Saturday, March 24, 2012

Impurities on Chromium Plating

Metallic Impurities can merge on chrome electroplating bath when certain condition happened, like if the area of cathode too large and the area of anode too small. Cathode is the area that connected to positive pole of battery and anode is the part that connected to the negative pole of battery. Chromium III, can merge when bath is not operated. Other cations that may be present in chromium plating baths such as iron, copper, nickel, zinc, and sodium.

Iron, copper, nickel and othe metallic impurities may be introduced into the bath in various ways; if permitted to acccumulate, they cause an increase in the resistivity of the bath. Chromium III particularly is detrimental, although contrary statements, the tradition that a small amount of chromium III is beneficial when added to a new bath may have grown up due to make such additions in the early days in the form of chromic sulfate or chromium hydroxide precipitated from chromic sulfate and containing some sulfate.