Abstract: Methods for reducing a concentration of hexavalent chromium within a first aluminum slurry by adding a reducing agent to form a second aluminum slurry are provided. The reducing agent causes a chemical reduction reaction with the hexavalent chromium compound of the first aluminum slurry to form a trivalent chromium compound within the second aluminum slurry such that a first weight ratio of hexavalent chromium to trivalent chromium in the first aluminum slurry is decreased to a second weight ratio of hexavalent chromium to trivalent chromium in the second aluminum slurry, with the second weight ratio being less than the first weight ratio.

Abstract: Provided is a surface-treated steel sheet with a compound layer containing F and composed essentially or Zr at least on one surface thereof, wherein the Zr amount is 80 to 350 mg/m2 and the F amount is 0.5 to 10 mg/m2 within the layer, and an organic resin coated metal container manufactured using the surface-treated steel sheet. The surface-treated steel sheet of the present invention is manufactured through forming a layer having the Zr amount of 80 to 350 mg/m2 at least on one surface of a steel sheet by cathode electrolytic treatment in an aqueous solution containing a Zr ion and F ion, and subsequently adjusting the surface to control the F amount to 0.5 to 10 mg/m2 by one or more treatments selected from immersion and spraying with an ion-containing aqueous solution and cathode electrolytic treatment in the ion-containing aqueous solution.

Abstract: A method of forming a coating of an Al—Zn—Si—Mg alloy on a steel strip to form an Al—Zn—Mg—Si coated steel strip is disclosed. The method includes the steps of dipping steel strip into a bath of molten Al—Zn—Si—Mg alloy and forming a coating of the alloy on exposed surfaces of the steel strip and cooling the coated strip with cooling water. The cooling step includes controlling the pH of cooling water to be in a range of p H 5-9. Particular embodiments focus on Al—Zn—Si—Mg alloys that contain the following elements in % by weight: Zn: 30 to 60, Si: 0.3 to 3, Mg: 0.3 to 10, and Balance Al and unavoidable impurities.

Abstract: Methods for treatment shaped bodies are described herein. The methods generally include contacting at least one shaped body with an aqueous acidic composition to form a conversion layer on a surface of the at least one shaped body, wherein the surface includes iron or steel and a carbon content in a range of 0 to 2.06 wt. % and a chrome content in a range of 0 to <10 wt. % and wherein the surface is optionally galvanized or alloy galvanized. The aqueous acidic composition includes water; from 2 to 500 g/L oxalic acid; and from 0.01 to 20 g/L of at least one catalyst based on guanidine, nitrate or combinations thereof, wherein a pickling removal of the aqueous acidic composition is in a range of 1 to 6 g/m2.

Abstract: An aqueous acidic composition is provided for forming a chromium-containing chemical conversion coating on a member having an iron-based metal surface. The composition contains a water-soluble trivalent chromium-containing substance, a water-soluble zinc-containing substance, and a water-soluble polyvalent carboxylic acid compound. On the total composition basis, the water-soluble trivalent chromium-containing substance has a content of 60 mmol/L or more in terms of chromium, the water-soluble zinc-containing substance has a molar content in terms of zinc such that a ratio of the content is 0.6 or more to a molar content in terms of chromium of the water-soluble trivalent chromium-containing substance, and the water-soluble polyvalent carboxylic acid compound has a content of 55 mmol/L or more in terms of polyvalent carboxylic acid.

Abstract: A treating solution for forming on a surface of either zinc or a zinc alloy a hexavalent-chromium-free trivalent-chromium chemical conversion coating which has an even black appearance and satisfactory corrosion resistance. The treating solution has a long treating-bath life. Also provided is a method of forming a black trivalent-chromium chemical conversion coating. The aqueous treating solution, which is for forming a black trivalent-chromium chemical conversion coating on zinc or a zinc alloy, contains trivalent chromium ions, a phosphoric ester and/or phosphorous ester, and a sulfur compound. The method is a method of chemically treating zinc or a zinc alloy which comprises using the aqueous treating solution to chemically treat the zinc or zinc alloy at a solution temperature of 10-60° C., whereby a black trivalent-chromium chemical conversion coating is formed on the zinc or zinc alloy.

