LAUSR

ABSTRACT In this paper, electrodeposited tinplates with different coating mass have been characterised by SEM, XRD, XPS, and EDS. The results indicate that a much lower coating mass may lead to an ununiformly distributed tin coating layer. To obtain a qualified tin coating with lower tin mass, the roughness of the base steel surface should be strictly controlled to gain a flat surface with lower roughness and defects. Cr2O3 and Cr(OH)3 were found as the main composition of passivation film with Cr2O3 locating at the outermost film surface, and the amount of Sn element increases and Cr element decreases as a function of depth from the surface of tin coating. In addition, the amount of Fe impurity in the plating bath should be strictly controlled as its presence in tin coating is harmful to coating corrosion resistance.