RESEARCH OF THE INFLUENCE OF SILICONIZING ON THE STRUCTURE AND PROPERTIES OF HOT-PRESSED POLYCRYSTALLINE SILICON CARBIDE

Abstract

The regularities of sintering under pressure of polycrystalline SiC–materials of different dispersion are studied. The peculiarities of structure formation, phase composition and properties of hot pressed materials produced from SiC powders at a pressure of 10 and 25 MPa with followed by siliconizing have been researched. It is shown that in materials made from 5–micron SiC, impregnation with silicon occurs completely. It was found that after the siliconization of polycrystalline silicon carbide, the bending strength increased by 10%–80%, and crack resistance by 30%–80% depending on the initial porosity. For a SiC material, made from 5 μm powder, physical and mechanical properties reach acceptable values: Rbm = 320 МПа, К1с = 3,5 МПа∙м1/2