Treatment of Turbine Blades via Cr2O3-Ni5%Al System Using Plasma Thermal Spraying

Abstract

A plasma thermal spraying method was used for the purpose of coating the pre-prepared surfaces of turbine blades. Chromium oxide (Cr2O3) was used as a matrix reinforced with a metal material of Ni-5%Al at rates of 10, 20, 30, 40 and 50. The cermet powders were stirred for one hour then used to coat bases of steel (316L). A spray distance of 8cm was applied, and the binding material of Ni-22%Cr-10%Al-1%Y was sprayed with a thickness of 100μm. Then, the reinforced matrix was sprayed with a thickness of 300–350μm and the final thickness of the samples prepared was 400–450μm. The samples produced were sintered at 900°C for an hour and a half and underwent a hardness test, which gave the best hardness of the samples after sintering at a reinforcement rate of 50% by 612Hv. The lowest porosity value for the above rate was obtained at 3.88%. The results of the adhesive strength gave a value of 31.5 MPa after sintering and at the same 50% reinforcement. The results of the scanning electron microscope (SEM) showed that there was weakness and cracking in the coating layers at the low reinforcement ratios. However, the mechanical and physical properties improved with the increase in reinforcement ratios to reach the highest value of 50%. KEYWORDS Adhesion force, ceramites, scanning electron microscope, Vickers hardness