Abstract: A method for preparing a Cr(III)-plating solution is disclosed. The method comprises or consists of the steps of (a) providing an aged aqueous Cr(III)-solution; (b) adding a polycarbonate or a derivative thereof to the solution of step (a); and (c) adding a borate to the solution of step (b). In addition, a plating solution obtainable by the present method is disclosed, and a plating solution comprising or consisting of Cr(III)-ions, a polycarbonate or a derivative thereof, a borate, water, sulfate, and positive ions selected from the group consisting of hydrogen ions, alkali metal ions and earth alkali metal ions.

Abstract: An apparatus for maintaining trivalent chromium plating bath efficiency includes an aqueous electroplating bath, which includes trivalent chromium ions and a sulfur compound, and an ultraviolet (UV) radiation source that provides UV radiation to the bath effective to inhibit a reduction in plating efficiency of the bath.

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 aqueous acidic trivalent chromium electrolyte comprising trivalent chromium ions and a complexing agent for maintaining the trivalent chromium ions in solution is provided in which the aqueous electrolyte comprises additives capable of producing a coating on a substrate having a desired dark hue. The additives typically comprise a dispersion of colloidal silica and an additional additive selected from thiocyanate ions and/or iron ions. The electrolyte is used in a method of producing the desired dark-hued decorative chromium coating on a substrate by electrodeposition.

Abstract: An aqueous acidic trivalent chromium electrolyte comprising trivalent chromium ions and a complexing agent for maintaining the trivalent chromium ions in solution is provided in which the aqueous electrolyte comprises additives capable of producing a coating on a substrate having a desired dark hue. The additives typically comprise a dispersion of colloidal silica and an additional additive selected from thiocyanate ions and/or iron ions. The electrolyte is used in a method of producing the desired dark-hued decorative chromium coating on a substrate by electrodeposition.

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: An aqueous acidic trivalent chromium electrolyte comprising trivalent chromium ions and a complexing agent for maintaining the trivalent chromium ions in solution is provided in which the aqueous electrolyte comprises additives capable of producing a coating on a substrate having a desired dark hue. The additives typically comprise a dispersion of colloidal silica and an additional additive selected from thiocyanate ions and/or iron ions. The electrolyte is used in a method of producing the desired dark-hued decorative chromium coating on a substrate by electrodeposition.

Abstract: Provided is hard trivalent chromium plating solution having improved covering power. The trivalent chromium plating solution comprises a trivalent chromium compound comprising a compound of formula (1) below; wherein Cr2(SO4)n(OH)6-2n (n<3) ??(1).

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: The invention consists of a chromium electroplating solution comprising a chromium electroplating solution comprising: (1) a water soluble trivalent chromium salt; (2) at least one complexant for trivalent chromium ions; (3) a source of hydrogen ions sufficient to create a pH of from 2.8-4.2; (4) a pH buffering compound; and (5) a sulfur-containing organic compound. The chromium electroplating solution is usable in a method for producing an adherent metallic coating on a decorative article, such coating having enhanced resistance to corrosion in environments containing calcium chloride.

Abstract: A plating process for plating chromium metal onto substrates is disclosed. The process uses a trivalent chromium plating bath with a sulfate and/or sulfonate matrix. The process also utilizes insoluble anodes. An addition of manganese ions to the plating bath inhibits the formation of detrimental hexavalent chromium ions upon use of the plating bath.

Abstract: Chromium hydroxide of the invention has an average particle size D determined from a scanning electron micrograph of 40 to 200 nm and a degree of agglomeration of 10 and more and less than 70, the degree of agglomeration being defined to be a ratio of a volume average particle size D50 determined with a particle size analyzer to the average particle size D, D50/D. The chromium hydroxide is suitably obtained by adding an aqueous solution containing trivalent chromium to an aqueous solution of an inorganic alkali at a reaction temperature of 0° C. or higher and lower than 50° C. The inorganic alkali is preferably an alkali metal hydroxide.

