Preparation and strengthening mechanisms of in-situ HF catalyzed highly porous mullite with whisker frame structure

Abstract

Using HF as catalyst and based on sol-gel chemical precursor powder molding and sintering process, porous mullite with whisker frame structure was in-situ synthesized in the blank body. Due to the high efficiency catalysis of HF, this structure has both of high porosity and high strength. The effects of HF addition and sintering temperature on the formation of mullite whisker frame, phase transition process, porosity and strength of porous materials were discussed, and the optimal process parameters were determined. The mechanism of strengthening the porous materials was preliminary analyzed, and under the catalysis of HF, the close connection between whisker frame lap joints was formed. When the porosity of mullite is up to 83.22%, the compressive strength of can reach 16.48 MPa.