Abstract The present study deals with the formation of Al2O3 fibers during self-propagating high-temperature synthesis of the TiO2–Al–C system triggered in argon, oxygen, nitrogen and air environments. Results showed TiC and Al2O3 were the primary products obtained in the argon and oxygen atmospheres. However, the dissolution of nitrogen in the structure of TiC resulted in the formation of Ti(C, N) after synthesis in nitrogen and air environments. Al2O3 fibers just were extensively attained in an air atmosphere with a low partial pressure of oxygen. Long nanofibers were primarily formed at the surface of the compact, while short fibers were developed at the inner part; especially adjacent to the internal pores. The formation mechanism of Al2O3 fibers was proposed as (a) the formation of Al2O gas through reaction of Al with O2 in the environment having low oxygen partial pressure like air; (b) further reaction of Al2O vapor with O2 and the development of Al2O3; and (c) precipitation of Al2O3 in the form of fibers by vapor-solid mechanism.

中文翻译：

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不同环境下TiO2-Al-C体系自蔓延高温合成过程中Al2O3纳米纤维的形成

摘要 本研究涉及在氩、氧、氮和空气环境中引发的 TiO2-Al-C 系统自蔓延高温合成过程中形成 Al2O3 纤维。结果表明 TiC 和 Al2O3 是在氩气和氧气气氛中获得的主要产物。然而，氮在TiC结构中的溶解导致在氮和空气环境中合成后形成Ti(C,N)。Al2O3 纤维是在低氧分压的空气气氛中广泛获得的。长纳米纤维主要在压块表面形成，而短纤维在内部形成；特别是靠近内部孔隙。Al2O3 纤维的形成机制被认为是 (a) 在空气等低氧分压环境中，Al 与 O2 反应生成 Al2O 气体；(b) Al2O蒸气与O2的进一步反应和Al2O3的发展；(c) 通过气固机制以纤维形式沉淀 Al2O3。