The Synthetic and Mechanical Properties of a Silica Matrix Cermet Composite

Abstract

A cermet composite was prepared by employing thermal spraying flame onto stainless steel surfaces of (304) type. Hence 25,50% of aluminum was mixed with matrix of (10% Al₂O₃- SiO₂). A spray system consistis of oxygen barrel, acetylene and spray gun that contains powders feeder at different spray distances (5, 10, 15, 20 and 25 cm). The thermal treatment of the samples resulting from spraying was performed at 1 100 °C for 1.5 hr. Some physical examinations (porosity and adhesion), mechanical tests (hardness and wear rate) and Atomic Force Microscope (AFM) test were performed before and after thermal treatment. The test results showed that the best mixing rate was (50%) and the best spray distance was (15cm) where the quality of coating layer improved after thermal treatment at 1 100 °C for 1.5 hr with a porosity ratio reduced from 11.2% to 6.6%, and adhesion strength improved with the increase in the alumina content to 50%. The results demonstrated that the best adhesion value after thermal treatment was 30.98 MPa. The hardness of coating layer increased from 45.78 to 54.88 HV; while the lowest rate of wear was at 50% of alumina with a spray distance of 15cm. Also, there was a clear improvement based on AFM within grain size, root mean square and roughness rate.