Effects of low-melting-point sintering aid MoO3 on the performance of SiC ceramic membrane supports and the underlying mechanisms

Silicon carbide (SiC) ceramic membrane supports, as critical components of ceramic membrane filters , must exhibit outstanding performance in mechanical properties, porosity, and chemical stability. In this study, MoO₃ was employed as a sintering aid , with SiC and α-Al₂O₃ serving as raw materials and walnut shell powder as a pore-forming agent. The effects of varying sintering temperatures (1250–1400°C) and MoO₃ contents on the properties of SiC porous ceramic membrane supports were systematically investigated. Special emphasis was placed on elucidating the mechanisms by which MoO₃ addition influences porosity, flexural strength , pore size distribution , and chemical stability. Experimental results demonstrate that the introduction of MoO₃ facilitates low-temperature sintering of SiC supports through a dissolution-precipitation mechanism. This process promotes the formation of mullite whiskers that reinforce interparticle necking regions while enhancing the uniformity of neck connections. Optimal performance was achieved at 1350°C with 8 wt% MoO₃ addition, yielding a bending strength of 37.01 ± 1.72 MPa, average pore size of 1.735 μm, most probable pore size of 1.7 μm, open porosity of 39.12 %, and exceptional corrosion resistance . This work establishes both theoretical foundations and practical strategies for low-temperature fabrication of high-performance SiC porous ceramics, while expanding the application potential of molybdenum-based sintering aids in structure-function integrated ceramic materials. • Low-temperature sintering enabled by MoO₃: The use of MoO₃ as sintering aid significantly reduces the sintering temperature of SiC ceramic membrane supports. • In-situ mullite whisker formation: MoO₃ promotes the in-situ generation of mullite whiskers through a dissolution-precipitation mechanism. • Mechanistic insights and practical applications: The role of MoO₃ in SiC ceramic membrane is described, offering a cost-effective and scalable strategy for industrial applications.