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The paper describes the corrosion resistance comparison of hot-dip zinc galvanized cast iron with flake graphite in relations to bronze. The practical application of investigated cast iron is planned as a materials for fitting elements working in corroding medium of sea water. The surface of cast iron was prepared in different way: crude, turned, sandblasted and oxidized. Oxidation effect was evaluated by optical microscopic tests, surface roughness measurements and corrosion resistance potentio-dynamic tests. It was stated that oxidation process influence both on the level of surface development as well as the zinc coating structure and zinc diffusion depth in cast iron matrix. The observed influence causes the essential cast iron corrosion resistance increase which level reaches value characteristic to bronze. Structure of coating layers – alloyed and zinc and their thickness is in direct correlation with a kind of surface preparation and in consequence corrosion resistance. Examination presented in the elaboration confirmed the thesis that in analysed case high temperature oxidation is not a corrosion process but rather a kind of surface treatment that makes wider the cast iron application range.
Keywords: Cast iron, oxidation, surface preparation, corrosion resistance, zinc coating© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.