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 chromium plating bath containing trivalent chromium ions and hexavalent chromium ions is prepared by a method including the steps of: (A) mixing chromic acid and an organic acid in an aqueous solution containing these acids and reducing chromic acid by the organic acid so as to prepare an aqueous solution not containing hexavalent chromium ions; (B) adding a pH adjustor to the aqueous solution not containing hexavalent chromium ions so as to adjust pH to a value of 1 to 4; and (C) further adding chromic acid to the aqueous solution not containing hexavalent chromium ions and having undergone the pH adjustment so as to prepare an aqueous solution containing trivalent chromium ions and hexavalent chromium ions. The chromium plating bath containing both trivalent chromium ions and hexavalent chromium ions can be prepared while easily and assuredly adjusting the contents (content ratio) of trivalent chromium ions and hexavalent chromium ions to predetermined values (a predetermined value).

Abstract: An electrodeposited crystalline functional chromium deposit which is nanogranular as deposited, and the deposit may be both TEM and XRD crystalline or may be TEM crystalline and XRD amorphous. In various embodiments, the deposit includes one or any combination of two or more of an alloy of chromium, carbon, nitrogen, oxygen and sulfur; a {111} preferred orientation; an average crystal grain cross-sectional area of less than about 500 nm2; and a lattice parameter of 2.8895+/?0.0025 A. A process and an electrodeposition bath for electrodepositing the nanogranular crystalline functional chromium deposit on a substrate, including providing the electrodeposition bath including trivalent chromium, a source of divalent sulfur, a carboxylic acid, a source of nitrogen and being substantially free of hexavalent chromium; immersing a substrate in the bath; and applying an electrical current to electrodeposit the deposit on the substrate.

Abstract: A method of making an integrated circuit including a composition of matter for electrodepositing of chromium is disclosed. One embodiment provides a bath having a solution of a chromium salt in a substantially anhydrous organic solvent, to uses of certain chromium salts for electrodepositing and to processes for electrodepositing chromium.

Abstract: A trivalent chromium-based electroplating solution in accordance with the present invention a trivalent chromium salt, a bivalent nickel salt, a complex agent, a conductive salt, a buffering agent and an additive for electroplating a chromium-nickel alloy deposit on a component. By using the lowly toxic trivalent chromium to substitute highly toxic hexavalent chromium, an electroplating procedure with the present trivalent chromium-based electroplating solution has less pollution and high current efficiency to allow the electroplating performing at the room temperature.

Abstract: A trivalent chromium electroplating solution in accordance with the present invention contains at least one trivalent chromium salt for electroplating a chromium coating layer on a workpiece. By using the low toxic trivalent chromium to substitute highly toxic hexavalent chromium, an electroplating process of the present trivalent chromium electroplating solution has less pollution.

Abstract: An electrolyte bath and method of electrolytically plating a layer of metallic chromium on a substrate comprises providing an electrolyte bath of a trivalent chromium, passing a current through the bath from an anode to a cathode which receives the substrate, maintaining the electrolyte bath at a desired temperature and a desired pH and depositing the trivalent chromium onto the substrate at a desired rate.

Abstract: An electrode adapted for chromium plating from trivalent chromium baths which comprises a conductive base, an electrode material layer comprising iridium oxide formed thereon, and a porous layer formed on the surface of the electrode material layer. The porous can comprise an oxide containing at least one element selected from the group consisting of silicon, molybdenum, titanium, tantalum, zirconium, and tungsten. Use of this electrode for chromium plating reduces the oxidation of trivalent chromium into hexavalent chromium.

Abstract: An improved aqueous acidic trivalent chromium electrolyte and process for increasing the tolerance thereof to the presence of deleterious contaminating metal ions and organic impurities which normally progressively increase during commercial operation of the electrolyte ultimately resulting in chromium electrodeposits which are commercially unsatisfactory due to the presence of streaks, clouds, and hazes in the deposit. The improved composition contains an effective amount of at least one EDTA compound which is effective to mask the adverse effects of such contaminating metal and organic impurities and which also enhances the codeposition of such metal contaminants on the parts being plated thereby reducing, and in some instances, preventing the accumulation of such contaminating metal ions in the electrolyte.

Abstract: A method for depositing chromium on metal substrates is disclosed in which the chromium hardens when heated. The electrolytic plating bath includes water soluble Cr(III), a sulfate catalyst, a metal ion buffer, and sufficient amounts of a reducing agent such as methanol to reduce substantially all Cr(VI) to Cr(III). The heat-hardenable chromium deposit allows the plated substrate to be heat tempered after plating, which eliminates the necessity of removing oxidation products from an unplated heated substrate. Moreover, the amount of toxic Cr(VI) present in the bath is greatly diminished, and replaced with a Cr(III) species that is environmentally safer.