Surface characterisation of electroplated tinplate with different coating mass

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.

KEYWORDS:

• Tinplate
• coating mass
• electrodeposition
• tin coating
• thickness

Disclosure statement

No potential conflict of interest was reported by the authors.