NL8201599A - PASSIVE LAYER WITH CHROME EXTREME SOLUTION AND METHOD FOR APPLICATION THEREOF. - Google Patents

Abstract

Metal surfaces, particularly zinc and zinc alloy surfaces, are treated with an aqueous acidic solution containing effective amounts of A) hydrogen ions to provide a pH of about 1.5 to about 2.2, B) an oxidizing agent, C) at least one of iron, cobalt, nickel, molybdenum, manganese, aluminium, lanthanum, lanthanide mixtures or cerium ions or mixtures thereof, or instead of C) iron and cobalt ions. Other treating solutions also incorporate D) chromium ions substantially all of which are 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 bath soluble and compatible silicate compound 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 two or more of E), F) and G). The treating solution may optionally further contain halide ions and a wetting agent. )

Description

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Passive layer with chromium-appearing solution and method for applying it

The present invention relates to the passivation of metal surfaces by applying a passive layer with a chrome appearance thereon.

To date, a large number of chromium-containing aqueous solutions have been used or proposed for treating surfaces of zinc, zinc alloys, cadmium, cadmium! alloys and aluminum to improve their corrosion resistance and to further improve the appearance of such surfaces by applying a yellow or blue gloss coating thereon, the latter simulating a chrome finish. In such treatment solutions, originally chromium was in hexa-. valent state while in the last few years the chromium best part was a mixture of the hexavalent and trivalent forms. The reduced toxicity of tri-valent chromium and the increased simplicity and efficiency of treating trivalent chromium-containing waste liquids has led to a stronger commercial use of passivating solutions in which the chromium component is mainly present in the tri-valent state. Such known trivalent chromium passivation solutions have been found to be slightly less effective than traditional hexavalent chromium passivating solutions in imparting good corrosion resistance to zinc and zinc alloy surfaces, cadmium, eadmium alloys and aluminum, aluminum alloys, magnesium and magnesium alloys so that there has thus always been a need for further improvement of trivalent ehrocal passivation solutions and methods for their use.

The excellent corrosion protection offered by hexa-valiant chromium-passivating solutions is generally associated with a pale yellow iridescent passivating film which is, inter alia, recorded and listed in the ASTM standards. Trivalent chromium passivation films normally have a clear to light blue color and give poorer corrosion. 30 protection than the yellow hexavalent passivating film. This problem has been further aggravated by a transition from conventional cyanide zinc and cadmium plating methods to acidic and alkaline non-cyanide electroplating baths, resulting in metal deposits not so receptive to chromium passivation treatments.

Typical known compositions and methods for treating metal surfaces are described in U.S. Patent Nos. 2,393,663; 2,559-878; 3,090,710; 3,553,031 *; 3,755-018; 3-795-5 ^ 9; 3,880,772; 3,932,198; U.126.W9; 171,231; British patents 586,517 and 11761.21 * 1 *; and German Patent 2,526,832.

Thus, the invention in its broadest aspect provides an aqueous acidic solution useful for treating receptive metal substrates to apply a passivating film thereon comprising A) hydrogen ions supplying an acidic pu, B) an oxidizing agent; and C) at least one of the following ions: iron, cobalt, nickel, molybdenum, manganese, aluminum, lanthanum, lanthanide mixtures or cerium ions or mixtures thereof in an effective amount to impart increased corrosion resistance to the treated substrate.

The invention is particularly useful for, but not limited to, the treatment of alkaline and acidic non-cyanide electrolytic zinc-20 and cadmium deposits to impart improved corrosion resistance thereto. Particularly satisfactory results have been obtained with decorative electrolytic deposits of zinc and cadmium of glossy and semi-gloss types, although beneficial effects have also been achieved with zinc and zinc alloy substrates such as galvanized substrates, zinc castings and substrates consisting of cadmium or cadmium alloys consisting mainly of cadmium. Although the invention in its various aspects as described herein is particularly directed to the treatment of zinc zinc alloy surfaces, it has been observed that also beneficial results can be obtained in the treatment of aluminum, aluminum, magnesium and magnesium alloy surfaces to to provide a passivating film or coating thereon. Accordingly, the invention in its broadest sense is directed to the treatment of metal surfaces receptive to the formation of a passive film thereon by contact with the solution of the invention in accordance with the process parameters described herein.

According to the process aspects of the invention, surfaces of zinc, cadmium, zinc alloys, cadmium alloys, aluminum and magnesia.

Contacted with the aqueous acidic treatment solution, it has a temperature ranging from about U to 66 ° C for a time period typically ranging from about 10 seconds to at most about 1 minute after formation of the desired passive film.

A treatment bath composition according to the various aspects of the invention described in detail below can be applied to a substrate to be treated by spraying, dipping, flooding and the like for a period of time sufficient to form the desired passive film thereon. The treatment solution 10 is set in a temperature range of about U-66 ° C, with a temperature range of about 21-32 ° C being preferred. Temperatures above about 32 ° C tend to cause a rapid loss of the peroxide-type oxidizing agent, while temperatures below about 21 ° C decrease bath activity requiring increased contact times to obtain a passive film of the same thickness or color intensity as can be achieved at higher temperatures at shorter time intervals.

Typically, contact times of from about 20 or 30 seconds to about 1 minute are satisfactory, with contact times of about 30 seconds being preferred.

According to a first aspect of the invention there is provided a passivating solution which does not contain chromium ions and which imparts effective corrosion resistance to zinc, cadmium and aluminum surfaces as well as alloy surfaces thereof.

According to this aspect of the invention, there is provided an effective treatment solution and method which selectively selects a clear blue-gloss or clear light-yellow passive film on zinc, zinc alloy, cadmium, cadmium alloy, aluminum and. magnesium surfaces are applied to provide improved corrosion resistance.

The invention has the further advantages that the method is simple to control and can be carried out efficiently and economically.

The advantages and beneficial properties of the first aspect of the invention are achieved according to the composition aspects thereof by providing an aqueous acidic treatment solution containing as substance essential ions some substance ions, preferably providing a solution pH of about 1.2 to about 2.5, which can be conveniently adjusted by inorganic acids, such as sulfuric, nitric or \ hydrochloric acid; a self-preferred oxidizing agent, preferably present in an amount of from about 1 to about 20 g / l, iron and kohalt ions in an effective amount to impart increased corrosion resistance to the treated substrate, and which are preferably present in an amount from about 0.02 to about 1 g / l to form a blue-glossy or clear passive film.

The treatment solution contains an oxidizing agent in an effective amount to activate the metal surface and to form a passive film thereon, effective amount as well as iron and cobalt ions contained in a bath activator and imparting an integral initial hardness to it. the passive film effective amount may be present. The treatment solution may optionally further comprise cerium ions which are present in an amount effective to further activate the bath and promote the formation of a clear light yellow passive film. The treatment solution may optionally contain halide ions including fluoride, chloride and bramide ions to increase the hardness of the film, as well as one or more compatible wetting agents, preferably in a small amount to provide an efficient .. establish contact time with the substrate to be treated.

The iron and cobalt ions are conveniently introduced into the bath by bath-soluble and compatible salts including sulfates, nitrates or halides. The concentration of the combined iron and cobalt ions to achieve appropriate activation of the treatment bath is adjusted in a range from about 0.02 to about 1 g / l, preferably from about 0.1 to about 0.2 g / l . The iron and cobalt ions are individually present in an amount of from about 0.01 to about 0.5 g / l, with individual amounts of about 0.05-0.1 g being preferred.

When the passivating film is desired to have a pale yellow appearance, the treatment bath further contains cerium ions which are in one to further activate it. bath and to impart a bright yellowish color, preferably an iridescent light yellow color, to the film on the treated substrate. The cerium ions can be introduced in the form of bath-soluble and compatible cerium salts, including cerium sulfate, (CeiSO 4. + H + O); halogen! the salt and such as cerium (III) chloride (CeCl 2 OH 2 O); or nitrate salts, such as cerium nitrate (Ce (NOg), 51 ^ 0); (Ce ^ O ^ giOH) .3H2 O). Usually at least some \ \ 8 2 0 1 5 9 9 Η ........

of the cerium ions in it had been introduced in the tetravalent state to bring the characteristic yellow color of the tetravalent cerium ions into the passivating film. Certain oxidizing agents, such as hydrogen peroxide, act as reducing agents under the acidic conditions present in the bulk of the treatment bath and reduce some of the tetravalent cerium ions to the trivalent state. However, oxidizing agents such as hydrogen peroxide convert from a reducing agent to an oxidizing agent at the interface of the treated substrate because of the higher pH at the interface and oxidize at least some of the trivalent cerium ions to the tetravalent state. which are deposited in the film and impart to it the characteristic yellow color. Thus, if oxidizing agents, such as hydrogen peroxide, are used, all cerium ions can initially be introduced. the trivalent state is introduced into the treatment bath, part of which is oxidized to the tetravalent state at the interface of the substrate. The passive film usually includes a mixture of trivalent. and tetravalent cerium compounds and the intensity of the yellow color of the film is dictated by the concentration of the tetravalent cerium compounds present. In addition to the light yellow color to the film, the cerium ions also improve the corrosion resistance of the treated substrate. The cerium sulfate compound is added to the bath because of solubility problems, preferably in the form of an acidic solution, such as a dilute sulfuric acid solution containing the cerium sulfate dissolved therein. ·

The concentration of cerium ions in the treatment bath can range from about 0.5 to at most about 10 g / l, with concentrations from about 1.0 to about 1.0 g / l being preferred. The concentration . of the cerium ions is partly influenced by the size of the desired yellow. coating, wherein higher concentrations of the cerium ions produce a corresponding enhancement of the yellow color of the passivating film.

For reasons of cost, the cerium ions are preferably introduced as a commercially available mixture of rare earth salts of metals into the lantanide series containing cerium compounds as the major component. Such a material is, for example, a cerium-chloride solution containing about 6% solids, of which CeCl 2 .HgO predominates. The cerium (-IIl) chloride solution is derived from a rare ____ earth oxide (BEO) concentrate sold by Molycorp. Inc. or "White Plains, \ 8201599 -6- 4"

New York under product code 5310 which contains at least 99% total EEO, of which CeOg $ 96, La2 ° 3 2.7 $, Hd2 ° 3 ^ and Pr6 ° i1. Commercially available from the same supplier is a cerium (IY) sulfate solution containing about k2% solid, of which Ce (SO4) predominates and is also prepared from the product (code 5310) which contains other rare earth compounds in the same minor amounts.

The treatment bath according to the first aspect of the invention can be suitably prepared by using a concentrate containing the active ingredients, except for the cerium ions and the oxidizing agent, which is adapted to be diluted with water containing cerium ions, if used, and the oxidizing agent is added separately to form a bath containing the ingredients in the desired concentration range. Analogously, replenishing the bath can be done continuously. nue or intermittent basis are achieved by using a concentrate of the active ingredients, except for the cerium ions and the oxidizing agent, which are individually added to the processing bath individually. Suitably, a bath supplement concentrate may contain from about 0.5-50 g / l iron and cobalt ions, halide ions up to 20 g / l and a suitable surfactant in amounts up to 20 g / l, if used , contain. Such an additional concentrate is adjusted to be diluted with about 96 volume% water, to which cerium ions, if used, and an oxidizing agent are added to form a treatment bath containing the active ingredients within the indicated ranges. The oxidizing agent, such as, for example, what peroxide is introduced separately into the bath, preferably in a form that is commercially available and contains about 35% by volume of hydrogen peroxide.

As previously recommended, due to the low solubility of the cerium sulfate, it is desirable to introduce this ingredient into the treatment bath in the form of an aqueous acidic solution. Normally, the use of cerium sulfate in the high concentrations necessary to form a concentrate with the remaining active ingredients other than the peroxide component causes precipitation and the cerium compound.

Even when the cerium is introduced as a halide or nitrate, the presence of sulfate ions introduced into the concentrate by the other ingredients causes precipitation.

Thus, preferably, the cerium ion street is treated as a separate 8201599 • ..... '' "ί1" ".........................

The component to be added is formed and may comprise aqueous acidic solutions of cerium chloride or cerium sulfate with a cerium ion concentration of resp. about 200 to about 320 g / l and about 60 to about 100 g / l. Such cerium concentrations may suitably be composed of the 5 commercially available materials previously described and available from Molyeorp. Ine.

The treatment bath comprises hydrogen ions, preferably in an amount such that a pH of about 1.2 to about 2.5 is obtained, with a pH in the range of about 1.5-2.0 being preferred. Acidification of the treatment bath to the desired pH range can be performed with a variety of mineral acids and organic acids, such as sulfuric, nitric, hydrochloric, formic, tartaric or propionic acids, of which sulfuric and nitric acids are preferred. The presence of sulfate ions in the bath has proven beneficial in achieving the desired passivation of the substrate and these can be introduced via the sulfuric acid or sulfate salt and other bath ingredients. Sulfate ion concentrations can be as high as 15 g / l, with concentrations of about 0.5-5 g / l being preferred.

The treatment bath further comprises an oxidizing agent or agents compatible with the bath, the peroxides of which contain. including hydrogen peroxide and ale oxides such as the alkali metal peroxides are preferred. Commercial grade hydrogen peroxide itself, which contains about 25-60 volume% peroxide, is a preferred material. Other peroxides that are useful include zinc peroxide. Ammonium-alkali metal persulfates also appear to be useful as oxidizing agents.

The concentration of the oxidizing agent or mixture of oxidizing agents is adjusted to achieve the desired surface appearance of the treated substrate. Typically, the concentration of the 30 oxidizing agent can range from about 1 to about 20 g / l, with an amount of about 3-T g / l being preferred, based on a weight equivalent effectiveness basis over hydrogen peroxide.

As a desirable but also preferred component, the bath may contain halide ions, including. chlorine, bromine and fluorine ions, which have been found to improve the hardness of the passive film on the treated substrate. The halide ions or mixtures thereof can be conveniently introduced using "all the alkali metal and ammonium salts." - · --- - · - - - - - - - -. ----- - 8201599 i # -8- thereof, as well as the salts of the metal ions mentioned here The concentration of the total halide component in the had can normally be up to about 8 g per liter, with concentrations of about 0.1-2, 5 g / 1 are typical.

In the second, fourth and fifth aspects of the invention, it is preferred that the concentration of the total halide component in the had normally rises to at most about 2 g per liter, with concentrations of about 0.1-0.5 g / 1 are typical.

In addition to the aforementioned, the use of a small effective amount of a series of wetting agents compatible with the had may also have beneficial results. the nature of the deposited passive film. When used, the wetting agent may be present in concentrations of up to 1 g / l, with concentrations of about 50-100 mg / l being preferred.

. Suitable wetting agents for use in the treatment bath include aliphatic fluorocarbon sulfonates available from 3M under the trade name Fluorad, such as, for example, Pluorad PC 98, which is a non-wetting humectant, the use of which is in an amount of about 100 mg / 1 in the treatment bath improves the color and the hardness of the passive film. A second group of suitable wetting agents are the sulfo derivatives of succinates. An example of this group is Aerosol MA.-80, the dihexyl ester of sodium sulfonic succinic acid, commercially available from American Cyanamid Company. A third group of suitable wetting agents are the naphthalene sulfonates, ie linear alkylnaphthalene sulfonates such as, for example, Petro BA, available from Petrochemical-Co.

According to the second aspect of the invention, there is provided a treatment solution and a method which effectively: • Zinc, zinc alloy, cadmium and cadmium alloy as well as aluminum surfaces; and magnesium can be given improved corrosion resistance and also provide a desired surface finish that can range from a bright gloss to a light blue gloss appearance, which method is easy to control and is efficient and economical to perform. In this and in the third to seventh aspects of the invention, trivalent chromium ions are always used.

The beneficial properties and advantages of the second aspect of 35, the invention are consistent with the composition aspects 820 1 5 9 9 r .......................; ....... wn * -9- thereof "achieved by providing an aqueous acidic treatment solution containing chromium ions as essential components, substantially all of which are present in the trivalent state, preferably at a concentration of about 0 .05 g per liter (g / l) up to the saturation point, hydrogen ions which preferably provide a solution pH of about 1.5-2.2 and which can be conveniently introduced via mineral acids, such as sulfuric, nitric or hydrochloric acid, an oxidizing agent of which hydrogen peroxide itself is preferred, preferably present in an amount of about 1-20 g / l and iron ions preferably present in an amount of about 0.05-0.5 g / l , for example, in the ferrite state, in further combination with at least one additional metal ion selected from the group consisting of cobalt, nickel, molybdenum, manganese, lantanum, lantanide mixture and mixtures thereof, which are in a manner to impart increased resistance to erosion it behan the substrate, and for activating the bath 15 and forming a dreamlike passive film, effective amount are present on the treated substrate. As mentioned for the first aspect of the invention, the solution may further optionally contain halide ions. to impart initial hardness to the coating, as well as a wetting agent.

