In situ investigation of SiC powder's microwave sintering by SR-CT technique  

作　　者：LI YongCun XU Feng HU XiaoFang QU HongYan MIAO Hong ZHANG Zhong XIAO TiQiao 

机构地区：[1]Chinese Academy Sciences Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230026, China [2]National Center for Nanoscience and Technology of China, Beijing 100190, China [3]Shanghai Synchrotron Radiation Facility, Shanghai 201204, China

出　　处：《Science China(Technological Sciences)》2011年第6期1382-1388,共7页中国科学（技术科学英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos 10902108, 10732080, 10872190);the National Basic Research Program of China ("973" Project) (Grant No 2007CB936800)

摘　　要：Microwave sintering is being developed as a novel technique for the preparation of dense structural ceramics,but the mature theory has not been established due to the technical difficulties.The synchrotron radiation X-ray computed tomography(SR-CT) technique was introduced for the first time into the study of microwave sintering to in-situ observe the microstructure evolution of silicon carbide(SiC) material in this paper.By applying the SR-CT technique,the reconstructed 2D and 3D images of the specimen were obtained and the double logarithm curve of mean neck size and time(Ln(x)-Ln(t)) were obtained from these reconstructed images.Various sintering phenomena including sintering neck growth during microwave treatment were observed from the reconstructed images.Furthermore,the differences in microstructure evolution and sintering kinetics between microwave and conventional sintering were analyzed based on the reconstructed images and the Ln(x)-Ln(t) curve.1) The sharp surface of grains near the contact region distinctly grew blunt and the sintering neck growth between these grains were obviously observed at the early stage.Besides,the larger particles grew faster than smaller ones.The main reason for these phenomena may be the micro-focusing effect of electric fields.2) During each of the three sintering stages,the sintering kinetics curve of double logarithm relationship between mean neck size and time shows a good linear relationship,but at the middle stage the slope of the curve increases dramatically,which is quite larger than conventional sintering.The preliminary interpretation for these extraordinary phenomena has been discussed in details.

关 键 词：silicon carbide synchrotron radiation X-ray computed tomography microwave sintering 

分 类 号：TP274.51[自动化与计算机技术—检测技术与自动化装置] TQ174.758[自动化与计算机技术—控制科学与工程]