentrate containing the acidic components, the metal ions

  in an amount of about 5 to about 100 g / l, up to 80 g / l of the organic carboxylic acid

  and / or its salt as an additive agent, if used

  This second concentrate may also optionally contain some or all of the halogenides and wetting agents if they are not used in the process.

  first trivalent chromium concentrate.

  In the preparation of such a trivalent chromium / silicate concentrate 7 the organic silicate is first diluted with water to the desired concentration range, after which the trivalent chromium component is added with the halide and silicate. Optional wetting agent, if used A commercially available, particularly suitable organic silicate compound includes product 38.

  says Quram 220 available to the so-called Emery Indus-

  tries which comprises a quaternary amine silicate.

  This sixth aspect of the present invention

  additionally takes a new concentrate composition con-

  Suitable for the addition of the working bath by dilution with water containing as essential constituents ions

  trivalent chromium and a quaternary ammonium silicate

  which provides compatibility and stability

  storage for extended periods of time.

  As indicated above for aspects number one to number five, the treatment bath can be applied to the substrate in different ways and the conditions of

  The treatment described for these aspects can and, therefore,

  desirable, should be used for this sixth

pect of the present invention.

  At the end of the passivation treatment, the

  trat is extracted from the treatment solution and dried, for example by circulating hot air.

  these passivated substrates, particularly pieces of

  treated while supported on a

  work matry are characterized by the fact that they

  have a uniform film of passivation product on the

  faces, not requiring further treatment In the case of

  small workpieces that are processed in bulk or in mas-

  for example in a rotary drum, some damage, such as scratches, may occur in the passivation product film during

  treatment, and it is desirable in such cases to submit

  these parts to a rinse treatment after treatment.

  silicate (as indicated below in the seventh aspect of the present invention) to seal all these surface defects, thereby substantially improving the

  protection against corrosion of treated parts

  neau. When such a silicate rinse treatment is used, optional after passivation, the substrate after the passivation treatment is preferably subjected to.

  at least one or more steps of rinsing with water,

  at room temperature, to remove the

  residual solution of surface passivation product,

  after which the substrates are brought into contact with the solu-

  rinse after the silicate treatment according to

  lessons given below in relation to the seventh

  aspect of the present invention.

  According to the seventh aspect of the present invention,

  tion, a method of treatment is provided which deals with the

  same problem as the sixth aspect of the present invention.

  tion, namely that of damage to passive parts

  during the further processing So while

  improvements were made to the compositions and procedures

  dice to obtain tri-chromium passivation products

  are suitable for producing commercially acceptable passivation product films, it has been found in some cases that these films, as initially formed, lack sufficient initial hardness to allow the handling of the substrate in other stages of work without that there is damage to the films of passivation product In

  Moreover, it has also been found that these compositions and

  assigned to obtain tri-chromium passivation products

  In some cases, corrosion resistance, optimum hardness and longevity were lacking and produced films which are sometimes veiled and do not exhibit

  optimum clarity in terms of appearance.

  Thus, this seventh aspect of the present invention

  tion is intended to provide a method which is effective in conferring

  improve the resistance to corrosion on surfaces

  of zinc, zinc alloy, cadmium and cadmium alloy.

  mium, as well as aluminum and magnesium surfaces, and to impart a desirable surface finish that can range from a bright glossy finish to a bright blue glossy appearance to a yellow iridescent appearance, which produces a film

  passivation product with improved resistance to corrosion

  better hardness, greater longevity,

  improved clarity and initial hardness, this process being

  40. to be controlled and put into operation, and the

  functioning being efficient and economical.

  The advantages of the seventh aspect of this

  invention are achieved by a method which provides a

  acidic aqueous treatment, containing as essential constituent, chromium ions, all substantially

  present in the trivalent state, preferably at a concentration

  from about 0.05 gram per liter (g / l) to saturation (and which can be introduced as indicated

  1 for aspects number two to number six), hydro-

  gene preferably to provide a p H in solution of approximately

  1.2 to about 2.5, which can be conveniently introduced

  derived from mineral acids such as sulfuric acid, nitric acid or hydrochloric acid, an oxidant, the hydrogen peroxide itself being preferred, preferably present in an amount of about 1 to about 20 g / l at least one additional metal ion selected from the group consisting of iron, cobalt, nickel, molybdenum,

  manganese, aluminum, lanthanum, mixtures of lanthani-

  and cerium, and mixtures thereof, by contacting the substrate with the aqueous acid solution for a period of time sufficient to form a passivation product film thereon, and contacting for a period of time

  a period of at least about 1 second the passive substrate

  with a dilute aqueous rinsing solution containing and compatible with a bath-soluble silicate compound present in an amount to impart improved corrosion resistance and improved

  passivation product film hardness, and drying in

  then the passivated substrate in which the silicate has been rinsed.

  The aqueous acid solution can be such that

  in relation to any of the above aspects.

  teeth number one to number six, and it can be used

of the nxm way.

  After the passivation treatment, the substrate is preferably subjected to one or more steps of

  rinsing with water that may be at room temperature

  41. or at elevated temperatures, after which the licked substrate is contacted with a dilute aqueous solution

  of silicate in the form of a final rinsing step.

  The contact time of the passivated substrate with the silicate solution can range from a period of at least about

  one second until about a minute or more, and the

  silicate may have a temperature ranging from

  10 C at about 66 ° C, after the rinsing step at

  the substrate is dried, for example by

blow hot air.

  The aqueous silicate rinse solution

  preferably, as a

  organic or mineral silicate soluble in the bath and compatible therewith, and mixtures thereof,

  present in an amount of about 1 to about 40 g / l, preferably

  From about 5 to about 15 g / l (calculated as SiO 2). Suitable inorganic silicates for practicing the present process include silicates.

  alkali metals and ammonium, some of which are

  for economic reasons, sodium silicate (Na 20 x SiO 2 (where x is 2 to 4 ") and the silicate of

  potassium (K 20 y Si Q 2 (where y is 3 to 5))

  organic substances that can also be used

  satisfactorily include ammonium silicates

  quaternary which contains the tetramethylammonium silicate

  nium, silicate, disilicate and trisilicate

  These silicates suitable for use in the present invention have the following general formula: ROR ': x SiO 2; y H 20 oe R represents a quaternary ammonium radical substituted by four organic groups selected from the group consisting of alkyl, alkylene, alkanol, aryl, alkaryl or mixtures thereof, and R 'represents either R or

  a hydrogen atom, and x is 1 to 3 and y to 0 to 15.

  These organic silicates soluble in water, 42.

  their synthesis and characterization are more

  described in the literature, for example in the article

  by Merrill and Spencer, "Some Quaternary Ammonium Silica

  cates "published in the Journal of Physical and Colloid Che-

  mistry, 55, 187 (1951) Similar silicates and an identical synthesis are described in US Pat.

  No. 3,993,548 to which reference is made for further details.

  As a result of the relatively higher cost price of these organic silicates, the silicate rinse solution preferably comprises inorganic silicates, among which sodium and potassium silicates,

  as described above, are particularly preferred.

  In addition to the silicate compound, the silicate rinse solution may optionally include a bath-soluble and compatible wetting agent to enhance surface contact.

  passivated, present in a conventional amount of about 0.05

  approximately 5.0 g / l Silicate rinse can also be

  optionally include an organic substance

  an emulsifiable oil such as an emulsifiable oil, for example present in an amount of from about 1 to about

  g / l to provide an oily film on the int surfaces 6-

  are not subject to the electrolytic coating of

  ferrous metals to provide temporary protection against

  the formation of rust during other processing stages.

  When these parts have surfaces that are completely passivated, such as, for example,

  zinc die castings, the optional use of

  Emulsifiable oil is not necessary.

  In a similar way, there are applications ot

  an oil is not desired but a temporary protection

  rust against uncoated interior surfaces

  is still required In these cases 1 l, a final rinse containing

  An amount of from about 0.1 to about 1.0 g / l may be used, for example, a wetting agent or a combination of ammonium nitrite or alkali metal nitrite such as sodium nitrite. wetting agents is 250415 and 43. preferably used in connection with sodium nitrite,

  for example in amounts of about 0.05 to about 5.0 g / l.

  The presence of silicates in the final rinse is also

compatible with this treatment.

  The present invention may be practiced in a variety of ways and a number of specific embodiments will be described to illustrate the present invention.

  present invention with reference to the accompanying examples.

  Examples 1 1 and 1 2 relate to the first aspect of the present invention which provides a chromium passivation product by use of a bath

free of chromium ions.

  Examples 1-28 relate to the second aspect of the present invention which uses iron and cobalt as a metal enhancer and also incorporates

  trivalent chromium to produce passiva-

bluish blue.

  Examples 3 1 to 3 5 relate to the third

  aspect of the present invention which utilizes cerium

  me metal activator and again incorporates trivalent chromium but this time gives a passivation product

  similar to the hexaval chromium passivation product

  slow. Examples 4 1 to 4 3 relate to the fourth

  aspect of the present invention which utilizes a carboxylic acid

  xylic in baths of the same general types as those

  present in the examples of the second and third

  pects The carboxylic acid reinforces the initial hardening

passivation product.

  Examples 5.1 to 5.8 relate to the fifth

  aspect of the present invention which utilizes a silicate silicate

  luble in the bath of passivation product as well as trivalent chromium in baths of the same general types

* that those presented in the examples of the second and fourth

  third aspect The silicate strengthens the initial hardness of the

  passivation product and corrosion resistance.

  Examples 6 to 6 relate to the sixth aspect of the present invention which uses a mixture

2504156,

  44. citric acid and a particular phosphonic acid to inhibit the loss of oxidant and increase the pH during use of the baths of the types described in the second

and fifth aspects.

  Examples 1-7 relate to the seventh aspect of the present invention which is a post-pass passivation silicate rinse

  hardening of the passivation product.

EXAMPLE 1 1

  A chromium-free passivation concentrate was prepared containing 12 g / l ammonium bifluoride, 12 g / l ferrous ammonium sulfate, 80 g / l sulfate

  of cobalt, and 4.5% by volume of concentrated sulfuric acid.

