Protection of turbine blades by adding metals to ceramic materials using flame coating method

Abstract

Different methods were employed to address the issue of turbine blade failure caused by gases and high-temperature steam. Among these methods, the thermal spray painting technique was utilized to address cracks and pores in the turbine blades. This method involved using a cermet system composed of an alumina ceramic base reinforced with iron metal at a fixed rate of 10 %. In addition, copper was incorporated as a variable reinforcement at different percentages (5 %, 10 %, 15 %, 20 %, and 25 %). The powders were mixed and dried to eliminate any moisture present. To coat the bases, stainless steel type 316L was used and a thin layer of binding (Al80–Ni20) was applied. The bases were then further coated with the composite (Al2O3–10 %Fe–%Cu). This coating process was conducted using a spray gun found in the laboratory. Afterward, the coated samples underwent thermal processing in a thermal oven at 1,100 °C for a duration of 2 h. Several tests were conducted on the resulting coating, namely scanning electron microscopy, Vickers hardness testing, adhesion strength analysis, sliding wear assessment, and measurement of thermal conductivity. The results showed an improvement in the composition of the coating with repeated additions of metals. It was found that adding 25 % copper after thermal sintering yielded the most favorable outcomes. This resulted in increased hardness and adhesion strength while also gradually reducing the wear rate.