自蔓延高温合成Ti_2SC材料

Synthesis of Ti_2SC material by self-propagation high temperature synthesis

以钛粉、硫粉和石墨粉体为原料,采用自蔓延高温合成技术(SHS)制备钛硫碳(Ti2SC)陶瓷材料,研究不同原料配比和助剂对反应合成Ti2SC的影响。利用X射线衍射仪和扫描电镜对合成产物进行物相组成和形貌分析,探讨反应合成Ti2SC材料的反应机制。研究结果表明,2Ti/S/C粉体自蔓延高温合成的产物中主相为Ti2SC,还包括少量的TiC与Ti3S4。主产物Ti2SC的晶粒有片状和板条状2种形貌。原料中添加过量的S,可抑制TiC形成,促进Ti3S4合成;添加适量的Al助剂可促进Ti2SC合成,抑制TiC和Ti3S4形成。2Ti-S-C体系的绝热燃烧温度达2 398 K。Ti2SC的形成机制是:在Ti-S-C反应体系中,Ti与S首先反应形成液相Ti-S,然后Ti与C反应形成TiC,最后,液相Ti-S与TiC反应形成Ti2SC。

The Ti2SC was synthesized by self-propagation high temperature synthesis （SHS） using Ti/S/C powders as raw material. The effects of different materials ratio and auxiliary agents on the synthesis of Ti2SC were investigated. The phase composition and morphology of the products were analyzed by XRD and SEM, respectively. The reaction mechanism of Ti2SC synthesis was also studied. The results show that the majority products are Ti2SC and small amounts of TiC and Ti3S4 in the synthesized sample. Adding excess S in the raw materials can inhibit the synthesis of TiC phase and enhance the synthesis of Ti3S4;adding suitable Al can enhance the synthesis of Ti2SC and restrain the formation of TiC and Ti3S4. The adiabatic temperature of 2Ti-S-C system reaches 2 398 K. The reaction mechanism for synthesizing Ti2SC has been proposed, which implicates that in the Ti-S-C reaction system, Ti reacts with S to form Ti-S liquid firstly;then Ti reacts with C to form TiC;at last, liquid Ti-S reacts with TiC to form Ti2SC.