  A working bath with water was prepared

  2% by volume of the pre-passivation concentrate was added.

  yield in excess of 1.5% by volume of hydrogen peroxide (

  38%) The working bath had a nominal

1.5 to about 2.0.

  Experimental panels with an 8t electrolitic bright zinc coating that had

  rinsed with water after the electrocoating step.

  tick and which were rinsed in a solution of nitric acid

  5% by volume were immersed in the working bath for a period of 20 seconds in the presence of moderate agitation. The experimental panels were then rinsed with water and air dried. The experimental panels, after drying, were visually inspected and characterized as having a blue passivation film on the surface.

  The work had a nominal pH of about 1.5 to about 2.0.

EXAMPLE 1,2

  To produce a light yellow iridescent passivation product film on electrolytically coated zinc panels, cerium ions were introduced into a 2% experimental working bath.

  volume of chromium-free passivation concentrate de-

  written in example 1 1, 2% by volume of a concentrate of

2504156 1

45.

  cerium sulphate comprising a 6% sulphate solution

  of cerium (Ce (504) 2) in a solution of sulfuric acid

  As diluted and 1.5% by volume of a hydrogen peroxide concentrate (38%) the normal pH of the working bath was about 1.5 to about 2.0.

  Experimental panels of zinc after coating

  water rinsing and immersion in nitric acid were immersed in the experimental solution in the presence

  moderate stirring for a period of 45 seconds.

  The treated experimental panels were rinsed with water and air-dried. A visual inspection of the surface of the

  experimental panel was releasing a film of passive product

  light yellow iridescence substantially uniform.

EXAMPLE 2 1

  A working bath was prepared containing the following products: Ingredient Concentration, g / l Cr 2 (504) 3 2.2

NH 4 HF 2: 0.18

H 2504 1.2

H 22 5.3

  Fe NH 4 SO 4 R 0.25 Co SO 47 H 20 1.6 x Ferrous ammonium sulphate = Fe (504) (NH 4) 2504 6 H 20

  Experimental steel panels have been

  proceeded to a cyanide-free alkaline electrolytic coating step to deposit a zinc coating, whereupon they were completely rinsed with water and immersed with agitation

  in the working bath indicated above during a

  By the end of the treatment, the passive panels were rinsed with hot water and air-dried. An inspection of the coating of the panels after drying revealed an exceptionally light blue color.

  clear without any veiled aspects,

  was the appearance of an electrolytic coating of nickel-

  brilliant chrome and also had excellent

  stain resistance by light friction with the finger.

2504156 i 46.

EXAMPLE 2

  A working bath containing; Ingredient Concentration, g / l Cr 2 (504) 3 5.6

NH 4 HF 2 0.4

H 2504 2.7

H 202 5.3

  Fe NH 4 SO 4 0.58 Co SO 4 7 H 20 3.75

  The working bath of Example 2 2 is similar

  than that of Example 2 1 with one exception, this is

  that the components trivalent chromium, ammonium bifluoride

  Most of the zinc-coated experimental panels treated with the bath of Example 2 produced results substantially equivalent to those obtained with zinc, sulfuric acid, iron and cobalt.

  obtained with the working bath of Example 2 1.

EXAMPLE 2

  A working bath containing: Ingredient Concentration, g / l Cr 2 (504) 3 3.0 was prepared

NH 4 HF 2 0.24

H 2 SO 4 1.54

H 202 5.3

  Fe NH 4 SO 4 0.25 Ni NH 4 SO 4 m 2.1 x Ammonium and nickel sulphate = Ni SO 4 (NH 4) 2504 6 H After drying, it was observed that the experimental panels coated with zinc treated with this working bath under the same conditions as those described in

  Example 2 1 had a coating that was very shiny.

  lant with a light bluish colorati and no appearance

  The coating also had a good

  stain resistance during light friction with the

finger.

EXAMPLE 2

  A working bath identical to this was prepared

2504156 J

  47. presented in Example 2 3 with one exception,

  it is that 1.6 g / l of nickel sulphate was used in

  2.1 g / l ammonium sulphate and nickel

  Zinc coated experimental waters treated in the manner previously described in Example 2 using the treatment solution of Example 2 4 produced results substantially comparable to those obtained with the treatment bath of Example 23 except that the coating

  had a slightly less bluish coloring.

EXAMPLES 2 5 A A 2 5 E

  A series of solutions for passiva-

  to process experimental steel panels coated with

  The compositions of solutions 5A, 5B, 5C, and 5D are given in Table I below, in order to evaluate their relative corrosion resistance with respect to a 5% neutral salt spray after passivation. below:

TABLE IA

Concentration, g / l

  Solution 25 A contains only chromium ions

  trivalent me; solution B further contains ferrous ions, solution C contains a combination of ions

  iron and cobalt whereas the solution 25 D contains a

combination of iron and nickel ions.

  In addition to the above working solutions, a traditional hexavalent chromium passivation solution (Example 25E) was prepared as a control containing 0.63 g / l sodium dichromate, 0.63 g / l bifluoride d ammonium, 0.01 g / l of sulfuric acid and 0.65 g / l of nitric acid This solution is referred to as

2.5 A 2 5 B X 2 5 C 2 5 D

3,0 3,0 3,0 3,0

0.24 0.24 0.24 0.24

1.54 1.54 1.54 1.54

, 3 5,3 5,3 5,3

0.25 0.25 0.25

_ 1,6 -

2.1

2504156 J

  48. Solution name 2 5 E. Duplicate series of 7.6 cm by 10.2 cm steel panels were cleaned and zinc plated.

  using a zinc coating electrolyte without cyanide

  After a period of 15 minutes at a coating current density of 2.0 amperes per square decimeter, they were thoroughly rinsed. Each series of zinc-coated experimental panels was then immersed in the respective treatment solution for a period of one hour. 20 seconds, after which they were rinsed with hot water,

  dried in the air and allowed to age for 24 hours.

  Before experimental salt spray testing in accordance with ASTM standards The experimental panels were sprayed with 5% neutral salt for a total of

  43 hours For other purposes of comparison, a series

  duplicate trial of zinc panels without any passivation treatment was also tested

  Neutral salt spray The results are presented

in Table IB.

TABLE IB

  RESULTS OF THE NEUTRAL SALT SPRAY TEST

  Example I Expected panel Percentage of Percentage of Corrosion Red Rust, _____ _____ _ __ _____ ____ white, __ 2 5 F Untreated 50 50%

2.5 A 5 A 45 55 O

2.5 B 5 B 10 15 O

  2.5 C 5 C less than 2 O 2.5 D 5 D less than 10 O l 2 5 E 5 E 45 55 O

  Based on the experimental results

  In this case, it appears that the untreated experimental panel coated with zinc represents a major failure; the experimental panel treated with the 25 A solution is a failure; the

  experimental panels treated with the 2.5 B solution

  feel a marginal passage; the experimental panels treat

  with the solutions 25 C and 25 D pass the test; and the 2504156 l 49.

  experimental panel treated with the solution 2 5 E repre-

you a failure.

EXAMPLE 26

  A working bath containing the following products was prepared: Ingredient Concentration, g / l Cr 2 (504) 3 3.0

NH 4 HF 2 0.24

H 2504 1.54

Fe NH 4 SO 4 0.24

H 202 5.3

  Mn SO 4 H 20 1.0 O Electrolytically coated zinc panels prepared according to the procedure set forth in Example 25 were immersed in the bath

  of Example 2 for a period of 30 seconds, rinse

  hot water, air-dried, and left

  age for 24 hours before experimenting with

  5% neutral salt test verification For the purpose of

  parison, experimental zinc panels were processed

  with solutions 2 5 A to 25 E of Example 25 and

  set to naoe salt spray evaluation.

  After a salt spray lasting 48 hours,

  An inspection of the various experimental panels revealed that the panels treated with

  Example 26 had superior corrosion resistance.

  than the panels treated with 5 A and 5 E solutions.

EXAMPLE 2

  A working bath containing the following products was prepared; Ingredient Concentration, g / l Cr 2 (SO 4) 3 3.0 NH 4 HF 2 Qf 24

H 2504 1.54

Fe NH 4504 0.24

H 202 5.3

  H 2 Mo O 4H 20 1.0 2504156 50. Experimental electrolytically coated zinc panels prepared according to Example 25 were

  immersed in the bath of Example 27 for a period

  of 30 seconds, rinsed with hot water, air-dried, and allowed to age for 24 hours before the 5% neutral salt spray experiment. For comparison purposes, the experimental panels zinc

  were treated with solutions 25 A and 25 E of the example

  25 and subject to the same spray assessment of

O 10 salt.

  After 48 hours of salt spray testing, a panel inspection revealed that the panels

  treated with the solution of Example 2 7 had a

  corrosion resistance superior to that of the outer panels

  periments treated with solutions 25 A and 25 E.

EXAMPLE 2

  A working bath containing the following ingredients was prepared: Ingredient Concentration, g / l Cr 2 (504) 3 3.0

NH 4 HF 2 0.24

H 2 SO 4 1.54

Fe NH 4 SO 4 0.24

H 202 5.3

  (NH 4) 4 (Ni Mo O 24 H 6) 4 4 H 201.0 Experimental panels of zinc coated with

  electrolytic route prepared according to the procedure described in

  in Example 2 were immersed in the bath of Example 28 for a period of 30 seconds, rinsed

  in hot water, air-dried, and left them old.

  read for 24 hours before a salt spray test

  5% neutral For comparison purposes,

  periments of zinc have been treated with the solutions

  2.5 A and 2.5 E of Example 25 and subjected to the same evaluation.

salt spray.

  After a 48 hour salt spray,

  inspection of the panels revealed that the panels

51.

  with the solution of Example 28 had a resistance

  this is superior in corrosion compared to panels treated with solutions 25 A and 25 E.

