Si含量对放电等离子烧结制备(1-x)Ti_3SiC_2+xSiC复合材料的影响

Influence of Si content on(1-x)Ti_3SiC_2+xSiC composites prepared by spark plasma sintering

以钛粉、硅粉和石墨粉为原料,制备出（1-x）Ti3SiC2＋xSiC（x=0.1-0.8）复合材料,并利用X射线衍射仪对样品进行相组成分析。结果表明：经1 300℃放电等离子烧结15 min后,可以得到纯净的0.9Ti3SiC2-0.1SiC和含有微量石墨的0.2Ti3SiC2-0.8SiC复合材料,0.9Ti3SiC2-0.1SiC和0.2Ti3SiC2-0.8SiC复合材料的显微硬度分别为8.8和10.5 GPa,均明显高于Ti3SiC2的（4 GPa）。随着SiC含量的增加,复合材料的硬度也增加,但杂质（石墨）和孔洞的含量也增多,成分为0.5Ti3SiC2-0.5SiC的复合材料在烧结过程中有少量Si流出;而当SiC含量增加到0.2Ti3SiC2-0.8SiC时,烧结过程中大量的Si流出使得复合材料无法成功烧结。

The elemental powders were used to prepare（1-x）Ti3SiC2＋xSiC composite（x=0.1-0.8） by using spark plasma sintering.X-ray diffractometer was employed to analyze the phase constituents.The results show that,after sintering at 1 300 ℃ for 15 min,pure 0.9Ti3SiC2-0.1SiC and 0.2Ti3SiC2-0.8SiC composites with tiny amount of graphite as impurities were obtained.The microhardness of 0.9Ti3SiC2-0.1SiC and 0.2Ti3SiC2-0.8SiC composites is 8.8 and 10.5 GPa,respectively,which is significantly higher than that of Ti3SiC2（4 GPa）.As the SiC contents increase,the impurity（graphite） and pore concentration of the sintered composite increase.During the sintering of 0.5Ti3SiC2-0.5SiC,some Si melts out from the sample.When the SiC content reaches 0.2Ti3SiC2-0.8SiC,the sintering is failed because significant amount of Si melts out from the sample.