材料期刊网

分别以多壁碳纳米管-氧化铝( CNT-Al2 O3)复合粉体和直接加入的添加方式,以MWCNTs为增强材料,电熔白刚玉(粒径为1~3 mm和0~1 mm)为骨料,板状刚玉粉(粒径≤0.043 mm)、鳞片石墨粉(粒径≤0.147 mm)、单质硅粉(粒径≤0.074 mm)为基质,热固性酚醛树脂为结合剂,制备出MWCNTs复合低碳Al2 O3-C材料,研究MWCNTs及其不同的加入方式对复合材料的常温物理性能、高温抗折强度、抗热震性和抗氧化性的影响。采用扫描电子显微镜和高分辨率透射电镜对MWCNTs及复合材料的表观形貌进行观察。结果表明,CNT-Al2 O3复合粉体中的MWCNTs在基质中分散均匀,可降低试样的气孔率,提高试样的致密度、机械强度、高温抗折强度和抗热震性；直接加入的MWCNTs不但对试样的常温物理性能和抗热震性无明显改善,而且降低了试样的高温抗折强度下降。 MWCNTs的加入可改善低碳Al2 O3-C试样的抗氧化性,其中以加入CNT-Al2 O3复合粉体的加入形式效果最佳。

A new type of low carbon Al2 O3 refractory material was prepared using coarse-grain white fused alumina , tabular alu-mina (≤0.043mm), graphite flake (≤0.147mm), silicon powder (≤0.074mm) and carbon nanotubes (CNTs) as fillers, and thermosetting phenolic resol as binder. The CNTs were added directly to the fillers or coated onto tabular alumina by catalytic chemi-cal vapor deposition ( CVD) . Properties of the samples were tested, such as apparent porosity, bulk density, mechanical strength, modulus of rupture at 1 100℃, thermal shock resistance and oxidation resistance. The morphologies of the CNTs and fractured sam-ples were examined by scanning and transmission electron microscopy. Results indicate that bulk density, mechanical strength, mod-ulus of rupture at 1 100℃, thermal shock resistance and oxidation resistance of the sample obtained by the CVD method are higher while apparent porosity is lower than for the sample obtained by the direct addition method. The addition of CNTs improves the oxi-dation resistance of the refractory materials. The direct addition method not only has no influence on thermal shock resistance, but also decreases the modulus of rupture at 1 100℃.