Abstract: Aqueous compositions useful as pretreatments prior to painting and to prevent the formation of white rust in the uncoated condition include an organopolyphosphonic acid or salt thereof, an organosilane, and a trivalent chromium compound. A method for treating a surface of a zinc-containing metal includes contacting the surface with an aqueous composition including an organopolyphosphonic acid or salt thereof, an organosilane, and a trivalent chromium compound. The composition may also include an agent for reducing hydrophilicity, such as a polyacrylic acid. The aqueous composition has been found to be particularly well-suited for treating a zinc-containing metal to passivate the surface, improve paint adhesion, and/or improve corrosion resistance.

Abstract: In one embodiment, the invention provides a composition useful for passivating a metal surface, in particular a zinciferous surface, comprising, preferably consisting essentially of, most preferably consisting of water and: (A) dissolved phosphate ions; (B) dissolved trivalent chromium ions; (C) dissolved anions of at least one complex fluoride of an element selected from the group consisting of Ti, Zr, Hf, Si, Sn, Al, Ge and B; preferably Ti, Si and/or Zr; (D) an optional component of dissolved free fluoride ions; (E) organic acid inhibitor, preferably comprising quaternary ammonium compounds; and, optionally (F) a pH adjusting component; and optionally organic hydroxyl acids.

Abstract: The invention refers to a process for producing an anticorrosive coating in which a surface to be treated is brought into contact with an aqueous treatment solution containing chromium(III) ions and at least one phosphate compound and an organosol. The corrosive protection of metal surfaces, in particular those containing zinc and zinciferous surfaces with conversion layers is improved. The decorative and functional properties of the surfaces are retained or improved. In addition, the well-known problems associated with the use of compounds containing chromium(VI) or with multi-stage processes are avoided in which a passivation layer containing chromium ions and a sealing are applied one after the other.

Abstract: A method for surface treatment of a part made of aluminum, magnesium, or one of the alloys thereof, to protect the part from corrosion. The method comprises consecutively immersing the part in a first aqueous bath containing a corrosion-inhibiting metal salt and an oxidizing compound, and a second aqueous bath containing an oxidizing compound and a corrosion-inhibiting rare-earth salt. The method can be carried out for the chemical conversion of aluminum or the alloys thereof, and of magnesium or the alloys thereof, on parts that have not been previously treated, or after anodizing the part to seal the anodic layer.

Abstract: The object of this present invention is to provide novel means for inhibiting elution of hexavalent chromium from a chemical conversion coating. A composition for chemical conversion treatment comprises at least 0.1 g/L of a polyphenol and at least 1.5 g/L in chromium ion equivalent of an aqueous trivalent chromium compound and has a pH of 6 or less. A chemical conversion coating formed on a metallic surface of a member by contacting the surface with the composition for chemical conversion treatment has a hexavalent chromium content of 0.04 ?g/cm2 or less after exposure to an environment having a temperature of 80 degrees C. and a relative humidity of 100% for 120 hours. The content of hexavalent chromium is measured by a method compliant with EN15205. A composition containing at least 0.1 g/L of a polyphenol can be used as a composition for post-coating treatment of a chemical conversion coating obtained by conventional chemical conversion treatment.

Abstract: A substrate includes an iron-nickel alloy core or a cobalt-nickel ferrous alloy core, a chromium conversion coating on at least a portion of the core, and an insulating coating on the chromium conversion coating. A method of making a substrate includes: providing an iron-nickel alloy core or a cobalt-nickel ferrous alloy core, applying a chromium conversion coating on at least a portion of the core, and applying an insulating coating on the chromium conversion coating.

Abstract: An aqueous acidic composition is provided for forming a chromium-containing chemical conversion coating on a member having an iron-based metal surface. The composition contains a water-soluble trivalent chromium-containing substance, a water-soluble zinc-containing substance, and a water-soluble polyvalent carboxylic acid compound. On the total composition basis, the water-soluble trivalent chromium-containing substance has a content of 60 mmol/L or more in terms of chromium, the water-soluble zinc-containing substance has a molar content in terms of zinc such that a ratio of the content is 0.6 or more to a molar content in terms of chromium of the water-soluble trivalent chromium-containing substance, and the water-soluble polyvalent carboxylic acid compound has a content of 55 mmol/L or more in terms of polyvalent carboxylic acid.

