Study on Improvement of Mechanical Properties after Heat Treatment of Hard Chromium Electrodeposits with Additives

Abstract

The addition of cyclo propane carbonyl (cpc) to chromium electroplating bath resulted in a chromium deposit which had greatly improved mechanical properties compared to conventional chromium deposits in condition of heat treatment at high temperature. The as?deposited layers had a Vicker's hardness of about 1170, which is comparable to that of conventional chromium plating deposits. With annealing, the hardness goes through a maximum of 1650 at 600°C. Generally speaking, the hardness of conventional plating decreases monotonically with heat treatment. X?ray diffraction show that annealing up to above 400°C causes formation and growth of chromium crystallites and that chromium carbides form at above 500°C temperature.

Study on Zn-Mn Alloy Plating on the Surface of Steel Sheet Prepared in Hydrochloric Acid Bath

“…The composition of the plating bath and the electrodeposition potential affect the manganese content, surface morphology and corrosion characteristics of the Zn-Mn alloy. The relationship between the surface morphology of the plated layer and the composition ratio of manganese has been studied [1][2][3][4][5][6][7][8][9][10].…”