Trivalent black chromium electroplating agent easy to prepare and preparation method thereof

Abstract

A trivalent black chromium electroplating agent easy to prepare comprises potassium chloride, ammonium chloride, boric acid, chromium trichloride, potassium thiocyanate and methionine. The potassium chloride, the ammonium chloride and the boric acid are used as main materials, the chromium trichloride is added, so that the color can be changed from white to green, other additives do not need to beadded to adjust the color, and meanwhile, the mixed use of the potassium chloride, the ammonium chloride, the boric acid and the chromium trichloride can maintain the chromium concentration of a bathsolution without separately adding chromium salt in the process of preparing an electroplating solution; therefore, the preparation process can be simplified, the preparation time can be shortened, the purchase cost of raw materials can be saved, and the preparation process can be simpler and more convenient; and by adding the potassium thiocyanate and the methionine, the plating layer depositionspeed of the plating solution of the trivalent black chromium electroplating agent can be improved, the covering capacity of the trivalent black chromium electroplating agent can be improved, a chromium layer can be deposited on the surface of a workpiece plated by the trivalent black chromium electroplating agent, and the corrosion resistance of the surface of the workpiece can be greatly improved by the chromium layer.

Description

technical field [0001] The invention relates to a trivalent black chromium electroplating agent with simple preparation and a preparation method thereof. Background technique [0002] Due to its unique color and good decorative and ornamental properties, electroplated black coating has always been loved by consumers and is widely used in instrumentation components, electronic and electrical products, and optical instruments. Based on the requirements for environmental protection, the trivalent chromium plating solution electroplating process has been rapidly popularized after 2004. With the maturity of the process technology, it has gradually replaced the hexavalent chromium plating solution electroplating process. However, the black chromium plating process with trivalent chromium plating solution may be due to the lag of market demand and application technology. Until 2008, there has been relatively strong domestic market demand, and it has been growing at a relatively rap...

AI Technical Summary

Problems solved by technology

[0004] At present, the composition of trivalent black chromium commonly used in the market is usually all more complicated, and the color of its electroplating agent is generally all white, such as the publication number is CN101792917A, and the patent name is "normal temperature environment-friendly sulfate trivalent chromium electroplating solution" The preparation method of "and the publication number is CN101280440A, the patent name is "a kind of full sulfate type trivalent chromium electroplating solution and the electroplating method using the electroplating solution" Chinese invention patent and the publication number proposed by the applicant before is CN109652827A, the patent A Chinese invention patent titled "A Sulfate Trivalent Chromium Electroplating Solution and Its Manufacturing Process and Electroplating Process" with a publication number of CN110512240A and a patent title of "A Hydrochloric Acid Type Highly Corrosion-Resistant Trivalent White Chromium Electroplating Solution" , the above patents not only need to add other additives to adjust its color during normal production and maintenance, but also need to frequently add chromium salts to maintain the chromium concentration of the bath

Moreover, the electroplating agents currently on the market require a high temperature during electroplating, and they generally need to be electroplated at a temperature of 35-70°C. However, after the electroplating agents on the market are adjusted by a pH regulator, their pH value can be adjusted to the maximum. The range is only between 2.7-3.3, its deposition rate is generally 0.02-0.1μm / min, the coating thickness of the workpiece after electroplating is generally 0.5-3μm, and the current density is generally 10-25A / dm 2 , which has problems such as large power consumption, slow deposition rate, thin coating thickness, narrow current density range, and uneven color plating of workpieces, which limit the development factors of commonly used trivalent black chromium

Images