Abstract: An acidic, aqueous composition contains a trivalent chromium compound, an organo-functional silane, and a compound of a group IV-B element. The composition protects metal surfaces, preferably aluminum and aluminum alloys, against corrosion and improves their paint adhesion. The trivalent chromium compound may comprise chromium fluoride and optionally others, such as chromium nitrate. The organo-functional silane is preferably an aminopropyltriethoxy silane, and the compound of a group IV-B element is preferably fluorozirconic acid. The composition can either be dried-in-place or rinsed before a further coating layer is applied. The composition may also include at least one polymer having a plurality of both carboxylic functional groups, alone or with hydroxyl groups.

Abstract: The invention relates to a treatment solution for producing substantially chromium(VI) free black conversion layers on alloy layers containing zinc, the solution comprising the following: (i) at least one first carboxylic acid having 1 to 8 carbon atoms, the acid containing no polar groups with exception of the carboxyl group and being a monocarboxylic acid, (ii) at least one second carboxylic acid having 1 to 8 carbon atoms, comprising at least one further polar group that is selected from —OH, —SO3H, —NH2, —NHR, —NR2, —NR3+, and —COOH (wherein R is a C1-C6 alkyl group), (iii) 20 to 400 mmol/l Cr3+ and (iv) 50 to 2000 mmol/l NO3?. The invention further provides a method for the black passivation of surfaces containing zinc, wherein the surface to be treated is immersed into such a treatment solution.

Abstract: A method of preparing an aqueous composition of a chromium III compound, comprising adding hydrogen peroxide to a mixture comprising water and a chromium VI compound in the presence of at least one acid according to the formula H2GF6, in which G is a Group IV-B element. The composition may contain less than 500 ppm of alkali metal ions and less than 200 ppm of halide ions, relative to chromium and may test negative for chromium VI using s-diphenylcarbazide. The composition may be used for treating a metal surface, among other applications.

Abstract: The invention relates to a method for producing a coating layer protecting against corrosion wherein a surface which is to be treated is brought into contact with an aqueous treatment solution containing chromium(III) ions and at least one phosphate compound, wherein the ratio of the molar concentration of the chromium(III) ions to the molar concentration of the at least one phosphate compound (calculated as orthophosphate) lies between 1:1.5 and 1:3. The method improves the corrosion protection of metallic, in particular, zinc-containing, surfaces provided with conversion layers. The decorative and functional properties of the surface are maintained or improved. Furthermore, the known problems resulting from the use of chromium(VI)-containing compounds or from post-treatments with polymer dispersions are avoided.

Abstract: A composition for forming a protective coating on a metal surface includes water; Cr2(GF6)3 in which G is a Group IV-B element; and at least one polymer having a plurality of carboxylic acid groups and at least one polymer having a plurality of hydroxyl groups, and/or at least one polymer having a plurality of both carboxylic acid and hydroxyl groups; wherein the composition contains less than 500 ppm of alkali metal ions and less than 200 ppm of halide ions relative to chromium. A method of forming a protective coating on a metal surface includes contacting the metal surface with the composition.

Abstract: A method of preparing an aqueous composition of a chromium III compound, comprising adding hydrogen peroxide to a mixture comprising water and a chromium VI compound in the presence of at least one acid according to the formula H2GF6, in which G is a Group IV-B element. The composition may contain less than 500 ppm of alkali metal ions and less than 200 ppm of halide ions, relative to chromium and may test negative for chromium VI using s-diphenylcarbazide. The composition may be used for treating a metal surface, among other applications.

Abstract: Disclosed is a treatment solution for use in the formation of a black trivalent chromium chemical conversion coating film with uniformly stabilized black wash, luster and corrosive resistance irrespective of the type of the acidic, neutral or alkaline zinc plating bath employed or the presence or absence of nickel eutectoid. Also disclosed is a method of forming the black trivalent chromium chemical conversion coating film. The treatment solution comprises a trivalent chromium ion, a chelating agent capable of forming a water-soluble complex with the trivalent chromium, at least one metal ion selected from the group consisting of a cobalt ion, a nickel ion and an iron ion, and formic acid or a salt thereof as a buffer for hydrogen ion concentration. The treatment solution can be used for forming a black hexavalent chromium-free chemical conversion coating film on zinc or a zinc alloy.

