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October 24, 2008

Electropolishing Bath

As have known that electropolishing is the fast and effective way on preparing the metals before anodized or electroplating process applied. This process also become a key on getting a best result, because if you do in careless way on this process you will difficult to get a best result or even no metal is stick to the product.

The most common used in electropolishing bath are based on sulfuric and phosphoric acids in about 50/50 weight proportion at about 54 to 105oC for ferrous alloys, 85% phosphoric acid for copper at about 43 to 60 oC; and phosphoric acid with about 5 to 7% chromic anhydride (CrO3) at about 60oC for brass.

Current density of practical electropolishing range from 5 to 40 A/dm2, depending on the metal being finished, type of bath, and temperature. The time required usually is 2 to 7 min for current densities of 15 to 30 A/dm2 and temperature of 54 to 82 oC.

Electroplating bath are less subject than electroplating bath to contamination and are easily controlled to maintain optimum result. Except for the perchloric acid – acetic acid type of bath, safe operation is easily maintained. Perchloric acid-acetic bath require failsafe temperature controls and strict avoidance of contamination with easily oxidizable materials.






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