Phase composition and pore evolution of porous periclase-spinel ceramics prepared from magnesite and Al(OH)3

Porous periclase-spinel ceramics with 30.5-43.6% apparent porosities were prepared from magnesite and Al(OH)3 via an in-situ decomposition pore-forming technique. The reaction process of the pseudomorphs of magnesite and Al(OH)3 was analyzed through X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and a microscopy measurement method, and the effects of the sintering temperature and Al(OH)3 content on the phase composition and microstructure were investigated. It is found that the decompositions of magnesite and Al(OH)3 can create a large amount of micro-sized pores in the pseudomorphs of magnesite and Al(OH)3, and that sintering temperature promotes the reaction between the pseudomorphs of magnesite and Al(OH)3 by the interdiffusion of Mg2+ and Al3+ through liquid. The Al(OH)3 content affects the formed spinel and the liquid phase between periclase particles, which influences the pore size and porosity.