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 ion separation instrument includes an ion source coupled to at least a first ion mobility spectrometer having an ion outlet coupled to a mass spectrometer. Instrumentation is further included to provide for passage to the mass spectrometer only ions defining a preselected ion mobility range. In one embodiment, the ion mobility spectrometer is provided with electronically controllable inlet and outlet gates, wherein a control circuit is operable to control actuation of the inlet and outlet gates as a function of ion drift time to thereby allow passage therethrough only of ions defining a mobility within the preselected ion mobility range. In another embodiment, an ion trap is disposed between the ion mobility spectrometer and mass spectrometer and is controlled in such a manner so as to collect a plurality of ions defining a mobility within the preselected ion mobility range prior to injection of such ions into the mass spectrometer.

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: A method of forming a surface finish of trivalent chromium on metal or plastics substrates by electrodeposition from an aqueous plating solution of trivalent chromium ions in which the trivalent chromium is deposited on a layer of silver or silver alloy whereby the color and/or corrosion resistance of the trivalent chromium is comparable to surface finishes of hexavalent chromium. The invention avoids the health and safety risks associated with the electrodeposition of hexavalent chromium surface finishes.

Abstract: Excessive evolution of hydrogen in electrolytic deposition of metals on a cathode substrate can be controlled by using a pulsed reverse current. Reverse current pulses interposed between the forward current pulses consume at least some of the nascent hydrogen and prevent the local pH at the cathode surface from becoming excessively alkaline. Control of hydroxide ion concentration by pulsed reverse current alleviates problems caused by reaction of metal-bearing-ions with hydroxide ions generated near the cathode by evolution of hydrogen. The method is useful in depositing functional chromium coatings on electrically conductive substrates from plating baths comprising aqueous solutions of trivalent chromium salts. In such a method the current comprises forward pulses having a duty cycle of from about 50% to about 90% and reverse pulses having a duty cycle of from about 5% to about 30%, and a frequency of from about 5 Hz to about 700 Hz.

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: The present invention provides a method of coating a tin article with a non-hexavelant trivcalent chromium oxide and/or hydoxide in which the tin article is contacted with a trivalent chromium protective coating composition having an acid pH of about 2.0 to 3.0 which is free of chromium complexing agents.

Abstract: Process suitable for providing a substrate with a protective coating based on chromium, including a chromium matrix in which solid particles are distributed. The process includes a step of electrodeposition of the coating carried out by passing an electric current between a cathode or cathodes of the substrate to be coated and an anode or anodes. The cathode(s) and anode(s) are immersed in an electroplating solution, wherein the electroplating solution is based on an aqueous solution including trivalent chromium obtained from the reduction of chromic acid by a reducing agent, and contains solid particles.

Abstract: A trivalent chromium protective coating composition for zinc or a zinc plated article having an acid pH of about 3.0 to 4.0 and a process for coating the zinc or zinc plated article in which the article is contacted with the composition and trivalent chromium is deposited on the article by electrolysis and an article of zinc or zinc plate is coated with a protective trivalent chromium composition.

Abstract: A waste water stream containing a heavy metal such as chromium, zinc, copper, and the like is directed from a source after pH adjustment to a tank containing adsorption material in the form of granular activated carbon. A waste water stream is directed to the tank in either an upward or downward flow mode. The heavy metal is adsorbed onto the surface of the adsorption material which is pretreated to an initial pH in the range between about 1.5 to 2.5. The water stream free of the metal contaminant is directed to an effluent tank for safe discharge. Thereafter a stripping solution preferably containing sulfuric acid is circulated through the tank to remove the adsorbed metal for the adsorption material. The metal is carried by the stripping solution from the tank to an electrolytic metal recovery unit. The unit includes a cathode terminal and the stripping solution passes through a voltage potential resulting in electrolytic deposit of the heavy metal onto the cathode terminal.

