Formation of titanium carbonitride phases via the reduction of TiO2 with carbon in the presence of nitrogen
Formation of titanium carbonitride phases via the reduction of TiO2 with carbon in the presence of nitrogen
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DOI：
10.1023/a:1004457622751
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发表时间：
1999-01-15
影响因子：
4.5
通讯作者：
Yoon, SJ
中科院分区：
文献类型：
--
作者：
Jha, A;Yoon, SJ
在一系列氮气气氛下研究了碳对金红石 (TiO2) 的还原。在 1173 K 至 1773 K 的温度范围内研究了碳的反应性对 TiO2 还原为碳氮化钛相 (TiCxNy) 的影响。本研究还报告了氨、CO 和氢气的存在对 TiO2 还原为碳氮化物 (TiCN) 的反应平衡的影响。还讨论了 TiCN 相的晶格参数对间隙原子、C、N 和 O 浓度的组成依赖性。 TiO2 形成 TiCN 相的机理是根据 Ti-C-N-O 系统中的主面积图建立的，该主面积图源自 1573 K 和 1 atm N-2 气体下的吉布斯自由能数据。根据间隙离子通过 B1（NaCl 型）结构的扩散，讨论了 TiO2 同时还原氮化为 TiCN 的活化能的导出值。还建立了 TiC 晶格参数对间隙亚晶格位点 N 和 O 浓度的依赖性。对于两种类型的还原剂：石墨和活性炭，活化能的表观值在 220 kJ 至 240 kJ mol(-1) 范围内。 (C) 1999 Kluwer 学术出版社。
The reduction of rutile (TiO2) with carbon was studied in a range of nitrogen atmospheres. The effect of the reactivity of carbon on the reducibility of TiO2 to titanium carbonitride phase (TiCxNy) was investigated over a range of temperatures between 1173 K and 1773 K. The present study also reports the effect of the presence of ammonia, CO, and hydrogen gases on the reduction reaction equilibrium of TiO2 to carbonitride (TiCN). The compositional dependence of the lattice parameter of TiCN phase on the concentrations of interstitial atoms, C, N, and O is also discussed. The mechanism of TiCN phase formation from TiO2 has been established on the basis of a predominance area diagram in the Ti-C-N-O system derived from the Gibbs free energy data at 1573 K and 1 atm of N-2 gas. The derived values of the activation energies for simultaneous reduction-nitridation of TiO2 to TiCN are discussed in the light of interstitial ion diffusion through the B1 (NaCl type) structure. The dependence of TiC lattice parameter on the concentrations of N and O at the interstitial sublattice sites is also established. The apparent values of the activation energies were found to be in the range of 220 kJ to 240 kJ mol(-1) for both types of reducing agents: graphite and activated charcoal. (C) 1999 Kluwer Academic Publishers.