Rare earth activated sintering of MoSi2 and its electric conductivity
(1. Department of Mechanical Engineering and Automation,
Xiangtan Polytechnic University, Xiangtan 411201， P.R.China;
2. Department of Materials Science and Engineering, Central South University,
Changsha 410083, P.R.China；
3. Department of Mechanical Engineering, Shaoyang Higher Technical College,
Shaoyang 422004, P.R.China)
Xiangtan Polytechnic University, Xiangtan 411201， P.R.China;
2. Department of Materials Science and Engineering, Central South University,
Changsha 410083, P.R.China；
3. Department of Mechanical Engineering, Shaoyang Higher Technical College,
Shaoyang 422004, P.R.China)
Abstract: The effects of rare earth on activation sintering of MoSi2 and electric conductivity of the matrix were analyzed on the basis of a method proposed by German and Munir. The results show that the addition of rare earth could refine the powder size and obviously reduce sintering activation energy of MoSi2 which, for rare earth/MoSi2 system, is 83.1kJ/mol at 1 200 ～ 14 00 ℃, about half of that of pure MoSi2. This decreases the sintering temperature of MoSi2 by about 200℃at least, and decreases the resistivity of the matrix as well. The mechanism of rare earth activated sintering of MoSi2 is an integrated process mostly ruled by grain boundary diffusion. When the density of materials is identical, the rare earth addition is found to have no noticeable effect on the electric conductivity of MoSi2.
Key words: activated sintering； rare earth； MoSi2； electric conductivity