High-temperature self-healing behavior of reaction-bonded silicon carbide porous ceramic membrane supports

Reaction-bonded silicon carbide porous ceramics (SCPCs) are increasingly employed as membrane supports for the high-temperature filtration. However, the inevitable expansion of cracks limits their application. Herein, we studied the crack propagation behavior of SCPCs and discovered the commendable self-healing properties at high temperatures. Results show that the optimal healing conditions are 1200 degrees C for 2 h, which can recover the strength from 41.9% to 88.4%, and maintain the initial pore structure and permeance. This is mainly attributed to the infiltration of the multi-phase oxide melt that healed the cracks rather than the oxidation of SiC. Neck cracks are more prone to healing than surface cracks on SiC particles due to the residual compressive stress and a high proportion of melt volume. Nonetheless, the recovery of residual compressive stress and the crack width constrain the upper limit of strength recovery. These insights lay the groundwork for the high-temperature industrial application of SCPCs.