Zhejiang Ruifeng Machinery Equipment Co., Ltd.
Contact person: Mr. Ma
Mobile phone: 18905728938
Address: 88 Tianxin Road, Xinshi Town, Deqing County
Main Procedures for Pretreatment of Stainless Steel Electroplating
(1) Oil removal by soaking in organic solution
Some stainless steel parts can not be degreased by electrochemical degreasing method, because the surface of stainless steel parts is black after electrochemical degreasing, even acid cleaning can not make its surface bright. In order not to destroy the bright state of the stainless steel surface, the oil stains on the stainless steel surface are first washed with industrial gasoline, and then transferred to the chemical deoiling process.
(2) Chemical deoiling
The stainless steel parts can be put into the tank with industrial cleaning agent (the temperature is usually 50-70 C), which can be equipped with ultrasonic wave to completely remove the oil contamination on the surface of the parts; the oil removal time is controlled until the oil contamination on the surface is removed.
Pickling is an indispensable process in the pretreatment of stainless steel electroplating. Because pickling can remove the rust and passive film on the surface of stainless steel, expose the matrix on the surface and improve the adhesion of the coating.
The purpose of activation is to remove the oxide film on the surface of stainless steel and activate it to ensure sufficient adhesion between the coating and the stainless steel matrix. The activation process includes impregnation activation and cathodic activation. Experiments show that the passive film on the surface of stainless steel can be removed quickly by impregnation and activation, and then electrochemical pre-plating treatment can quickly generate a layer of coating, which greatly improves the adhesion between the coating and stainless steel.
After the parts enter the pre-plating bath, do not turn on the electricity, stop for 2-3 minutes, then turn on the electricity for pre-plating treatment. The formation rate of oxide layer on stainless steel surface is very fast. After chemical activation, it is possible to grow an oxide layer on the surface of stainless steel. Therefore, in the pre-plating process, the parts are immersed in the solution, the hydrochloric acid in the solution activates the surface of the parts again, and the parts are chemically adsorbed by nickel ions in the solution, then react with electricity to form a thin nickel layer.
(6) Nickel pre-plating
After the stainless steel parts are pre-plated, the stainless steel parts are immediately put into the pre-plated nickel bath for electroplating treatment, so as to ensure good adhesion of the coating. After nickel pre-plating, it is washed twice with flowing water before subsequent electroplating.
Activation and pre-plating are very important in the pre-plating process of stainless steel parts. The passivation film on stainless steel parts was removed by chemical activation and pre-plating pretreatment, and a good adhesion coating was formed on the surface of stainless steel parts, thus realizing the plating of various metals on stainless steel substrates.