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研究了晶种引入和烧结方式对氧化铝长柱状晶粒生长和氧化铝陶瓷断裂韧性的影响.实验以氢氧化铝为初始啄料,通过湿法球磨把高纯氧化铝磨球的磨屑作为晶种引入到氢氧化铝粉料中,使氢氧化铝粉在较低温度锻烧转相为α相氧化铝.研究发现这种转相后的α相氧化铝粉(含有晶种)经热压烧结可获得长柱状晶显微结构,并且Al2O3晶粒形貌随晶种的引入量的不同而发生变化,而无压烧结Al2O3晶粒主要呈等轴状.具有长柱状α—Al2O3晶粒的微观结构可显著提高氧化铝材料的断裂韧性.在40MPa热压烧结(1600℃×2 h)的试样,断裂韧性达到7.10 MPa·m1/2,比普通的氧化铝陶瓷断裂韧性提高1倍,并且抗弯强度也高达630 MPa.
The effect of seed introduction and sintering method on the growth of alumina long columnar grains and the fracture toughness of alumina ceramics was studied.The experiment uses aluminum hydroxide as the initial pecking material and the wear debris of high purity alumina grinding balls Seeds introduced into the aluminum hydroxide powder, the aluminum hydroxide powder calcined at a lower temperature phase α phase alumina was found that the phase transition α-phase alumina powder (containing seeds) by the heat The long columnar crystal microstructure was obtained by pressure sintering, and the grain morphology of Al2O3 changed with the introduction amount of seed crystal, while the non-pressure sintered Al2O3 grains were mainly equiaxed.The grains with long columnar α-Al2O3 , The fracture toughness of the alumina material can be remarkably improved, the fracture toughness reaches 7.10 MPa · m1 / 2 at 40MPa hot-press sintering (1600 ℃ × 2 h), and the fracture toughness of the alumina ceramic increases by one time , And bending strength up to 630 MPa.