Electrodeposition of Ni-Co/Al2O3 composite coating by pulse reverse method under ultrasonic condition

Ni-Co/Al2O3 composite coating was deposited by pulse reverse current (PRC) method under ultrasonic condition. The influence of ultrasonic power on morphology, microstructure, composition, micro-hardness and residual macrostress of composite coating was investigated by means of SEM, TEM, XRF and XRD. The results indicate the composite coating deposited under ultrasonic power becomes uniform, compact and the grains become fine; the composite content of Al2O3 is decreased; the micro-hardness of composite coating is improved firstly, then decreased: while the residual macrostress is increased. (C) 2008 Elsevier B.V. All rights reserved.