Abstract: A method of preparing an aqueous composition of a chromium III compound, comprising adding hydrogen peroxide to a mixture comprising water and a chromium VI compound in the presence of at least one acid according to the formula H2GF6, in which G is a Group IV-B element. The composition may contain less than 500 ppm of alkali metal ions and less than 200 ppm of halide ions, relative to chromium and may test negative for chromium VI using s-diphenylcarbazide. The composition may be used for treating a metal surface, among other applications.

Abstract: For producing corrosion resistant yellow passivate layers on zinc and zinc alloy surfaces, an aqueous reaction solution is utilized that contains trivalent chromium ions, at least one acid as well as at least one heteroaromatic compound selected from the group comprising nicotinic acid, the salts and derivatives thereof.

Abstract: Improved compositions and processes for zincating magnesium and magnesium alloy substrates. An aqueous zincating composition having a pH of from about 8 to about 11 and including zinc ions, a complexing agent, fluoride ions and a reducing agent. A non-electrolytic process for zincating a magnesium or magnesium alloy substrate, including immersing the substrate in the non-electrolytic aqueous zincating composition for a time sufficient to deposit a zincate on the substrate. A non-electrolytic process for zincating a magnesium or magnesium alloy substrate, including preparing a aqueous non-electrolytic composition comprising zinc ions, a complexing agent, fluoride ions and a pH in the range from about 8 to about 11; adding to the composition an amount of a reducing agent sufficient to improve deposition of zincate on the magnesium or magnesium alloy substrate; and immersing the substrate in a composition for a time sufficient to deposit the zincate on the substrate.

Abstract: A method for adhesively bonding a metallic substrate and a component together includes treating the metallic substrate to form an oxide layer thereon, treating the oxide layer with a conversion coating solution to form a bond promoter coating on the oxide layer, and depositing an adhesive material on the bond promoter coating to bond the component and the metallic substrate together.

Abstract: Disclosed is an aqueous solution of a chromium salt, in which the oxalic acid content is 8% by weight or less relative to chromium. In the aqueous solution of the chromium salt, the total organic carbon content is 4% by weight or less relative to chromium. The chromium salt is preferably a chromium chloride, a chromium phosphate, or a chromium nitrate. The chromium chloride preferably contains a basic chromium chloride represented by the composition formula Cr(OH)xCly (wherein 0<x?2, 1?y<3, and x+y=3). The chromium phosphate is preferably one represented by the composition formula Cr(H3?3/nPO4)n (wherein n is a number satisfying 2?n?3). The chromium nitrate is preferably a basic chromium nitrate represented by the composition formula Cr(OH)x(NO3)y (wherein 0<x?2, 1?y<3, and x+y=3).

Abstract: A treatment solution that is used to form a chemical coating of trivalent chromium free of hexavalent chromium having uniform black appearance and good corrosion resistance on the surface of zinc or zinc alloy and that attains prolongation of treatment bath lifetime; and a method of forming a black trivalent chromium chemical coating on the surface of zinc or zinc alloy. There is provided a treatment solution for forming of a black trivalent chromium chemical coating on zinc or zinc alloy, comprising trivalent chromium ions, a chelating agent capable of forming a water-soluble complex with trivalent chromium, zinc ions, a sulfur compound and phosphite ions.

Abstract: In a method for manufacturing an aqueous solution containing a source of chromium (III) according to the present invention, an aqueous solution containing trivalent chromium is added to an aqueous solution of an inorganic alkali under the condition of a reaction liquid temperature of 0° C. or more and less than 50° C., so that the amount of the trivalent chromium is not locally excessive with respect to the amount of the alkali, to produce chromium hydroxide, and then the chromium hydroxide is dissolved in an aqueous solution of an acid to obtain an aqueous solution containing a source of chromium (III). Preferably, after production of the chromium hydroxide, filtration is performed, and the chromium hydroxide is washed with water until the conductivity of the filtrate is 5 mS/cm or less.

Abstract: A chemical conversion treatment solution comprising, based on the total composition, 0.1 g/L to 3.0 g/L of an aqueous cobalt-containing substance in cobalt equivalent, 0.05 g/L to 3.0 g/L of a pyrogallol compound in pyrogallol equivalent, and at least 1.5 g/L of an aqueous trivalent chromium-containing substance in chromium equivalent, the composition being acidic and the ratio of the content of the pyrogallol compound in pyrogallol equivalent to the content of the aqueous cobalt-containing substance in cobalt equivalent being 0.015 to 10, wherein a chemical conversion film formed on the metallic surface of a member by contacting the metallic surface with the composition for chemical conversion treatment has a content of hexavalent chromium of 0.050 ?g/cm2 or less as measured by a method compliant with EN15205 after exposure to an environment having a temperature of 80° C. and a relative humidity of 100% for 72. hours.

