Investigation of processing, microstructure and mechanical properties of nano-SiC/Si3N4 composite

• Main Authors: Shao-Min Lee, 李紹民
• Other Authors: Jow-Lay Huang
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/n2zh5u

碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 90 === Abstract Industry application of silicon nitride ceramics is hindered because of its softening at high temperature and also its brittleness . In order to overcome the problems , one of the ways suggested some years ago is to prepare SiC-nanoparticle-reinforced Si3N4-matrix composites . This thesis reports the results of processing of SiC(n.p) / Si3N4 composites and characterization of the composites . SiC(n.p) /Si3N4 composites were fabricated by hot pressing at 1850℃ for 1 h in N2 atmosphere with Al2O3 and Yb2O3 as sintering additives . The optimum experimental procedure for manufacturing nanocomposites investigated by sedimentation test , planet ball milling test and different drying methods test . TEM observation showed that the SiC particles located within Si3N4 grain and on the grain boundary . While SiC particles dispersed in grain boundary are bonded to Si3N4 grain without glassy phase . The influence of SiC fine particle dispersion on microstructure and mechanical properties of Si3N4 ceramics has been investigated .The mean size and the aspect ratio of the obtained β- Si3N4 grains decreased as a result of the SiC dispersion , thus bringing about increased flexural strength and decreased fracture toughness .