Tin is a silver-white metal, non-toxic, with good weldability and ductility. Widely used in electronics, food, automotive and other industries. The tin plating process of hexagonal bolts is classified by the ph value of the bath, which is divided into acidic plating bath process and alkaline tin plating process.
The advantage of acidic tin plating is the fast plating speed. Plating bright and meticulous, deep plating ability is good. The plating liquid is strong to the impurity tolerance, the room temperature operation saves energy. The disadvantage of Minamata is that the dispersion ability of the plating solution is poor, the porosity of the coating is higher, the brazing is less than the alkaline tin, and the bivalent tin is hydrolyzed. In the acidic tin of hexagonal bolt, the different conductive medium is divided into the process of sulfate tin plating, fluorine borate tin plating and chloride tin plating.
Sulfuric acid tin plating cost is low, the plating liquid is easy to control, the coating is bright and meticulous, but the dispersing ability is poor. The market is most widely used. The advantage of fluorine borate tin plating is fast plating, which can use larger current and good stability of plating solution. It is widely used in the continuous electroplating of flange nut, wire and strip. The disadvantage is that the bath cost is high, the toxicity is big, the waste water treatment is difficult.
Chloride tin plating mainly in the crystal grain, the advantages of low cost, stable plating, coating white. The disadvantage is that the current is not open. Hexagonal bolts The advantages of alkaline tin plating are: simple composition, good dispersion of plating fluid, coating, fine, less pore, good brazing performance. The disadvantage is: operating temperature is high, energy consumption, the current use of narrow range, low current efficiency, can not obtain bright coating, plating hard plating small, anode behavior is greatly affected