Corrosion resistance of coatings deposited using the HP/HVOF (High Pressure/High Velocity Oxygen Fuel) thermal spraying technology requires high coatings density and a good adhesion to the substrate. The majority of thermally sprayed materials meet the requirements for high corrosion resistance in terms of their composition. However, the porous structure raises doubts about the performance of thermally sprayed coatings in providing sufficient protection to the base material. In fact, corrosion protection is one of the basic coating functions. Anyway, in comparison with wear resistance research, an insufficient attention is paid to the issue of component protection against corrosion attack using the HVOF sprayed coatings. This paper summarizes the results of immersion corrosion tests performed on six selected corrosion resistant coatings, which are compared with the Wr.Nr. 1.4923 nitrided stainless steel. The following coatings were tested: two based cermet coatings (Cr3C2-NiCr, Cr3C2-CoNiCrAlY), three alloy based coatings (CoCrWC - Stellite 6, NiCrBSi, and NiCrMo - Hastelloy C-276) and one experimental coating (TiMoCN-29%Ni). These coatings were selected as good candidates for the use in corrosive aggressive environments. Steel Wr.Nr. 1.0421 was used as the base material. Corrosion experiment was performed in 5% solution of H2SO4 (further H2SO4). The evaluation of corrosion attack was made before and after corrosion tests on surface and in coating cross-section after metallographic grinding using an optical microscope (OM).Keywords: HP/HVOF, corrosion resistance, immersion corrosion test, coating
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