The chrome treatment is mainly for anti-corrosion. According to the production of different materials, the double alloy screw needs chrome corrosion protection. The chrome plating layer has good chemical stability and does not function in alkali, sulfide, nitric acid and most organic acids, but it is soluble in hydrohalic acid, such as hydrochloric acid in sulfuric acid. Screw chrome plating can prevent rust, corrosion, surface hardness, decorative effect, and looks good.
Double alloy screw requires chrome plating
Chrome plating is generally referred to as chrome plating. There are two methods for chrome plating. The first one is electroplated decorative chrome and the second is electroplated hard chrome. Electroplated hard chrome is a better way to increase the surface hardness. This method has many advantages, so in most cases, electroplating is not used.
Double alloy screw requires chrome plating advantages
Advantages one, the surface finish is good, the advantage is two, it will not rust, there will be no rust spots; Third, the original parts are less deformed during the plating process. Fourth, if the part size is not in place, you can achieve the size by adding a few chrome. In the visible range, chromium has a reflectivity of about 65%, between silver (88%) and nickel (55%), and because chromium does not change color, it can maintain its reflective ability for a long time and is superior to silver and nickel. .
Chrome plating process
The main component of the chrome plating solution is not a metal chromium salt, but a chromium oxyacid-chromic acid, which is a strong acid plating solution. In the electroplating process, the cathode process is complicated, and the cathode current is mostly consumed in the two side reactions of hydrogen evolution and hexavalent chromium reduction to trivalent chromium. The cathode current efficiency of the chromium cylinder of the screw barrel is very low (10% to 18%). Moreover, there are three anomalies: the current efficiency decreases with increasing chromic anhydride concentration, and decreases with increasing temperature; it increases with increasing current density.