Microstructure and Properties of Thermal Electrode Material Si3N4–MoSi2 Composite Ceramics

Abstract

With good high temperature and corrosive resistance performance, ceramic based composites can be used as promising materials to replace metal thermocouple materials. In this study, Si3N4–MoSi2 composites were prepared via hot pressing technology. X-ray diffraction (XRD), optical microscopy (OM), and scanning electron microscopy (SEM) were used to analyze the microstructure of the composites. The mechanical properties and electrical conductivity were tested. The results showed that the composites were composed of β-Si3N4, MoSi2, a small amount of Mo5Si3, and an amorphous glassy phase. The MoSi2 phase was evenly distributed in the matrix. The percolation network was formed with increasing MoSi2 content. The strength of the composites reached its maximum value when the MoSi2 content reached a critical point. The electrical conductivity behaved like a typical percolation phenomenon. The percolation threshold was about 30% to 45%.

Effects of V and Co Element Addition on Microstructures and the Mechanical Properties of In Situ Biphasic Hybrid (TiCxNy–TiB2)/Ni Cermets

“…Ni has excellent plasticity, ductility and impact resistance and high temperature and corrosion resistance, and the wettability between Ni and ceramic phase is good [ 21 ]. Therefore, Ni as a binder with biphasic ceramics as the matrix of cermets has better strength, hardness, wear resistance, oxidation resistance and adhesion resistance [ 22 , 23 , 24 ]. At present, many studies and reports have considered Ni-based composites with TiC x , TiB 2 and TiC x N y as single-phase reinforcements [ 25 ].…”