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采用印度沿海锆石粉与硅线石海滩砂反应烧结,制备含20%(质量分数)氧化锆的莫来石-氧化锆复合材料。添加4%~12%(摩尔分数)的氧化钙作为添加剂。研究了添加剂对压实性能、显微组织、力学性能和热力性能的影响。添加氧化钙可以使压实温度从1600°C降低至1550°C。氧化钙可以形成少量的液相(铝硅酸钙),有利于烧结进行。添加4%氧化钙可使复合材料的晶粒尺寸减小,当添加量大于4%时,材料的晶粒尺寸随氧化钙添加量的增加而增大。添加4%氧化钙样品的弯曲强度约为225MPa,断裂韧度约为6MPa·m~(1/2),且抗热冲击性能得到明显提高。氧化钙可以稳定四方氧化锆,从而提高材料的力学性能。
Adopting the zircon powder from the coast of India and sillimanite beach sand, the mullite-zirconia composite material containing 20% (mass fraction) zirconia was prepared. Add 4% ~ 12% (mole fraction) of calcium oxide as an additive. The effects of additives on compaction, microstructure, mechanical properties and thermal properties were studied. Calcium oxide can be added to reduce the compaction temperature from 1600 ° C to 1550 ° C. Calcium oxide can form a small amount of liquid phase (calcium aluminosilicate), is conducive to sintering. The addition of 4% calcium oxide reduced the grain size of the composites. When the addition amount was more than 4%, the grain size of the composites increased with the addition of calcium oxide. The flexural strength of 4% calcium oxide sample is about 225MPa, the fracture toughness is about 6MPa · m ~ (1/2), and the thermal shock resistance is obviously improved. Calcium oxide can stabilize the tetragonal zirconia, thereby enhancing the mechanical properties of the material.