Influence of the W Content on the Characteristics of MoxW1-xSi2 Heating Elements Fabricated by Self-Propagating High-Temperature Synthesis

MoSi2-based composites are promising structural materials for high-temperature applications. MoxW1-xSi2 (x=1, 0.9, 0.8, and 0.7) powders were successfully synthesized by self-propagating high-temperature synthesis. These powders were used to fabricate heating elements, which were then subjected to a post-annealing process to improve the structural quality. To determine the influence of the W content (0-30mol%) on the characteristics of MoxW1-xSi2 composites, the surface morphologies, densities, and bending strengths of the MoxW1-xSi2 heating elements were investigated. Moreover, to validate the durability of the MoxW1-xSi2 heating elements, an accelerated degradation test (ADT) was conducted at temperatures up to 1700 degrees C (heating rate=5 degrees C/min). The MoxW1-xSi2 heating element with 30mol% of W exhibited a high density, a high bending strength, and superior durability after the ADT test. In contrast, the MoxW1-xSi2 heating element with 0mol% of W showed inferior durability owing to the formation of bubbles at the MoxW1-xSi2 /SiO2 interface. Thus, the addition of W enhances the reliability and durability of MoxW1-xSi2 composites as heating elements. [GRAPHICS]