Abstract: Aqueous compositions useful as pretreatments prior to painting and to prevent the formation of white rust in the uncoated condition include an organopolyphosphonic acid or salt thereof, an organosilane, and a trivalent chromium compound. A method for treating a surface of a zinc-containing metal includes contacting the surface with an aqueous composition including an organopolyphosphonic acid or salt thereof, an organosilane, and a trivalent chromium compound. The composition may also include an agent for reducing hydrophilicity, such as a polyacrylic acid. The aqueous composition has been found to be particularly well-suited for treating a zinc-containing metal to passivate the surface, improve paint adhesion, and/or improve corrosion resistance.

Abstract: A processing solution for forming a hexavalent chromium free, corrosion resistant trivalent chromate conversion film on zinc or zinc alloy plating layers comprises: trivalent chromium and oxalic acid in a molar ratio ranging from 0.5/1 to 1.5/1, wherein the trivalent chromium is present in the form of water-soluble complex with oxalic acid; and cobalt ions, which do not form a hardly soluble metal salt with oxalic acid and are stably present in the processing solution without causing any precipitation; wherein the solution reacts with zinc when bringing it into contact with the zinc or zinc alloy plating to form a hexavalent chromium free, corrosion resistant, trivalent chromate conversion film containing zinc, chromium, cobalt, oxalic acid and silicon on the plating.

Abstract: This invention comprises an acidic aqueous solution for treating metal substrates to improve the adhesion bonding and corrosion protection of the metal surface which comprises effective amounts of water soluble trivalent chromium compounds, fluorozirconates, effective amounts of at least one corrosion inhibitors such as benzotriazole, fluorometallic compounds, zinc compounds, thickeners, surfactants, and at least about 0.001 mole per liter of the acidic solution of a polyhydroxy and/or carboxylic compound as a stabilizing agent for the aqueous solution.

Abstract: A processing solution for forming a hexavalent chromium free, corrosion resistant trivalent chromate conversion film on zinc or zinc alloy plating layers comprises: trivalent chromium and oxalic acid in a molar ratio ranging from 0.5/1 to 1.5/1, wherein the trivalent chromium is present in the form of water-soluble complex with oxalic acid; and cobalt ions, which do not form a hardly soluble metal salt with oxalic acid and are stably present in the processing solution without causing any precipitation; wherein the solution reacts with zinc when bringing it into contact with the zinc or zinc alloy plating to form a hexavalent chromium free, corrosion resistant, trivalent chromate conversion film containing zinc, chromium, cobalt, oxalic acid and silicon on the plating.

Abstract: A processing solution for forming a hexavalent chromium free, corrosion resistant trivalent chromate conversion film on zinc or zinc alloy plating layers comprises: trivalent chromium and oxalic acid in a molar ratio ranging from 0.5/1 to 1.5/1, wherein the trivalent chromium is present in the form of a water-soluble complex with oxalic acid; and cobalt ions, which do not form a hardly soluble metal salt with oxalic acid and are stably present in the processing solution without causing any precipitation; wherein the solution reacts with zinc when bringing it into contact with the zinc or zinc alloy plating to form a hexavalent chromium free, corrosion resistant, trivalent chromate conversion film containing zinc, chromium, cobalt, oxalic acid and silicon on the plating.

Abstract: Disclosed is an aqueous solution of a chromium salt, in which the oxalic acid content is 8% by weight or less relative to chromium. In the aqueous solution of the chromium salt, the total organic carbon content is 4% by weight or less relative to chromium. The chromium salt is preferably a chromium chloride, a chromium phosphate, or a chromium nitrate. The chromium chloride preferably contains a basic chromium chloride represented by the composition formula Cr(OH)xCly (wherein 0<x?2, 1?y<3, and x+y=3). The chromium phosphate is preferably one represented by the composition formula Cr(H3-3/nPO4)n (wherein n is a number satisfying 2?n?3). The chromium nitrate is preferably a basic chromium nitrate represented by the composition formula Cr(OH)x(NO3)y (wherein 0<x?2, 1?y<3, and x+y=3).

