Hard chrome plating is a hard chrome plating process. It is to plate a thick chromium plating layer on the surface of various substrates. Its thickness is generally above 20μm. The characteristics of chromium are used to improve the hardness, wear resistance, temperature resistance and corrosion resistance of the parts.
Hard chromium plating is a traditional surface electroplating technology that has been used for more than 70 years. The chrome-plated layer has high hardness, wear resistance, corrosion resistance and can keep the surface bright for a long time. The process is relatively simple and the cost is low. For a long time, in addition to being used as a decorative coating, chromium plating has also been widely used as a wear-resistant and corrosion-resistant coating for mechanical parts. Electroplating hard chrome plating technology is often used to repair damaged parts.
But the hard chromium electroplating process can cause serious environmental problems. The chromic acid solution used in the chromium plating process will produce chromic acid mist and waste water, and there are other shortcomings. For example, the hardness is generally 800~900HV, which is higher than some ceramics and The cermet material is low, and the hardness will decrease with the increase of temperature; there are micro-cracks in the chrome plating layer, which inevitably produce penetrating cracks, causing corrosive media to penetrate from the surface to the interface and corrode the substrate, causing rust spots or even peeling on the surface of the plating layer; The deposition speed of the electroplating process is slow, and the 0.2~0.3mm thick coating often requires 2~3 shifts, which is not conducive to the application of thick coatings.
Therefore, the research field has been striving to find a new process to replace hard chromium electroplating. Many new processes have appeared and have been applied and developed.