In this second aspect of the invention, which is applicable in the same way as the first aspect, for the case of decorative zinc electroplating, in addition to the corrosion resistance imparted, one. enhancement of the appearance of such substrates achieved by "the passive film, which varies from a bright glossy blunt light blue glossy appearance simulating a chrome deposition or coating.

The treatment solution contains an oxidizing agent in an amount to activate the hydrated trivalent chromium. recording of a chramate film. it. metal surface effective ds., iron ions · present in the treatment bath in the ferrite state. in. a concentration ranging from about 0.05-0.5 g / l and at least one additional metal ion selected from the group consisting of cobalt, nickel, molybdenum, manganese, lantanum, and mixtures thereof, in an amount to provide an integral initial hardness to the gelatinous chromate film are effective.

The trivalent chromium ions can be introduced in the form of any bath-soluble and compatible salt, such as chromium sulfate (Cr ^ SOj ^), chromium - alum (KCriSOj ^), chromium chloride (CrCl ^), chromium bromide (CrBr ^), chromium - 820 1 5 99 ”-to-.

fluoride (CRF ^) ° f chromium nitrate (CrHO ^).

The trivalent chromium ions can also be introduced by reduction of a solution comprising hexavalent chromium ions using an appropriate reducing agent of any of the types known in the art to achieve a substantially complete stoichiometric reduction of all hexavalent chromium in the trivalent state to establish.

The concentration of the trivalent chromium ions in the treatment solution can range from a low value of about 0.05 g / l to the saturation point, with amounts of about 0.2-2 µg / l being preferred. The bath contains approximately 0.5-1 g / l of trivalent chromium ions.

The treatment solution further comprises iron ions which are preferably present in an amount of about 0.05-0.5 g / l, with concentrations of about 0.1-0.2 g / l being preferred. The iron ions in the bath are mainly in. the. ferrite state due to the presence of the badoxy that means, although they are also in the ferrous form. can be applied. As is the case with the chromium ions, the iron ions can be added to the bath in the form of any bath soluble and compatible iron salt, such as ferro-arammonium sulfate, ferrous sulfate, ferric nitrate or iron halide salts. reasons the preferred material and also because the application of! this salt leads to introduction of the desired sulfate ions into the solution.

In addition to the iron ions, the bath further comprises at least one additional metal ion selected from the group consisting of cobalt, nickel, molybdenum, manganese, tantalum or mixtures thereof. The aforementioned metal ions or mixtures of metal ions are suitably introduced as in the case of the iron ions .... . , by bath-soluble and compatible metal salts, including the sulfates, nitrates or halide salts. For economic reasons, the lantanum ions are preferably not introduced as a pure lantanum compound but as a mixture of rare ones. earth salts of the metals of the lantanide series (hereinafter referred to as "lantanide mixture"), which contains lantanum compounds as the major component. A commercially available lanthanide mixture suitable for use in the invention is lantanum rare earth chloride, product 5252 available from

Molycorp. Ine., White Plains, Hew York. This product has the general formula La - EEC1 .6 HgO and is available as a solution of about 8201599-11-55-60 wt.% Solid. The solution is "prepared from a rare earth oxide (REO) concentrate containing at least k6 wt. # Total REO" consisting of 60 # lanthanum oxide (La ^ O ^), 21.5% neodyminum oxide (M ^ O ^) 10 # cerium oxide (CeQ ^), 7.5 # praseodymium oxide (Pr ^ O ^) and with% residual BEO.

The presence of such other rare earth metals in the solution "does not appear" to exert any adverse effect at the low concentration in which they are present and they may further "contribute to activating the" treatment solution to form the passivation film.

The concentration of the additional metal ions for suitable activation of the bath is set in the range of about 0.02-1 g / l, with concentrations of about 0.1-0.2 g / l being preferred.

The performance bath: According to this second aspect of the invention, it can be suitably prepared using a concentrate containing the active ingredients, except for the oxidizing agent, which is adapted to be diluted with water to form a bath. contains the ingredients in the desired concentration range.

Likewise, replenishment of the bath on a continuous or intermittent basis can be accomplished using a concentrate of the active ingredients, except for the oxidizing agent added separately to the performance bath. Typically, a bath supplement concentrate can contain about 10-30 g / l chromium ion, about 0.5-10 g / l iron ion, about 5-50. g / 1. of at least one. additional metal ion selected from cobalt, nickel, molybdenum, manganese, lantanum, lamtanide mixture, or mixtures thereof, halide deions up to about 20 g / l and a suitable surfactant in an amount up to maximum 5 g / l, if used. Such a supplement concentrate is adapted to be diluted with about 98.5 volume # of water to form a bath containing the active ingredients within the ranges indicated. The oxidizing agent, such as hydrogen peroxide, is preferably introduced into the bath separately, preferably in a form that is commercially available and contains about 35% by volume of hydrogen peroxide.

According to the third aspect of the invention there is provided a treatment solution and method effective for applying a clear light yellow passive film to zinc, zinc alloy, cadmium, cadmium alloy, aluminum and magnesium surfaces, which give him an 8201599-12 improvement in corrosion resistance approximating or comparable to that obtained using conventional hexavalent chromium passivation solutions.

The invention is further characterized by a method which is easy to control and which is efficient and economically feasible.

The advantages and beneficial properties of the third aspect of the invention are achieved according to the composition aspect and thereof by providing an aqueous acidic treatment solution containing chromium ions as essential ingredients, substantially all of which are present in the tri-valent state, preferably · at a concentration of about 0.05 g per liter (g / l) up to the saturation point, hydrogen ions are preferably sufficient to provide a solution pH of about 1.2 to about 2.5 and which can be conveniently introduced via mineral acids, such as. sulfuric, nitric or hydrochloric acid, an oxidizing agent, of which hydrogen peroxide itself is preferred, preferably present in an amount of about 1 to about 20 g / l, as well as cerium ions present, in an amount which is to activate the bath and the formation of a clear light yellow passivating chroma film on the treated substrate is effective.

In addition to the cerium ions, the treatment solution may optionally and preferably further contain an additional metal ion selected from iron, cobalt, nickel, molybdenum, manganese, lantanum, seed mixes, and mixtures thereof to provide for further activation of the bath and passive film formation . As stated in the previous aspects of the invention, the solution may optionally contain, in addition to a small amount of a wetting agent, halide ions to impart hardness to the coating. The cerium ions can be introduced with the treatment solution in this third aspect of the invention in the same manner as described. for the first aspect of the invention.

In addition to the cerium ions, the bath may further optionally contain and preferably at least one additional metal ion selected from the group consisting of iron, cobalt, nickel, molybdenum, manganese, lantanum, lantanide mixtures as well as mixtures thereof. Such metal ions can be incorporated into this third aspect of the invention. the are introduced for the second aspect in the same manner as already described.

The bath according to this third aspect of the invention can be suitably formulated using a concentrate containing the active ingredients except the cerium ions and the oxidizing agent, which is adapted to be diluted with water and to which the cerium ions and the oxidizing agent are added separately to form a bath containing the components within the desired concentration ranges. Likewise, replenishment of the bath on a continuous or intermittent basis can be achieved by using a concentrate of the active ingredients except for the cerium ions and the oxidizing agent, which are separate. the bath. Typically, a bath supplement concentrate may contain about 10-80 g / l of chromium ions, about 10 0.5-50 g / l of additional metal ions consisting of iron, cobalt, nickel, molybdenum. manganese, lantanum, lantanide mixture or mixtures thereof, containing halide ions of up to about 20 g / l and a suitable surfactant in an amount of up to about 5 g / l when used. Such a supplement concentrate is adapted to be diluted with about $ 6 volume% water, to which cerium ions and an oxidizing agent are added to form a treatment bath containing the active ingredients in the indicated amounts. The oxidizing agent, such as, for example, hydrogen peroxide, is introduced separately into the bath, preferably in a form that is commercially available and contains about 35% by volume of hydrogen peroxide.

Due to the low solubility of the cerium sulfate, it has previously been desirable to introduce this ingredient into the treatment bath in the form of an aqueous acidic solution. Normally, the use of cerium sulfate in the high concentrations necessary for the formation of a concentrate with the remaining active ingredients other than the peroxide additive causes precipitation of the cerium compound.

Even when the cerium is introduced as a halide or nitrate salt. the presence of sulfate ions in the applied concentrate introduced by the other ingredients causes precipitation. Thus, the cerium concentrate is preferably formed as a. separate additive and may be an aqueous acidic solution of cerium chloride. or cerium sulfate with a cerium ion concentration of 'resp. about 200-300 g / l and about 60-100 g / l. Such cerium concentrates may suitably be composed of the previously described commercially available materials supplied by Molycorp. Ine.

According to the fourth aspect of the present invention, for -______ is seen in a treatment solution and method which effectively improves ..... 82 015 99 - 'Γ' -lil · - corrosion resistance to zinc, zinc alloy, cadmium and cadmium alloys - as well as imparts aluminum and magnesium surfaces and gives a desired surface finish which can range from a bright gloss to a light blue gloss to a yellow iridescent appearance, yielding a passivating film with improved clarity and initial hardness, . which method is easy to control and which is efficient and economically feasible.

The advantages and beneficial properties of the fourth aspect of the invention are achieved according to its composition aspects by providing an aqueous acidic treatment solution containing as essential constituents chromium ions which are substantially all in the trivalent state, preferably in a concentration from about 0.05 g / l to the saturation point, (and which can be introduced as described for the second and third aspects), hydrogen ions, preferably such that they give a solution pH from about 1.2 to about 2.5, and. which may conveniently be introduced via mineral acids, such as sulfuric, nitric or hydrochloric acid, an oxidizing agent of which hydrogen peroxide itself is preferred, preferably present in an amount of about 1-20 g / l, a bath-soluble and compatible organic car-20 carboxylic acid which is present in an amount effective to impart initial hardness and clarity to the passivating film, said organic acid having the structure formula (OH) R (COO1). a b, where a has an integer from 0-6; b an integer from 1-3; And R represents an alkyl, alkenyl or aryl group having 1-6 carbon atoms as well as the base soluble and compatible salts thereof; and at least one additional metal ion selected from iron, cobalt, nickel, molybdenum, manganese, lantanum, cerium and lantanide mixtures, as well as mixtures thereof present in an effective amount to activate the bath and form a passivating chromium film of the desired appearance on the substrate to impart initial hardness to the gelatinous chromate film. As mentioned in the previous aspects of the invention, the solution may further optionally contain halide ions to impart additional hardness to the coating as well as a wetting agent. In this fourth aspect of the invention, that. the same way as the first aspect is useful for 8201599 '\ \ -15-' * in the case of decorative electrolytic zinc coatings, in addition to the corrosion resistance obtained, a further improvement in the appearance of such substrates can be achieved by the passive film ranging from a clear glossy to pale blue glossy appearance simulating that of a chromium layer and optionally a bright pale yellow appearance simulating the appearance obtained by using known hexavalent chromium solutions.

The bath further contains at least one additional metal ion selected from iron, cobalt, nickel, molybdenum, manganese, lanthanum, lanthanide mixtures, and cerium as well as mixtures thereof. The aforementioned metal ions or mixtures of metal ions are suitably introduced into the bath by bath-soluble and compatible metal salts, including the sulfates, nitrates or halide salts as discussed for the second and third embodiments and such materials as discussed above for those aspects. may be desired employed in this aspect of the invention.

The. concentration of the additional metal ions, other than cerium ions, vc for an appropriate activation of the treatment bath to form a clear to blue gloss appearance is adjusted to provide a concentration ranging from about 0.02 to at most about 1 g / 1.20 with concentrations of about 0.1-0.2 g / l being preferred. Although such metal ions can be used in concentrations above 1 g / l, such as up to 10 g / l, the use of such higher concentrations has even in the absence of cerium ions. the tendency to form dull films of a yellow hue instead of the desired clear or light blue films »For these reasons, these higher concentrations are undesirable from the viewpoint of appearance.

A further essential component of the improved bath of the invention includes an organic ceric acid or salt thereof having the structure as indicated above, present in an amount to impart increased clarity, and initial hardness to the deposited gelatinous. chromate film is effective. The unexpected improvement in film clarity is particularly striking in connection with the light yellow iridescent films formed from cerium ion-containing solutions. The particular concentration range or range of concentrations of the brightness / hardness agent will depend on the molecular weight of the certain acid and / or metal salt used, higher concentrations for equivalent effectiveness being required as the molecular weight of the additive increases. The particular concentration to achieve optimum clarity and hardness is also dictated to some extent by the concentration of the other metal ions present in the bath, with higher concentrations being used when the metal ion concentrations. increase. Generally, the organic carboxylic acid additive or its metal salts can be used in amounts ranging from about 0.05 to at most k.0 g / l, with concentrations of about 0.1-1.0 g / l usually being preferred .

The additive may be introduced as the organic acid itself or as any bath-soluble and compatible metal salt, including the alkali metal salts, ammonium salts and salts of the various additional metal ions in the bath. For economic reasons, the organic acid is usually introduced as an acid or as its sodium or potassium salt.

Organic carboxylic acids, such as malonic acid, maleic acid, tartaric acid, gluonic acid, tartaric acid and citric acid, have been found to be particularly suitable within the framework of the structural formula as mentioned above, with succinic acid and its salts being found to be particularly effective.

The treatment bath according to the fourth aspect of the invention can be suitably prepared by using a concentrate containing the active components except the oxidizing agent and the cerium ions, if used, and which is adapted to be diluted with water to form a bath contains the constituents within the desired concentration range. Likewise, replenishment of the bath and continuous or intermittent base can be accomplished by. use of a concentrate of the active ingredients, except for the oxidizing agent and cerium ions, if used, which is added separately to the treatment bath. Stuttering can be one. bath replenishing concentrate about 10-80 g of chromium ions, about 1.0-80 g / l of the organic carboxylic acid 30 and / or salt additive, about 5-50 g / l of at least one additional metal ion of the group consisting of iron, cobalt, nickel, molybdenum, manganese, lantanum, lantanide mixtures or mixtures thereof, containing halide ions up to 5 g / l when used. Such an additional concentrate is adapted to be diluted with about 9% water to a treatment bath containing the active ingredients in the indicated amounts. The oxidizing agent, such as hydrogen peroxide, is preferably introduced into the bath separately, preferably in a form which is commercially available and which contains about 35-40 volumes of 1% or peroxide.

The cerium ions, when used, are "preferably introduced in the form of an aqueous acidic solution of cerium chloride or cerium sulfate, with a cerium ion concentration of about 200-320 g / l and about 60-100 g, respectively. / 1. Such cerium concentrates can usually be formulated from commercial materials as described above, available from Molycorp. Ine.

