ABSTRACT

Aluminum titanate (AT) ceramics exhibit a high melting point and an excellent thermal shock resistance. Therefore, they have long been expected to serve as useful refractory materials. AT ceramics have been so far known to have two fatal disadvantages; low fracture strength owing to poor sinterability and thermal decomposition. When the AT ceramics are kept at temperatures of 1123 − 1553 K for more than several tens hours, they decompose into rutile (TiO₂) and corundum (Al₂O₃). Many attempts to improve their thermal and mechanical properties have been made by introducing various metal oxides containing Si, Mg, Zr and so on to them, AT ceramics with satisfactory features have not been realized yet. Recently, the feldspar-doped AT (f–AT) ceramics are prepared through liquid phase sintering process possess both a good thermal stability and better mechanical strength in addition to the low thermal expansion, that are brought about the microstructure design and chemical modification of f–AT ceramics. In addition, Al₂TiO₅–MgTi₂O₅ ceramics doped with alkaline feldspar (f–MAT) was found to be a decomposition free ceramics over 300 hours of heat treatment at 1373 K in an ambient atmosphere. The decomposition free f–MAT ceramics is expected for variety of high temperature applications including diesel particulate filters. In this article, recent progresses on doped-AT ceramics will be reviewed.