The investigation of the properties and production of Mg-SiO2 metal matrix composites

In this study, SiO2 particle reinforced pure magnezyum based composites were produced by powder metallurgy method (P/M). The weight fractions of SiO2 particles were varied from 5%, 10% and 15% in the mixtures. The mixed powders were pressed under a pressure of 550 MPa in a cylindrical die and the cylindrical specimens were produced. The produced samples were sintered at 550 ºC for 45 minutes in a vacuum control led diffusion oven under argon inert gas. Optical microscopic examination, hardness, density and porosity measurement were carried out. In addition, wear tests were performed in a pin-on-disc type of wear machine under different loads and speeds. Furthermore, scanning electron microscope (SEM) were used to characterize the worn surfaces of the composites.The experimental results indicated that hardness and density increased with increasing particle contents. It was found that wear rate of the composite and its mixture increased with increasing load while it decreased with increasing the particle size. The wear rate decreased significantly with increasing SiO2 content in the composite. Furthermore, the wear rate also increased with increasing applied load for both mixture and the composite.