  A relative comparison of experimental panels

  The levels prepared according to Examples 26, 27 and 28 revealed that the solution of Example 26 contained iron ions and molybdic acid and that the solution of Example 28

  contained iron ions in combination with 6-molybdonick-

  The ammonium salt exhibited a higher corrosion resistance than the experimental panels treated with the working solution of Example 26 containing iron ions in combination with manganese ions.

  Experiments treated according to Examples 27 and 28 can

  also seduced with superior corrosion resistance

  to that of experimental panels treated with

  Experiment 2 5 B of Example 2 containing only

  While the experimental panels treated with the solution of Example 26 containing both iron and manganese ions had a somewhat comparable corrosion resistance to the panels treated with the B solution.

EXAMPLE 3 1

  A 3 L concentrate was prepared, including a

  aqueous acid solution containing 25 g / l of tri-chromium ions

  are introduced in the form of chromium sulphate (product called Korean MF from the company called Allied Chemical Company), 12 g / l of ammonium chloride, 12 g / l of ferrous sulphate

  and ammonium and 4% by volume of concentrated sulfuric acid

tré.

  A second aqueous acid concentrate 3, 1 B has been prepared.

  prepared with 60 g / l of tetravalent cerium ions introduced

  in the form of Ce (504) 2 4 H 20 and 5% by volume of sulfuric acid.

concentrate.

  A working bath was prepared comprising water containing 2% by volume of concentrate 3 1 A, 2% by volume of concentrate 3 1 B and 1.5% by volume of a solution at 38% hydrogen peroxide Experimental panels of zinc 52. electrolytically coated, immersed in this bath of

  work for 40 to 60 seconds, had professional films

  iridescent yellow iridescent passivation on their surfaces.

EXAMPLE 3 2

  A concentrate similar to Concentrate 1A of Example 1 containing 25 g / l of trivalent chromium ions, 20 g / l of sodium chloride, 40 g / l of sulfate was prepared.

  ferric acid and 4% by volume of concentrated sulfuric acid.

  A working bath comprising water containing 2% by volume of concentrate 32A, 2% by weight was prepared.

  volume of concentrate 3 1 B of Example 3 1 and 1.5-3% by volume.

  lume of a solution with 38% hydrogen peroxide

  experimental zinc electrolytically coated, im-

  merged into the working bath, gave results

similar to Example 3 1.

EXAMPLE 3

  A concentrate 3 3 A similar to

  centered 3 1 A of Example 3 1, except that nitric acid

  at 6% by volume was used in place of sulfuric acid

than 4%.

  A working bath consisting of

  water containing 2% by volume of concentrate 3 3 A, 2% by volume

  concentrate 3 1 B of Example 3 1 and 1.5-3% by volume

  of a solution containing 38% hydrogen peroxide.

  Electrolytically coated Zinc Plants, immersed in the working bath, gave similar results

in example 3 1.

EXAMPLE 3

  A concentrate 34 A similar to the concentrate was prepared.

  3 2 A in Example 3 2, except that

  nitric to 6% by volume in place of sulfuric acid

at 4% by volume. A working bath containing water containing 2% by volume was prepared

  of concentrate 3 4 A, 2% by volume of concentrate 3 IB of Example 3 1 and 1.5 3% by volume

  of a solution containing 38% hydrogen peroxide Experimental panels

  Electrolytically coated zinc diapers immersed in the working bath gave similar results.

Example 3 1.

EXAMPLES 3 5 TO 3 5G

  A series of seven aqueous solutions was prepared

  its experimental ones each containing i g / l of trivalent chromium ions, i g / l of nitric acid, i g / l of sulfuric acid

  that 7 g / l of hydrogen peroxide, these solutions having a p H nomi-

  about 1.5 to each experimental solution we have

  made controlled additions of metal ions to

  the effect of this addition on the color, hardness and salt spray resistance of

  passivation product produced on experimental panels.

  electrolytically coated zinc levels, immersed in each experimental working bath in the presence

  moderate agitation for a period of about 30 seconds.

  and at a temperature of about 210 C. The cerium ions were introduced in the form

  of a solution of Ce Ci 3 containing approximately 300 g / l of

  rium; the manganese ions were introduced in the form of Mn SO 4 H 20; ferric ions were introduced under

  form of Fe 2 (SO 4) 3 dissolved in a sulfuric acid solution

  diluted; the molybdenum ions were introduced in the form of a dry salt consisting of sodium molybdate, the lanthanum ions were introduced in the form of a solution of La C 13 containing about 85 g / l of lanthanum ions; and the

  cobalt ions were introduced as co-sulphate

  balt Experimental solutions are referred to as

  examples of examples 3 A to 35 G and the additive concentrations of

Metal ions are summarized in Table II.

54.

TABLE II

  CONCENTRATION OF METALLIC IONS g / l Example

  3 5 A 3 5 B 3.5 C 3 5 D 3 5 E 3 5 F 3 5 G

Ion

metal-

  Cr + 3 1 1 1 1 1 I 1 Ce + 3 2 2 2 2 2 2 2 Mn + 2 0.9 Fe + 3 0.22 0.08 0.08 Mo + 6 1, O La + 3 1.0 Co + 2 - 0.13 Each experimental panel after immersion in the experimental working bath was rinsed with water and

  dried in the air, and was visually inspected to

  undermine the color and clarity, all the experimental panels

  The rates treated in solutions 35 A & 35 G had a

  their light yellow, which is generally uniform and whose clarity

  laughed with a clear yellow film until films that were slightly veils or veiled as shown in Table III Each experimental panel after drying & air was immediately experimented to determine the

  hardness of the passivation product film by a slight rub

  The experimental results compared with

  the hardnesses of the passivation product film on the

  experimental panels treated in experimental solutions.

  3 5 A to 35 G are presented in Table III.

  after 24-hour aging of the experimental panels, the passivation product film became hard and resistant to friction, The advantage of a film of

  passivation product that is hard immediately after

  air drying is that it can be handled during a

  subsequent action without damage to the film

  Each experimental panel treated with solutions

  Experimental work 3 5 A to 3 5 G was also

  put in a neutral salt spray for a period 55.

  72 hours and the specific surface, expressed as

  centage, where a white corrosion deposit has been formed, is

  also shown in Table III.

TABLE III

EXPERIMENTAL RESULTS

  Example Clarity | Hardness Neutral Salt Spray

72 hours -

  Corrosion percentage __blanche Based on the results presented in Table II, based on an assessment of clarity and

  hardness, example 3 5 G is an example that passes without

  Examples 3 C and 35 F are acceptable,

  while Examples 35 A, 35 B and 35 E are less

  Ceptables based on general appearance From the point of view of corrosion resistance, Examples D, 3.5 F and 35 G pass without hesitation, Example C represents a marginal passage, while Examples 35A, 35B, and 3.5E are considered unacceptable based on ASTM corrosion standards for an evaluation of the neutral salt spray for 72 hours.

  it should be emphasized that each of the experimental samples

  rate has improved corrosion resistance by

  compared to an experimental panel of untreated zinc

  electrolytically coated and passivation product films that failed the 72-hour neutral salt spray test are nonetheless acceptable.

  for less severe exposures during their

  The corrosion resistance provided by the example

  3.5 G is substantially comparable to that which can be obtained

  3.5 A Soft sail Soft 50 3.5 B Light sail Soft 100 3.5 C Light sail Hard 10 3.5 D Hard sail O 3.5 E Light sail Soft 100 3.5 F Clear Soft 2 3.5 G Clear Hard O 56. nier with solutions of passivation product at hexavalent chromium of the prior art, of the type previously known, it will also be appreciated that

  variations in types, combinations and concentra-

  metal ions contained in the experimental solutions can be realized to optimize and

  improve clarity, hardness and resistance to

  erosion of the experimental panels compared to the result

  tat, as shown in Table III The choice of a 72-hour neutral salt spray is relatively

  severe and is generally used for the parties

  put to an outside exposure, for example for auto components The salt spray test

  72 hours is normally applied to

  yellow hexavalent chromium passivation, although some standards require only 48 hours while others require 96 hours exposure The 72 hour experimental period was therefore chosen

  as being of average severity.

EXAMPLES 4 1 TO 4G

  A series of concentrates containing trivalent chromium suitable for dilution with

  water to form a combined working bath for

  with an oxidant and cerium or lanthanum ions as follows CONCENTRATE 4 l A Ingredient Concentration, g / l Cr + 3 24 Co SO 47 H 20 25 Ferrous and ammonium sulphate 12 Sodium fluoroborate 15 Succinic acid 25 Nitric acid (100% ) 60

CONCENTRATE 4 1 B

  Ingredient Concentration, g / l Cr + 3 24 NaCl Ferrous and ammonium sulphate 57. Sodium succinate Nitric acid (100%)

CONCENTRATE 4 1 C

  Ingredient Concentration, g / l Cr + 3 24 Ferrous and ammonium sulphate 50 Sodium succinate 55 NaCl 20 Nitric acid (100%) 60

CONCENTRATE 4 1 D

  Ingredient Concentration, g / l Cr + 3 24 Ferrous and ammonium sulphate 50 Succinic acid 25 NaCl 20 Nitric acid (100%) 60

CONCENTRATE 4 1 E

  Ingredient Concentration, g / l Cr + 3 24 Ferric and ammonium sulphate 50 NaCl 20 Malonic acid 25 Nitric acid (100%) 60

CONCENTRATE 4 1 F

  Ingredient Concentration, g / l Cr + 3 24 Fe 2 (504) 3 Na C 1 20 Gluconic acid 20 Nitric acid (100%) 60

CONCENTRATED 4.1 G

  Ingredient Concentration, g / l Cr + 3 24 Ferric and ammonium sulphate 50 Na Cl Maleic acid 25 Nitric acid (100%) 60 58.

EXAMPLES 4 2 A A 4 2 G

  A cerium ion concentrate containing

  about 80 g / l of ceric ions in the form of

  in a dilute solution of sulfuric acid.

