Effect of carbon and titanium carbide on sintering behaviour of zirconium diboride
Effect of carbon and titanium carbide on sintering behaviour of zirconium diboride
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DOI：
10.1016/j.jallcom.2007.11.004
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发表时间：
2008-10
影响因子：
6.2
通讯作者：
S. Mishra;L. Pathak
中科院分区：
文献类型：
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作者：
S. Mishra;L. Pathak
在0<；x<；10(x=wt.%)范围内添加C(C)，在0<；y<；30(y=wt.%)范围内添加碳化钛TiC，系统地研究了ZrB2粉末的烧结。不同工艺制备的二硼化锆粉末具有相似的烧结行为，其中自蔓延高温合成的粉末形貌最为均匀。C的加入促进了0<；x<；4的致密化，阻碍了4<；x<；10的致密化，而添加5wt.%以上的TiC不利于ZrB2的烧结。C的加入抑制了复合材料的晶粒度，可获得致密化程度较高的细晶ZrB2-C复合材料。C的加入增加了致密化，这是由于去除了粉末表面的氧杂质，防止了通常观察到的在烧结过程中通过氧化物相的蒸发冷凝而导致的夸张的晶粒长大。当C含量较高时，由于第二相的体积分数增加，致密化速度降低，第二相起到扩散阻挡的作用。
Systematic sintering studies on the ZrB2powder were carried out with the addition of carbon (C) in the range of 0<x<10 (x=wt.%) and (titanium carbide) TiC in the range of 0<y<30 (y=wt.%). Zirconium diboride powder made by different routes showed similar sintering behaviour and amongst all the powders, the SHS made powder exhibited most homogeneous morphology. The addition of C facilitate densification in the range of 0<x<4 and hinders densification for 4<x<10, whereas, the addition of TiC above 5wt.% was found to be detrimental for the sintering of ZrB2. The addition of C also found to inhibit the grain size and fine grained ZrB2–C composite could be obtained with high densification. The increased densification with the C addition was due to removal of oxygen impurities on the ZrB2powder surfaces that prevented the commonly observed exaggerated grain growth through evaporation condensation of oxide phases during sintering of boride ceramics. At higher percentages of C addition, the densification rates decreased due to increased volume fraction of second phase that acted as diffusion barrier.