Abstract: First,Al/Si composite powder coating modified corundum particles were prepared using tabular corundum particles (1-3 mm),Al/Si composite powder (mass ratio of Al powder to Si powder=4∶0,3∶1 or 2∶2),and phenolic resin-ethylene glycol mixed solution as raw materials,stirring,baking at 180 ℃ and disintegrating.Then,Al₂O₃-C samples were prepared according to the conventional process.The cold and hot properties of the samples were tested.The phase composition and the microstructure were analyzed.The results show that:(1)adding Al/Si composite powder coating modified corundum particles into Al₂O₃-C samples can improve their density,cold and hot strengths,thermal shock resistance and oxidation resistance;the Al/Si composite powder with the mass ratio of Al powder to Si powder of 3∶1 is the optimum;(2)the Al powder and the Si powder fill in the depressions on the surface of the modified tabular corundum particles,which improves the forming density of the samples as well as the density,the strength and the oxidation resistance of the samples after baking and carbon embedded heat treatment;after high temperature carbon embedded heat treatment,the Al powder and the Si powder react to form non-oxides such as AlN,Al₄C₃ and SiC,which enhance the bonding of the modified corundum particles and the matrix,thus improving the thermal shock resistance and the strength of the samples.

Key words: alumina-carbon materials, coating modification, corundum particles, non-oxides, bonding strength

摘要： 首先,以3~1 mm的板状刚玉颗粒,Al粉、Si粉质量比分别为4∶0、3∶1、2∶2的Al/Si复合粉,以及酚醛树脂-乙二醇混合液为原料,通过搅拌、180 ℃烘烤、解体制成Al/Si复合粉包覆改性板状刚玉颗粒。然后,按常规工艺制备Al₂O₃-C试样,检测试样的常温和高温性能,分析试样的物相组成和显微结构。结果表明:1)在Al₂O₃-C材料中加入Al/Si复合粉包覆改性刚玉颗粒,可提高材料的致密度、常温强度、高温强度、抗热震性和抗氧化性;Al/Si复合粉中Al粉、Si粉的质量比以3∶1最佳。2)改性板状刚玉颗粒表面的Al粉和Si粉填充在颗粒表面的凹陷处,提高了试样的成型致密度以及烘烤后和埋炭热处理后试样的致密度、强度和抗氧化性;高温埋炭热处理后,这些Al粉和Si粉反应生成AlN、Al₄C₃、SiC等非氧化物,增强了改性刚玉颗粒与基质的结合,提高了试样的抗热震性和强度。

关键词: Al₂O₃-C材料, 包覆改性, 刚玉颗粒, 非氧化物, 结合强度