OBJECTIVEThis investigation was to analyze the mechanism of formation of porous structure by studying some characteristics of the alumina powder used for GI-II Infiltrate Ceramic.

METHODSThe alumina powder crystal type was analyzed with X-diffractometer, and its size distribution was obtained by powder size analysis device, and fracture surface of alumina adobe was observed under scanning electronic microscope.

RESULTSAlumina crystals were purely alpha type, with firmest structure and best stability. Fine powder whose size was smaller than 0.5 micron occupied 9 wt% (mass) and, coarse powder with sizes between 1 to 3.5 microns occupied 75 wt% (mass). The SEM graphs of adobe showed that fine powders were attached to the surface of coarse powders, dispersed evenly, and alumina powders contacted each other firmly.

CONCLUSIONThe crystal type, size distribution and even dispersion of the studied alumina powder contributed to the formation of porous structure of alumina sintered body (preform), which was the material prerequisite in forming porous preform and one of the key factors to the rise of strength of GI-II Infiltrated Ceramic.