Abstract: An aqueous conversion coating composition for treating metal substrates such as aluminum, aluminum alloys, zinc, zinc alloys, magnesium, magnesium alloys and steel to provide a conversion coating thereon. The conversion coating composition comprises a) a source of aluminum ions; b) a fluoro compound; c) at least one pH adjuster; d) a source of Group VIB metal ions selected from the group consisting of tungstate ions and trivalent chromium ions; and e) optionally, a preservative. The conversion coating composition provides a corrosion resistant coating on the metal surface and improves the adhesion of subsequently applied layers.

Abstract: For producing corrosion resistant yellow passivate layers on zinc and zinc alloy surfaces, an aqueous reaction solution is utilized that contains trivalent chromium ions, at least one acid as well as at least one heteroaromatic compound selected from the group comprising nicotinic acid, the salts and derivatives thereof.

Abstract: The present invention is directed to trivalent chromate conversion coatings for plated metals, and more particularly, to methods for reducing hexavalent chromium in trivalent chromate conversion coatings. In one embodiment, such method includes placing a metal article having a trivalent chromate conversion coating in a reducing solution. The trivalent chromate conversion coating includes hexavalent chromium and the reducing solution including a reducing agent, which reduces the hexavalent chromium so as to reduce or eliminate the hexavalent chromium on the plated metal article.

Abstract: Disclosed is a treatment solution for use in the formation of a black trivalent chromium chemical conversion coating film with uniformly stabilized black wash, luster and corrosive resistance irrespective of the type of the acidic, neutral or alkaline zinc plating bath employed or the presence or absence of nickel eutectoid. Also disclosed is a method of forming the black trivalent chromium chemical conversion coating film. The treatment solution comprises a trivalent chromium ion, a chelating agent capable of forming a water-soluble complex with the trivalent chromium, at least one metal ion selected from the group consisting of a cobalt ion, a nickel ion and an iron ion, and formic acid or a salt thereof as a buffer for hydrogen ion concentration. The treatment solution can be used for forming a black hexavalent chromium-free chemical conversion coating film on zinc or a zinc alloy.

Abstract: A hexavalent chromium-free surface treating agent for Sn- or Al-based coated steel sheet, comprising a trivalent chromium compound (A), a water-dispersible silica (B), a lubricity imparting component (C) made of one or more waxes of polyolefin wax, fluorine-containing wax and paraffin wax, and water, a mass ratio on the solid content basis of the water-dispersible silica (B) to the lubricity imparting component (C), (B)/(C), being within a range from 5/95 to 95/5.

Abstract: In a preferred embodiment of the present invention, a conversion coating composition comprising chromium (III) ions, cobalt (II) ions, and nitric acid is provided. The coating composition is substantially free of chromium (VI) ions and substantially free of an oxidizing agent. The present trivalent chromium based conversion coating provides corrosion protection equal to or greater than most hexavalent chromium conversion coatings.

Abstract: An acidic aqueous solution containing a water soluble trivalent chromium compound is provided with a additive for improving corrosion resistance and reducing precipitation of trivalent chromium over time. A suitable additive is nitrilotris (methylene) triphosphonic acid (NTMP).

Abstract: A chromium(VI)-free, chromium(III)-containing and substantially coherent conversion layer on zinc or zinc alloys presenting, even in the absence of further components such as silicate, cerium, aluminum and borate, a corrosion protection of approx. 100 to 1000 h in the salt spray test according to DIN 50021 SS or ASTM B 117-73 until first attack according to DIN 50961 Chapter 10; being clear, transparent and substantially colorless and presenting multi colored iridescence; having a layer thickness of approx. 100 nm to 1000 nm; and being hard, adhering well and being resistant to wiping.

Abstract: A metal substrate is anodized in a phosphoric acid anodizing solution. The anodized metal substrate is thereafter contacted with a hexavalent chromium free, trivalent chromium containing acid solution to coat the anodized metal substrate. The coated anodized metal substrate can be adhesively bonded to another such treated metal substrate to form a composite article. The resulting article exhibits excellent bonding and corrosion properties.

