抄録
Optimum bath compositions and plating conditions were experimentally sought for obtaining bright chromium deposits from CrCl3·6H2O-ethanol baths with tetraalkyl ammonium halides. The appearance of the deposits was affected by plating time and applied current density. For promising chromium deposition, additives had the effectiveness in the following order (CH3)4NCl≈(C2H5)4NCl >(CH3)4NBr≈(C2H5)4NBr>(CH3)4Nl≈(C2H5)4Nl. The highest current efficiency of ca. 50% was obtained in a chromium plating bath of CrCI3⋅6H2O 100g/l and (C2H5)4NCl 0.1g/l as an additive at 20mA/cm2, 30°C and 1.0-1.5min. plating time. The current density range and plating time for optimum plating efficiency varied from 10 to 40mA/cm2 and 0.5 to 120min. respectively depending on the concentration of the additives in the baths. Comparison with results in the Sargent Bath and fluorosilicate bath showed that this trivalent chromium bath employed in this study had advantages over these baths inthe preparation of the solution, current efficiency and covering power.