  Oxidant center was also supplied containing about% hydrogen peroxide. A series of working baths were prepared to form a yellow film of

  passivation on a substrate, each containing 2% by volume

  Concentration of cerium ion concentrate, 2% by volume of the oxidant concentrate and 2% by volume of one of the chromium concentrates 4.l A to 4 l G of the examples 4; LA to 4 l G. Experimental panels steel were submitted

  at an alkaline electrolytic coating step without cyanide

  re to deposit a zinc coating, after which they were completely rinsed with water and immersed with agitation in each of the experimental baths working for a period of about 30 seconds, maintained at a temperature

  about 21 l C and having a p H ranging from about 1.5 to about

  2.0 At the end of the passivation treatment, the panels

  Passives were rinsed with hot water and air dried.

  An inspection of the coating of each of the experimental panels

  that had been immersed in each of the experimental working solutions revealed the formation of a film

  light yellow passivation product.

EXAMPLES 4 3 A A 4 3 G

  A lanthanum ion concentrate containing about 60 g / l of lanthanum ions was provided in the form of a lanthanum chloride solution.

  oxidant containing approximately 35% hydrogen peroxide.

  adorned a series of working baths for forming a film of blue passivation product glossy on a substrate,

  each containing 2% by volume of the lanthan

  2% by volume of the oxidant concentrate, and 2% by volume of one of the chromium concentrates 4 1 A to 4.1 G of Example 4 1, experimental panels coated with zinc as

  described in Example 4.2, were immersed in the conditions

  The examples described in Example 4 2 were rinsed with hot water and air-dried.

  coating each of the experimental panels after

  chage revealed a film of passivation

  bluish, hard, clear, exceptionally bright.

  The yellow passivated panels of Examples 42A, 42B and 42C produced using the working baths containing, respectively, the concentrates 41A, 41B and 4.1C described above were aged for at least 24 hours and tested for neutral salt spray corrosion according to the ASTM procedure

  B-117 The following Table IV shows the results of the

  know of the corrosion resistance that has been obtained using these formulations:

TABLE IV

  The results above show that

  treated with working baths containing the

  centered A, B and C passed the 96-hour salt spray test Similar results were obtained

  with panels produced using the other concentra-

very.

EXAMPLE 5.1

  A working bath suitable for depositing a

  yellow film of passivation product on a substrate recep-

  The catalyst was supplied by forming a trivalent chromium-containing concentrate designated "5.1 A concentrate" having the following composition: Example Neutral Salt Spray Concentrate chrome 72 hours 96 hours 4.2 A 4 1 A Clear with Clear with

some ta certain

  dark colors darker 4.2 B 4 1 B Clear with Clear with

some ta certain

  Dark darkness 4.2 C 4 1 C Clear with Certain dark spots-1% ______________ _____________ Dark dark spots bl 60. CONCENTRATED 5 l A Ingredient Concentration, g / l Cr + 3 50 Ferric and ammonium sulphate 30 Chloride sodium 20 Nitric acid (100%) 60 Succinic acid 20 Trivalent chromium ions were introduced under

Cr 2 form (504) 3.

  A concentrate of cerium ions designated as "concentrate 5.l B" was provided containing about 80 g / l of ceric ions in the form of ceric sulfate in a dilute solution (about 5%) of sulfuric acid. planned a

  oxidant concentrate containing about 35% hydrogen peroxide.

  A sodium silicate concentrate containing 300 g / l of sodium silicate calculated as

of Si O 2 -

  A working bath of product of pas-

  yellow sivation comprising water containing 2% by volume of concentrate 1A, 2% by volume of cerium ion concentrate

  5.1 B, 2% by volume of the oxidant concentrate and 0.4% by volume

  me of the sodium silicate concentrate.

  Experimental steel panels were submitted

  at an alkaline electrolytic coating stage, without cyanide

  nite to deposit a zinc coating, after which they were completely rinsed with water and immersed with agitation

  in the working bath to deposit the product of passiva-

  during a period of about 30 seconds at a

  about 211 C, and at a p H ranging from about 1.5 to

  Viron 2.0 The experimental panels were then ex-

  of the working bath and dried with recirculated hot air, the experimental panels after drying were inspected visually and found to have

  very light yellow passivation product film

  experimental waters after aging for at least 24 hours

  res were subjected to a spray corrosion test

  of neutral salt according to the procedure ASTM B-117

  61. The experimental waters thus treated according to the present process had excellent resistance to spraying.

  salt after exposure lasting more than 96 hours.

EXAMPLE 5

  A working bath for depositing a yellow film of passivation product on a receiving substrate was provided forming a trivalent chromium-containing concentrate designated "2A concentrate" having the following composition:

CONCENTRATE 5 2 A

  Ingredient Concentration, g / l Cry 50 Ferric and ammonium sulphate 40 Sodium chloride 20 Nitric acid (100%> 60 Sodium silicate (calculated as SiO 2) A working bath was prepared to deposit a product yellow passivation composition comprising water containing 2% by volume of concentrate 2 A, 2% by volume of the cerium ion concentrate 5 1 B of Example 1 and 2% by volume of

  oxidant concentrate of Example 5 1.

  Experimental panels prepared according to the procedure described in Example 1 were immersed in the working bath for a period of about 30 seconds.

  at a temperature of about 21 VC and a p H ranging from

  1.5 to about 2.0 The treated experimental panels were dried with recirculation of hot air and

  observed that the dried panels had a film of

  very light yellow passivation

  After aging were subjected to a neutral salt spray corrosion test as described in Example 5.1 and it was observed that they had a

  excellent resistance to salt spraying after

  more than 96 hours.

EXAMPLE 5

  A working bath allowing to deposit a film of

2504156.

  62. yellow passivation product on a receptor substrate was provided by forming a concentrate containing chromium

  trivalent designated "concentrate 3A" having the composition

following

CONCENTRATED 5 3 A

  Ingredient Concentration, g / l Cr 3 50 Ferric ammonium sulphate 40 Nitric acid (100%) 60 Sodium chloride A working bath was prepared comprising water containing 2% by volume of concentrate 3 A, 2% by volume of the 5 1 B concentrate containing cerium ions of Example 1, 2% by volume of the oxidation concentrate of

  Example 1, and 0.5% by volume of the silica concentrate.

The amount of sodium of Example 5

  Experimental zinc panels coated with

  electrolytic route were treated in the bath of

  according to the procedure described in Example 1 and, after drying, it was observed that they had a good film of

light yellow passivation product.

  Experimental panels also have good resistance to salt spray,

  evidence of excellent protection against corrosion.

EXAMPLE 5

  A working bath for depositing a film of yellow passivation product on a receiving substrate has been provided by forming a concentrate containing chromium

  trivalent incorporating a quaternary amine silicate de-

  signed by "concentrated 5.4 A" having the following composition:

CONCENTRATE 5 4 A

  Ingredient Concentration, g / l Cr 3 Quaternary amine silicate X 15 Sodium chloride 15

  m Product called Quram 220, calculated as Si O 2.

  Concentrate 54 A containing trivalent chromium 63 was subjected to prolonged storage and observed

  that he possessed excellent stability during

prolonged storage.

  In addition, a second concentrate was prepared

  bound by "concentrated 5 4 B" having the following composition

CONCENTRATE 5 4 B

  Ingredient Concentration, g / l Nitric acid (100%) 60 Sulfuric acid (100%) 30 1 Ferric sulphate 25 Cerium chloride 120 A working bath was prepared comprising water containing 2% by volume of concentrate 5 A, 2% by volume concentrate 5 4 B, and 2% by volume concentrate

  oxidant as described in Example 1.

  Experimental zinc coating panels were contacted with the working bath according to the procedure and under the conditions described in Example 1, after which the experimental panels were dried with recirculation of hot air. at

  observed that the experimental panels had an excellent

  slow film of passivation product light yellow and hard and had excellent resistance to salt spray with zero formation of white corrosion

  after exposure to a neutral salt spray test

be of 96 hours duration.

EXAMPLE 5

  A second series of experimental panels was

  electrolytically coated zinc bath with the working bath previously described in Example 4 under the same conditions, whereupon the experimental panels were rinsed with water and then post-strained for a period of time.

  period of 30 seconds in an aqueous solution at

  ambient temperature containing 10 g / l of sodium silicate

  calculated as Si O 2 panels after the post-

  rinsing were extracted and dried with hot air.

  The experimental panels were inspected and found to have a very light yellow passivation product film after aging.

  the experimental panels were subjected to a cor-

  neutral salt spraying and had excellent resistance to salt spray after

  position of 96 to 140 hours.

  also note that when a silicate post-rinse treatment is used, the presence of certain nitrate ions

  in the working bath for the deposition of passive product

  is desirable to avoid the formation of a certain

  in some cases, in the product film of

  passivation as a result of the post-immersion operation.

EXAMPLE 5

  A working bath allowing to deposit a film

  brilliant blue passivation product on a substrate

  The receptor was provided forming a concentrate designated "6 A Concentrate" having the following composition:

CONCENTRATE 5 6 A

  Ingredient Concentration, g / i Nitric acid (100%) Sulfuric acid 1 <0%) Succinic acid La-TR-C 13 80 A working bath for the deposition of passivation product was prepared comprising water containing 3% by volume of concentrate 4A of Example 4, 4.3% by volume of concentrate 6A and 3% by volume of oxidant concentrate of Example 5, Experimental panels of zinc coated with

  electrolytic route have been treated with the bath of

  according to the procedure previously described in

  Example 1, and it has been observed that experimental panels

  after drying had an excellent film

  bright blue passivation duvet The experimental panels

  rate also had excellent corrosion resistance, revealed by the absence of white corrosion after being subjected to a spray corrosion test

  of neutral salt with a duration of 48 to 72 hours.

65.

