THE SHRINKAGE, PHASE COMPOSITION AND MECHANICAL PROPERTIES OF CERAMICS WITH DIFFERENT β-SiAlON MAIN CRYSTALLINE PHASES PREPARED BY STEREOLITHOGRAPHY

In this paper, using Si 3 N 4 , Al 2 O 3 and AlN particles as raw materials, -SiAlON ceramics with different main crystal phases were designed. The green body of the -SiAlON-matrix ceramic samples were obtained by using stereolithography (SLA) additive manufacturing. After degreasing, dense -SiAlON ceramics with different SiAlON phases were fabricated through gas pressure sintering at 1800 C for 1 hour at GPa. The effects of the different Al 2 O 3 contents on the shrinkage, phase composition, relative density, microstructure, mechanical property and hardness were studied. The results indicate that the main phase of the ceramics was -SiAlON and the specific chemical compositions of it were Si 5 AlON 7 , Si 3.1 Al 2.9 O 2.9 N 5.1 and Si 2 Al 4 O 4 N 4 . The intergranular phases that exists were mainly Y 3 Al 5 O 12 , YAlO 3 and Al 2 O 3 . With a relative density of 90.03 %, the Vickers hardness (Hv5), bending strength and fracture toughness of the fabricated -Si 5 AlON 7 ceramics were 16.8 GPa, 465 MPa and 4.84 MPam 1/2 , respectively. Meanwhile, the shrinkage of the materials was 28.7 % Ceramics -Silikty 64 (2) 155-163 (2020)