FABRICATION OF THE CERAMICS BASED ON SILICON NITRIDE BY FREE SINTERING AND COLD ISOSTATIC PRESSING

This research paper presents the results of a study of the mechanical properties and microstructure of the ceramics based on silicon nitride. In view of its high properties, such as high hardness and strength, low coefficient of thermal expansion, resistance to abrasive wear etc. ceramics based on silicon nitride is one of the leading candidate materials for a lot of applications. Some of these applications are mechanical engineering, aerospace industry, engine-building, metallurgy, welding industry. As additives, activating sintering material were used yttrium oxide (Y2O3) with aluminum oxide (Al2O3) . It was used cold isostatic pressing as a method of compacting. Sintering the compacts was carried out in a nitrogen atmosphere at a temperature of 1600 C. Thus, ceramics based on Si3N4 with high dense and strength can be produced by cold isostatic pressing and free sintering. The main results can be summarized as follows: 1. Obtained the ceramic materials of high dense and increased mechanical properties. Compressive strength is 1500 MPa. Microhardness is 1300 HV.