Problematika galvanického zinkování tvářeného čepu automobilového dílce

Abstract

HETO, J. The Problems of Galvanic Zinc Coating the Wrought Peg at Automobile Part. Ostrava: Department of Mechanical Technology, Faculty of Mechanical Engineering VSB-Technical University Of Ostrava, 2011, 63 p. Thesis, head: Ševčíková, X.

This thesis deals with defects in electroplated zinc coating in the pivot area of an automotive part, and the influence of these defects on the corrosion resistance in a neutral salt spray corrosion test. To identify the causes of defects a microscopic evaluation of the coating structure and chemical composition analysis on the base material - coating boundary were performed. According to this analysis there are contaminants (cinder) present at the boundary, with remnants of quenching oil, which were formed during the quenching when the controlled atmosphere of the furnace was disrupted. Tumbling performed to remove these impurities is not efficient enough to remove them from the less accessible areas. Impurities are then pushed into the material and subsequently are the cause of coating defects. The solution for preventing these irregularly recurring defects is changing the technology of tumbling.