Electrical Conductivity of MoSi₂-Sic Ceramics Prepared by Reaction Sintering of Polysilazane with Molybdenum Metal

Abstract

To develop high-temperature heat elements with a small temperature-coefficient electrical conductivity, small-grained MoSi₂-SiC ceramics were prepared by reaction sintering ceramic precursor with molybdenum powder. By second sintering at 1773 K for 10 h, two phases of MoSi₂ and β-SiC were formed. The average grain size of both MoSi₂ and SiC ranges several tens nanometers. Electrical conductivity measurement revealed that conductive behavior changed from semiconductive to metallic with increasing molybdenum disilicide content. 54.3 wt% MoSi₂/β-SiC composite showed an almost constant temperature coefficent in the temperature range at around to 600-850 K.