Abstract: A process for galvanic deposition of chromium coatings is provided in which the base material is subjected to a galvanic chromium plating bath to form a hard chromium coating with beaded or columnar type surface structure, and the beaded or columnar type surface structure is subsequently filled and smoothed with galvanically applied black chromium. The resulting combined coatings yield increased wear resistance, lower friction values, even without lubricants, and increased corrosion resistance.

Abstract: A chromium plating method using a plating bath comprising trivalent chromium and an electrode which is an anode comprising an electrode substrate of titanium, tantalum, zirconium, niobium or an alloy thereof, coated with an electrode catalyst comprising at least iridium oxide and, optionally, at least one of titanium, tantalum, niobium, zirconium, tin, antimony, ruthenium, platinum, cobalt, molybdenum, tungsten or an oxide thereof. The anode may be placed directly in the chromium plating bath or may be placed in an anode chamber partitioned from the chromium plating bath with an ion-exchange membrane. The chromium plating method may be a barrel plating method.

Abstract: There is disclosed a method of manufacturing a plated steel sheet with a Zn--Cr composite plating, wherein a total of 0.01 to 300 g/l of at least one type of salt having a pH buffering action in a pH range of 2 to 6 in a bath containing only zinc are added to an acidic Zn--Cr composite plating bath containing zinc ions and trivalent chromium ions to prepare a plating bath, and plating film is formed on a steel sheet using the resultant plating bath.

Abstract: Methods for electrodepositing a chromium coating on a substrate comprising mmersing the substrate in an aqueous electrolyte, and passing a sufficient current through the electrolyte to effect deposition of a chromium coating on the substrate. The aqueous electrolytes comprise from about 0.2 to about 0.6 mol/l of trivalent chromium ions, greater than about 1.4 mol/l of an amidosulfonic acid or a salt thereof, ammonium ions, formic acid or a salt thereof, and water.

Abstract: Functional chromium and chromium-alloy deposits are obtained from an electroplating solution having substantially the composition: 22 g/l Cr.sup.+3 ; 250 g/l KCl; 63 g/l H.sub.3 BO.sub.3 ; 30 g/l HCO.sub.2.sup.= ; 15 g/lKBr; and 120 ppm of a wetting agent. The plating solution provides improved efficiency, stress values and appearance over the prior art, and is tolerant of metallic iron and ionic iron and ammonium.

Abstract: A process and apparatus for regenerating a plating bath comprising trivalent chromium cations (a trivalent chromium bath). The bath can be continuously, or more preferably, periodically with an ion exchange resin, preferably a cation exchange resin. A useful apparatus comprises a plating tank containing a trivalent chromium plating bath in communication with an ion exchange bed continuing ion exchange resin.

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 is shown for constructing portions of a sucker rod pump of the type having a steel plunger with an exterior cylindrical wall and a barrel with a cylindrical bore. A chromium case if formed on the cylindrical bore to a selected depth for receiving the plunger in sliding contact. The chromium case is formed by forming a base electrolyte bath including water, chromic acid, a sulfate component, an alkyl sulphonic acid, and an anion of molybdenum. The bore is then exposed to the aqueous electrolyte bath at a current density and at a plating temperature sufficient to form a chromium deposit of desired thickness on the bore.

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.

Abstract: A new method for purification of trivalent chromium electroplating baths contaminated with cationic metal ions is disclosed. In this purification process, the contaminated trivalent chromium is passed at the pH level of the bath through one or more columns containing an ion-exchange resin having the picolylamine group as the functional moiety. The cationic metal ions are preferentially bound to the resin while the trivalent chromium is passed through the resin with substantially no adsorption thereby purifying the electroplating bath. This process is preferably performed simultaneously with the electroplating process.

Abstract: A process and apparatus for regenerating a plating bath comprising trivalent chromium cations (a trivalent chromium bath). The bath can be continuously, or more preferably, periodically with an ion exchange resin, preferably a cation exchange resin. A useful apparatus comprises a plating tank containing a trivalent chromium plating bath in communication with an ion exchange bed continuing ion exchange resin.