2001 Volume 109 Issue 1271 Pages 596-601
Alumina-zirconia-graphite (AZG) refractories were obtained through a baking technique using fused Al2O3, partially stabilized ZrO2 and flake graphite as the starting materials with Al, Si, and SiC powder additives. A particle size distribution was designed by the Furnas model for coarse Al2O3 (500-1000μm/medium Al2O3 (61-125μm/fine Al2O3 (<44μm, in which the contents of coarse, medium and fine Al2O3 powders were varied with a constant amount of fine particles in the matrix. The bulk density increased from 3.05 to 3.29g·cm-3 for the sample with a mass ratio of (coarse Al2O3)/(medium Al2O3)=2.14 the forming pressure being from 100 to 150MPa. However, when the forming pressure increased from 150 to 170MPa, the bulk density gradually decreased from 3.29 to 3.26g·m-3. The lowest porosity (5.1%) was achieved by compacting the powders with a mass ratio of 2.14 at 150MPa. The average pore size readily decreased from 5.3-5.8 to 3.1-3.9μm as the forming pressure increased from 100 to 150MPa. Besides, the average pore size gradually decreased from 3.1-3.9 to 3.0-3.7μm when the forming pressure increased from 150 to 170MPa. The bulk density increased with increasing baking temperature and attained an inflection value at 200°C above which it gradually increased up to 240°C.
