387 results about "Chromium coating" patented technology

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.

A turbine engine rotor component, such as a compressor or turbine disk or seal element, is protected from corrosion by depositing an aluminum or chromium coating on the component. The deposition can be performed by a vapor deposition process, such as metal organic chemical vapor deposition (MOCVD), to a coating thickness of from about 0.2 to about 50 microns, typically from about 0.5 to about 3 microns. In one embodiment, the method is conducted in a vapor coating container having a hollow interior coating chamber, and includes the steps of loading the coating chamber with the component to be coated; and flowing a tri-alkyl aluminum or chromium carbonyl coating gas into the loaded coating chamber at a specified temperature, pressure, and time to deposit an aluminum or chromium coating on the surface of the component. The coated component is then heated in a nonoxidizing atmosphere to a specified temperature to form an aluminide or chromide coating on the surface. The coated component is typically then heated or maintained at an elevated temperature in the presence of oxygen to form an oxide coating on the surface of the component.

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.

The invention discloses a sulfate trivalent chromium electroplating solution and a preparation method thereof. Ionic solution; add a predetermined amount of brightener, wetting agent and accelerator, then electrolytic test plating. The sulfate trivalent chromium electroplating solution includes: conductive salt 150g/L~250g/L, buffer salt 60g/L~120g/L, trivalent chromium ion 5g/L~20g/L, complexing agent 10g/L~ 20g/L, brightener 0.1g/L~1g/L, C~S compound 1g/L~5g/L, saccharin sodium reactant 1g/L~4g/L, wetting agent 0.1g/L~1g/L. The invention improves the performance of the sulfate trivalent chromium electroplating process; the obtained trivalent chromium plating layer is white and fine, has fast deposition rate of the plating layer, and has excellent covering ability and throwing ability.

The invention discloses an aluminum alloy cylinder sleeve for an automobile engine. The aluminum alloy cylinder sleeve comprises a tubular aluminum alloy substrate and a chromium coated layer, wherein the chromium coated layer is arranged on the inner surface of the aluminum alloy substrate; the aluminum alloy substrate is prepared from the following aluminum alloys in percentage by weight: 13-15% of Si, 1-2% of Cu, 0.2-0.5% of Mg, 0.1-0.3% of Mn, 0.1-0.3% of Cr, 0.1-0.3% of C, 0-0.5% of Zn, 0-0.15% of Ti, 0.1-0.3% of RE and the balance of Al. The invention further provides a preparation method of the aluminum alloy cylinder sleeve for the automobile engine. By adopting the aluminum alloy cylinder sleeve, the strength, the hardness, the high temperature stability and the wearing resistance of a cylinder sleeve are improved, the use property of the aluminum alloy cylinder sleeve is improved, the service life of the aluminum alloy cylinder sleeve is prolonged, and requirements of a conventional engine can be met.

A process for forming a coated substrate comprises providing a nickel base alloy substrate, depositing a chromium coating onto the nickel base alloy substrate and diffusing chromium from said coating into the substrate, applying a MCrAlY coating onto the nickel base alloy substrate and heat treating the substrate with the deposited chromium and the MCrAlY coating so that chromium diffuses into an outer region of the substrate. Further, in accordance with the present invention, a strip process for removing a coating from a substrate broadly comprises the steps of providing a nickel base alloy substrate having chromium diffused into an outer region and a MCrAlY coating deposited over the substrate with the diffused chromium and removing the MCrAlY coating by immersing the nickel base alloy substrate in an acid solution containing a sulfuric acid-hydrochloric acid mixture in water.

The manufacture technique for a crystallized copper tube with transient Cr-plating layer and hard Cr-plating layer comprises: cleaning the base copper tube to remove dust and oil; reverse nicking treatment before plating; preparing electroplate liquid; plating; cleaning; then, arranging transient plating layer with medium thermal-expansion coefficient and hardness between the base tube inner wall and surface hard plating layer. This invention ensures the tube resistance to high temperature, wear and corrosion, and endows the plating layer resistance peel, and has high yield efficiency with stable quality and low cost.

The invention discloses a method for manufacturing a nickel-chromium plating steel band for a battery steel shell. According to the method, ingredients of low-carbon steel are adjusted, proper amount of alloy elements of Ti, Ni, Nb and the like is added, and the content of N and O is controlled to improve surface states; parameters of a cold milling process and an annealing process are adjusted aiming at the adjusted ingredients of the steel; a chromium coating is used as a diffusion impervious layer, so that the diffusion of iron can be blocked effectively; and an anticorrosive coating which contains 20 to 30 percent of chromium and has a quasi-stainless steel structure is formed in the diffusion layer, so that the anticorrosive performance is enhanced doubly. Aiming at double-layer plating design concept of nickel-chromium plating, the ingredients of a nickel plating solution and a chromium plating solution and a plating process are adjusted, so that the coating has the characteristics of bright surfaces, low porosity and high mechanical performance.

The invention provides a method for recovering copper and nickel from plastic chromium coatings. The method is characterized by consisting of the following steps of: 1, weighing the plastic chromium coatings, adding mixed solution of H2SO4 and H2O2 to the plastic chromium coatings for leaching, and filtering the mixed solution to obtain leachate and insoluble substances; 2, adjusting a pH value of the leachate, extracting the leachate by a mixture, serving as an extractant, of 2-hydroxyl-5-dodecyl salicylaldoxime and 2-hydroxyl-5-nonyl acetophenone oxime to obtain copper containing extraction solution and nickel containing raffinate, and back-extracting the copper containing extraction solution by sulfuric acid to obtain the copper containing back extraction solution; and 3, electrolyzing the copper containing back extraction solution and the nickel containing raffinate to obtain metal copper and metal nickel respectively. The method for recovering copper and nickel is lower in cost, causes little environmental pollution, and is suitable for the recycling of the plastic chromium coatings.

