Research of morphology and microstructure of trivalent chrome conversion coating on zinc electroplating

Abstract

In this paper, the morphology, microstructúre, thickness, weight and composition of the trivalenl chrome conversion coating (CCCs) on zinc electroplating with different dipping times (10, 20, 40, 50, 60, 70 and 80 s) have been studied. The thickness, weight of the layer increases with dipping time in hie bath. Thickness, weight of the CCCs as a function of dipping time. When the dipping time increases to 80 seconds the layer reaches a thickness 596 nm and weight 17.9 mg/dm2. No cracks can be observed in these coatings. The vibration bands at 508 cm-1 are attributable to Cr(III)-0. No band at 960 cm-1 has been observed, which means that no Cr^ exists in these CCCs.