According to the fifth aspect of the invention, there is provided a treatment solution which aims to reduce the severity of the oxidant loss problem encountered in the known baths. . Thus, while improvements have been made in trivalent chromium passivation compositions and methods of forming commercially acceptable passivation films, it has been a constant in such treatment baths. problem arises the relatively rapid loss of the peroxide type oxidant, especially hydrogen peroxide, which is present as a necessary bath component to achieve an acceptable passive film. Such known treatment baths have also been subjected to a relatively rapid rise in pH, necessitating careful control, and addition of acids to maintain the pH level within the optimum operating range. The increasing loss of the peroxide-type oxidizing agent, especially hydrogen peroxide, is due in part to the activating metal ions present in the solution, as well as contaminating metal ions, such as zinc or cadmium, which are, for example, . introduced by dissolving the metal of the substrates being treated which have been found to catalyze the decomposition of the peroxide-oxidizing agent. The increasing loss of the peroxide-type oxidizing agent occurs not only during the treatment but also during the storage of the bath during the night and weekends when the plant is shut down. In a fresh treatment bath containing 3 volume% of a 35% hydrogen peroxide solution, overnight storage will lose approximately 1 volume% per hour of the hydrogen peroxide oxidizing agent, while a solution used, containing about 2-10 g per liter of contaminant zinc ions will experience a loss of hydrogen peroxide equivalent to about 0.4% by volume per hour It will be apparent from the foregoing that careful monitoring of the bath composition and a repeated replenishment of the peroxide oxidizing agent is required to maintain optimum bath efficiency which is not only costly but also time consuming,

Thus, the object of the fifth aspect of the invention is to provide a treatment solution and method useful for imparting improved corrosion resistance to zinc, zinc alloy, cadmium, cadmium alloy, as well as aluminum and magnesium surfaces and imparting a desired surface finish that can range from a bright gloss to a pale blue glossy to yellow iridescent appearance, providing a passive film with improved corrosion resistance, hardness, durability, purity and initial hardness, which provides a treatment solution which is stabilized against rapid loss of peroxide-oxidizing agent and against a rapid rise in pH, which method is simple to control and which is efficient and economically feasible,

The beneficial properties and advantages of the fifth aspect of the invention are attained according to the composition aspects thereof by providing. an aqueous acidic treatment solution containing as its essential constituents chromium ions substantially all present in the trivalent state, preferably in a concentration of from about 0.05 g per liter (g / l) to. the saturation point (and which can be introduced as discussed for the second through fourth aspects), hydrogen ions preferably to give a solution pH of about 1.2-2.5 and which can be suitably introduced via mineral acids, such as. sulfuric acid, nitric acid, hydrochloric acid and the like, an oxidizing agent of which hydrogen peroxide itself is preferred, preferably present in an amount of about 1-20. g / l, a stabilizing additive comprising a mixture of 1-hydroxy-ethylidene-1,1-diphosphonic acid and citric acid and bath-compatible and soluble salts thereof which are present in a peroxide oxidizing agent loss and stabilizing agent of the pH of the. treatment bath effective amount is present and at least one additional metal ion selected from iron, cobalt, nickel, molybdenum, manganese, aluminum, lantanum, lantanide mixtures, and cerium as well as mixtures thereof, which are present in an amount sufficient to activate the bath and form a passive chrome film of the desired appearance on the treated substrate. As mentioned in the previous aspects of the invention, the solution may optionally contain halide ions to impart additional hardness to the coating, and optionally a wetting agent. It can also be a bath-soluble and compatible

V

including a silicate compound which is present in an amount effective to impart increased corrosion resistance and hardness to the passivation film, for example in an amount of about 0.01-5 g / l, calculated as SiO4 as discussed in conjunction with the sixth aspect below. It may also include a bath-soluble, compatible organic carboxylic acid, which is present in an amount effective to further impart initial hardness and clarity to the passive film as discussed in connection with the fourth aspect above.

In this fifth aspect of the invention, which is applicable to decorative electrolytic zinc coatings in the same manner as the first aspect, in addition to the imparted corrosion resistance, a further improvement of the embankment is made. such substrates are achieved by the passive film ranging from a clear gloss to a pale blue glossy outer dike simulating that of a chrocra deposition or optionally a bright light yellow outer dike simulating the outer dike obtained by using the known hexavalent chromium solutions. .

; A further essential component of a treatment bath according to the fifth aspect of the invention is that the stabilizing agent comprises a mixture of 1-hydroxyethylidene-1, dif-diphosphonic acid and citric acid as well as its bath soluble and compatible salts. The combination of the diphosphonic acid and citric acid components. appears to produce a synergistic effect because not only the. decomposition and degree. of loss of. the peroxide-type oxidizing agent are reduced, but also, the pH of the treatment bath is stabilized thereby avoiding a rapid rise thereof, as previously experienced in the known trivalent chromium passivation solutions, lurking the two stabilizer components in the. acid form or. as the alkali metal or ammonium salts! added. A commercially available and suitable material is sold. bought -under the trade name Dequest. .2010 from Monsanto Chemical Company and Γ30 includes 1-hydroxyethylidene-1,1-diphosphonate.

The diphosphonic acid or diphosphonate component may be present in the treatment bath in an amount of about 0.05-3 g / l. with amounts of about 0.1-0.5 g / l being preferred. The citric acid or citrate component may be present in the treatment bath in an amount of about 0.1-10 g / L, with amounts of about 0.5-1.5 g / L being preferred.

_____ A preferred optional component of the treatment bath includes. a silicate compound present in an amount effective to provide improved erosion protection. and impart hardness to the passive film formed on the treated surfaces or substrates. The silicates used and the amounts thereof are discussed in more detail below in connection with the sixth aspect of the invention.

The bath also further contains at least one additional metal ion selected from iron, cobalt, nickel, molybdenum or manganese, aluminum, lanthanum, lanthanide mixtures and cerium as well as mixtures thereof. The aforementioned metal ions or metal ion mixtures are suitably introduced into the bath by bath-soluble and compatible metal salts, including the sulfates, nitrates or. halide salts as discussed for the second through fourth aspects. Such materials as discussed above for said aspects may be advantageously employed in this aspect of the invention.

The said metal ions or combinations thereof with the exception of cerium ions are used to provide a clear or light blue passivating film. When a light yellow iridescent film is desired, cerium ions are used, preferably in combination with a 20 or more. other metal ions to form a film which simulates in appearance the light yellow passive film obtained heretofore using hexavalent chromium passivation solutions as defined in ASTM standards for their characteristic color. excellent corrosion resistance associated with it. · 25 The cerium ions can on the. method as discussed in connection with the first, third and fourth .as aspects .are introduced *

The concentration of the additional metal ions other than the cerium. ... ions for a suitable activation of the treatment bath to form a clear to blue-glossy appearance should be discussed as discussed in connection with the fourth aspect of the invention. to be controlled * When the treatment bath is to contain an organic carboxylic acid or salt thereof, as discussed in connection with the fourth aspect of the invention, the following procedures should be followed.

However, the presence of a silicate compound in the treatment bath as discussed hereinafter in connection with the sixth aspect of the invention has also been found to contribute to improved film clarity and thus addition of the organic carboxylic acid is usually unnecessary. 82 0 1 5 9 9 ~~ ~ '' -21- «When a silicate compound is used in the bath.

The treatment bath according to this fifth aspect of the invention may. suitably prepared by using a concentrate containing the active ingredients, excluding the oxidizing agent and the cerium-5 ions, if used, and which is adapted to be diluted with water to form a bath containing the ingredients in the desired concentration area. Analogously, replenishment of the bath on a continuous or intermittent basis can be accomplished using a concentrate of the active ingredients excluding the oxidant and the cerium ions, if used, which is added separately to the treatment bath. Typically, a bath supplement concentrate can contain about 10-80 g / l of chromamions, about 5-50 g / l of at least one additional metal. ion. from iron, cobalt, nickel, molybdenum, manganese, aluminum, lanthanum, lantanide mixtures or mixtures thereof, halide ions up to a maximum of 50 g / l, about 5-30 g / l of a silicate compound, when used, calculated as. SiO4, as well as a suitable surfactant in an amount up to 5 g / l when used. Such supplemental concentrate is adapted to be diluted with. about 98 volume% water to form a treatment bath that. the active ingredients in the indicated ranges contain the oxidant, such as hydrogen peroxide, for example, is introduced into the bath separately, preferably in a form commercially available and approximately. 35 - + 0 volume of hydrogen peroxide. The cerium ions, when used, are preferably in the form. of an aqueous acidic solution of cerium (III) chloride or cerium (IV) sulfate introduced with a cerium ion concentration of resp. about 200-320 g / 1 and about 60 g - 100 g / 1. Such cerium concentrates may suitably be composed of the cammerj. . commercially available materials described above are obtained from. Molicorp. Inc.

30.. The aforementioned trivalent chromium concentrate containing the metal ions and. " . . acid components in combination with an inorganic silicate compound tends to form precipitates on long term storage caused by the high concentrations present and the acidic conditions.

Thus, soon after they are prepared, such concentrates are normally diluted with water to provide a treatment bath containing the active ingredients at the desired concentration. Concentrates with significantly improved stability and extended shelf life can be obtained by (* - · - - ->. · - - - -. - - ..........

8201599-22 use of organic silicates as discussed below in connection with the sixth aspect in combination with the trivalent chromium ions, and optionally halide ions and a wetting agent. Such stable concentrations usually contain about TO-85 g / l trivalent chromium ions, about 5-50 g / l of an organic quaternary ammonium silicate calculated as SiO, halide ions up to about 50 g / l and 2 an area. active agent in an amount of up to 5 g / l.

Such a stable concentrate is adapted to be used in conjunction with a second concentrate containing de-acidic components, the additional 10 metal ions in an amount of about 5-50 g / l, up to a maximum of 80 g / l of the organic carboxylic acid and / or the salt additive, if used. Such a second concentrate may also optionally contain some or all of the halides and wetting agents, if not used in the first trivalent chromium concentrate.

In the preparation of such a trivalent chromic / siliate acetate concentrate, the organic silicate is first diluted with water to the desired concentration range, then the trivalent chromium component is added together with the selection halide and wetting agent, if used. commercially available organic silicate compound includes Quaran 220 from EMERY Industries which includes a quaternary amine silicate.

The diphosphonic acid and citric acid and / or diphosphonate and citrate stabilization additive may be in any of them. the aforementioned concentrates are included, including the peroxydecone entrant in an amount sufficient to achieve the desired concentration in the treatment bath. The stabilizing additive may optionally be prepared as a. separate aqueous concentrate containing about 30-170 g / l of the diphosphon. acid / diphosphonate compound, mixed with about 16p. to approximately . 500 g / l of the citric acid / citrate compound and separately added to the treatment bath to provide the desired activity concentration within the limits previously indicated, in particular U-5 g / l of the stabilizer concentrate. According to a preferred embodiment, the stabilizing additive is incorporated directly in the chromium-containing concentrate, the cerium ion concentrate in the case of a yellow passivation process or in the second concentrate used in conjunction with the organic silicate concentrate, in amounts of about 3-17 g / l diphosphonic acid / di-phosphonate compound and about 16-50 g / l citric acid / citrate compound.

8201599 -23-

As discussed above for the first through fourth aspects, the treatment bath can be applied to the substrate in a variety of ways and the disclosure conditions described for these aspects can be used for this fifth aspect of the invention. .

At the end of the passivation treatment, the substrate is taken from the treatment solution and dried as by warm circulating air. Typically, such passivated substrates are used, especially workpieces that have been machined while on a work rack.

10 are characterized by a uniform passive film over the surfaces thereof so that no further machining is necessary. In the case of small workpieces which are mass-treated, such as in a rotary processing tub, - some damage, such as scratches, may occur in the passive film occur during the treatment and it is desirable in such cases to subject these workpieces to a post-rinse cylinder (as discussed below in conjunction with the seventh aspect of the invention) to seal any such surface defects. thereby. improve corrosion protection of the parts processed in a tub.

When such an optional post-passivate silicate rinse is used, the substrate after the passivation treatment is preferably subjected to at least one or more water rinsing steps, usually. at room temperature to remove. residual passivation solution from the surfaces thereof, after which the substrates are contacted with the silica additional rinse solution according to the instructions given in connection with the seventh aspect of the invention.

According to the sixth aspect of the invention, there is provided a treatment solution which aims to address the severity of the problem of damage to the protective passive layer of passivated workpiece. 35 in the subsequent operation. Although: so improvements. have been achieved with passivating trivalent chromium compositions and methods of forming commercially acceptable passive films, such films initially do not appear in some instances to have sufficient initial hardness to allow substrate handling during the subsequent steps without the movie. is damaged. Also, these passivating trivalent chrome compositions and methods have been found to lack optimum corrosion resistance, hardness and durability in some cases, and provide films which are slightly cloud-like and lack optimum clarity in appearance.

Thus, this sixth aspect of the invention aims to provide a treatment solution as well as a method useful in imparting improved corrosion resistance as well as an improved corrosion resistance to zinc, zinc alloy, cadmium, cadmium alloy, and aluminum and magnesium surfaces. provide a desired surface finish that can range from a bright gloss to light blue glossy to yellow iridescent appearance, thereby obtaining a passive film with improved corrosion resistance, hardness, durability, clarity and initial hardness, which method is easy to control and efficient and. economically feasible.

The beneficial properties and advantages of the sixth aspect of the invention are achieved according to the composition aspects thereof by providing an aqueous acidic treatment solution containing as essential ingredients chroamionea, substantially all of which are present in a trivalent state, preferably in a concentration from about 0.05 g / l to the saturation point (and which can be entered as discussed for the second through fifth aspects), hydrogen ions preferably to a solution pH of about 1.2- about 2.5 which can be conveniently introduced via mineral acids such as sulfuric, nitric or hydrochloric acid, an oxidizing agent of which hydrogen peroxide itself is preferred, and is preferably present in an amount of about 1-20 g / l, a bath-soluble and compatible silicate compound present in an amount effective to provide increased corrosion resistance and passive hardness, film (preferably present in an amount of about 0.01-5 g / l, calculated as SiO4), and at least one additional metal ion selected from iron, cobalt, nickel, molybdenum, manganese, aluminum. lantanum, lantanide mixtures and cerium, as well as, mixtures thereof, 1 present in an amount effective to it. bath and to form a passivating chrome film of the desired appearance on the treated substrate. As mentioned, in the earlier aspects of the invention, the solution may optionally contain halide ions to impart additional hardness to the coating, as well as optionally a wetting agent. It may also contain a base soluble compatible organic carboxylic acid present in an amount effective to impart initial hardness and clarity to the film.

In this sixth aspect of the invention, although this is used in the same manner as the first aspect in zinc decorative electrolytic coatings. In addition, a further improvement in the appearance of such a substrate, in addition to the imparted corrosion resistance for the passivation film, is achieved, which ranges from either glossy to pale blue glossy, simulating that of a chromium deposit, or optionally a pale yellow outwardly includes that obtained by applying. simulates basin hexavalent chromium solutions.

A further essential component of the treatment bath according to the sixth aspect of the invention is the silicate compound present in an amount that effectively improves the corrosion protection and hardness of the passivating film formed on the treated substrate.

The silicate compound may comprise a bath-soluble and compatible organic and inorganic silicate compound, and mixtures thereof, which are preferably present in an amount from about 0.01 to at most about 5 g / l SiO 2, with concentrations of about 0.1-0.5 g / 1 are preferred. When inorganic silicates are used, concentrations above about 2 g / l in the treatment bath are undesirable because of the tendency of the silicate to form fine flocculate precipitates under the acid conditions present, with the metal ions contained in the bath, which enhances bath instability. On the other hand, organic silicates provide improved bath stability and are preferred for making make-up and refresh concentrates because of the improved stability and. the extended service life.

. Inorganic silicates suitable for the invention include alium metal and ammonium silicates of sodium silicate (Na 2 S 2 O 2 (x 2 -J +) and potassium silate (K 2 O 2 SiO 2 (y = 3-5)) for economic reasons. Preferred organic silicates which may also be used satisfactorily include quaternary ammonium silicates, which include tetramethyl ammonium silicate, phenyl trimethyl ammonium silicate, disilicate and tri- silicyl benzyl trimethyl ammonium silicate and disilicate. silicates that fulfill the purposes of the invention are indicated by the following general formula-ROE ': xSiO 2: yH 2 O wherein R represents a quaternary ammonium group, which is substituted with four-organic groups selected from alkyl, alkylene, alkanol, aryl, alkylaryl or mixtures thereof, R 'represents either R or a hydrogen atom. "" 82 0 1 5 9 9 ~~ = "' -26- x equals 1-3 and y equals 0-15 *

Such water-soluble organic silicates including their synthesis and properties are described extensively in the literature, such as in the article by Merrill and Spencer "Some Quaternary 5 Ammonium Silicates" published in the Journal of Physical and Colloid Chemistry, 55, 18T (1951). , the contents of which are incorporated herein by reference. Similar silicates, including typical syntheses thereof, are disclosed in U.S. Patent 3,999,5½, to which reference is made for further details.

The bath also further comprises at least one additional metal ion selected from iron, cobalt, nickel, molybdenum, manganese, aluminum, lantanum, lanthanum mixtures and cerium, as well as mixtures thereof. The aforementioned metal ions or mixtures of metal ions are suitably introduced into the bath by bath-soluble and compatible metal salts, including the sulfates, nitrates, halide salts, as discussed for the second through fifth, aspects and the like materials as in the aforementioned aspects can be discussed in. this aspect of the invention may be practiced.

The aforementioned metal ions or combinations thereof with the exception of 2Q of cerium ions. used to provide a clear to pale blue passivating film. When a light yellow, iridescent film is desired, cerumones are used, e.g. preferred in. Combination with one or more of the other metal ions to form a passivating film simulating in Uitijk dike the light yellow films so far obtained using hexavalent chromium solutions, which are enshrined in ASTM standards because of their characteristic color and associated excellent corrosion resistance. The cerium ions can be introduced in the manner described above, in -samehhang with the first, third, fourth and fifth aspects.

30 The. concentration of the additional metal ions other than cerium ions for suitable activation of the treatment bath to form a clear to blue-glossy appearance should be controlled in the manner discussed in connection with the fourth and fifth aspects of the invention.

When the treatment bath. an organic carboxylic acid or salt thereof, as discussed in the fourth and fifth aspects of the invention, the following procedures should be followed.

