In the present study, the effect of adding yttria-stabilized zirconia nanoparticles (YSZ) at the rate of 5% by weight to NiCoCrAlTaReY powder on the microstructure, surface properties, resistance to hot oxidation, hot wear and hardness of the spray coatings created by the oxygen fuel method at high speed above (HVOF) was investigated. In order to prepare NiCoCrAlTaReY-5%YSZ nanocomposite powder, a hybrid method was used including a chemical step of using PVA glue along with rotary milling in a controlled amount, and then by applying the HVOF method and Using optimal industrial variables, it was coated on the substrates of CMSX-4 nickel-based superalloy and AISI 304 steel. In order to eva‎luate the microstructure and morphology of the created coatings, an optical microscope and a scanning electron microscope equipped with The energy spectrometer analysis system was used. X-ray diffraction test was used for the phase analysis of the above coatings, and also the hardness of the resulting coatings was determined by the Vickers microhardness test method. The eva‎luation of the resistance to hot oxidation of the resulting coatings was done by Isothermal hot oxidation test for 100 hours at a temperature of 1000 degrees Celsius and eva‎luation of hot wear resistance at a temperature of 600 degrees Celsius using the pin on disc method under a load of 20 newtons, speed of 120 rpm with distance 1000 meters were done. The findings of the research showed that by adding YSZ nanoparticles to the amount of 5% by weight, a compact structure with small grain size is formed, which has better oxidation, abrasion and mechanical behavior than the powder without YSZ nanoparticles. The results of the hot oxidation test showed that the sample with NiCoCrAlTaReY-5%YSZ coating had a higher resistance to hot oxidation than the uncoated sample by 26.5% and the sample with NiCoCrAlTaReY coating by 16.5%. Also, the eva‎luation of the hot wear behavior of the above coatings showed that the steel sample with NiCoCrAlTaReY-5%YSZ coating is more resistant to hot wear than the AISI 304 steel substrate (by 74.4%) and the sample with NiCoCrAlTaReY coating (by 19.1 percent), has However, the surface roughness of the coating containing YSZ nanoparticles was higher than that of NiCoCrAlTaReY coating. In general, it seems that adding YSZ nanoparticles to NiCoCrAlTaReY coating will improve the performance of this coating at high temperature.

مهران نحوي , احمد كرمانپور

مهدي رفيعائي , محمد خدائي