Tuesday, March 30, 2010

Throwing Power on Nickel Electroplating

Plating speed generally on electroplating such as on chromium plating and on nickel plating will increase in increasing the current density, this can be seen on the drawing below the relationship between current density and plating speed. Throwing POWER and covering power of chromium plating baths are poor compared with copper on nickel plating bath. The conductivity is high but is reduced by such impurities as iron and copper.

The cathode polarisation during chromium deposition is relatively constant and substantially the same as than obtained during the electrolysis of the same concentration of pure chromic acid without chromium deposition.

Consequently, the major variables connected with throwing power in bright plating are the current efficiency and the bright plating range. If a given set of conditions gives the widest possible bright plate range and the plating is done at an average cathode current density near the upper limit of current density for this bright plate range, the optimum throwing power will be attained.

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