The presence of the silicate compound in the treatment bath 8201599 -27- according to the sixth aspect of the invention unexpectedly also appears to contribute to improved film clarity, so that the use of the organic carboxylic acid additive is therefore not essential when, according to this aspect of the In the present invention, a silicate is present in the bath, although it may be desirable.

The treatment bath. according to this sixth aspect of the invention, ... can be suitably prepared by using a concentrate containing the active ingredients with the exception of the oxidizing agent and the cerium ions, if used, which is adapted to be diluted with water to form a bath containing the ingredients in the desired concentration areas.

Similarly, replenishment of the bath on a continuous or intermittent basis can be accomplished by using a concentrate of the active ingredients, excluding the oxidizing agent, and the cerium ions, if. present, which are added separately to the treatment bath. Typically, a bath supplement concentrate may contain about 10-80 g / l of chromium ions, about 5-30 g / l of the silicate compound calculated as SiOg, about 5-50 g / l of at least one additional metal ion consisting of iron, cobalt, nickel, molybdenum, manganese, aluminum, lanthanum, lanthanum mixture, mixtures thereof, halide ions up to about 50 g / l and a suitable surfactant, in an amount of about 5 g / 1 »if. applied. Such a supplement concentrate is adapted to be diluted with about 98 volume% water to form a treatment bath containing the active ingredients within the indicated ranges. The oxidizing agent, such as hydrogen peroxide, is; for example, introduced separately into the bath, preferably in a form that is commercially available and contains about 35-5 volume% hydrogen peroxide. . ,. ·

The cerium ions, when used, are preferably introduced in the form of an aqueous acidic solution of cerium (III.), Chloride or ceriumClV sulfate with a cerium ion concentration of resp. about 200-320 g / l and about 60-100 g / l. Such honor concentrates may suitably be composed of the previously described commercially available materials from Molycorp. The aforementioned trivalent chromium concentrate containing the silicate compound, the metal ions and the acidic components tends to form precipitates on prolonged storage caused by the high concentrations present and the acidic conditions.

82 0 1 5 9 9 "-28-

Accordingly, the aforementioned concentrates are normally diluted with water shortly after their Preparation to provide a Treatment Bath containing the active ingredients at the desired concentrations. It has further been discovered according to this sixth aspect of the invention that concentrates with significantly improved stability and extended shelf life can be obtained by using organic silicates of the aforementioned type in combination with the trivalent chromium ions and optionally halide ions. a humectant. Such stable concentrates may suitably contain about 10-80 g / l trivalent chromium ions, about 5-50 g / l of an organic quaternary ammonium silicate Calculated as SiQ2, halide ions up to about 50 g / l and a surfactant Contain in an amount of about 5 g / l. Such a stable concentrate is adapted to be used in conjunction with a second concentrate containing the acidic components, the additional metal ions in an amount of from about 5-100 g / l, up to a maximum of 80 g / l of the organic carbon acid and / or salt additive, if used Contains. Such a second concentrate may also optionally contain some or all of the halides and fastening agent, if these have not been used in the first trivalent ehrome concentrate.

20 In the Preparation of a. such trivalent chromosilicate concentrate, the organic silicate is first diluted with water to the desired concentration range, after which it becomes the trivalent chromium component. added together with. the optional halide and the wetting agent, if used. A particularly suitable commercially available organic silicate compound comprises. Quaram 220 from Emery Indsutries which includes quaternary amine silicate.

This sixth aspect of the invention further includes a new focus. street composition suitable for replenishing the Treatment Bath by dilution with water, which contains as its Essential Ingredients triva-spring chromium ions and an organic quaternary ammonium silicate, which provides compatibility and storage stability over long periods of time.

As Above. Discussed for the first through fifth aspects, the Treatment Bath can be applied to the substrate in various ways, and the process conditions described for these aspects should also be used for this sixth aspect of the invention.

8201599: -29-

Upon termination of the passivation treatment, the substrate is taken from the treatment solution and dried, such as by hot circulating air. Usually such passivated substrates, especially workpieces that are processed while supported on a work rack, are characterized by a uniform film over its surfaces, requiring no further processing.

In the case of small workpieces that are mass-treated, such as in a rotary processing tub, some damage such as by scratching in the passivating film may occur during the treatment and it is desirable in such cases to subject these workpieces to a silicate rinse aftertreatment (as described below as the seventh aspect of the invention) to seal any surface defects thereby improving the corrosion protection of tubular parts.

When such a silicate rinse treatment is used after the passivation, the substrate after the passivation treatment is preferably subjected to at least one or a plurality of water rinsing steps, usually. at room temperature, to remove residual passivation solution from its surfaces, after which the substrates are contacted with the silicate rinse solutions according to the procedures given below in connection with the seventh aspect of the invention.

According to the seventh aspect of the invention, a. treatment method which aims to solve the same problem as the sixth aspect of the invention, namely that of damage to the passive layer of the workpieces during subsequent processing. Thus, although improvements have been made in trivalent passivating chromium compositions and methods of commercially manufacturing acceptable films, such films as initially formed do not appear to be sufficient in some cases. have initial hardness to allow handling of the substrate via further capping without damaging the passivation film.

Furthermore, such trivalent chrome compositions (and methods) have also been found to lack, in some instances, optimum corrosion resistance, hardness and durability, and films are obtained which are slightly cloudy and lack optimum clarity from the viewpoint of appearance.

8 2 0 1 5 9 \ 9: \ ~ \ '\ -30-

Thus, this seventh aspect of the invention aims to provide a process that effectively imparts improved corrosion resistance to zinc, zinc alloy, cadmium and cadmium alloy, as well as aluminum and magnesium surfaces and provides a desired surface finish that can range from a both glossy to light blue glossy to a yellow iridescent appearance, which produces a passive film with improved corrosion resistance, hardness, durability, clarity and initial hardness, which method is easy to control and which is efficient and economically feasible.

The beneficial properties and advantages of the seventh aspect of the invention are achieved by a process which provides an aqueous acidic treatment solution containing chromium ions as essential constituents substantially all present in the trivalent state, preferably in a concentration of about 0, Contains 05 grams per liter (g / l) up to the saturation point (and which can be introduced as discussed for the second through sixth aspects. 15), hydrogen ions preferably to have a solution pH of about 1, 2-2.5 and which can be conveniently introduced via mineral acids such as sulfuric, nitric or hydrochloric acid, an oxidant of which hydrogen peroxide itself is preferred, preferably present in an amount of about 1 to 20 g / l, at least one additional metal ion selected from iron, cobalt, nickel, molybdenum, manganese, aluminum, lantanum, lantanide mixtures and cerium, as well as mixtures thereof, the substrate containing said water. acidic solution is contacted for such a period of time that a passivating film is formed, and. the passivated substrate, a passivating film 25 is contacted for about 1 second with a dilute aqueous rinse solution containing a bath-soluble and compatible silicate compound in an amount that imparts an effectively improved corrosion resistance and hardness to the passivation film, after which the passivated silicate rinsed substrate is dried.

The aqueous acidic solution can be the same as described in connection with each. from the first through sixth aspects and can be applied in the same manner.

After the. passivation treatment, the substrate is preferably subjected to one or a plurality of water rinsing steps which can be carried out at room temperature or at elevated temperature, after which the passivated substrate is contacted with a dilute aqueous solution. silicate solution in the form of a final rinse stage. The contact time of the passivated substrate with the silicate solution can range from a period of at least about 1 second to about 1 minute or longer, and the silicate solution can range in temperature from about 5 to 66 ° C. In the silicate rinsing stage, the substrate is dried as for example by circulating hot air.

The aqueous silicate rinse solution preferably contains, as an essential ingredient, a bath-soluble and compatible inorganic or organic silicate compound as well as mixtures thereof, present in an amount of about 1.10 g / l, preferably about 5-15 g / l, calculated as SiOg. Inorganic silicates suitable for use in the present process include alkaline language and ammonium silicates of which sodium silicate (HagO.xSiOg) (where x equals 2-1 and potassium silicate (K ^ O.ySiO ^) (where y equals is preferred for 3-5). From organic considerations, organic silicates which can also be satisfactorily employed include quaternary ammonium silicates, which include tetramethyl ammonium silicate, phenyl trimethyl ammonium silicate and disilicate and tri silicate and benzyl trimethyl ammonium silicate and disilicate.

Such silicates suitable for use in the invention have the following formula ROE ': xSiO2: yi20 where R is a quaternary ammonium group substituted with four organic groups selected from alkyl, alkylene, alkanol, aryl, alkyl-aryl groups or mixtures thereof, while R 'represents either R or a hydrogen atom and x equals 1-3 and y equals 0-15 ·

Such water-soluble organic silicates and their synthesis and characterization are described extensively in the literature, such as the article by Merrill and Spencer, "Some Quaternary Ammonium Silicates" published in the Journal of-Physical and Colloid Chemistry, 30 55 s 1 ST ( 1951), the contents of which are incorporated herein by reference .. Similar silicates and a typical synthesis thereof are described in U.S. Patent 3,993,5-8, to which reference is made for further details.

Due to the relatively high cost of such organic silicates, the silicate wash solution preferably includes inorganic silicates, the potassium and sodium silicates of which are particularly preferred as described above.

In addition to the silicate compound, the silicate rinse solution may optionally contain a bath-soluble and compatible preservative for improving contact with the passivated surface, which is present in conventional amounts of about 0.05 to at most 5.0 g / l. The silicate rinse solution may also optionally comprise an emulsifiable organic substance, such as an emulsifiable oil, for example, present in an amount of about 1 - at most 50 g / l to form an oily film on the non-galvanized interior surfaces of the fer-10 substrates to provide temporary rust protection during the further processing step of the parts.

When such parts have surfaces that have been made fully passive, such as, for example, zinc die castings, the use of the optional emulsifiable oil is not necessary.

Similarly, there are applications in which an oil is not desired and yet a temporary rust protection of internal non-galvanized surfaces is required. In these cases, a final rinse solution containing a. alkali metal or ammonium nitrite, such as sodium nitrite, for example in an amount of about 0.1 to 1.0 g / l, are used. Preferably, a wetting agent or a combination of wetting agents is used, together with the sodium nitrite, for example in amounts of about 0.05-5.0 g / l. The presence of silicates in. the. final rinse solution is also compatible with this treatment.

The invention can be practiced in various ways, and a number of specific embodiments will now be described to illustrate the invention with reference to the accompanying examples.

Examples 1.1 and 1.2 relate to the first aspect of the invention which provides chromium-like passivating layers by using a chromium ion-free bath. Examples II. 1- II. 8 relate to the second aspect of the invention which utilizes iron and cobalt as the metallic activator and also incorporates trivalent chromium to form glossy blues.

35 like passivating layers.

Examples III.1-III.5 relate to the third aspect of the invention using cerium as metallic acetic acid

—87 0Ύ5Τ9; T

And which again contains tri-valent chromium, but in this case a yellow passivating layer is obtained analogous to hexavalene. chrome layers.

Examples IV. 1-7.3 relate to the fourth aspect of the invention using a carboxylic acid in baths of the same general type as shown in the examples of the second and third aspects. The carboxylic acid improves the initial hardening of the passivating layer.

Examples V.l-V. 8 relate to the fifth aspect of the invention using a bath soluble silicate in the bath, as well as trivalent chromium in baths of the same general types as shown in the examples of the second and fourth aspects. The silicate improves the initial hardening of the passivating layer and the corrosion resistance.

Examples VI.1-VI.5 relate to the sixth aspect of the invention, which uses a mixture of citric acid, and certain phosphonic acid to prevent loss of oxidizing agent and pH increase during the baths of the types such as described in the second and fifth aspects, too. obstruct.

: 2.0 Examples VU. 1-VII. 3 relate to the seventh aspect of the invention consisting of a silicate rinsing method after passivation whereby the passivation layer is cured.

Example 1.1

A chromium-free passivation concentrate was prepared containing 12 s / l ammonium difluoride, 12 g / l ferroammonium sulfate, 80 g / l cobalt sulfate and 4.5 volume% concentrated sulfuric acid. A treatment bath was prepared containing water to which 2 volume% of the aforementioned passivation concentrate was added in addition to 1.5 volume% hydrogen peroxide (38 # 's concentration). The treatment bath had a nominal pH of about 1.5-2.0.

Test panels with a glossy electro-galvanized film, which were rinsed with water after the electro-galvanizing step, and which were rinsed in a 5 volume% dilute nitric acid solution, were immersed in the treatment bath for a period of 20 seconds with light stirring. The test panels were then rinsed with water and air dried. The test panels were visually evaluated after drying and found to have a uniform clear on their surface

Bluish passivating film. The treatment bath had a nominal pH

^ of about 1.5-2.0.

\ 82 0 1 5 9 9 ”-3 ^ -

Example 1.2

In order to form a light yellow iridescent film on zinc electrogalvanized test panels, cerium ions were introduced into a test treatment bath containing 2 volt% of the bromine-free passivation concentrate as described in Example 1.1, 2 volume% of a cerium sulfate concentrate containing a 6 % cerium sulfate (Ce (SO2) 2) solution in a dilute sulfuric acid solution and contained 1.5% by volume of a hydrogen peroxide concentrate (38 #). The normal pi of the treatment bath was about 1 ., 5-2.0. ".

The test zinc panels were immersed after electroplating, cooling with water and dipping. stirring nitric acid into the test solution with light stirring for a period of 1 * 5 seconds. The treated test panels were rinsed with water and air-dried. On visual inspection, the surface of the test panels was found to have a sufficiently uniform light-yellow iridescent passivation film.

Example Π. 1 ^> A treatment bath was prepared containing:

Ingredients Concentration, g / 1

Cr2 (S (γ3 2.2 20 ÏÏÏÏj ^ ^ ^ HF HF HF HF HF HF HFgggg.

FeHH 2 SO 4 0.25.

CoSO4 .THgO. 1.6

25 * Ferrous ammonium sulfate * Pe (SO ^). (HH ^ JgSO ^ .óEgO

Steel test panels were subjected to an alkaline, non-cyanide electrogalvanizing stage before applying a zinc coating thereto, after which they were rinsed thoroughly with water and immersed in the aforementioned treatment bath for 20 seconds » After completion of the treatment, the passivated panels were rinsed with warm water and air dried. Examination x of the coating on the panels after drying found them to be particularly bright bluish without cloudiness. In addition, the coating exhibited the appearance of a shiny nickel chromium galvanizing coating as well as excellent stain resistance upon contact with the coating. 8201599 Γ -35- fingers.

Example II.2

A treatment bath was prepared containing:

Ingredient Concentration g / l _ 5 Cr2 (S0u) 3 5.6 nh4hf2 0.4

-¾8¾ 2 * T

ï2 ° 2 5.3

FeEH ^ SO ^ 0.58 CoSO ^ THgO3, T5

The treatment bath of Example II.2 is the same as that of Example II. 1, except that the trivalent chromium, ammonium bifluoride, sulfuric acid, iron and cobalt components are all present in higher concentrations *. Zinc galvanized test panels treated with the bath of Example 11.2 gave results substantially equivalent to those obtained with the. treatment bath of Example II. T.

Example H.3 ... _

A treatment bath was prepared containing: • Ingredient Concentration g / l 20 Cr2 (S0 ^) 3 3.0 ILH ^ HFg 0.24 H2S0 ^ 1.54 H2 ° 2 5.3

PeEH 2 SO 2 0.25 25. . . 2.1; ,,, '..

: 36 Nickel ammonium sulfate - EiSO ^ jiNH ^ JgSO ^ .OHgO

♦; · \

The zinc-galvanized test panels made under the same conditions as described in Example II. 1 were treated with this treatment bath. In addition, after drying, it was found to be provided with a coating which was very glossy with a clear bluish color without cloudiness. The coated. It also showed good stain resistance when touched by the fingers. Example II.4 A treatment bath was prepared identical to that of Example II. 3 8201599 -36- except that 1.6 g / l of nickel sulfate are used instead of 2.1 g / l of nickel ammonium sulfate. The zinc galvanized test panels. Treated in the same manner as described in Example 11 * 1 using the treatment solution of Example II.4 gave 5 results almost comparable to those obtained with the treatment bath. of Example 11 * 3, except that the coating showed a slightly less bluish discoloration.

Examples II.5A-II.5E

A series of passivation solutions were prepared to treat 10 zinc-galvanized steel test panels to reduce their relative corrosion. evaluate resistance to a $ 5 neutral salt atomization after passivation. The composition of the solutions 5A, 5B, 50 and 5D are listed in Table AI.