EXAMPLES 5 7 1 AND 5 7 2

  A trivalent chromium-containing concentrate was prepared, referred to as "5 7 A concentrate" having the following composition

CONCENTRATE 5 7 A

  ingredient Concentration, g / i Cr 3 Sodium chloride Sodium silicate (calculated as SiO 2) A working bath (Example 5 7 1) for depositing a film of yellow passivation product on a

  receptor substrate was prepared using 2% in volu-

  Concentration 5 7 A, 2% by volume of the concentrate 5 4 B of Example 5 4 and 2% by volume of the oxidant concentrate of Example 5 1 On the other hand, unbain of work (example

  5.7 2) for depositing a film of passiva-

  Brilliant blue was obtained using 2% by volume of 5 7 A concentrate, 2% by volume of 6 6 A concentrate of Example 6 and 2% by volume of the oxidant concentrate.

Example 5

  Experimental panels treated according to the mode

  procedure described in Example 5 1 showed excellent

  slow passivation product films and excellent

protection against corrosion.

EXAMPLE 5

  A working bath for depositing a bright blue passivation product film on a receiving substrate was provided forming a trivalent chromium-containing concentrate designated as "8A Concentrate" having the following composition:

CONCENTRATE 5.8 A

  Ingredient Concentration, g / l Cr + 3 Sodium Chloride 13 Sodium Gluconate 10 Quaternary Amine Silicate x 15

  x Product called Quram 220, calculated as Sio 2.

  66. A second concentrate designated as "Concentrate 58 A" having the following composition was provided:

CONCENTRATE 5 8 B

  Ingredient Concentration, g / 1 Nitric acid (100%) 60 Sulfuric acid (100%) 30

A 12 (SO 4) 3 30

  A working bath comprising water containing 3% by volume of concentrate 8A, 3% by volume of concentrate 8B and 3% by volume of concentrate was prepared.

of oxidant of Example 5 1 -

  Experimental zinc panels coated with

  electrolytic route were treated according to the

  As described in Example 1 and after drying it was observed that they had a clear bright passivation product film. Experimentation of these panels in

  Neutral salt spray corrosion showed a

  corrosion resistance for at least 12 to 24 hours.

EXAMPLE 6 1

A working bath for depositing a yellow passivation product film on a receiving substrate has been provided by forming a trivalent chromium concentrate designated "6 1 A concentrate" having the following composition:

CONCENTRATE 6 1 A

  Ingredient Concentration, g / l Cr Quaternary ammonium silicate NaCl The trivalent chromium ions were introduced as Cr 2 (504) 3 while the silicate compound was introduced as the so-called Quram 220 product. Emery Industries, A concentrate of cerium ions designated "concentrate 6.l B" was supplied having the following composition: 67. CONCENTRATE 6 l B Ingredient Concentration, g / l

HNO 3 (100%) 60

H 2504 (100%) 30

  Fe 2 (504) 3 Ce + 3 120 The cerium ions were introduced by means of a solution of cerium chloride containing approximately +3

300 g / l of Ce + 3 ions.

  In addition, an oxidant concentrate is provided

  containing about 35% hydrogen peroxide.

  A series of 1 liter working baths comprising 3% by volume of 6 1 A concentrate, 3% by volume of 6 L concentrate and 3% by volume of oxidant concentrate was prepared to simulate an aged working bath used.

  for the passivation of zinc parts, it was dissolved in each

  that experimental solution 1 g / l of zinc dust.

  One of these experimental solutions without

  addition was called experimental solution 6 1 1 and served as a control sample. In a second experimental solution designated 6 1 2, it was added

  of stabilization 1 g / l of citric acid and 0.4 g / l of 1-

  hydroxyethylidene-1,1-diphosphonate (product Fequest 2010) In a third experimental solution designated 6 1 3, 1 g / l of citric acid and 0.08 g / l of 1-hydroxyethylidene-1 was added. diphosphonate

Dequest 2010).

  Each experimental solution was stirred at room temperature to simulate the typical industrial practice.

  at the end and the measured peroxide concentration into

  cent in volume of a 35% hydrogen peroxide concentrate

  The results were as follows: 68. CONCENTRATION OF OXYGENIC WATER AND p H Experimental sample Example 6 1 1 6 1 2 6 1 3 Time H 202 p HH 202 p HH 202 p H First 2.56% 1.6 2.95% 1.6 3.05% 1.4 After

3.5 hours

res 2.39% 2.92% 2.84% -

  After 21 hours 0.83% 1.72% 2.37 1.7 After 26 hours 0.50% 2.5 1.42% 1.8 Based on the results presented in the previous table, it appears that the control sample 6 1 1 devoid of any stabilizing agent rapidly lost the peroxide oxidizing agent which must be present at a concentration of at least 2% by volume to maintain

  a suitable passivation treatment A replenish-

  almost complete reduction of the oxidant in the 6 1 1 sample would be necessary after a period of about one day. In contrast, the 6 1 3 sample showed only a slight loss of peroxide after 21 hours while the sample 6 1 2 containing a smaller quantity of the product called Dequest 2010 in combination with 1 g / l of citric acid was also superior

  surprising stability of the peroxide compared to the

checkpoint 6 1 1.

  The stabilization of p H is also evident in the results presented in the previous table. The p H of the control sample 6 1 1 was up to

  value of 2.5 after 26 hours, which would have required

  acid addition to the working bath to keep it within the preferred working range of 1.5 to 2.0 On the other hand, both samples 6.1 2 and 6.1 3 were substantially stable.

  and remained in the optimum range during the

test.

EXAMPLE 6 2

  An aqueous stabilizer concentrate 69 was prepared.

  containing 570 g / l of citric acid and 110 g / l of 1-hydrol

  xylidene-1,1-diphosphonate (product called Dequest 2010).

  These working solutions were prepared as described in Example 6 1 containing 3% by volume of 6 1 A concentrate, 3% by volume of 6 1 B concentrate, 3% by volume of the oxidant concentrate and 1 g / l zinc dust to age the baths A control sample designated 6.2 1 without any stabilizer had a

  initial peroxide concentration of 3% but after

  a period of B hours under the conditions of the

  he had a residual concentration of peroxide

  only equal to 1.05% requiring replenishment

  A second experimental solution designated 6.2 was stabilized by the addition of 2.5 milliliters / liter of the stabilization concentrate and had an initial peroxide concentration of 3% and after a period of 18 hours a residual peroxide concentration. of

2.43%.

EXAMPLE 6 3

  To evaluate the effectiveness of peroxide and

  the stabilization officer of p H in this aspect of the pre-

  In a real industrial operation, the stabilization concentrate defined in Example 6 2 was

  used to stabilize a product solution of pas-

  trivalent chromium salt with a similar composition

  ble in the working bath of Example 6 1 containing ions

  trivalent chromium, iron and cerium ions so as to obtain

  a pH between about 1.5 and about 2.0 at a temperature of about 21 C and containing hydrogen peroxide

  as an oxidant under normal operating conditions

  In the absence of the stabilizing agent, the commercial working bath required a peroxide oxidizer replenishment with the addition of 3% by volume of a 35% oxygenated water concentrate each morning.

  at the beginning of the operation, as well as the addition of

  1% by volume of the oxidizing concentrate consisting of peroxygen

  after about 4 hours of operation to maintain

  the bath to a minimum of 2% in oxidant volutme.

70.

  By adding 1 liter of stabi- concentrate

  reading 378 liters of working bath, the restocking

  The reduction of the peroxide oxidizing concentrate was reduced to only 1% by volume of replenishment each day of operation and only a 2% volume replenishment after resting during the weekend to bring the bath back to suitable operating conditions.

  In addition, the addition of the stabilizer concentrate

  operation bath still stabilized the working pH during the experimental period of 6 days when the pH remained substantially constant, avoiding the need

  addition of acid to control the p H By contrast

  the same commercial bath without any concentration

  stabilization required frequent p H control and periodic addition of acid to maintain p H

  in the desired range of 1.5 to 2.0.

  Electrolytically coated parts of

  polished zinc treated by using the working bath

  After aging for a period of at least 24 hours were subjected to a neutral salt spray corrosion test according to ASTM B-117. The excellent corrosion resistance of the yellow passivation product film was observed. been highlighted by the absence of white corrosion on the pieces after a

salt spray 96 hours.

EXAMPLE 6 4

  The stabilization of an industrial working bath having a composition and employing the procedure described in Example 6.3 was obtained by preparing a

  aqueous stabilizer concentrate containing about 30 to

  170 g / l of 1-hydroxyethylidene-1,1-diphosphonate

  (Dequest 2010 product) blended with about 160 to about

  500 g / l of citric acid Concentrate of stabilisa-

  has been added to the industrial working bath to

  To provide an operating concentration of 1-hydroxyethylidene-1,1-diphosphonate in an amount of about 0.05 to about 3 g / l 71.

  and an operating concentration of the acid component

  from about 0.1 to about 10 g / i. The results obtained

  nudes are similar to those described in Example 6 3.

EXAMPLE 6

  A working bath for depositing a film of yellow passivation product on a receiving substrate

  has been supplied by forming a concentrate designated by

  6 5 A "having the following composition

CONCENTRATE 6 5 A

Ingredient Concentration, g / l

HN 03 (100%) 60

  H 2 So 4 (100%) Fe 2 (504) 3 25 Fe C 13 5 Diphosphonate x 8.5 Citric acid 36 Ce + 3 120 X Dequest 2010 A working bath comprising 3% by volume of the chromium ion concentrate was prepared 6 IA of Example 6 1, 3% by volume of concentrate 6 5 A and 3% by volume of concentrate

  oxidant containing about 35% hydrogen peroxide.

  Experimental steel panels have been

  put in a cyanide alkaline electrolytic coating step to deposit a zinc coating, after which they

  were completely rinsed with water and immersed with

  in the working bath to deposit the product of

  during a period of about 30 seconds at a temperature of about 211 ° C. and at a pH of about 1.5 to about 2.0. The experimental panels were then extracted from the working bath and dried. with discount

circulating hot air.

  The experimental panels were, after drying

  The small addition of ferric chloride to the working bath provides an improvement in the color intensity of the 72. yellow passivation product film in comparison with that obtained by using the working bath for

  deposit of the passivation product of Example 6 1.

  The experimental panels after aging were subjected to a neutral salt spray test according to the procedure described in Example 6, and

  similar results were obtained.

