1、 Different nature
1. Chromium plating: a kind of silvery white metal with slight blue. Metal chromium is very easy to passivate in the air, and a very thin passivation film is formed on the surface, thus showing the properties of precious metals. Make the dissolved products on the surface of the workpiece separate, and the corrosion or electrolyte near the surface is uniform; The cavitation effect of ultrasonic wave in liquid can also inhibit the corrosion process, which is conducive to surface brightening.
2. Polishing: using mechanical, chemical or electrochemical effects to reduce the surface roughness of the workpiece to obtain a bright and flat surface. That is, by selectively dissolving the small protruding parts on the surface of the material, the surface is smooth.
2、 Different functions
1. Chrome plating: you can get Silver Blue specular luster. It will not change color in the atmosphere for a long time. It has high reflection ability to light and can be used as a reflector.
2. Polishing: increase the brightness of the workpiece surface to achieve the mirror effect.
3、 Different characteristics
1. Chromium plating: the dispersion ability is very low. For parts with complex shapes, pictographic anode or auxiliary cathode should be used to obtain a uniform chromium plating layer. The anode uses insoluble anode instead of metallic chromium. Lead, lead antimony alloy and lead tin alloy are usually used. Chromium consumed in the plating solution due to deposition or other reasons needs to be supplemented by adding chromic anhydride.
2. Polishing: it is mainly manual operation. For special parts such as the surface of swivel, auxiliary tools such as turntable can be used. Ultra precision grinding and polishing can be used for those with high surface quality requirements. Ultra precision lapping and polishing adopts special abrasive tools. In the lapping and polishing liquid containing abrasive, it is tightly pressed on the machined surface of the workpiece for high-speed rotation.