from the conferences organized by TANGER Ltd.
Cr3C2-NiCr, Cr3C2-CoNiCrAlY, TiMoCN-Ni (experimental coating), Stellite 6, NiCrBSi and Hastelloy C-276 coatings were deposited on substrate material Wr.Nr. 1.4923 (X22) which is in nitrided state used as an effective constructional material for components in power equipment. All evaluated coatings were deposited using HVOF (High Velocity Oxygen Fuel) thermal spraying technology. The evaluation of resistance against high temperature corrosion was conducted for all selected thermally sprayed coatings. Furthermore, corrosion resistance comparative study between coating surface protection and nitrided stainless steel X22 was also carried out. All evaluated coatings were exposed to corrosive-aggressive environment in the form of molten salts mixture with composition of 60% V2O5 and 40% Na2(SO)4 at the selected temperature of 750 °C. Further, all coatings were exposed to cyclic conditions. Each cycle included one hour long exposure of evaluated coatings with salts mixture layer on the surface at 750 °C in a silicon carbide furnace. 20 minutes cooling in air followed the exposure period. Weight changes of individual samples were measured after every cycle and the results were recorded in the diagram.After the corrosion tests, all coatings were analyzed using scanning electron microscope (SEM), and also the analysis of elemental composition (EDAX) was conducted. Alloys-based coatings showed very similar corrosion mechanism in the selected aggressive environment and the same can be stated about cermet coatings. The obtained results prove that HVOF deposited coatings can replace current surface protection of components in power equipment such as nitriding.
Keywords: HP / HVOF, hot corrosion, corrosion resistance, aggressive corrosive environments© 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.