Formation of TiN/TiC-Fe composites from ilmenite (FeTiO3) concentrate
Formation of TiN/TiC-Fe composites from ilmenite (FeTiO3) concentrate
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DOI：
10.1007/s11663-998-0077-z
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发表时间：
1998-10-01
影响因子：
3
通讯作者：
Willis, PE
中科院分区：
文献类型：
--
作者：
Welham, NJ;Willis, PE
由矿物精矿直接制备陶瓷硬质材料-金属复合材料具有很大的应用潜力。对钛铁矿（FeTiO3）和石墨的混合物进行均质预处理，然后在氩气环境下退火，结果表明碳化钛和单质铁的形成。将相同的粉末在氮中退火，形成元素铁和氮化钛的复合材料。在1000℃下，1小时后，碳化物的形成温度低于碳化物，几乎完全转化，碳化物的形成速率由碳扩散控制，而氮化反应则由氧或氮扩散控制。TiC是通过TiC0.5形成的，TiC0.5使TiC的含碳量缓慢增加，直至形成接近化学计量的TiC；化学计量TiN直接形成，没有中间相。碳化钛表现出第二相的存在，其晶胞尺寸略小；这是由于铁和TiC之间的相互扩散。碳化钛复合材料由分散在富钛基体中的3 ~ 4 μ m的多面体铁颗粒组成。氮化铁/钛复合材料无偏析，分布明显为亚微米级。
The production of a ceramic hard material-metal composite directly from a mineral concentrate has great potential application. An homogenizing pretreatment of a mixture of ilmenite (FeTiO3) and graphite, followed by annealing under an argon ambient, showed the formation of titanium carbide and elemental iron. Annealing of the same powder in nitrogen resulted in the formation of a composite of elemental iron and titanium nitride. The nitride was formed at a lower temperature than the carbide with almost complete conversion after 1 hour at 1000 degrees C. The rate of carbide formation was controlled by carbon diffusion, whereas the nitridation reaction was controlled by either oxygen or nitrogen diffusion. The TiC was found to form via TiC0.5, which slowly increased its carbon content until near stoichiometric TiC was formed; stoichiometric TiN formed directly with no intermediate phases. Titanium carbide showed the presence of a second phase with a slightly smaller unit cell size; this was due to interdiffusion between the iron and TiC. The titanium carbide composite was found to be composed of 3 to 4 mu m anhedral iron grains dispersed in the titanium-rich matrix. There was no segregation in the iron/titanium nitride composite with apparently submicron distribution.