; 15; T A.B EDA1

Concentration / 1 ** ·· * ï, "" -

Ingredient II.5A II.5B II.5C II. 5D

Cr (80 ^ 2. 3.0 3.0 3.0 3.0 M ^ HPg '0.24 0.24 0.24 0.24 20 HgSO ^ 1.54 1.54 1.54 1.54 H202 5.3 5.3 5.3 5.3 - FeM ^ SO ^. - 0.25 0.25 0.25: CoSO3 - - 1.6 JTiHH ^ SO ^ - * - 2.1 - 25 Solution: II.5A contains only trivalent chromium ions; solution, II.5B also contains ferrous ions; solution II * 50 contains a combination of.

. :. iron and cobalt ions, while solution II.5D contains a combination of iron and nickel ions *

In addition to the aforementioned treatment solutions, a traditional hexavalent chromium passivation solution (IX. 5E) was prepared, serving as a control, and 0.63 g / l sodium dichrornate, 0.63 g / l ammonium difluoride, 0.01 g / l sulfuric acid and 0 65 g / l nitric acid. This solution is referred to as solution H.5E.

7.6 x 10.2 cm double sets of steel panels were cleaned and zinc galvanized for 15 minutes using a non-cyanide zinc galvanizing electrolyte at an electroplating current. ----- -------- ------- - - —- - - 8201599 2 -37- current density of 2.2 amps per dm (ASD), after which they were carefully rinsed. Then, each set of zinc-galvanized test panels was run in the resp. treatment solution after which they were rinsed with warm water, air dried and aged for 2 hours before being subjected to salt spray tests according to ASTM standards. The test panels were run for a total of 1 + 3 hours with the 5% neutral salt sprayed. For further comparison purposes, a double set of test zinc panels without any passivation treatment was also subjected to the neutral salt atomization test. The results are reported in Table A.

10. TABLE · A

Neutral salt atomization test results

Example Test Percentage of Fits Percentage of Red Naneels Corrosion,% Rust,% H.51, Untreated 50 50 15 II, 5A 5A 14-5-55 0 II.5B 5B 10-15 .0 IX. 5C 5C less than 2 0 II.50 50 Less than 10 0 II. 51 -51 1 + 5-55: 0 20 Based on the previous test results, it appears that the untreated zinc-galvanized leek panel is a major failure; the test panel treated with solution II.5A is a failure, the test panels treated with solution II.5B are magically sufficient; the test panels treated with solutions II. 5C and 11.50 pass the test; while the test panel treated with solution II.5E is a failure.

Example II. 6

A treatment bath was prepared containing:

Ingredient Concentration g / 1 '

Cr2 (SO4) 3 3.0 30 NH4 HFg 0.21+ K2 sock 1.51+

Feïï ^ SO ^ 0.21+ _ H2O2 5.3 -

MnSO ^. ^ O 1.0 82 0 1 5 9 9 ~ ...... ”'' vv '"

Zinc galvanized test panels obtained according to the procedure of Example II.5 were immersed in the bath of Example II for a period of 30 seconds. 6 immersed, rinsed with warm water, dried on air and aged for 2½ hours before conducting atomization tests with 5% neutral salt. For comparison purposes, test zinc panels were treated with solutions II.5A and II.5E of Example 11.5 and subjected to the same salt atomization evaluation.

Ha U8 hours with salt. sprayed, it was found on evaluation of several test panels that the panels treated with the solution of Example II.6 had excellent corrosion resistance compared to the panels treated with solutions 5A and 5E.

Example II.7

A bandage bath was prepared containing:

Ingredient Concentration g / l 15 Cr ^ CSO ^) 3.0. 0.2½% S01; 1.5½

FeHH ^ SQ ^ 0.2½ A ° 2 · 5’3 20 HgMoO ^ .H ^ O 1.0

With zinc. galvanized test panels obtained according to example 11.5 were placed in the bath of example IX for a period of 30 seconds. T immersed, rinsed with warm water, air dried and aged for 2½ hours before conducting nebulization tests with neutral salt. For comparison purposes, zinc test panels were treated with solutions II. 5A and II. 5E of Example II. 5 *. i I and · subject to the same salt misting evaluation. * * - - - ί t “-’ ”“ ‘-“

After being sprayed with salt for half an hour it was found after examination that the panels were treated with the solution of Example IX. T an excellent cor-.

Showed rosy resistance to the test panels treated with solutions II. 5A and II. 5E.

820 1 5 9 9 ”........." "" ....... '-39-

Example II.8

A treatment bath prepared containing:

Ingredient Concentration g / l

Cr ^ SO ^ 3.0 * 5 0.2¾

H2SO4 1.5U

FeUH ^ SO ^. 0.21 »H2 ° 2 5.3 (ΝΗ ^) ^ (ΐίίΜο02 ^ Ξ6) ^. 1» Η20 1.0 10

Zinc galvanized test panels obtained according to. the procedure described in example II.5 were immersed in the bath of example II.8 for a period of 30 seconds, rinsed with warm water, air dried and aged for 2 hours before being subjected to a. atomization test with 5% 1 s neutral salt ».

* 15 For comparison purposes, test zinc panels were treated with the solutions II. 5A and II. 5E of Example II »5 and subjected to the same high-mist evaluation.

Ha 1 »8 hours z nebulisation ·. it was found after evaluation of the panels that the panels treated with the solution of Example II.8 had an excellent corrosion resistance edge compared to the panels treated with the solutions U.5A and II.5E.

A relative comparison of the test panels treated according to examples II.6, II. 7 and II.8 showed that the solution of Example H.6 containing iron ions and molybdenumic acid and the solution of Example II.8 containing iron ions in combination with ammonim-6-molybdenum nickelate had better corrosion resistance than the test panels treated with the treatment solution of Example II.6, which combines iron ions; nation with manganese! The test panels treated according to examples II. 7 and II. 8 also had better corrosion resistance than the 30 test panels treated with the test solution II. 5B of example II. 5, which contained only iron ions, whereas the test panels treated with the solution of Example II.6, which contained both iron and manganese ions, had a corrosion resistance somewhat comparable to that of the panels treated with solution II.5B, 8201599 “~ -35 ......................................... -1 + 0 -.......... ....... ~~

Example IU.1

A concentrate III.1A was prepared containing an aqueous acidic solution with 25 g / l trivalent chromium ions introduced as chromium (III) -. sulfate (Korean MF from Allied Chemical Company), 12 g / l ammonium chloride, 12 g / l ferrous ammonium ulphate and 1+ volume l concentrated sulfuric acid.

A second aqueous acid concentrate III.1B was prepared containing 60 g / l trivalent cerium ions introduced as CeiSO ^ J ^. HgO and 5 volume% concentrated sulfuric acid.

A treatment bath was prepared containing water with 2 volume% concentrate III.1A, 2 volume% concentrate III. 1B and 1.5 volume% of a 38 # 's hydrogen peroxide solution contained. Galvanized test zinc panels immersed in this treatment bath for 1 + 0-60 seconds. had on them. surface a light yellow iridescent passivating film. Example III.2

A concentrate III.2A was prepared similar to. concentrate I.A

from example. I containing 25 g / l trivalent chromium ions, 20 g / l sodium chloride, 1 + 0 .g / l ferrous sulfate and 1+ volume% concentrated sulfuric acid.

f

A treatment bath was prepared containing water with 2 volume% concentrate III.2A, 2 volume%. concentrate ΙΙΧ.ΊΒ of example III. 1 and 20 1.5-3 volume% of a 38 # fs solution of hydrogen peroxide. Galvanized test zinc panels immersed in the treatment bath. gave results similar: to those of Example III. 1.

Example ΙΠ. 3

A concentrate IH.3A was prepared similar to concentrate 25 UI.IA of Example III. 1, except that 6 volume% nitric acid was used instead of k% sulfuric acid.

A treatment bath was prepared comprising water with 2 volume% concentrate III.3A, 2 volume% concentrate III.1B of Example III. 1 and 1.5-3 volume% of a sejS's solution of hydrogen peroxide. Galvanized test zinc panels immersed in the treatment bath gave results similar to those of Example 1.

Example III.k

A concentrate III. 1 + A was prepared similar to concentrate III.2A of Example III.2 with the exception that 6 volume # 's of nitric acid was used instead of 1+ volume% sulfuric acid.

A treatment bath was prepared with water containing 2 volume% IH.1 + A, 2 volume% concentrate IH.1B of Example III. 1 and 1.5-3 volume% of 82 0 1 5 9 9 -Ui - contained a 38 # 's solution of hydrogen peroxide. Galvanized test zinc panels immersed in the treatment bath gave results similar to those of Example III .. 1.

Examples III.5A-III.5G

A series of 7 aqueous test solutions were prepared, each containing 1 g / l trivalent chromium ions, 1 g / l nitric acid, 1 g / l sulfuric acid, 7 g / l hydrogen peroxide and with a nominal pH of about 0.5. test solution, controlled amounts of metal ions were added to evaluate the effect of such additions on the color, hardness and salt atomization resistance of the passivating films formed on galvanized test zinc panels, which stir under light for one. period of about 30 seconds and a temperature of about 21 ° C were immersed in each test treatment bath.

The cerium ions were introduced as a CeCl 2 solution.

15 contained about 300 g / l cerium ions; the manganese ions were introduced as MnSO 4 .H 2 O; the ferric ions were introduced as Fe 2 SO 4 dissolved in a dilute sulfuric acid solution; the molybdenum ions were introduced as sodium molybdate dry salt ·; the lanthanum ions were introduced as a LACl 2 solution containing about 85 g / l of lanthanum ions; and the cobalt ions were introduced as cobalt sulfate.

The test solutions are indicated as examples III. 5A-III-5G and the concentration of metal ion additives is summarized in Table B.

MYTH B

Metal ion concentration g / 1

25 Fore- .III.-5A III.5B: 111.50 III. 5D- III.5E: III.5F III.5G

statue “Metal ion”. CR + 3. 1 11 1 '1 1' 1

Ce * 3 2 2 2 2.2 2 2 30 Mn + 2 - 0.9 - - -

Fe + 3 - - 0.22 - - 0.08 0.08

Mo + é - - 1.0

La + 3 - - - 1.0 - - +2

Co ------ 0.13 82 0 1 5 9 9: -42-

Each test panel was immersed in the test treatment bath after immersion. rinsed with * water and air-dried and visually assessed for color and clarity. All test panels treated in solutions III.5A-III.5G had a substantially uniform pale yellow color in brightness ranging from a bright yellow film to films that were slightly cloudy or cloudy as listed in Table C. Each test panel was dried after drying. the. immediately air on hardness of the passivating film. Tested by light rubbing with the fingers * The comparable hardness test results of the film on the test panels treated in the test solutions III.5A-10 III * 5G are reported in Table C. It will be noted that after an aging period of 2b hours of the test panels , the film became hard and resistant to rubbing. The advantage of a film that is hard to air immediately after drying is that it can be handled during further processing without being damaged. Every tasting panel. that had been treated with test 15 treatment solutions III.5A-III.5G was also subjected to a neutral salt atomization for a period of 72 hours and the surface area, expressed as a percentage on which a white corrosion precipitate was formed. is also listed in Table C ..

TABLE · C

20; Trial results

Example Brightness Hardness Nebulization with neutral salt, 72 hours percentage white corrosion. 25 HI * 5A Slight cloudiness Soft 50 III. 5B "" "Soft 100:" III. 5 C "-" V. vHard. 10 III. 5D Turbidity Hard. 0 III .. 5E Slight Turbidity Soft 100 '30 III.5F Clear Soft 2 III.5G Clear Hard 0

Based on the data listed in Table B evaluated from the point of view of clarity and hardness, Example II.5G is a clear success, are Examples III.5C and 1115? acceptable, while examples 35 III.5A, III.5B and HI.5E are less acceptable with regard to the general appearance 8201599 '7 "' ~ .............” -43-. From the point of view of corrosion resistance, examples III.5D, III.5P and III.5G are a clear success, III.5C is just sufficient, while examples III.5A, III.5B and III5E are considered unacceptable based on the ASTM corrosion standard specifications for a 72 hour neutral salt atomization evaluation, however, it should be noted that each of the test samples has an improved corrosion resistance compared to an untreated galvanized zinc test panel and that the passivating films that did not pass the 72 hour neutral salt-1Ό atomization test for less severe The corrosion resistance according to Example III.50 is almost entirely comparable to that achieved with conventional hexavalent chromium passivation solutions of the types as known so far.

It is also clear that such variations in these types of combinations and concentrations of the metal ions present in the test solutions can be applied that the brightness, hardness and corrosion resistance of the test panels can be optimized and improved from the results as indicated in Table C. The choice of a 72 hour neutral salt atomizing condition is relatively strict and is generally used for parts intended for external use, such as automotive components. This 72-hour neutral salt atomization test is normally applied to yellow hexavalent chromium passivation layers although some specifications require only 8 hours while others require a treatment of. 96h: prescribe. The 72-hour trial period was thus adopted as the standard of average severity.

Examples IV. 1A-IV.1G

A series of trivalent chromium-containing concentrates was prepared suitable for dilution with water to supplement a treatment; bath in further combination with an oxidizing agent and cerium or lantamum.

! * * .. *** · 30 .ions as follows: - 82 0 1 5 9 9 \\\ l l

Concentrate IV.IA i

Component Concentration, g / 1

Cr + 3 '2k

CoSO ^ .TT ^ O 25 5 Ferrous ammonium sulfate 12 Sodium fluoroborate 15 Succinic acid 25 Nitric acid ($ 100) 60

Concentrate IV.1B

10 Component Concentration, g / 1

Cr + 3 2b

NaCl '20

Ferrous ammonium sulfate 25 sodium succinate 55 15 nitric acid ($ 100) 60

a

f

Concentrate IV.1C

Component Concentration, g / 1

Cr + 3 2b ferric ammonium sulfate 50 20 sodium succinate 55

NaCl 20 nitric acid ($ 100) 60

Concentration IY.1D

Component Concentration, g / l. 25. Cr + 3: - 2k.

ferric ammonium sulfate 50 succinic acid 25

UaCl '20 nitric acid (100 $) 60 82 0 1 5 9 9 «v - \ ____ -ί + 5-

Concentrate IV.IE

Component Concentration, g / 1 _ __

Cr + 3 2h ferric ammonium sulfate 50 5 HaCl 20 malonic acid 25 nitric acid ($ 100) 60

Concentrate IV. IE.

Component Concentration, g / 1 10 Cr * 3 2k? * 2 (SOk) 3 30 liaCl 20 - gluconic acid 20 nitric acid ($ 100) 60 \

15 Concentrate IV, 1G

Component Concentration, g / 1

Cr * 3 2t ferric ammonium sulfate 50

NaCl 20 20 maleic acid 25 nitric acid. (100 $) 60.

Examples ry.2A ~ IV-.2G

A cerium ion concentrate became. formed containing about 80 g / l cerium (IV) ions in the form of cerium (IV) sulfate in a dilute sulfur (25, acid solution). An oxidizing agent concentrate containing about 35% hydrogen peroxide was also provided * A series of treatment baths was prepared to form a yellow passivation film on a substrate, each containing 2 volumes of the cerium ion concentrate, 2 volumes of the oxidizing agent concentrate and 2 volumes of one of the chromium concentrates IV.1A-IV.1G of Examples IV.1A-IV.1G.

Steel test panels were subjected to an alkaline. non-cyanide galvanizing step for applying a zinc layer thereon. after which they were rinsed thoroughly with water and stirred in each of the test treatment baths with stirring for about 30 seconds. -. Immersed in a temperature of about 21 ° C, and having a pH ranging from about 1.5 to 2.0. After termination of the passivation treatment, the passivated panels were rinsed with warm water and air dried. Evaluation of the coating 5 on each of the test panels immersed in each of the treatment test solutions showed that a clear hard yellow passivation film had been formed.

Examples XV.3A-XV.3g

A late anumone concentrate containing about 60 g / l of lanthanum ions in the form and a solution of lantanum chloride was dispensed. An oxidizing agent concentrate containing about 35 # hydrogen peroxide was also used. A series of treatment baths were prepared, suitably. to form a blue-gloss passivating film on a substrate, each containing 2 volume% of the lanthanum ion concentrate, 2 volume% of the oxidizing agent concentrate and 2 volume% of one of the chromium concentrates. IV.aa-IV.1G of example IV. 1. "

Electrolytic zinc-coated test panels as described in preamble. picture IV..2 were taken at the in. the conditions described in Example IV.2 were then rinsed with warm water and air-dried. When evaluating the coating of each of the test panels after drying, a particularly glossy, clear, hard bluish colored passivating film.

