【摘要】 通过液相磁力搅拌混合原料粉末,压片后无压烧结合成了三元Ti₃SiC₂,研究不同原料配比Ti/Si/C,Ti/SiC/C/和TiC/Si/Ti对合成Ti₃SiC₂的影响,同时为了比较,在相同条件下加入少量Al或Sn,研究其对Ti₃SiC₂的合成过程及最终产物的影响,并探讨Ti₃SiC₂的合成机理。结果表明:3Ti/1.2Si/2C/0.1Al在1400℃无压烧结合成了较高纯度的Ti₃SiC₂,Al粉的加入可以降低混合粉末的起始反应温度,有利于三元层状化合物Ti₃SiC₂的合成和纯度的提高,其合成机制为,在铝粉形成的熔池中,经形核钛和硅反应生成钛硅金属间化合物,钛与石墨反应生成碳化钛,随后扩散,长大,随着温度的升高,反应生成三元层状Ti₃SiC₂。而以TiC或SiC为Ti或Si源制备的Ti₃SiC₂含杂质较多,不适用于无压烧结合成Ti₃SiC₂。合成的Ti₃SiC₂在HF溶液中经200℃溶剂热反应后,产物主要为两种不同晶型的SiC和AlF₃立方体,且随着反应时间的延长,AlF₃的含量增加,结晶更完善。更多还原

【Abstract】 Ternary carbide Ti₃SiC₂ was synthesized by pressureless sintering the mixture powders with preliminary liquid magnetic stirring mixing,the influence of Ti/Si/C,Ti/SiC/C/and TiC/Si/Ti raw material systems on the synthesis of Ti₃SiC₂ was studied,the addition of appropriate Al or Sn to the synthesis process and final product were also evaluated. The powder was characterized with X-ray diffraction and scanning electron microscopy. The results show that high purity Ti₃SiC₂ was obtained by pressureless sintered 3 Ti/1. 2Si/2C/0. 1 Al at 1400 ℃,the addition of Al powder can reduce the initial reaction temperature of mixed powder and conducive the synthesis of high purity Ti₃SiC₂,however,use TiC or SiC as Ti or Si source,the product has more impurities and is not suitable for the preparation of Ti₃SiC₂. After solvothermal reaction of Ti₃SiC₂ in HF solution at 200 ℃,the products are mainly composed of two different crystal forms of SiC and AlF₃ cube,along with the increase of reaction time,the content of AlF₃ increases and the crystallization is improved.更多还原