Influence of the substitution of Y2O3 for CeO2 on the mechanical and microstructural properties of silicon nitride

Cerâmica

J. V. C. De Souza¹  C. A. Kelly²  M. R. V. Moreira²  M. V. Ribeiro²  C. Dos Santos²  O. M. M. Silva¹  M. A. Lanna¹ 

[1] ,FAENQUIL DEMAR Lorena SP

关键词: Si3N4;    liquid-phase;    Y2O3;    CeO2;    fracture toughness;    hardness;    Si3N4;    fase líquida;    Y2O3;    CeO2;    tenacidade à fratura;    dureza;   

DOI  :  10.1590/S0366-69132005000300018

来源: SciELO

【 摘 要 】

This work investigated the substitution of Y2O3 for CeO2 in liquid-phase sintered silicon nitride ceramics. Cost reduction as well as good physical, mechanical and microstructural properties are the main objectives of the present study. Two powder mixtures were prepared, varying the contents of alpha-Si3N4, Al2O3, AlN, Y2O3 and CeO2. The mixtures were homogenized in ethanol, dried in a rotating evaporator and kiln, respectively, and then uniaxially (100 MPa) and cold isostatically pressed (300 MPa). The samples were sintered at 1850ºC for 1 h in a graphite resistive furnace under nitrogen atmosphere. After sintering the density of the samples was higher than 97% of the theoretical value. The fracture toughness and hardness were higher than 5.28 MPa.m½ and 17.12 GPa, respectively. Phase analysis by X-ray diffraction and scanning electron microscopy revealed the presence of alpha-SiAlON and beta-Si3N4.

【 授权许可】

CC BY-NC   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License