The yellow passivated panels of Examples IV.2A, IV.2B and ·. IV.2C formed ... using. treatment baths .. which resp. the concentrates described above IV. IA, IV. 1B and IV. 1C, were aged for at least 2k hours and subjected to neutral salt spray atomization corrosion tests according to ASTM procedure B-117. The next ; Table D indicates the results of the corrosion resistance obtained under J.

application of these compositions! \ 8201599 '· "' Γ \ \ - ^ 7-

TABLE D

Chrome hours, neutral salt spray

Example of one-street tram 72 96 IV.2A IV. 1A 'clear with some Clear with some dark spots dark spots IV.2B IV.1B Clear with some Clear with some dark spots dark spots IV.2C IV.1C Clear with some Some dark spots- dark spots 1 $ Flecks The "above results indicate that panels" treated with treatment baths containing concentrates A, B and C "passed the 96 hour salt spray test. Similar results were obtained with panels formed using the other concentrates.

EXAMPLE V.1 A treatment bath suitable for applying a yellow passivating film to a receptive substrate was started using a trivalent chromium-containing concentrate designated "concentrate V, 1A" having the following composition:

Concentrate V.IA _____________ 20 Component Concentration, g / 1

Cr + 3 50 ferric ammonium sulfate 30 sodium chloride 20 nitric acid (100 $) 60 25 succinic acid 20

The trivalent chromium ions were introduced as Cr ^ iSO ^) ^

It was started from a cerium ion concentrate designated as "concentrate V. 1B" containing about 80 g / l cerium (IV) ions as cerium (IV) sulfate in a dilute (about 5%) sulfuric acid solution.

Also, an oxidizing agent concentrate containing about 35% hydrogen peroxygen was used. It was further started from a sodium silicate concentrate containing 300 g / l of sodium silicate, calculated as SiO4.

A yellow passivating layer treatment bath was prepared starting from water containing 2 volume $ of the concentrate V.1A, 2 volume $ 35 of the cerium ion concentrate, 5.1B, 2 volume $ of the oxidizing agent. -48- concentrate and. 0. U volume 1 of the sodium silicate concentrate ".

Steel test panels were subjected to an alkaline, non-cyanide galvanizing step to form a zinc layer thereon, after which. they were rinsed thoroughly with water and immersed in the treatment bath at a temperature of about 30 seconds with stirring. about 21 ° C and a range ranging from about 1.5 to 2.0. Then the test panels were taken from the treatment bath and dried with recirculating warm air.

After drying, the test panels were visually inspected to reveal a very hard, bright yellow passivating film.

After aging for at least 2b hours, the test panels were subjected to the corrosion test in which neutral salt was sprayed according to the ASÜM procedure B-11T. The thus treated according to the present method. Partial test panels were found to be excellent-stocked after treatment for a period of more than 96 hours. to be against this salt atomization.

Example V. 2 • A treatment bath suitable for applying a yellow passivating film to a receptive substrate was started from by forming a tri-chromium-containing concentrate designated as "concentrate 20 V.2A" having the following composition:

Concentrate V.2A .....______ ^

Component Concentration, g / 1

Cr + 3 50 ferric ammonium sulfate 4-0 25 sodium chloride 20 nitric acid ($ 100) 60 sodium silicate (calculated - - ->. 'As SiOg)' 10

It was assumed that one. yellow passivation bath consisting of water with 2 volume% of. concentrate: V.2A, 2 volume% of cerium ion concentrate 30 V, 1B of example V. 1, and 2 volume% of the oxidizing agent concentrate of example V.1.

Test panels formed according to the procedure described in Example V. 1 'were treated for a period of about 30 seconds. . O

the immersion bath at a temperature of about 21 DEG C. and a pH

Ranging from about 1.5 to about 2.0. The treated test panels were supplied with recirculating dehydrated air and the dried panels "showed a very hard, bright yellow passivating film.

After aging, the test panels were subjected to the salt spray corrosion test as described in Example V. 1 and found to have excellent salt spray resistance after treatment for a period of more than 96 hours,

Example V.3 ______________

A treatment bath suitable for applying a yellow passivating film to a receptive substrate was used using a trivalent chrome-containing concentrate designated as "concentrate -V.3A", having the following composition:

Concentrate V.3A * _______________

Component Concentration, g / 1 _____

Cr + 3 50 15 ferric ammonium sulfate 40 nitric acid ($ 100) 60 sodium chloride20

A treatment bath was prepared comprising water containing 2 volume% of concentrate V.3A, 2 volume% of the cerium ion-containing concentrates. 7. 1B of Example V. 1.2 volume% of the oxidizing agent concentrate of Example V, 1, and 0.5 volume% of the sodium silicate concentrate of Example V, 1. ·

Galvanized zinc test panels were treated in the bath. according to the procedure of Example V..1 and after drying were found to have a good bright yellow passivating film.

The test panels also had a good salt deadening resistance, indicating excellent corrosion resistance.

Example Y.b

A treatment bath suitable for applying a yellow passivating film to a receptive substrate was started from by forming a trivalent chromium-containing concentrate incorporating a quaternary aminesilicate designated "concentrate V.UA", with the following composition: \ 8201599 \ ~ -50-

Coneentraat V.kA

Component Concentration. G / 1 + 3

Cr J 30

3E

Quaternary amines silicate 15 sodium chlorine -15 s Quram 220, calculated as SiO 2.

The trivalent chromium-containing concentrate V.kA was stored for a long time and was found to have excellent stability during such a long storage period.

In addition, a second concentrate, indicated as "concentrate V.kB", was prepared with the following composition.

Concentrate V.kB

Component Concentration, g / 1 nitric acid (100 #) 60 15 sulfuric acid (100 #) 30 ferric sulfate. Cerium chloride 120

A treatment bath was prepared comprising water with 2 volume # of concentrate V.kA, 2 volume # of concentrate V.kB and 2 volume # of 20 antioxidant concentrate described in Example V.1.

Zinc-galvanized test panels were contacted with the treatment bath according to the procedure, and under the conditions described in Example V. 1, after which the test panels were dried with circulating warm air. The test panels, after evaluation, proved to be an excellent hard and bright yellow passivating film in addition to a protrusion; Known to have salt atomization resistance, with no white corrosion formed after neutral salt atomization tests over a period of 96 sails,

EXAMPLE V.5 A second series of galvanized test panel panels were treated with the bath as described in Example Vk under the same conditions, the test panels were rinsed with water and then rinsed in room temperature for a period of 30 seconds. an aqueous solution containing 10 g / l sodium silicate, calculated as SiO 2, V 8201599 -51-. After rinsing, the panels were taken out of the solution and dried with warm air. .

The test panels were evaluated and found to have a very hard, bright yellow, passivating film. After aging, the test panels. subjected to the salt haze corrosion test, where they were found to have excellent salt haze resistance after a treatment of 96 H + O hours. to own. These tests also showed that when a silicate rinse is used, the presence of some nitrate ions in the passive film-forming treatment bath is desirable to avoid, in some cases, some haze in the film as - consequence of the ~ after immersion treatment.

Example V.6

A treatment bath suitable for applying a blue-gloss passivating film was started. on a receptive substrate.

15 using a concentrate designated as "concentrate V. 6A" having the following composition:

V

t

Concentrate V.6A -_________________

Component Concentration- g / 1 · _______ nitric acid ($ 100) 30 20 sulfuric acid ($ 100) 20 barastenic acid 20

La-BE-Cl ^ 80. ,>

A treatment bath was prepared comprising water containing 3% by volume of concentrate Y.kA of Example V-Λ, 3% by volume of concentrate V.6A and 3% by volume of the oxidizing agent concentrate of Example V. 1.

Galvanized test zinc panels were treated with the bath full.

• according to the procedure of example V.1. And after drying the test panels were found to have an excellent blue-glossy film. also excellent corrosion resistance as demonstrated by the absence of white corrosion after being subjected to the salt spray corrosion test for a period of 78-82 hours.

Examples V.7-.1 and V.7.2. .. -.

A trivalent chromium-containing concentrate was prepared designated "concentrate V.7A" having the following composition: 820 1 5 9 9 —-: - · -: "" \ -52-

Concentrate V.7A _ _ __ Component Concentration, g / 1

Cr + 3 30 sodium chloride 10 5 sodium silicate (calculated as

SiOg) 10

A treatment bath (example VT1) suitable for applying ... a yellow passivating film to a receptive substrate was prepared using 2 volume% of concentrate V.TA, 2 volume% of concentrate Y.k3 of example Υ ' Λ and 2 volume% of the oxidizing agent concentrate of Example V. 1. In addition, a treatment bath (Example V.7 * 2) suitable for applying a blue glossy passivating film was prepared using 2 volume % of concentrate Y. YES, 2 volume% of concentrate Y.6a of Example Y.6 and 2 volume% of the oxidant in one portion. from example. 7.1-15 v Test panels treated according to the. procedure described in. Example V. 1 was found to have excellent passivating films with excellent corrosion resistance.

Example 7.8

A treatment bath suitable for application was started. 20 of a blue-gloss passivating film on a receptive substrate by forming a trivalent chromium-containing concentrate, referred to as "concentrate Y.8A", having the following composition: Λ

Concentrate V.8A

Component Concentration, g / l -. . 25 Cr + 3 30: ''. . v. , sodium chloride 13 -Vvr · ..- ·>. * sodium gluconate 10 '·.

quaternary amine silicate * 15 s Quram 220, calculated as SiO4.

A second concentrate, referred to as "concentrate V.8B", was used with the following composition: 820 1 5 9 9 ~ ...... '-53-

Concentrant V.8B ____________________

Component Concentration, g / 1 nitric acid ($ 100) 60 sulfuric acid ($ 100) 30 5 Al ^ SO ^ 30. A treatment bath was prepared comprising water containing 3 volume% of concentrate V8A, 3 volume% of concentrate V.8B and 3 volume% of the oxidizing agent concentrate of Example V. 1.

Galvanized test zinc panels were treated according to the procedure described in Example V.1 and found to have a clear-gloss passivating film upon drying. Corrosion tests with such panels carried out by neutral salt atomization showed a corrosion resistance of at least 12 to 2 hours.

Example 71.1 A treatment bath suitable for applying a yellow passivating film to a receptive substrate was started from by forming a trivalent chromium concentrate, referred to as concentrate "VX.1A", with the following composition:

• - I

Concentrate VI. 1A

- 20 Component. Concentration, g / 1 • +3

Cr ° 30 quaternary ammonium silicate 15

HaCl - 15

The trivalent chromium ions were introduced as Cr 2 iSO 2, while the silicate compound was introduced as Quram 220 from Emery Industries. -I; A cerium ion concentrates designated as "Concentrate VI.1S *", having the following composition, were used: · "

Concentrate VI. 1B

Component Concentration, g / 1 30 HN03 (100 $) 60 - "

HgSO ^ (100 $) 30 - fe (SOl () 3 25 -Ce S 120 _____ '' -5U '' ........

The cerium ions were introduced by means of a cerium chloride +3 solution containing about 300 g / l Ce ions.

In addition, an oxidizing agent concentrate containing about 35% hydrogen peroxide was prepared.

A series of one liter treatment baths was prepared containing 3 volume% of concentrate VI. 1A, 3 volume% of concentrate VI. 1B and 3% by volume of the oxidant concentrate. In order to simulate an aged treatment bath used to passivate zinc workpieces, 1 g / l zinc powder was dissolved in each test solution.

Such a test solution without further additives was designated as test solution VI.1.1. And served as a control sample. To a second test solution, designated VI.1 »2, Tg / l citric acid and 0A g / l 1-hydroxyethylidene 4i-diphosphonate (Dequest 2010) was added as a stabilizing agent. To a third test solution, designated 15 VI. 1.3 T g / l citric acid and 0.08 g / l 1-hydroxyethylidene-1,1-diphosphonate (Dequest 2010) were added.

. Each test solution was stirred at room temperature. simulate a typical commercial implementation. The pH at the beginning and end and the peroxide concentration measured in volume% of a 35% 1 s hydrogen peroxide concentrate remaining in the bath was monitored for a period of. Analyzed for 1 day. The results are as follows:

Hydrogen peroxide concentration and nS Test sample

Example VI.1.1 VI. 1.2 VI. 1.3

25 Time H202 pH pH S202 pH

Start 2.56 $ 1.6 2.95 $ 1.6 3.05 $ 1A '. ·. ; ·, After 3.5 hours, ·. 2.39 $. "A" · 2.92 $; -v 2.8U $ '. ,.

After 21 hours '0.83 $ - 1, T2 $', - 2.3T $. "W7

After 26 hours 0.50 $ 2.5 1, b2% 1.8 -. -

From the results reported in the table above, it is clear that Control Example VI.1.1, which did not contain any stabilizing agent, quickly lost the peroxide oxidizing agent, which was in a concentration of. at least 2 volumes of $ had to be present to enable and maintain a suitable passivation treatment: A nearly complete charge *.

8201599 ~ -55- filling of the ozydatide agent in sample VI. 1.1 would therefore already be necessary after a period of about 1 day. In contrast, sample VI.1.3 showed only a slight loss of peroxide after 21 hours, while sample VI.1.2, which contained a small amount of Dequest 2010 5 in combination with 1 g / l citric acid, relative to the control sample. VI.1.1 also exhibited surprising and excellent peroxide stability.

The stabilization of the pH is also clear from the data in the preceding table. Control sample VI.1.1 rose to a pH level of 2.5 after 26 hours, which would have required the addition of acid to the treatment bath to maintain the pE within the preferred range of 1.5-2.0 * In contrast, both samples were VI.1.2 and VI. 1 * 3 practically stable and remained within the optimal PI range throughout the test.

15 Example VI.2 ____

An aqueous stabilizer concentrate was prepared containing 570 g / l citric acid and 110 g / l 1-hydroxyethylidene-1,1-diphosphonate (Dequest 2010). These treatment solutions were prepared as described in Example VI. 1 and contain 3 volume% of concentrate VI. 1A, 3% by volume of 20 concentrate · VI..133, 3% by volume of the oxidation concentrate and 1 g / l zinc substance to age the baths. A control sample designated VI.2.1, which did not contain any stabilizing agent, had an initial peroxide. concentration of 3% but haclna for a period of 18 hours under the conditions of Example VI * 1. stored a residual peroxide concentration of only 1.05%, necessitating replenishment.

A second test solution, designated VI, 2.2, was stabilized by adding 2.5 ml / l of the stabilizer concentrate and had an initial *. peroxide concentration of 3% and after one period. of 18: hours of residual peroxide concentration; ivan 2, k3 $. . 30 Example VI.3

In order to improve the effect of the peroxide and the pH stabilizing agent of this aspect of. To evaluate the invention under current commercial operating conditions, the stabilizer concentrate as defined in Example VI.2 was used to stabilize a trivalent chromium passivation solution with a composition analogous to the treatment bath of Example VI.1 containing trivalent chromium ions, iron and cerium ions contained the pH in the range of from about 1.5 to about 2.0 820 1 5 9 9 -5 -56-. .. to be set at a temperature of about 21 ° C and containing hydrogen peroxide as an oxidizing agent. Under normal operation, in the absence of the stabilizing agent, it was necessary to replenish the peroxide oxidizing agent in the commercial treatment bath each morning at the beginning of the treatment adding 3 volume% of a 35% hydrogen peroxide concentrate, as well as after about ^ For hours, add a further 1 volume% of the peroxide oxidation concentrate to maintain the bath at a minimum of 2 volume% oxy oxidant.

By adding 1 L of the stabilizer concentrate per 378 L of the treatment bath, the replenishment of the peroxide oxidation concentrate was reduced to only 1 volume% each operating day and after standing during the weekend to only 2 volume% needed to return to suitable operating conditions.

In addition, the addition of stabilizer concentrate 15 added. The treatment bath further stabilized the pH over a 6 day test period, keeping the pH practically constant and avoiding the need for acid addition to control the pH.

In. in contrast, when no stabilizer concentrate was added to the same commercial treatment bath, it was necessary. The pH was frequently controlled and it was periodically necessary to add acid to maintain the pH within the desired range of 1.5-2.0.

Shiny electrolytic zinc coated parts used in the aforementioned commercial bath. were treated after aging for at least 2b hours subjected to the neutral salt spray salt corrosion test according to ASM procedure B-117. The excellent corrosion resistance of the yellow passivating film was demonstrated by the absence of white corrosion on the parts after a 96-hour salt spraying (field test. · ··· _ / ·; ^.

"Example TL Λ" - 30 Stabilization of a commercial treatment bath with the composition of and using the procedure described in Example VI.'3 was achieved by preparing an aqueous stabilizer concentrate containing about 30-170 g / l 1- hydroxyethylidene-1,1-diphosphonate (Dequest 2010) mixed with about 160-500 g / l citric acid. The stabilizer concentrate was added to the commercial treatment bath in such an amount that an operating concentration of 1-hydroxyethylidene-1,1-diphosphonate of. about 0.05-3 g / l and an operating concentration of the. ________- -57- hydrochloric acid component of about 0.1-10 g / l was obtained. The results obtained are similar to those described in Example 71.3.

