熔渗烧结制备Ti_3SiC_2反应机理的研究

以Ti/Si/C粉末和Ti/Si/TiC粉末为原料,采用液态熔渗硅方法制备出纯度较高的Ti3SiC2材料,Ti3SiC2的相对质量分数分别达到91.2%和92.3%。研究表明,熔渗烧结制备Ti3SiC2的反应过程为:温度在1 300℃以上,且未发生熔渗时,试样中单质Ti的含量高于Si的含量,在Ti的富集区优先生成Ti5Si3,随着温度的升高,少部分Ti5Si3和β-Ti先熔合形成Ti-Si液相;在1 500℃时,随着液态Si的渗入及流动扩散,液态Si和剩余的Ti5Si3形成大量Ti-Si液相,将试样中的TiC包覆,通过液相反应生成大量的Ti3SiC2。

Study on the reaction mechanism of Ti_3SiC_2 by melt infiltration sintering method

The purer bulk Ti_3SiC_2 ceramic had been prepared from Ti/Si/C and Ti/Si/TiC mixed powders by melt infiltrating method, and the content of Ti_3SiC_2 in the two test samples which were made from Ti/Si/C and Ti/Si/TiC mixed powders is up to 91.2 wt% and 92.3 wt%, respectively. The results showed that the reaction mechanism of Ti_3SiC_2 by melt infiltrating sintering method is that the Ti_5Si_3 is easier to obtain in the rich Ti areas in which the content of Ti is higher than that of Si at 1 300℃. With the increase of temperature, few Ti_5Si_3 reacts with β-Ti to form liquid phase of Ti-Si. When the liquid Si infiltrates at 1 500℃, liquid Si react with the rest Ti_5Si_3 to form liquid phase of Ti-Si. The formed liquid phase of Ti-Si would wrap the TiC particles to form a great deal of Ti_3SiC_2 by liquid phase reaction.