- Aug 28, 2018 -
Stainless steel is resistant to atmospheric, water, sea water, acids and other corrosive media and has high chemical stability. The mass fraction of chromium in stainless steel is usually higher than 12%, and also contains a certain amount of one or more elements of nickel, manganese, silicon, molybdenum, vanadium, niobium, titanium, copper, aluminum, boron, nitrogen, etc. and a certain amount of carbon.
Stainless steel has excellent corrosion resistance and generally does not require surface treatment. Even if it is used, passivation treatment is used. However, in recent years, as the requirements for aircraft manufacturing have increased, it is required to plate stainless steel parts. Due to its high chromium content, stainless steel forms an extremely dense oxide film on its surface. Its main components are CrO, Cr2O3, etc., which undoubtedly hinder the deposition of the coating. Therefore, the electroplating of stainless steel mainly depends on the pretreatment before plating.
Stainless steel is composed of iron, nickel, chromium, titanium and other components. The surface is easy to form a thin, transparent and firmly adhered passivation film. After the film is removed, it will form rapidly on the fresh surface. Therefore, the plating process is based on general steel parts. A coating with good adhesion is not obtained. Prior to the electroplating of stainless steel, in addition to the degreasing and etching of ordinary steel, activation pretreatment is usually required. The activation treatment is an important step to ensure sufficient adhesion of the plating layer. The general activation treatment methods include a cathode activation method, an immersion activation method, and a galvanization activation method.