Example VI.5

A treatment bath suitable for applying a yellow passivating film to a receptive substrate was started from by forming a concentrate referred to as "Concentrate VI, 5A" having the following composition:

Concentrate VI, 5A ___ "·

Component Concentration, g / 1 ____ _ 10 HN0 „(100 $) 60 3 H2S0 ^ (100%) 30 ϊ« 2 (8 ° ^) 3 25

PeC ^ .5 disphosphonate ^ 8.5 15 citric acid 36 +3, e 0 120 s Dequest 2010

A treatment bath was prepared containing 3 volume% of the chromium ion concentrate VI. 1A of Example VI. 1.3 volume% of the concentrate. VE..5A. 20% and 3% by volume of the oxidizing agent concentrate containing about 35% hydrogen per oxyde.

Steel test panels were subjected to an alkaline non-eyanide galvanizing step to apply a zinc coating thereon, after which. . they were rinsed thoroughly with water, and rinsed for about 30 seconds at a temperature of 21 ° C and a pH ranging from about 1.5 to about 2.0 in the passivation treatment bath. stirring was immersed. The test panels were then taken from the treatment bath and dried with recirculating warm air.

After drying, the test panels were visually assessed to be coated with a uniform clear yellow passivating film. A slight addition of ferric chloride to the treatment bath gives an improvement in the color intensity of the yellow film compared to that obtained using the passivation treatment bath of Example VI. 1.

The test panels were subjected to 35 ha of aging.

Neutral salt test according to the procedure described in pre-8201599 -58-.

picture VI.3 * where equal results were obtained.

Example VII.1

A treatment bath suitable for applying a yellow passivating film to a receptive substrate was prepared as follows: j First, a trivalent chroam-containing concentrate designated "concentrate. VIL.1A" was prepared having the following composition:

Concentrate VII.1A

- Component. Concentration, g / 1

Cr + 3 25 10 ferric ammonium sulfate 30 sodium chloride 20 nitric acid (10055) 60 succinic acid 20

Men. started from cerium ion concentrate VII .. 1B containing about 15 80 g / l cerium (IV) ions in the form of cerium (IV) sulfate in a dilute (about 5 / 5's) sulfuric acid solution. An oxidizing agent concentrate containing about 35/5 hydrogen peroxide was also provided.

A yellow passive film forming treatment bath was prepared comprising water containing 2% by volume of concentrate VII. 1A, 2 volume% of the cerium ion concentrate VII. 1B and 2% by volume of the oxidizing agent concentrate and CU. 1C. *

An aqueous silicate rinse solution was prepared containing 10 g / l sodium silicate, calculated as SiO4.

Samples, test panels were subjected to. an alkaline, non-cyanide galvanizing stage for applying a zinc layer thereto, after which they were rinsed thoroughly with water and for a period of: about 30 seconds at a temperature of about 21 ° C and a temperature ranging from about 1.5 to about -2.0. were immersed in the stirred treatment bath. The test panels were taken out of the treatment bath, rinsed with tap water and then in the silicate rinse solution for about 30 seconds at a temperature of about 21 ° C. touched. The silicate rinsed test panels were taken from the rinse solution and. dried with recirculating warm air.

During drying, the test panels were visually assessed, revealing that they were provided with a very hard bright yellow passivating film.

8201599 -59-

The test panels were subjected to aging for 2b hours. - to the corrosion test by spraying with neutral salt according to ASTM procedure B-117.

The test panels 5 treated according to the method of the invention exhibited excellent salt atomization resistance after being treated for a period of more than 96 hours *

Examples 711.2. i-VH. 2. I ____________...._________

A series of trivalent chromium-containing concentrates were prepared suitably by preparing a treatment bath by dilution with water in further combination with an oxidizing agent and cerium or lanthanum ions as follows:

Concentrate VII, 2A ________________

Component Concentration, g / 1 ____________

Cr * 3 2b - 15 CoS0 ^ .7H20 25 ferrous ammonium sulfate 12 t sodium fluoroborate '15.

succinic acid 2? nitric acid (100?) 60 20. Concentrate VII.2B -. '_____

Component · ~. Concentration, g / 1 · "'

Cr * 3 2b.

Had 20 ferrous ammonium sulfate 25 25 sodium succinate 55 nitric acid (100JS) _ 60 vol. -

Concentrate VII.2C

Component Concentration, -g / 1 '.

Cr * 3 2b 30 ferric ammonium sulfate 50 sodium succinate 55

NaCl 20 nitric acid ($ 100) 60 .. ·. I 1 · _ - - - - _ · - _t.

8201599 -6o-

Concentrate VII.2D

Component Concentration, g / 1

Cr + 3 2k ferric ammonium sulfate 50 5 succinic acid 25 aTaCl 20 nitric acid ($ 100) 60 Concentrate VII.2E j

Component Concentration, g / l 10 Cr + 3 2 \ feir ammonium sulfate 50

NaCl 20 malonic acid 25 nitric acid1 (100JS) βθ

15 Concentrate VII.2F

Component Concentration, g / 1

Cr "** 3 2k ^ (S0k) 3 30. BeCl 20 20 Gluonic acid 20 Nitric acid ($ 100) 60

Concentrate VII.2C

Component. Concentration, g / 1. Cr + 3 2h'25 ferric ammonium sulfate. . '50 ..

NaCl 20 maleic acid 25 nitric acid ($ 100) 60 /

It was started from a cerium iononeonrate containing about 80 g / l cerium IV) ions in the form of cerium (IV) sulfate in a dilute sulfuric acid solution. An oxidizing agent concentrate containing about 35% hydrogen peroxide was also provided. A series of treatment baths (examples VH.2.1-VII.2.7) were used. prepared ready to apply a 8201599 'I .......... i -6ι- yellow passivating film to a substrate »each of which contains 2 volume% of the cerium iononeonrate, 2 volume% of the oxidizing agent conene trant and 2 volume% of one of the chromium concentrates VII.2A-VII.2G, respectively.

A lanthanum ion concentrate with about 60 g / l of lanthanum anions in the form of a solution of. lantanum bloride ..

Also, an oxidizing agent concentrate of about. Contained 35% hydrogen peroxide. A series of treatment baths (examples VI.2.8-VTI.2.1U) was prepared suitable for applying a blue-gloss passivating film to a substrate, each containing 2 volume% of lanthanum ion concentrate, 2 volume% of oxidation gel - centrate and 2% by volume of one of the chrome concentrates of resp. VII..2.A-VII.2.G.

Zinc galvanized steel test panels as described in Example VII. 1 were treated under conditions of Example VEE.1 in each of the baths (Examples .VII.2.1-VII.2.1U) after which the passivating panels were rinsed with silicate using an aqueous silicate rinse solution, in which the silicate concentration was varied from about 1 to about 40 g / l, calculated as SiO 2, at temperatures ranging from 10 to 66 ° C. 35th panels were subsequently air dried and subjected to the neutral salt spray corrosion test as described in Example VII. 1. The same results as stated in Example VII were obtained. 1 obtained.

Examples VII. 3.1-VII.3.6 25 A series of treatment baths have been prepared; these are as follows:.

Treatment bath VII. 3A. . ...... ·. - -.

Component Concentration, g / 1

Cr2 (SQ ^) 3 2.2 30 HH ^ HFg 0.18 'H2S0 ^ 1.2 S2 ° 2 5.3 ...

FeMH ^ SO ^ * 0.25

CoSO ^ .THgO 1.6 -

35 s Ferrous ammonium sulfate = FefSO4). (Mj ^ SOj ^ .éHgO

v '82 0 15 99 \' v ~ ^ '\ -62-

Treatment bath YII.3B

Component Concentration, g / 1

Cr ^ SO ^ 5.6 mkBF2 0.4 5 H 2 SO 2 2.7 H 2 O 2 5.3

FeNH ^ SO ^ 0.58

CoS0u.7H20 3.75

Treatment bath VII, 3C

10 Component Concentration, g / 1

Cr ^ SO ^ 3.0 M ^ HFg 0.24 H2S0u 1.54.

2 5.3 5.3 FeHH 2 SO 4. 0.25 rfiBH ^ SO ^ * 2.1

g Onion ammonium sulfate = HiSO ^. (MH ^^ SO ^ .ÖB ^ O

Treatment bath VII.3D

Component Concentration, g / l 20 Cr ^ SO ^ 3.0 HH ^ HF ^ 0.24. 1, * 54 - '

FeHH ^ SO ^ 0.24 'H2 O2 5.3-25 MnSOj ^ O 1.0 #

Treatment b ad VII.3E

Component Concentration, g / 1 "<* 2 (* V3 ', 3, °' mkEF2, 0.24-30 E2SOk 1.54

FeM ^ SOj, 0.24 H2 ° 2 5-, 3 ^ MoO ^ .HgO 1.0 \ 82 0 1 5 9 9:

V

-63-

Treatment bath 7II.3F ...._____________________ Component Concentration, g / l __ ______ 0γ2 (80 ^) 3 3.0 UH ^ HF ^ 0.24 5 E2S0u 1.54

PeUE ^ SO ^ 0.24 H2O2 5.3 1.0

Zinc galvanized test panels obtained as described in Example I were treated in the aforementioned baths (Examples VII.3.1-VII.3.6) under the conditions described in Example VII. 1, after which they were rinsed with water, and rinsed with aqueous silicate in a rinsing solution in which the silicate concentration calculated as SiOg / was varied from about 1 to about 40 g / l at a temperature ranging from about 10 to 60 ° C ·. The passivated and rinsed panels after drying were subjected to salt atomization tests as described in Example VII.1 to obtain similar results.

___ · _ \ __.

8201599 \

Claims (80)