Abstract: A processing solution for forming a hexavalent chromium free, corrosion resistant trivalent chromate conversion film on zinc or zinc alloy plating layers comprises: trivalent chromium and oxalic acid in a molar ratio ranging from 0.5/1 to 1.5/1, wherein the trivalent chromium is present in the form of a water-soluble complex with oxalic acid; and cobalt ions, which do not form a hardly soluble metal salt with oxalic acid and are stably present in the processing solution without causing any precipitation; wherein the solution reacts with zinc when bringing it into contact with the zinc or zinc alloy plating to form a hexavalent chromium free, corrosion resistant, trivalent chromate conversion film containing zinc, chromium, cobalt, oxalic acid and silicon on the plating.

Abstract: A processing solution for forming a hexavalent chromium free, corrosion resistant trivalent chromate conversion film on zinc or zinc alloy plating layers comprises a silicon compound; trivalent chromium and oxalic acid in a molar ratio ranging from 0.5 to 1.5, wherein the trivalent chromium is present in the form of a water-soluble complex with oxalic acid; and cobalt ions, which form a hardly soluble metal salt with oxalic acid and are stably present in the processing solution without causing any precipitation, wherein the solution reacts with zinc when bringing it into contact with the zinc or zinc alloy plating to form a hexavalent chromium free, corrosion resistant, trivalent chromate conversion film containing zinc, chromium, cobalt, oxalic acid and silicon on the plating. This solution can provide a corrosion resistant trivalent chromate conversion film excellent in the corrosion resistance after heating.

Abstract: A surface-treated steel sheet includes a steel sheet, an Al—Zn-base alloy plating layer formed on the steel sheet, a chemical conversion film provided on the alloy plating layer, and a concentric layer of a Cr compound that is formed on the alloy plating layer of the chemical conversion film. The surface-treated steel sheet may include a steel sheet, an zinc-base plating layer formed on the steel sheet, and a film that contains chromium and calcium and that is formed on the zinc-base plating layer.

Abstract: Pretreated aluminum and aluminum alloys and the process and composition for pretreating said aluminum and its alloys to provide a coating with color recognition for identification purposes and to improved the corrosion-resistance, electrical conductivity, and adhesion properties which comprises pretreating said aluminum and its alloys with an effective amount of an acidic aqueous solution having a pH ranging from about 2.5 to 5.5 comprising water soluble trivalent chromium compounds, alkali metal hexafluorozirconates, divalent zinc compounds, alkali metal fluoro-compounds, and effective amounts of water soluble thickeners, surfactants or wetting agents.

Abstract: Pretreated aluminum and aluminum alloys and the process and composition for pretreating said aluminum and its alloys to provide a coating with color recognition for identification purposes and to improved the corrosion-resistance, electrical conductivity, and adhesion properties which comprises pretreating said aluminum and its alloys with an effective amount of an acidic aqueous solution having a pH ranging from about 2.5 to 5.5 comprising water soluble trivalent chromium compounds, alkali metal hexafluorozirconates, divalent zinc compounds, alkali metal fluoro-compounds, and effective amounts of water soluble thickeners, surfactants or wetting agents.

Abstract: Aqueous compositions for post-treating metal coated substrates such as cadmium-plated steel, and zinc-nickel coated substrates and the process for using said compositions to provide a color recognizable coating and to improve the corrosion-resistance, abrasion, electrical, and adhesion properties of the coating. The post-treatment composition comprises an acidic aqueous solution having a pH ranging from about 2.5 to 5.5 and contains effective amounts of trivalent chromium compounds, alkali metal hexafluorozirconates, at least one divalent zinc compound, alkali metal fluoro-compounds, and effective amounts of water soluble thickeners, wetting agents or surfactants.

Abstract: It is an object of the present invention to provide a processing method for preventing elution of lead in a lead-containing copper alloy to prevent lead from eluting from a faucet metal, etc. made of a lead-containing copper alloy, and a drinking water service fitting made of a lead-containing copper alloy in which elution of lead has been prevented. By forming a chromate film on the surface of a lead-containing copper alloy material, it is possible to reduce elution of the lead left in a limited amount on the surface. A drinking water service fitting made of a lead-containing copper alloy is immersed in an alkaline etching solution in a pre-processing step for a nickel chromium plating step to selectively remove lead on the surface of the lead-containing copper alloy material and is then activated in a solution such as sulfuric acid and hydrochloric acid.