LUKIANOVA Olga Belgorod National Research University

Physical and Mechanical Properties of the Silicon Nitride based Ceramics obtained by Cold Isostatic Pressing and Free Sintering

In this paper analysis of the mechanical and physical properties of silicon nitride ceramic were reported. This type of ceramics have a great potential for a large number of applications due to its successful combination of the high temperature and mechanical properties such as strength, hardness, corrosion resistance etc. In our article we used Si3N4 based ceramic material with Y2O3 and Al2O3 additives obtained by cold isostatic pressing (CIP) and free sintering. The results can be summarized as follows: 1. The microhardness of obtained material was 1380 HV0.5 and 970 HK2.5 2. The bending strength σ3pb of the obtained Si3N4 based ceramic is 280 MPa. 3. The density of the obtained material is about 2,94 g/cm3 by helium pycnometry and Archimedes methods. 4. The open porosity of the obtained material is about 0.1 %. The average size of the open pores is about 9.2 μm. The CTE of the obtained silicon nitride based ceramic is 4.6•10-6 K-1 up to 200 oC and 4.8•10-6 K-1 up to 900 oC. The obtained test results of ceramics based on silicon nitride can be used for further investigation of effective applications of this material. Combination of properties of obtained ceramic is attractive for a wide range of technical, structural and engineering applications.