The invention discloses a door rod strengthening technology for an air pump recycling regulation door, which comprises the following steps of: 1. preliminary working: abrading the rod part of the door rod to remove the thickness of 0.18-0.20mm; 2. workpiece surface purification: purifying the surface until the surface is free from macroscopic oil stains; 3. surface pretreatment: carrying out abrasive blasting on the surface of the rod part of the door rod by 12# brown fused alumina sand, wherein the pressure of compressed air is 0.5-0.7kg/cm<2>, and the surface roughness after abrasive blasting reaches Sa 3 level; 4. metal ceramic coating spraying: spraying a metal ceramic coating on the surface of the rod part of the door rod by a supersonic speed flame spray gun, wherein the material is NiCr-C2C3 spraying powder, the flame center line of the spray gun and the axis of the workpiece are intersectant with the error within +/-5 degrees, the spraying distance is 220-250mm, parameters are controlled as follows: 15-18SCFM (standard cubic foot per minute) of O2, and 200-240SCFH (standard cubic foot per hour) of C3H6, and the temperature of the workpiece is controlled to below 200DEG C; and 5. mechanical processing of the coating. In the door rod strengthening technology, the supersonic speed spraying coating replaces a chromium coating so as to improve the abrasive resistance of the door rod, and the door rod strengthening technology is convenient to operate, is flexible and efficient, is environmentally-friendly and protects environment.

The invention discloses an organic material shell with metal texture and a coating method thereof. The metal texture is obtained by depositing a chromium coating, an aluminum coating, a silicon dioxide coating and an AF (anti-fingerprint) coating on an organic material layer in a layer-by-layer manner; the obtained organic material shell has good characteristics that the coatings are good in stability and thin, the wear resistance is relatively good, the surface glossiness is high and the anti-fingerprint and dirt-resistant effects are achieved, and the requirements on electronic products caused by modern people are met.

A valve (10) for use in an internal combustion engine comprises a base metal. The base metal is covered with a thin, dense chromium coating.

The invention discloses a manufacturing method of a submarine oil well valve base. Chrome-molybdenum low-alloy steel is selected as a blank. The chrome-molybdenum low-alloy steel comprises the following components in percentage by mass: 0.3-0.32% of carbon, 0.18-0.36% of silicon, 0.50-0.70% of manganese, 0.90-1.10% of chrome, 0.20-0.30% of molybdenum, 0-0.02% of phosphorus, 0-0.025% of sulfur, 0-1.8ppm of hydrogen, 0-0.40% of nickel, 0-0.03% of vanadium, 0-0.30% of copper, 0-0.9% residual element and the balance of Fe. The manufacturing method disclosed by the invention can enhance the pressure resistance and toughness of the valve base and prevent the chrome coating from shedding.

A method for producing vacuum chromium-cladding layer on high-temperature-resisting plastic piece has chromium-plating and decorative functions. The process is carried out by selecting plastic piece with thermal-deformation temperature above 100degree, spraying baking paint onto plastic piece surface with curing temperature below 100degree as primer paint, obtaining vacuum chromium-cladding layer on primer surface of multi-arc vacuum ion coating apparatus, and re-spraying baking paint with curing temperature below 100degree onto chromium-cladding layer surface as finish. It has excellent abrasive and anti-corrosion performances.

The invention discloses a tin-cobalt alloy decorative chromium-substituted electroplate liquid and an electroplate method thereof. The electroplate liquid consists of the following components: 40-50 g/L of stannous chloride, 30-40 g/L of cobalt chloride, 60-90 g/L of potassium chloride, 10-12 g/L of EDTA disodium salt, 5-10 g/L of sodium potassium tartrate tetrahydrate, 0.2-0.5 g/L of crylic-2-ethyl hexyl ester, 0.1-0.2 g/L of benzalacetone, 0.1-0.2 g/L of polyoxypropylene glycerol ether and 0.02-0.05 g/L of coumarin. Compared with the electroplated coating obtained by the present tin-cobalt alloy electroplate liquid, the coating obtained according to the invention is closer to a chromium coating in apperance, can be widely applied to decorative chromium-substituted technique, and has the advantages of smoothness of the electroplated coating, uniformity and compactness, good adhesive force, long service life of the electroplate liquid and the like.

The invention relates to the field of electroplating, in particular to a trivalent chromium electroplating solution capable of being used for electroplating thick chromium through trivalent chromium and an electroplating method. The trivalent chromium electroplating solution and the electroplating method effectively solve the problem that trivalent chromium coatings cannot be thickened. The trivalent chromium electroplating solution is composed of 0.4-1.2 mol/L of chromic chloride, 0.5-3.0 mol/L of coordination agents, 0.1-0.8 mol/L of buffering agents, 0.5-2.0 mol/L of conducting salt, 3-35 g/L of organic additives and the balance water. By adopting a chloride plating solution system and a high-density graphite anode, trivalent chromium coatings with the smooth surface, compact crystals and the thickness higher than 60 micrometers can be prepared at the current density of 25-45 A/dm<2>, the binding force between the trivalent chromium coatings and base bodies is high, and the hardness of the coatings can be higher than HV800.