Influences Of Sintered Technologies And Additives On Properties Of Aluminum Oxide Ceramic

Al₂O₃ ceramic samples were formed by using 40MPa mold-pressed method and sintered in three atmospheres (vacuum, air, nitrogen gas). The main raw material is micron-sized Al₂O₃ powder and sintered additives are CaO, SiO₂, Y₂O₃, La₂O₃. Changed rules of sintered samples'mechanical properties concerned with sintered temperature and amount of addictives were studied. Analysis of phase structure and microcosmic morphology were made. Sintered mechanism was discussed as well. Experimental results indicate: sintered atmosphere has great effect on mechanical properties of 95 Al₂O₃ ceramic. Under the same circumstance, specimen prepared in vacuum has a few holes in relative compact body than specimens sintered in air and nitrogen gas. Tissue and property are optimal. The optimal sintered temperature is 1500℃, other performances are respectively relative density 92.2%, bending strength 168MPa, hardness (HRA) 78.2; Specimens prepared in air performed lightly better than specimens sintered in nitrogen gas. In the range of 1450℃¹600℃, the best sintered temperature is 1600℃, relative density 83%, bending strength 96.17MPa, hardness (HRA) 74; For specimens contained rare earth oxide, in air condition, property of specimen with Y2O3, La2O3 is better than conventional 95 Al2O3 ceramic. In the range of 1520℃¹600℃, the best sintered temperature is 1600℃and the optimal rare earth oxide content is 0.50wt%. Al2O3 have additive of Y2O3, La2O3 and additive of Y2O3, La2O3 mingled powder. Under the same circumstance, performances of the two latter samples are the same approximately, both better than the former one's. In vacuum, specimen with Y2O3, La2O3 shows more excellent mechanical property than conventional 95 Al2O3 ceramic sintered in air. When sintered temperature is 1600℃, specimens with 0.50wt%La2O3 have performances below: relative density 97%, bending strength 210.34MPa, hardness (HRA) 81.4.