杂凝聚法制备纳米复相陶瓷材料的微观组织及增韧机理研究

The microstructure and toughening mechanism of composite nano-ceramics prepared by mixed coagulative method

采用杂凝聚法制备了Al2O3-ZrO2（n）纳米复相陶瓷粉体,对经SPS烧结成型的纳米复相陶瓷材料块体进行了微观组织韧化机理的试验研究.研究表明,Al2O3-ZrO2（n）陶瓷中由于ZrO2的添加,改变了Al2O3的晶粒形状,提高了材料的致密度,并细化了晶粒;其微观组织为典型的晶内/晶界混合型纳米复相陶瓷,其中不规则的ZrO2团聚体主要存在于Al2O3的多晶粒相交的晶界处,一些细小、分散的球状ZrO2纳米颗粒（70-200 nm）分布在Al2O3晶粒内部.由于基体晶粒的细化以及因其形成的“内晶型”纳米结构,提高了基体的力学性能.研究认为,Al2O3-ZrO2（n）纳米复相陶瓷力学性能的改变是由于纳米粒子的增韧机制、ZrO2相变增韧机制和“内晶型”结构共同作用的结果.

Al2O3 -ZrO2 nano-composite ceramics powder is prepared by mixed coagulative method, and toughening mechanism of the microstructure of SPS-sintered nano-composite ceramics is studied. The result shows that because of the additive ZrO2, the grain shape of Al2O3 is changed, the density is improved in the A1EO3-ZrO2 ceramics, and its grain is refined. The microstructure is the typical nano-composite ce- ramics mixed with intracrystalline and intercrystalline. The irregular aggregate of ZrO2 is mostly existed on the grain boundary where many grains of Al2O3 is intersecting, some thin and dispersal globular nano grains （70-200 nm） of ZrO2 are distributed in the Al2O3 crystal grains. It enhanced the mechanical performance of the matrix because of grains refined and intracrystalline nanometer structure. The study considers that the changes of mechanical performance of Al2O3-ZrO2 （n） nano-composite ceramics are the results of the nanometer grains toughening mechanism, ZrO2 phase transition toughening mechanism and the intracrystalline structure.