碳热还原结合熔盐法制备碳化钛粉末与表征

Synthesis of stoichiometric titanium carbide by a combination of carbothermal reduction and the molten salt method and its characterization

摘要:

以NaCl为熔盐介质,采用锐钛矿型钛白粉和炭黑为原料,探索一种碳热还原结合熔盐法合成高纯碳化钛(TiC)的方法。借助XRD研究了反应温度和原料配比对合成碳化钛的影响,采用SEM、TEM、EDS,粒度分析仪,热力学分析等检测分析手段对合成产物的特性和过程进行分析。结果表明：相比传统的碳热还原合成碳化钛的方法,NaCl熔盐介质的引入可以有效的降低碳化钛的合成温度(从1700℃到1550℃)以及合成高纯碳化钛的时间(从10h到3h)。结合研究成果,提出了熔盐介质中溶解-沉淀的合成机理。

Abstract:

This paper presents a novel method of preparing stoichiometric titanium carbide (TiC) powders by combining carbothermal reduction and molten salt synthesis (MSS) from raw starting materials of titanium oxide (anatase), C (carbon black), and sodium chloride. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), laser particle size analysis, energy spectrum analysis (EDS), and thermodynamic analysis were used to characterize the powders. The effects of heating temperatures and molar ratios of titania to carbon black on the preparation of TiC are discussed. Results showed that the use of MSS to reduce the synthesis temperatures of both stoichiometric and pure TiC from 1700°C to 1550°C and the time required for synthesis decreased from 10 h for conventional carbothermal reduction of TiO₂ to 3 h. A dissolution-precipitation mechanism of synthesis of TiC by MSS was established based on these observed results.