EXAMPLE 7 1

  A working bath suitable for depositing a

  film of yellow passivation product on a substrate

  The receiver was made as follows: a concentrate containing trivalent chromium designated as "concentrate 7A" having the following composition was first made as follows

CONCENTRATE 7 1 A

  Ingredient Concentration, g / l Cr 25 Ferric and ammonium sulphate Sodium chloride 20 Nitric acid (100%) 60 succinic acid 20

  A cerium ion concentrate 7 1 B con-

  about 80 g / l of ceric ion in the form of sulfa

  ceric in a dilute solution (about 5%) sulfuric acid An oxidant concentrate was also provided

  containing about 35% hydrogen peroxide.

  A bath of work to deposit a product of pas-

  yellow sivation was prepared containing water containing

  2% by volume of concentrate 7 l A, 2% by volume of concentrate

  7 1 B cerium ions and 2% by volume of the oxy-

  C. A water-based rinse solution was provided.

  of silicate containing 10 g / J of sodium silicate, calcu-

in the form of Si O 2.

  Experimental steel panels have been

  put in a cyanide alkaline electrolytic coating step to deposit a zinc coating, after which they

  were completely rinsed with water and immersed with

  73. in the working bath to deposit the passivation product for a period of about 30 seconds at a temperature of about 21 ° C and a pH of about

  1.5 to about 2.0 The experimental panels were ex-

  features of the working bath, rinsed with water

  tap and were then placed in contact with the solution.

  The silicate rinsing panels were then extracted from the rinsing solution and dried with recirculation of hot air. The experimental panels after drying were inspected visually and found to have a very light yellow passivation product film. The experimental panels after aging for at least 24 hours were subjected to a salt spray corrosion test. Neutral according to ASTM B117 Procedure Experimental panels treated according to the present

  process had excellent resistance to spraying.

  salt after exposure lasting more than 96 hours.

EXAMPLES 7 2 1 TO 7 2 14

  A series of concentrates containing trivalent chromium were prepared which allowed dilution with water to provide a working bath subsequently combined with an oxidant and cerium or lanthanum ions as follows

CONCENTRATE 7 2 A

  Ingredient C Concentration, g / l Cr 24 Co So 4 7 H 20 25 Ferric ammonium sulphate 12 Sodium fluoroborate Succinic acid 25 Nitric acid (100%) 60 74.

CONCENTRATE 7 2 B

  Ingredient Cr + 3 Na Cl Ferric Sulfate and Ammonium Sodium Succinate Nitric Acid (100%) Concentration, g / l

CONCENTRATE 7 2 C

  Ingredient Cr + 3 Ferric and ammonium sulphate Sodium succinate NaCl Nitric acid (100%) Concentration, g / l

CONCENTRATE 7 2 D

  Ingredient Cr + 3 Ferric and ammonium sulphate Succinic acid NaCl Nitric acid (100%) Concentration, g / l

CONCENTRATE 7 2 E

  Ingredient Cr 3 + Ferric and ammonium sulphate NaCl Malonic acid Nitric acid (100%) 3 Q Ingredient Cr + 3 Fe 2 (504) 3 NaCl Gluconic acid Nitric acid (100%) Concentration, g / 1

CONCENTRATES 7.2 F

Concentration, g / l 75.

CONCENTRATE 7 2 G

  Ingredient Concentration, g / l Cr 3 24 Ferric and ammonium sulphate 50 NaCl 20 Maleic acid 25 Nitric acid (100%) 60 A cerium ion concentrate containing

  about 80 g / l of ceric ions in the form of

  In a solution of dilute sulfuric acid, there is also provided an oxidant concentrate containing about% hydrogen peroxide. A series of working baths (Examples 7-2 1 to 7-27) were prepared to form a film of hydrogen peroxide. yellow passivation product on a substrate, each containing 2% by volume of the cerium ion concentrate, 2% by volume of the oxidant concentrate, and 2% by volume of one of the

  chromium concentrates 7 2 A to 7 2 G, respectively.

  A concentrated lanthanum ion concentrate was

  approximately 60 g / l of lanthanum ions in the form of a lanthanum chloride solution.

  oxidant concentrate containing about 35% hydrogen peroxide.

  A series of working baths were prepared (examples 7 2 8

  7 to 14) for forming a product film of pas-

  brilliant blue sivation on a substrate, each containing 2% by volume of the lanthanum ion concentrate, 2% by volume of the oxidant concentrate and 2% by volume of one of the concentrates

  of chromium 7 2a to 7 2G, respectively.

  Experimental steel panels coated with

  zinc as described in Example 7 1 have been treated

  in each of the working baths (Examples 7-2 1 to 7.2 14) under the conditions set forth in Example 7 1,

  after which the passivated panels were subjected to

  silicate post-rinse using a

  silicate rinse solution o the concentration of

  silicate ranged from about 1 to about 40 g / i 1,

  in the form of Si O 2, at temperatures ranging from 10 ° C. to 660 ° C. The panels were subsequently air-dried 76. and subjected to a salt spray corrosion test.

  as described in Example 7 L

  those indicated in Example 7 1 were obtained.

EXAMPLES 7 3 1 TO 7 3 6

  A series of working baths have been prepared

  follows me: M Sulfate M Sulfate Ingredient Cr 2 (504) 3

NH 4 HF 2

4 2

H 25 04

  H 202 Fe NH 3 O 4 R Co SO 4 7 H 20 Ferrous and Ingredient Cr 2 (504) 3

NH 4 HF 2

H 2504

H 25 O 4

H 202 Fe NH 45 O 4 Co SO 4 7 H 20

WORKING BATH 7 3 A

  Concentration, g / l 2,2 0,18 1,2, 3 0,25 1,6 ammonium = Fe (SO 4) (NH 4) 2504 6 H 20

WORKING BATH 7 3 B

  Concentration, g / 1, 6 0.4 2.7, 3 0.58 3.75

WORKING BATH 7 3 C

  Ingredient Concentration, g / l Cr 2 (504) 3 3.0

NH 4 HF 2 0.24

H 2504 1.54

H 202 5.3

  Fe NH 4 SO 4 0.25 Ni NH 4 SO 4 2.1 Nickel and ammonium = Ni SO 4 (NH 4) 2504 6 H 20

WORKING BATH 7.3 D

  Ingredient Concentration, g / l Cr 2 (504) 3 3.0

NH 4 HF 2 0.24

H 2504 1.54

77. Fe NH 4 SO 4 0.24

H 202 5.3

Mn SO 4 H 20 1.0

WORKING BATH 7 3 E

  Ingredient Concentration, g / l Cr 2 (504) 3 3.0

NH 4 HF 2 0.24

H 2 SO 4 1.54

Fe NH 4 SO 4 0.24

H 202 5.3

H 2 Mo O 4 H 20 1, where

WORKING BATH 7 3 F

  Ingredient Concentration, g / 1 Cr 2 (504) 3 3.0

NH 4 HF 2 0.24

H 2 SO 4 1.54

Fe NH 4 SO 4 0.24

H 202 5.3

  (NH 4) 4 (NiO 024H 6) 4 4H 20 1.0

  Experimental panels coated with zinc prepa-

  as described in Example 1 have been processed

  in the above working baths (Examples 1-3-3-6) under the conditions previously described in Example 7, after which they were rinsed with water and subjected to a post-rinse treatment by aqueous solution of silicate in a rinse solution where the

  silicate concentration calculated as Si O 2

  laughed between about 1 and about 40 g / 1 at temperatures

  ranging from about 10 QC to about 66 C, passive panels

  After the drying and post-rinsing were subjected to the salt spray tests described in Example 7, and similar results were obtained.

  The present invention is not limited to the examples

  embodiments that have just been described, it is on the contrary susceptible of modifications and variants

  which will appear to those skilled in the art.

78.

Claims (96)

