부산대학교 도서관

Thermal spraying by flame is one of the methods employed in the treatment of cracks and pores that occur in materials subjected to elevated temperatures or varying climatic conditions. Nickel was used as a base material and reinforced with two ceramic materials, nickel oxide, NiO, at a fixed rate of 5%, and chromium oxide as the second material. The study involved using Triple Cr2O3 with varying reinforcement percentages (10%, 20%, 30%, 40%, and 50%). The materials were mixed for a duration of two hours, following the specified ratios. The coating process was carried out on a base of out-of-service turbine blades cut into coupons. The coating was subjected to a heat treatment at a temperature of 1000 °C for a duration of two hours. Various structural and physical tests were conducted on the resulting system to examine its crystalline structure. The scanning electron microscope analysis revealed a consistent pattern of regularity, with the most optimal outcome observed at 50%Cr2O3. Under optimal conditions and with a sintering rate of 50%, the material achieved a real density of 7.4 g/cm3, a real porosity of 18%, a water absorption rate of 0.893%, a Brinell hardness value of 770 Kg/mm2, and a wear rate of 1.31 × 10−8 g/cm of travel.