An aqueous acidic solution suitable for "treating receptive metal substrates to apply a passivating film thereon, characterized in that these a) are hydrogen ions to obtain an acidic pH, b) an oxidizing agent and c) at least one of the following ions: Iron, Cobalt, Nickel, Molybdenum, Manganese, Aluminum, Lantanum, Lantanide mixtures or Cerium ions, or mixtures thereof, in an increased corrosion resistance for imparting to the treated substrate effective amount 10 2, Aqueous acidic solution for treating receptive metal substrates, to apply a passivating film thereon, characterized in that they are: a) an acid, b) an oxidizing agent, 15 e.) contains iron and cobalt ions in an amount effective for imparting an increased corrosion resistance to the treated substrate. An aqueous solution according to claim 1 or 2, characterized in that: it also contains d) chromium ions which are substantially all in a trivalent state, 20 h. Aqueous acidic solution for treating receptive metal substrates to apply a passivating chromate film thereon, characterized in that it comprises: a) an acid, b) a. oxidizing agent · ,. C) iron ions in combination with at least one additional metal ion. from cobalt, nickel, molybdenum, manganese, -lantanum, lantanide mixtures and. blends thereof in one before it. to the treated substrate: imparting an increased corrosion resistance effective amount, and d) chromium ions which are practically all in the trivalent state. Aqueous acidic solution for treating receptive metal substrates to apply a passivating chromate film thereon, characterized in that it comprises: a) an acid b) an oxidizing agent c) cerium ions in a pre-treated substrate imparting "w \, δΤοΎίΠΓΓ" ”: '' ...... '-65- an increased corrosion resistance effective amount of 9 and d) chromium ions which are substantially all in the trivalent state. 6, Aqueous acidic solution for treating receptive metal substrates to apply a passivating chromate film thereon, characterized in that it comprises: a) hydrogen ions to obtain an acidic pH, b) an oxidizing agent. c) at least one additional metal ion selected from iron, cobalt, nickel, molybdenum, manganese, lanthanum, lanthanide mixtures, and cerium mixtures thereof, present in an amount effective to impart increased corrosion resistance to the treated substrate, and d) chromium ions which are substantially all are in the trivalent state, and e) a bath-soluble and compatible organic carboxylic acid which is in. a. effective amount is present to impart initial hardness and clarity to the passivating film, the organic acid having the following structural formula; V (OH) R (COOH)? D where; a is an integer from 0-6; 20. is an integer from 1 to 3; ; and R represents an alkyl, alkenyl or aryl group having 1 to 6 carbon atoms; as well as the bath soluble and compatible salts thereof. 7. Aqueous acidic solution to treat receptive metal substrates to apply a passivating chromate film thereon, characterized in that it comprises: a) hydrogen ions to obtain an acidic pi; . (b) an oxidizing agent,. v- c) at least one additional metal ion selected from iron, cobalt, nickel, molybdenum, manganese, aluminum, lanthanum, lanthanide mixtures and cerium, and mixture thereof in an increased corrosion resistance to impart to the treated substrate. effective amount, d) chromium ions which are substantially all in the trivalent state and are present in an amount effective to obtain a chromate film and f) a bath-soluble and compatible silicate compound present in an ef 8201599 P .....- c -66- ........ ~ ....... 'effective amount to give the passivating film an improved hardness and the substrate an improved corrosion protection. 8. Aqueous acidic solution for treating receptive metal substrates to apply a passivating chromate film thereon, characterized in that it comprises a) a hydrogen ion to obtain an acidic pH, b) an oxidizing agent, c) at least one additional metal ion selected from iron, cobalt, nickel, molybdenum, manganese, aluminum, lanthanum, lanthanide mixtures and cerium and mixtures thereof present in an amount effective to impart increased corrosion resistance to the treated substrate, d) chromium ions practically all in the trivalent state and present in an amount effective to form a chromate film, and 15 g) a stabilizing agent comprising a mixture of 1-hydroxyethylidene-1,1-diphosphonic acid and citric acid as well as the bath soluble and compatible salts thereof contained in an effective amount to reduce the loss of oxidizing agent and hinder an increase in the pH of the solution. Aqueous acidic solution according to claims 1-8, characterized in that component A is supplied by an acid. · An aqueous solution according to claim 9, characterized in that said acid is a mineral acid. An aqueous solution according to claim 10, characterized in that the mineral acid comprises sulfuric, nitric or hydrochloric acid or mixtures thereof. An aqueous solution according to claims 1-11, characterized in that the pH is about 1.2-2.5. -13 ·. Aqueous solution according to claims 1-12, characterized in that the 30 is pH 1.5-2.2. ' An aqueous solution according to claims 1-13, characterized in that the pH is about 1.5-2.0. Aqueous solution according to claims 1 -k, characterized in that the pH is about 1.6-1.8. An aqueous solution according to claims 1-15, characterized in that the oxidizing agent, component B, is present in an amount of about 1-20 g / l, calculated on an effective weight equivalent basis, 8201599. ......... -67- relative to hydrogen peroxide. An aqueous solution according to claim 16, characterized in that the oxidizing agent is present in an amount of about 3-7 g / l, calculated on an effective weight equivalent basis with respect to hydrogen peroxide. An aqueous solution according to claims 1 to 17, characterized in that ... the oxidizing agent comprises a peroxide. Aqueous solution according to claim 18, characterized in that the. oxidizing agent includes hydrogen peroxide. 20. Method according to claims 1-19, characterized in. that at least one additional metal ion is present in said aqueous acidic solution in. an amount up to about 10 g / l, for example in the range of about 0.5-10 g / l. An aqueous solution according to claims 15-20, characterized in that component C is present in an amount of about 1 g / l. Aqueous solution according to claim 21, characterized in that component C is present in an amount of about 0.02-1 g / l. An aqueous solution according to claim 22, characterized in that component. C is present in an amount of about 0.1-0.2 g / 1-20 2¾. Aqueous solution according to claims 1 to 23, characterized in that it further contains at least one additional metal ion selected from iron, cobalt, nickel, molybdenum, manganese, lantanum, lantanide mixtures as well as mixtures thereof. . . ·, ·. An aqueous solution according to claims 1-2U, characterized in that it further contains an additional aluminum metal ion. An aqueous solution according to claim 25, characterized in that said additional metal ion comprises iron. -> *. *. 27. An aqueous solution according to claim 21 +, / 25 or 26, characterized in that; . " . that said additional metal ion includes cobalt. 30.28. Aqueous solution according to claims 2 * 1-27, characterized in that said additional metal ion comprises nickel. An aqueous solution according to claims 21 + -28-, characterized in that said additional metal ion comprises molybdenum. An aqueous solution according to claims 2h-29, characterized in that said additional metal ion comprises manganese. An aqueous solution according to claims 21 + -30, with. characterized in that ... it contains the said additional metal ion lantanum, * An aqueous solution according to claims 2-h - 31, characterized in that '82 0 1 5 9 9' '...............- v δ -68- additional metal ion includes a lanthanide mixture. An aqueous solution according to claims 24-32, characterized in that said additional metal ion comprises α-internritium. 34. An aqueous solution according to claims 1-33, characterized in that the trivalent chromium ions, component D, are present in an amount of 0.05 g / l up to the saturation point. An aqueous solution according to claim 34, characterized in that the trivalent chromium ions are present in an amount of 0.2 * 2 g / l. ". An aqueous solution according to claim 35 *, characterized in that the. 10 trivalent chromium ions are present in an amount of 0.5-1 g / 1 An aqueous solution according to claims 1-36, characterized in that it further comprises halide ions. 38. An aqueous solution according to claim 37, characterized in that the halide ions are present in an amount of up to a maximum of 8 g / l .. An aqueous solution according to claim 38, characterized in that the halide ions are present in an amount of 0.1-2.5 g / l 40. Aqueous solution according to claim 37, characterized in that the. halide ions are present in an amount up to 2 g / l. ". 4l. Aqueous solution according to claim 40, characterized in that the halide ions are present in an amount of 0.1-0.5 g / l * An aqueous solution according to claims 1-4l, characterized in that it further has a surfactant. agent, ~ 43. An aqueous solution according to claim 42, characterized in that the surfactant is present in an amount up to about 1 g / l; 44. An aqueous solution according to claim 43, characterized in that the surfactant is present in a. amount. of 50-100 mg / 1. Aqueous solution according to claims 1-44, characterized in that it further sulphates ions in an amount up to about 15 g / l. ._ · An aqueous solution according to claim 45, characterized in that it comprises 30 sulfate ions in a. amount, from 0.5-5 g / l. 47. Aqueous solution according to claim 4 or according to any one of claims 9-46, when referring to claim 4, characterized in that said iron ions are present in an amount of 0.05-0.5 g / l. -48. Aqueous solution according to claim 47, with. characterized in that said iron ions are present in an amount of 0.1-0.2 g / l. An aqueous solution according to claim 2, or any one of claims 9-48, when referring to claim 2, characterized in that said iron ions and cobalt ions are present in an amount of 0.02-1 g / l. An aqueous solution according to claim 49, characterized in that the ... iron and cobalt ions are present in an amount of 0.1-0.2 g / l .. An aqueous solution according to any one of claims 2, 3 or 4 or 6-50 when relating to claims 2, 3 or 4, characterized in that it further contains cerium ions in an amount of 0.5-10 g / 1. 52. The aqueous solution according to claim 51, characterized in that it contains cerium ions in an amount of 1 * 0-4 g / l. . 53. An aqueous solution according to claim 5, or any one of claims 9-52, when referring to claim 5, characterized in that the cerium ions are present in an amount of 0.5-10 g / l *. -54. Aqueous solution according to claim 53, characterized in that the cerium ions are present in an amount of 1.0-4 g / l. 55. An aqueous acidic solution according to claims 1-52, characterized in. that it contains cerium ions in an amount of 0.5-10 g / l. Aqueous acid solution according to claim 55, characterized in that. it contains cerium ions in an amount of 1-4 g / l. Aqueous solution according to claim 6 or any one of claims 9-56, -20 if related to claim 6, characterized in that the carboxylic acid, component E, is present in an amount of 0.05-4 g / l. • 58. The aqueous solution according to claim 57, characterized in that the. Carboxylic acid is present in an amount of 0.1-T g / l. 59 ·. Aqueous solution according to claim 6, or any one of claims: 25.9-58, when referring to claim 6, characterized in that the organic carboxylic acid is malonic acid, malexic acid, tartaric acid, gluconic acid, tartaric acid or citric acid or mixtures thereof as well as salts thereof. . ; 4 _: ·:. ^ · _. ···; . *: '' 60c. Aqueous solution according to claim 57 or 58, characterized in that the carboxylic acid and dipping thereof comprise succinic acid. ; . ...... el. Aqueous solution according to claim 57 or 68, characterized in. that the carboxylic acid and its salts comprise malonic acid. An aqueous solution according to claim 57 or 58, characterized in that the carboxylic acid and its salts comprise maleic acid. An aqueous solution according to claim 57 or 58, characterized in that the carboxylic acid and its salts comprise gluconic acid. _______64. Aqueous solution according to claim 57 or 58, characterized in that the carboxylic acid and its salts comprise tartaric acid. “'' ..... 82 0 1 5 9 9 ....... F 7 .......- v-- ·· —- · ---...... -70 - 65. An aqueous solution according to claim 57 or 58, characterized in that the carboxylic acid and its salts comprise citric acid. 66. An aqueous solution according to claim 7 or any one of claims 9-65, when referring to claim 7, characterized in that the siliate compound is present in an amount of 0 »1-5 g / l, calculated as SiOg. An aqueous solution according to claim 66, characterized in that the silate compound is present in an amount of 0.1-0.5 g / l calculated as SiOg. 68, An aqueous solution according to claim 7 or any one of claims 9-67, when related to claim 7, characterized in that the silate compound comprises an inorganic bath-soluble and compatible silicate compound present in an amount up to 2 g / 1. 69. An aqueous solution according to claim 68, characterized in that the siliate compound comprises an alkali or ammonium silicate compound present in an amount up to 2 g / l. Aqueous solution according to claim 7 or any one of claims 9-67, characterized in that the silate compound comprises a quaternary ammonium silicate compound present in an amount of 0.01-5 g / l, calculated as SiO2. 71. An aqueous solution according to claim 70, characterized in that the silate compound comprises a quaternary ammonium silicate compound present in an amount of 0.1-0.5 g / l. calculated as SiO ^ .. 72. An aqueous solution according to claim 70 or 71, characterized in that said siliate compound has the following structural formula: R0R * txSiOg / yHgO, wherein: '* R comprises a quatera ammonium group substituted by four organic groups selected from alkyl, alkylene -, alkanol, aryl or alkylaryl groups or mixtures thereof; R 'R or a hydrogen atom; x is an integer from 1-3, and y is an integer from 0-15. 72. An aqueous acidic solution according to claims 1-71, characterized in that it further comprises a bath soluble compatible organic carboxylic acid or an 8201599. -71- contains compatible salt thereof. , - -.........- T3. Aqueous solution according to claim 72, characterized in that the bath-soluble and compatible organic carboxylic acid is present in an effective amount to impart initial hardness and clarity to the passivating film, the organic acid providing the structure formula:. .. (OH) E (CGOH). ad has, where: - -> ------ a is an integer from 0-6, b is an integer from 1-3, and - 10. represents an alkyl, alkenyl, or aryl group with 1-6 carbon atoms; as well. its bath-soluble and compatible salts thereof. 7¾. Aqueous solution according to claim 73, characterized in that the carboxylic acid is present in an amount of 0.05 µg / lr. Aqueous solution according to claim 7, characterized in that said carboxylic acid is present in an amount of 0.1-1-1 g / X. . ... 76. An aqueous solution according to claim 73, 75 or 75, characterized in that the organic carboxylic acid contains malonic, maleic, succinic, tartaric, tartaric or citric acid or a mixture thereof, as well as salts thereof. -. An aqueous solution according to claim 8 or any one of claims 9-76, when referring to claim 8, characterized in that the 1-hydroxyethylidene-1,1-diphosphonic acid, component G: is present in J in an amount of 0.05-3 g / 1.7 An aqueous solution according to claim 77, characterized in that the 1-hydroxyethylidene-1,1-diphosphonic acid is present in an amount of 0.1-0.5 g / l. . " An aqueous solution according to claim 8 or any of the claims: 9-78 if. pertaining to claim 8, characterized in that the *. citric acid is present in an amount of 0.1-10 g / l * 80 * aqueous solution according to claim 79, characterized in that the citric acid is present in an amount of 0.5-5 g / l · 8l. Aqueous concentrate suitable for dilution with water and by addition of a) hydrogen ions to obtain an acidic pH, b) an oxidizing agent, and. c) at least one metal ion selected from iron, cobalt, nickel, molybdenum, "8201599" -72-manganese, aluminum, lantanum, lanthanide mixtures and cerium, and mixtures thereof suitable to form a had to treat a receptive metal substrate to form a passivating chromate film, characterized in that said concentrate contains 10-80 g / l chromium ions which are substantially all in the trivalent state and 5-50 g / l, calculated as SiOg, of an organic quaternary ammonium sili caat. - - An aqueous concentrate according to claim 81, characterized in that it further contains up to 50 g / l halide ionea. An aqueous concentrate according to claims 81 and 82, characterized in that it further comprises a surfactant in an amount up to 5 g / l. An aqueous solution according to claim 4, essentially as described in particular with respect to Examples II.1, II.2, II.3, II.4, II, 5B, II.5C, 11.533, H.6, II.7, H.8. 85. A method of treating a receptive metal substrate to apply a passivating chromate film thereto, with. characterized in that the substrate is contacted with a solution according to claim 4 or one of. claims 9-80, when referring to claim 4, or claim 84, at a temperature of about 4-66 ° C sufficient to form a passivating film over a period of time. 86. A method according to claim 85, essentially as described in particular, with respect to one of Examples H. 1-II.4, II. 5B, II. 50, II.5D, II.6, H.7, or II.8. 87. A receptive substrate provided with a passivating layer by means of a method according to claim 85 or 86. 88. The solution of claim 2 essentially as described in particular with respect to example 1.1 or 1.2, '89. A method of treating a receptive metal substrate to ! to be applied to a passivating film, characterized in that the substrate is brought into contact with a solution according to claim 2 or one of claims 9-80, if related to claim 2 or claim 88, at a temperature of about 4-66 ° C for a period of time sufficient to form a passivating film thereon. 90. A method according to claim 89, essentially as described in particular with respect to example 1.1 or 1.2. 91. Receptive substrate provided with a passivating layer by means of a method according to claim 89 or 90. sr - 82 0 1 51 '9 "~ _ - · - · -73 -....... -92. Aqueous solution according to claim 5, as described in particular with regard to one of examples III.1, 111 * 2, 111.3, IIIΛ or III.5 93. Process for treating a receptive metal substrate in order to to apply a passivating chromate film, characterized in that the substrate is brought into contact with a solution according to claim 5 or one of claims 9-10 if related to claim 5, or claim 92., at a temperature of about 4-66 ° C for a period of time sufficient to form a passivating film thereon. A method according to claim 93, in fibers as described in particular with respect to one of the examples UI. 1, III.2, III.3, UI. 4 or III. 5-95 * Receptive substrate provided with a passivating layer by means of an adhesive as claimed in claim 93 or 94. 96. An aqueous solution according to claim 6, in fibers such as in the following. Tonder-described with respect to any of Examples 17.1, 17.2 or 17.3. · 97 · "Method of treating a receptive metal substrate to passivate. chromate film. to be applied, characterized in that ... the substrate is brought into contact with a solution according to claim 6 or any one of claims 9-80, when relating to con. Cl. 6 or Claim 96, at a temperature of about 4-66 ° C for a period of time sufficient to form a passivating film thereon. 98. A method according to claim 97 in-vesing as described in particular with respect to one of examples 17.1, 17.2. or 17.3. 99. Provide receptive substrate with a. passivating layer by means of an adhesive as claimed in claim 97 or claim 98. 100. An aqueous solution according to claim 7, such as in particular; 30 in relation to one of the examples 7.1., 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, or 7 * 8. 101. A method of treating a receptive metal substrate to apply a passivating chromate film thereon, characterized in that the substrate is contacted with a solution according to claim 7 or any of claims 9-80, if related, having claim 7, or claim 100, at a temperature of about 4-66 ° C. sufficient for a period of time to form a passivating film 1 ~ ff2 (H 597 * - -74- __- '· *) thereon. 102. A method of treating a receptive metal substrate for applying a passivating chromate film thereto, characterized in that the substrate is contacted with a solution according to claim 7 or any of claims 9-80, if pertaining to claim 7, or claim 100, at a temperature of about 4-66 ° C, for a period of time sufficient to form a passivating film thereon, contacting the passivated substrate for a period of at least about 1 second is applied with a dilute aqueous rinse solution containing a bath-soluble and compatible silicate compound in an effective amount to impart an improved corrosion resistance to the passivating film. and hardness, after which the passivated silicate-rinsed substrate is dried. A method according to claim 101 or 102 as in. specifically described with respect to one of examples V. 1-V.8. 104. A receptive substrate provided with a passivating layer by means of a method according to claim 101, 102 or 103- 105. An aqueous solution according to claim 8 essentially as in the following. without described with respect to any of Examples VI.1-VI.5. 106. A method of treating a receptive metal substrate to apply a passivating chromate film thereon, characterized by:. that the substrate is contacted with a solution according to claim 8 or any of claims 9-80, when related to claim 8, or claim. 105, at a temperature of about 4-66 ° C, for a period of time sufficient to form a passivating film thereon. 107. A method of treating a receptive metal substrate to make a passivating chromate film thereon. to be applied, characterized in that the substrate is brought into contact with a solution according to claim 8 or any of claims 9-80, if related to claim 8, or claim 105 at a temperature of approximately 4-66 ° C, for a period of time sufficient to form a passivating film thereon, the passivated substrate is contacted for a period of at least about 1 second with a dilute aqueous rinse solution containing a bath soluble and compatible silicate compound present in an effective amount to impart to the passivating film an improved corrosion resistance and hardness, after which it is only 82 0 1 5 9 9 ...... • 75—5U - made silicate rinsed substrate is dried. ___108. Method according to claim 106 or 107 in. essentially as described in particular with respect to one of Examples VI .. 1-VI.5. 109. A receptive substrate provided with a passivating layer by means of a method according to claim 106, 107 or 108. - 110. A method of treating a receptive metal substrate for - applying an improved passivating chromate film thereon, characterized in that it is based on an aqueous acidic solution containing effective amounts of chromium ions substantially all in the trivalent state, hydrogen ions to adjust a pH of about 1.2-2.5. an oxidizing agent, and at least one iron, cobalt, nickel, molybdenum, manganese, aluminum, lanthanum, lanthanide mixtures, and urium as well as mixtures thereof; the substrate is contacted with said aqueous acidic solution for a period of time sufficient to form thereon on a passivating film, the passivated substrate is contacted with a dilute aqueous rinse solution for a period of at least about 1 "second containing a bath soluble and compatible silicate compound present in an effective amount to impart an improved hardness to the passivating film and an improved corrosion resistance to the substrate 20, after which the passivated silicate-rinsed substrate is dried. 111. A method according to claim 110, characterized in that the passivated substrate is rinsed with water before contacting it with said aqueous silicate rinsing solution. 25 Π2. Method according to claim 111 or 112, characterized in that the aqueous rinsing solution is approximately. Contains 1-40 g / l of said silicate compound calculated as SiO4. '· | 113. Full-mesh method according to claim 112, characterized in that the aqueous rinsing solution contains 5-15 g / l of the said silicate compound calculated as 30 SiO2. 11. Process according to claims 110-113, characterized in that the silicate compound comprises an inorganic compound. 115. A process according to claim 11 h, characterized in that the inorganic silicate compound comprises an alkali metal or ammonium silicate, 35 Ho. A method according to claims 110-113, characterized in that the silicate compound comprises an organic silicate compound. 117. A method according to claim 116, characterized in that the organic. ·. '....... -76- .........': ............ -J rfc ... silicate compound comprises a quaternary aimonium silicate compound. 118. Process according to claim 116 or 117, characterized in that the organic silicate compound has the structural formula:. ROR: xSi02: yH20 has where: R represents a quaternary ammonium group substituted by four organ -. nic groups selected from alkyl, alkylene, alkanol, aryl, alkylaryl groups or mixtures thereof, R 1 represents a hydrogen atom; 10. is an integer from 1-3; and y is an integer from 0-15. 119. A method according to claims 110-118, characterized in that the aqueous rinsing solution has a temperature of about 10-66 ° C. 120. A method according to claims 110-119, characterized in that the passivated substrate is contacted with the aqueous rinse solution for a period of at least about 1 second to about 1 minute. 121. A method according to claims 110-120, characterized in that the rinsing solution further comprises 0.05-5 g / l. contains a compatible humectant. 122. Process according to claims 110-121, characterized in that the rinsing solution further contains 1-50 g / l of an emulsifiable oil. 123. Process according to claims 110-121, characterized in that the rinsing solution further contains an alkali metal or ammonium nitrite or mixtures thereof in an amount of 0.1-1 g / l. 25 12 ^. Method according to claim 110 essentially as described in particular with respect to one of the accompanying examples VII.1, ^ "vix.2A-vn.2ii, or vn.3A-vii.3F." "" Ί 125. A receptive substrate when treated according to a method of any one of claims 110-12. 126. The receptive substrate according to claims 87, 91, 95, 99, 10, 109 or 125, characterized in that the treated surface comprises zinc, zinc alloys, cadmium, eadmium alloys, aluminum, aluminum alloys, magnesium or magnesium alloys. 8 2 0 1 5 9 9 "1" ...