  1 Aqueous acid solution useful in the treatment   receptor metal substrates to impart   passivation product film on these substrates,   in that it comprises: A) hydrogen ions to provide an acidic acid, B) an oxidant, and C) at least one of iron, cobalt, nickel, molybdenum, manganese, aluminum, lanthanum, lanthanide mixture or cerium or mixtures thereof in an amount to impart greater corrosion resistance to treated substrate.   2 Aqueous acid solution for treating substances   receptor metal traps for imparting a passivation product film on said substrates, characterized in that it comprises; A) an acid, B) an oxidant, and   C) iron and cobalt ions present in a   putting more resistance to corro- ston to the treated substrate.   3. An aqueous solution according to claim 1 or claim 2, characterized in that it also comprises: D) chromium ions, being substantially all in the trivalent state.   4 Aqueous acid solution for treating substances   receptor metal traps for imparting a chromate passivation product film to said substrates, characterized in that it comprises; A) an acid, B) an oxidant,   C) iron ions in combination with at least one metal ion   additional tick chosen in the group consisting of   cobalt, nickel, molybdenum, manganese,   thane, a mixture of lanthanides and their pre-   in an amount to impart greater corrosion resistance to the treated substrate; and 250415 to   79. D) chromium ions, all of which are in the trivalent state. An aqueous acid solution for treating metal receptor substrates to impart a chromate passivation product film on these substrates, characterized in that it comprises A) an acid, B) an oxidant,   (C) cerium ions present in an amount   both to provide greater corrosion resistance to the treated substrate and D) chromium ions, all substantially in the trivalent state.   6 Aqueous acid solution for treating substances   Receptor metal traps for imparting a chromate passivation product film to such substrates, characterized in that it comprises: A) hydrogen ions to provide an acidic pH, B) an oxidant, C) at least one metal ion supplemented from the group consisting of iron, cobalt, nickel,   molybdenum, manganese, lanthanum, lanthan-   nides and cerium and their mixtures, present next   a quantity which makes it possible to confer greater resistance   corrosion rate to the treated substrate, D) chromium ions substantially all in the trivalent state and E) a soluble organic carboxylic acid in the bath and   compatible with this one in a   by imparting initial hardness and clarity to the passivation product film, said organic acid having the structural formula: (OH) a, (COOH) o a is an integer of 0 to 6; b is an integer of 1 to 3; and R represents an alkyl, alkyl or aryl group containing 1 to 6 carbon atoms; 80. and their soluble salts in the bath and compatible with this one.   An aqueous acid solution for treating metal receptor substrates to impart a chromate passivation product film on these substrates, characterized in that it comprises: A) hydrogen ions to provide an acidic acid, B) an oxidant, C) at least one additional metal ion selected from the group consisting of iron, cobalt, nickel,   molybdenum, manganese, aluminum, lanthanum,   of lanthanides and cerium and their mixtures   in an amount to provide greater corrosion resistance to the treated substrate, D) chromium ions, all substantially   trivalent and being present in an amount   both to produce a chromate film, and   F.) a silicate compound soluble in the bath and compatible with   with an amount to provide greater hardness to the product film of   passivation, and improved protection against corro- substrate.   An aqueous acid solution for treating metal receptor substrates to impart a chromate passivation product film on these substrates, characterized in that it comprises: A) hydrogen ions to provide an acidic H, B) an oxidant, C) at least one additional metal ion selected from the group consisting of iron, cobalt, nickel,   molybdenum, manganese, aluminum, lanthanum,   delanthanides, and cerium and their mixtures,   in an amount to provide greater corrosion resistance to the treated substrate, D) chromium ions, all substantially   trivalent and being present in an amount   both to produce a chromate film, and Ä 504156 81.   G) a stabilizing agent comprising a mixture of acid 1-   hydroxyethylidene-1,1-diphosphonic acid and citric acid and their bath-soluble and bath-compatible salts in an amount to reduce oxidant loss and inhibit an increase in p H of the solution.   9 Solution according to any of the claims   cations 1-8, characterized in that ingredient A is supplied by an acid.   Solution according to claim 9, characterized   in that the acid is a mineral acid.   The solution of claim 10, wherein   characterized in that the mineral acid comprises sulfuric acid   than, nitric or hydrochloric or their mixtures.   12 Solution according to any of the   Claims 1 to 11, characterized in that it has a p H from about 1.2 to about 2.5.   13 Solution according to any one of the   1 to 12, characterized in that it has a pH of about 1.5 to about 2.2   14 Solution according to any one of the   1 to 13, characterized in that it has a p H of 1.5 to about 2.0.   Solution according to any one of the   1 to 14, characterized in that it has a p H from about 1.6 to about 1.8.   16 Solution according to any one of the   1 to 15, characterized in that the oxidant, the   B, is present in an amount of about   1 to 20 g / l calculated according to an equivalent efficiency basis.   by weight relative to the oxygenated water.   Solution according to claim 16, characterized   in that the oxygen is present in an amount of about 3 to about 7 g / l calculated according to an efficiency basis   equivalent in weight relative to hydrogen peroxide.   18 Solution according to any one of the   1 to 17, characterized in that the oxidizing agent take a peroxide.   The solution of claim 18, wherein   characterized in that the oxidant comprises oxygenated water.   Solution according to any one of the   1 to 19, characterized in that at least one additional metal ion in the aqueous acidic solution is present in an amount of up to about   g / l, for example in the range of about 0.5 to about 10 g / l.   21 Solution according to any one of the   15 to 20, characterized in that ingredient C is present in an amount of up to about 1 g / 1.   Solution according to claim 21, characterized   in that ingredient C is present in accordance with   amount of about 0.02 to about 1 g / l.   The solution of claim 22, wherein   in that ingredient C is present in accordance with   amount of about 0.1 to about 0.2 g / l.   24 Solution according to any one of the   1 to 23, characterized in that it contains in   at least one additional metal ion selected from the group consisting of iron, cobalt, nickel,   molybdenum, manganese, lanthanum, lanthan- as well as their mixtures.   Solution according to any of the claims   cations 1 to 24, characterized in that it contains in   be aluminum as an additional metal ion.   Solution according to claim 25, characterized   in at least one additional metal ion includes iron.   27 Solution according to any one of the   24 to 26, characterized in that at least one additional metal ion comprises cobalt,   28 A solution according to any of the claims   24 to 27, characterized in that at least one metal ion is   Additional metallics include nickel.   29 Solution according to any one of the   82. Claims 24 to 28, characterized in that at least one ion   Additional metal includes molybdenum.   Solution according to any of the claims   24 to 29, characterized in that at least one metal ion is   Additional metallics include manganese.   31 Solution according to any of the claims   24 to 30, characterized in that at least one metal ion is   Additional metallics include lanthanum.   32 Solution according to any of the claims   24 to 31, characterized in that at least one metal ion is   Additional metallics comprise a mixture of lanthanides.   33 Solution according to any one of the claims   24 to 32, characterized in that at least one metal ion   The extra layer includes aluminum.   34 Solution according to any of the claims   cations 1 to 33, characterized in that the tri-chromium ions   are worth, the ingredient D are present in a quantity   ranging from about 0.05 g / l to saturation.   Solution according to claim 34, characterized   in that the trivalent chromium ions are present   from about 0.2 to about 2 g / l.   36 Solution according to claim 35, characterized   in that the trivalent chromium ions are present   from about 0.5 to about 1 g / l.   37 Solution according to any one of the claims   1 to 36, characterized in that it further comprises halide ions.   38. Solution according to claim 37, characterized   in that the halide ions are present according to   up to about 8 g / l.   39 Solution according to claim 38, characterized   in that the halide ions are present in an amount of from about 0.1 to about 2.5 g / l,   Solution according to claim 37, characterized   in that the halide ions are present according to   up to about 2 g / l.   41 Solution according to claim 40, characterized   in that the halide ions are present according to 84.   an amount of about 0.1 to 0.5 g / i.   42 Solution according to any one of the   1 to 41, characterized in that it contains in in addition to a surfactant product.   The solution of claim 42, wherein   in that the surfactant product is present   up to about 1 g / l.   44 Solution according to claim 43, characterized   in that the surfactant product is present   from about 50 to about 100 mg / l.   Solution according to any one of the   1 to 44, characterized in that it contains   in addition, sulfate ions in an amount up to only about 15 g / l.   46 A solution according to claim 45, characterized   in that it contains sulphate ions following a   amount of about 0.5 to about 5 g / l.   47 Solution according to claim 4 or according to   any of claims 9 to 46, when   are connected to claim 4, characterized in that the iron ions are present in an amount of about 0.05 to about 0.5 g / l.   48 Solution according to claim 47, characterized   in that the iron ions are present in a   amount of about 0.1 to about 0.2 g / i.   49 Solution according to claim 2 or according to   any one of claims 9 to 48 when   are connected to claim 2, characterized in that the iron ions and the cobalt ions are present according to   an amount of from about 0.02 to about 1 g / l.   Solution according to claim 49, characterized   in that the iron ions and the cobalt ions are pre-   in an amount of from about 0.1 to about 0.2 g / l.   51 Solution according to any one of the   2 to 4 or claims 6 to 50 when   are related to claims 2 to 4, characterized in that 85.   it also contains the cerium ions present   from about 0.5 to about 10 g / 1.   52 Solution according to claim 51, characterized   A solution according to claim 5 or claim 1, which contains cerium ions in an amount of about 1.0 to about 4 g / l.   any of claims 9 to 52 when they are   related to claim 5, characterized in that the cerium ions are present in an amount of about 0.5 to about 10 g / l.   54 Solution according to claim 53, characterized   in that the cerium ions are present in a   amount of about 1.0 to about 4 g / l.   Solution according to any one of the   Claims 1 to 52, characterized in that it contains cerium ions in an amount of about 0.5 to about g / l.   Solution according to claim 55, characterized   in that the aqueous acid solution contains ions   cerium in an amount of from about 1 to about 4 g / l.   57 Solution according to claim 6 or one of   any of claims 9 to 56, when   linked to claim 6, characterized in that the carboxylic acid, ingredient E, are present according to   an amount of from about 0.05 to about 4 g / l.   Solution according to claim 57, characterized   in that the carboxylic acid is present according to   from about 0.1 to about 1 g / l.   Solution according to claim 6 or according to   any one of claims 9 to 58 when   are connected to claim 6, characterized in that   the organic carboxylic acid comprises malonic acids   that, maleic, succinic, gluconic, tartaric or citric   that, or their mixtures and their salts.   60 Solution according to Claim 57 or 58, characterized in that the carboxylic acid and its salts include succinic acid.   The solution of claim 57 or   86. claim 58, characterized in that the carboxylic acid   and its salts include malonic acid.   Solution according to claim 57 or   claim 58, characterized in that the carboxylic acid   that and salts thereof include maleic acid. Solution according to Claim 57 or Claim 58, characterized in that the carboxylic acid   and its salts include gluconic acid.   Solution according to claim 57 or   claim 58, characterized in that the carboxylic acid   that and its salts include tartaric acid.   Solution according to claim 57 or   58, characterized in that the carboxylic acid   and its salts include citric acid.   