IN SITU PROCESSING OF POROUS MgTi_2O_5 CERAMICS WITH PSEUDOBROOKITE-TYPE STRUCTURE TOWARD THIRD GENERATION DIESEL PARTICULATE FILTER MATERIALS

摘要

Double-oxide-based porous ceramics are promising for third-generation DPF materials, following to cordierite (first-generation) and silicon carbide (second-generation). Up to now, mullite (3Al_2O_3-2SiO_2) and aluminum titanate (Al_2TiO_5) are of particular interest as candidates of the third generation, due to their low coefficients of thermal expansion (CTE) among oxides. Aluminum titanate has a pseudobrookite-type crystal structure, and this structure generally shows the anisotropic thermal expansion due to the distortion of atomic coordination polyhedra. As for other pseudobrookite-type ceramics, however, they are not so widely studied as aluminum titanate (especially in porous forms). In this study, porous MgTi_2O_5 ceramics with pseudobrookite-type structure have been successfully prepared by in situ processing (viz. reactive sintering). Preliminary microstructural observation of the porous MgTi_2O_5 will be presented.