Production of a double cermet coating to treatment of the turbine blades

Turbine blades commonly encounter external defects, such as cracks and high porosity, while in operation. To mitigate these challenges, the method of thermal spraying by flame is utilized for the application of cermet materials, which comprise both metal and ceramics, onto the blades. This process involved incorporating manganese (Mn) into a chromium oxide (Cr2O3) base in varying proportions (3,6,9,12,15)%. Before this, the two blends underwent multiple preparatory stages, such as being combined in a micro-mill for two hours and subsequently dried at 80 degrees C for thirty minutes to eliminate any moisture in the lab. The coating bases were prepared from an out-of-service turbine bit and shaped into squares with a side length of 1 cm. The bases were then roughened and indented using a paint gun. The resulting models were sintered at a temperature of 1000 degrees C for two hours. A number of structural and physical tests were carried out for the painted models before and after thermal sintering. Scanning electron microscope tests revealed crystalline regularity and lattice consistency of the outer surface especially at 15%Mn. The observed results of actual density indicated a gradual increase in density with successive additions of manganese. However, there was a consistent decrease in real porosity and water absorption, resulting in lower values at 15%. The hardness and adhesion strength exhibited significant improvements, increasing by approximately 15%. Conversely, the addition of the stiffener led to a continuous decrease in thermal conductivity. Consequently, it was concluded that the ideal coating settings for achieving favorable results were a coating distance of 16cm, a coating angle of 90 degrees, and thermal sintering at 1000 degrees C.