Investigation of processing, microstructure and mechanical properties of nano-SiC/Si3N4 composite
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-reinf...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2002
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| Online Access: | http://ndltd.ncl.edu.tw/handle/38775091487877429984 |
| Summary: | 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 .
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