熔盐辅助碳诱导Ti_(3)AlC_(2)分解制备碳化钛纳米片

Preparation of TiC nanosheets by molten salt assisted carbon induced decomposition of Ti_(3)AlC_(2)

二维过渡金属碳化物因其独特的性质而成为极具吸引力的纳米材料。以炭黑和Ti_(3)AlC_(2)粉体为原料,以期通过在熔盐环境下实现碳还原Ti_(3)AlC_(2)合成碳化钛(TiC)纳米片。研究结果表明,炭黑可以诱导Ti_(3)AlC_(2)分解,随着加热温度的升高,Ti_(3)AlC_(2)的分解程度逐渐加剧。Ti_(3)AlC_(2)在低温(1000~1100℃)下可以严重分解为Al、Ti、Ti_(2.9)Al_(2.1)和TiC,Al和Ti可与微量氧反应生成少量的TiO_(2)和Al2O3,生成的TiC为纳米颗粒,而引入熔盐是确保TiC纳米片形成的必要条件。通过优化制备工艺得到合成高含量TiC纳米片的适宜条件:炭黑与Ti_(3)AlC_(2)物质的量比为1.05∶1,氯化钠与氯化钾的质量比为1∶1,盐的总质量与炭黑和Ti_(3)AlC_(2)混合物的质量比为2∶1;氩气保护,1000℃保温2 h。通过熔盐热处理得到以TiC为主并含有少量Al2O3的试样。产物中TiC的形貌为细小的纳米片,厚度约为10 nm、长度约为170 nm。

2D transition metal carbides are very attractive nanomaterials due to their unique properties.Using carbon black and Ti_(3)AlC_(2) powder as raw materials,it was expected that Ti_(3)AlC_(2) can be reduced by carbon in a molten salt environment to synthesize titanium carbide(TiC)nanosheets.The results showed that carbon black may induce the decomposition of Ti_(3)AlC_(2) to synthesize TiC nanocrystals at low temperature.As the heating temperature increased,the degree of decomposition of Ti_(3)AlC_(2) was gradually intensified.Ti_(3)AlC_(2) could be seriously decomposed into Al,Ti,Ti_(2.9)Al_(2.1) and TiC at low temperature(1000~1100℃).Al and Ti could react with trace oxygen to produce a small amount of TiO_(2) and Al2O3.The generated TiC was nanoparticle.The introduction of molten salt was a necessary condition to ensure the formation of TiC nanosheets.By optimizing the preparation process,the most suitable conditions for the synthesis of high content TiC nanosheets were obtained.The molar ratio of carbon black to Ti_(3)AlC_(2) was 1.05∶1,and the mass ratio of NaCl to KCl was 1∶1.The mass ratio of the total salt to the mixture of carbon black and Ti_(3)AlC_(2) was 2∶1.The mixed powders were put into the tubular furnace under the protection of Ar.After holding at 1000℃for 2 h,the samples with TiC as the main component were obtained by molten salt heat treatment.The morphology of TiC was fine nanosheets with thickness of about 10 nm and length of about 170 nm.