烧成温度对Al2O3/Ni复合材料的致密化、物相组成和显微结构的影响

首先采用非均相沉淀合成出Ni包裹Al₂O₃粉体,然后热压烧结包裹粉体制备了Al₂O₃/Ni复合材料。本文作者主要研究了不同烧成温度对复合材料致密化、物相组成和显微结构的影响。结果表明:在1400℃保温1h,烧结体获得了最大相对密度,而致密度随Ni含量的增加反而降低;高于1350℃时,除Al₂O₃和Ni相外,在烧结体的表层生成一种由Al,Ni,O,C四种元素组成的新相;随着温度的升高,包裹层的纳米Ni颗粒聚合、长大,并退缩至三角晶界处,在适当的烧结温度(1400℃),少数小的纳米Ni颗粒被卷入Al₂O₃晶内,大的位于三角晶界,当烧成温度为1450℃时,不仅观察到Al₂O₃/Ni界面存在空隙,也发现了Al₂O₃晶粒异常长大现象。

EFFECT OF SINTERING TEMPERATURE ON DENSIFICATION PHASE COMPOSITIONS AND MICROSTRUCTURE OF Al2O3/Ni COMPOSITES

Al2O3/Ni composites were prepared by hot-pressing from Ni-coated Al2O3. In this paper, the effect of sintering temperature on densification, phase compositions and microstructure was mainly studied. The relation curve of relative densities and sintering temperature showed the composites obtained the maximum relative density at 1400℃, and the relative densities decreased with Ni content increasing. Phase analysis indicated the new phase composed of Al, Ni, O, C was produced on the surface layer of the sintered body besides Al2O3 and Ni when the temperature was higher than 1350℃. As observed from TEM images, the agglomerated and grown Ni particles were located at the triangle boundary at 1300℃;when sintering temperature was 1400℃, most large Ni particles were seated at the grain boundary and a small number of nano-Ni particles were located within Al2O3 grain; and at 1450℃, the interspace existed at the interface of Al2O3/Ni and the exaggerated growth of Al2O3 grain was found.