Evaluation of the corrosion resistance of some coating obtained by thermal spray in plasma jet, on the surface of some crankshafts made of C45 steel

Abstract

For modern engines the oil change interval can reach up to 30,000 km. If the oils lose their properties and are contaminated, they can adversely affect the corrosion resistance, the surface of the main bearing journals and the main journals of the crankshafts. In this study, the results obtained from the corrosion process were analyzed, in a solution of 3.5% NaCl of the layers obtained after spraying the surface of a C45 steel, used in the construction of crankshafts, with three powders: Cr3C2-(Ni20Cr), Al2O3-13TiO2, Cr2O3-SiO2-TiO2. The corrosion process was determined by the potentiodynamic polarization technique. The variations in time of the open-circuit potential and the Tafel curves were analyzed, for the samples with deposited layers and the basic material. Morphology and characterization of the structure of the layers after corrosion were performed by means of SEM microscopy and EDAX analysis. The results confirm that the powders sprayed by the atmospheric plasma spray method protect the surface of C45 steel from corrosion.