Synergetic enhancement of electrical conductivity and infrared emissivity of SiC-MoSi2 ceramics via N doping

Abstract

N-doped SiC-MoSi2 ceramics were successfully fabricated by hot pressing in N2 using Y(NO3)3.6 H2O as both sintering aids and additional N sources. The impact of Y(NO3)3.6 H2O content on the densification, electrical properties, and infrared emission performance of the resulting ceramics were investigated. The distribution of Y-based sintering aid is improved by melting of Y(NO3)3.6 H2O during slurry drying, enabling the relative density to increase up to 97.4%. Y(NO3)3.6 H2O subsequently decomposes during sintering and allows the substitution of atomic N for the C sites in SiC lattice and production of the N-derived donor level. A larger amount of N dopant elevates the carrier density up to 1.90 × 1016 cm-3. Remarkably, The SiC − 10 wt% MoSi2 ceramics sintered with 16.9 wt% Y(NO3)3.6 H2O exhibits the lowest electrical resistivity (0.791 Ω·cm at room temperature) and highest infrared emissivity (0.913 at 800 ℃), the latter of which may also be attributed to lattice distortion induced by N doping. This work demonstrates N doping as a prospective strategy for synergistically optimizing the electrical conduction and infrared emission performance of SiC-based ceramics for infrared source applications.