Solution according to claim 7 or according to   any of claims 9 to 65 when they are   related to claim 7, characterized in that the composition   silicate is present in an amount of about   0.1 to about 5 g / l, calculated as SiO 2.   67 Solution according to claim 66, characteristic 6-   in that the silicate compound is present in   from about 0.1 to about 0.5 g / l, calculated as SiO 2 to 68 solution according to claim 7 or   any one of claims 9 to 67, when   are connected to claim 7, characterized in that the silicate compound comprises a mineral silicate compound soluble in the bath and compatible therewith   in an amount up to about 2 g / l.   Solution according to claim 68, characterized   in that the silicate compound comprises an ammonium or alkali silicate compound present in an amount of up to about 2 g / l. The solution of claim 7 or   any of claims 9 to 67, characterized in that   that the silicate compound comprises a silicone compound   quaternary ammonium carbonate present in an amount of 87, from about 0.01 to about 5 g / l calculated as Sio 2.   71 Solution according to claim 70, characterized in that the silicate compound comprises a compound   of quaternary ammonium silicate present in a   amount of about 0.1 to about 0.5 g / i calculated under of Si O 2.   Solution according to claim 70 or   71, characterized in that the silicone compound   Cate has the following structural formula ROR ': x Si O 2: YH 2 O wherein: R represents a quaternary ammonium radical substituted with four organic radicals selected from the group consisting of alkyl, alkylene, alkanol, aryl, or alkylaryl, or mixtures thereof; R 'represents R or a hydrogen atom; x is an integer of 1 to 3, and y is an integer of 0 to 15.   An aqueous acid solution according to any one of   Claims 1 to 71, characterized in that it   additionally holds a compatible organic carboxylic acid   with the bath and soluble with it, or a salt compatible with ble of this acid.   An aqueous solution according to claim 72,   characterized in that the organic carboxylic acid   The bath-soluble and soluble solution is present in an amount to impart initial hardness and clarity to the passivation product film of the organic acid having the structural formula; (OH) a R (COOH) b o a is an integer of 0 to 6; b is an integer of 1 to 3; and R represents an alkyl, alkenyl or aryl group containing 1 to 6 carbon atoms, and its bath-soluble and compatible salts. with this one. 88.   The solution of claim 73, wherein   in that the carboxylic acid is present in   from about 0.05 to about 4 g / l.   Solution according to claim 74,   characterized in that the carboxylic acid is present next   from about 0.1 to about 1 g / l.   76 Solution according to any one of the   73 to 75, characterized in that the carboxylic acid   organic comprises malonic, maleic, succinic, gluconic, tartaric or citric acids or their mixtures and their salts.   77 Solution according to claim 8 or according to   any of claims 9 to 76, when   are connected to claim 8, characterized in that   1-hydroxyethylidene-1,1-diphosphonic acid, the   G, is present in an amount of about 0.05 at about 3 g / l.   78 Solution according to claim 77, characterized   characterized in that 1-hydroxy ethylidene-1,1 diphos-   phonic is present in an amount of about 0.1 to about 0.5 g / l.   79 Solution according to claim 8, or according to   any of claims 9 to 78, when   are connected to claim 8, characterized in that the citric acid is present in an amount of about 0.1 to about 10 g / l.   Solution according to claim 79,   in that the citric acid is present in a   amount from about 0.5 to about 1.5 g / l.   81 Aqueous concentrate, characterized in that   suitable for dilution with water, and in that it is   by adding A) hydrogen ions to provide an acidic pH, B) an oxidant, and C) at least one metal ion selected from the group consisting of iron, cobalt, nickel, molybdenum, of   manganese, aluminum, lanthanum, mixture of lanthani-   and cerium, and their mixtures, to produce an 89,   working bath for treating a metallic substrate   receiver in order to confer a passive product film.   chromate, this concentrate comprising about 10 to   approximately 80 g / l of chromium ions, substantially all of which are   in the trivalent state, and about 5 to about 50 g / l, calculated as Si O 2, of an ammonium silicate organic quaternary.   82 Concentrate according to claim 81, characterized   in that it comprises, in addition, up to about 50 g / l of halide ions.   83 Concentrate according to claim 81 or claim 82, characterized in that it further comprises   a surfactant product in an amount up to than about 5 g / l.   84 A method of treating a metal substrate   receiver to give a passive product film.   chromate, characterized in that it   to contact the substrate with a solution as indicated in claim 4 or in one of   any of claims 9 to 80 when they are   related to claim 4, at a temperature of about   C at about 66 ° C for a sufficient period of time.   te to form on a passivation product film.   Receiving substrate, characterized in that it is provided with a passivation product by a process according to claim 84.   86 Process for treating a metal substrate   receiver to give a film of this product of passiva-   characterized in that it consists in bringing the substrate into contact with a solution as indicated in FIG.   claim 2 or in any of the claims   9 to 80 when appended to claim 2 at a temperature of about 4 ° C to about 661 ° C for a period of time sufficient to form a film of passivation product.   87 - Receptor substrate, characterized in that   is provided with a passivation product by a se- according to claim 86. 90.   88 Method for treating a metal substrate   receiver to confer a film of passiva-   chromate composition, characterized in that it   is to bring the substrate into contact with a se-   according to claim 5 or according to any one of the   9 to 80, where they relate to the claim   5, at a temperature of about 4 WC to about 660 C, for a period of time sufficient to form thereon a film of passivation product.   Receptor substrate, characterized in that it is provided with a passivation product for a process according to claim 88.   Method of treating a metal substrate   receiver to confer a film of passiva-   chromate composition, characterized in that it   is to bring the substrate into contact with a se-   according to claim 6 or according to any one of the   9 to 80 when they relate to the   6, at a temperature of about 4 WC to about 66 WC, for a period of time sufficient to form a film of passivation product.   91 Receiving substrate, characterized in that it is provided with a passivation product by a process according to claim 90.   92 Process for treating a metal substrate   receiver to confer a film of passiva-   chromate, characterized in that it consists of   to bring the substrate into contact with a solution according to   claim 7 or according to any one of the claims   9 to 80 when appended to claim 7, at a temperature of about 41 C to about 66 WC, for a period of time sufficient to form a film thereon. of passivation product.   93 Process for treating a metal substrate   receiver to confer a film of passive product.   cation consisting of chromate, characterized in that it consists in bringing the substrate into contact with a solution   according to claim 7 or any of the 91.   9 to 80 when they are related to the   7, at a temperature of about 40 ° C to about 66 ° C, for a period of time sufficient to form a passivation product film thereon, to contact the passivated substrate with a dilute aqueous rinse solution.   for a period of at least approximately 1 second,   holding a soluble silicate compound in the bath and   with it, present in a   imparting improved corrosion resistance and hardness to the passivation product film, and   then drying the passivated substrate rinsed with silicate.   94 Receiving substrate, characterized in that   is provided with a passivation product by a se- according to claim 92 or 93.   95 A method of treating a metal substrate   receiver to confer a film of passive product.   chromate, characterized in that it   is to bring the substrate into contact with a se-   according to claim 8 or according to any one of the   9 to 80 when they relate to the   8, at a temperature of about 40.degree. C. to about 661.degree.   a sufficient period of time to form a film of passivation product.   96 Process for treating a metal substrate   receiver to confer a film of passive product.   chromate, characterized in that it   is to bring the substrate into contact with a solution   according to claim 8 or according to any one of the   9 to 80 when they are related to the   8, at a temperature of about 4 OC to about 66 WC, for a period of time sufficient to form a passivation product film thereon, to contact the   substrate passivated with a dilute aqueous solution of   for a period of at least about 1 second, containing a bath-soluble silicate compound and   compatible with it, present in a quantity   putting in place a resistance to corrosion and a   improved hardness to the passivation product film, and 92.   after drying the passivated substrate, rinsed with silicate.   97 Receiving substrate, characterized in that   is provided with a passivation product by a se- according to claim 95 or 96.   A method of treating a receiver metal substrate to impart an improved chromate passivate product film, characterized in that   what it consists in providing an aqueous acid solution con-   having effective amounts of chromium ions, all substantially trivalent, hydrogen ions to provide a pH of from about 1.2 to about 2.5, an oxidizer, and   at least one of iron, cobalt, nickel, molybdenum, manganese   ganesis, aluminum, lanthanum, lanthanide mixtures, and   cerium, and mixtures thereof, to contact the   treated with the aqueous acid solution for a period   enough time to form a product film of pas-   sivation, and put in contact for a period of at   less than about 1 second the substrate treated with a solution   dilute aqueous rinsing solution containing a silicone compound   and soluble in the bath, and present in an amount to impart improved hardness to the passivation product film and improved corrosion resistance to the substrate, and thereafter   to dry the passivated substrate, rinsed with silicate.   The method of claim 98, characterized   in that it also consists in rinsing the passivated substrate with water before it comes into contact with the   aqueous silicate rinse solution.   Process according to claim 98 or   claim 99, characterized in that the aqueous solution   rinse contains about 1 to 40 g / l of the   silicate, calculated as Si O 2.   The method of claim 100, wherein   characterized in that the aqueous rinse solution contains about 5 to about 15 g / l of the silicate compound, calculated in the form of Si O 2.   Method according to any of the claims 93   98 to 101, characterized in that the dialing compound   licate includes a mineral compound.   The method of claim 102, wherein   characterized in that the inorganic silicate compound comprises an ammonium or alkali metal silicate.   Method according to any one of the   98 to 101, characterized in that the compound of   silicate comprises an organic silicate compound.   Process according to claim 104, characterized   in which the organic silicate compound comprises   a quaternary ammonium silicate compound.   Process according to claim 104 or 105, characterized in that the organic silicate compound has the structural formula: ROR ': x SiO 2: y H 20 o R represents a quaternary ammonium radical substituted by four organic radicals selected from the group consisting of alkyl, alkylene, alkanol, aryl, alkylaryl, or mixtures thereof, R 'is hydrogen or R, x is an integer of 1 to 3 and y is an integer of 0 to 15.   Process according to any one of the   Claims 98 to 106, characterized in that the aqueous rinsing solution is at a temperature of about 101 ° C to about 661 ° C.   A process according to any one of the   98 to 107, characterized in that the setting   of the passive substrate with the aqueous rinse solution   is carried out for a period of at least second until about 1 minute.   109, Process according to any one of the   Claims 98 to 108, characterized in that the rinse solution further contains about 0.05 to about 5 g / l. a compatible wetting agent.   A process according to any one of the   dications 98 to 10 R, characterized in that the rinsing solution further contains from about 1 to about 50 g / l 94. an emulsifiable oil.   Method according to any one of the   98 to 109, characterized in that the solution of   rinsing contains, in addition, an ammonium or   alkaline solution or their mixtures in an amount of 0.1 to about 1 g / l.   Receiving substrate, characterized in that   has been subjected to a process according to any one of the dications 98 to 111.   Receiving substrate according to any one of   Claims 85, 87, 89, 91, 94, 97 and 112, characterized   in that the treated surface comprises zinc, a   zinc alloy, cadmium, an alloy of cadmium, aluminum   minium, an aluminum alloy, magnesium or an alloy magnesium.