放电等离子烧结制备SiC/Ti_3SiC_2复合材料

以钛粉、硅粉和石墨粉为原料,采用放电等离子烧结制备l了含20%(摩尔分数,下同)siC的SiC/Ti_3SiC_2复合材料,并研究了烧结助剂Al对该复合材料的性能影响.利用X射线衍射分析样晶相组成.运用扫描电镜分析材料的最微组织和断口形貌,并对试样的密度、硬度和抗弯强度进行了测定.结果表明,按Ti_3Si_(1.2)C_(2-)20%SIC和(Ti_3Si_(1.2)C_2-20%SIC)+2wt%Al进行成分配比,可制得纯度较高的Ti_3SiC_2-20%SiC复合材料,两者都含有少量未反应完全的石墨.未加Al的样品还含有微量的TiSi_2杂质;添加铝对样品的密度并没有明显影响,但对显微硬度有较大影响.含铝样品的显微硬度明显低于不含铝的样品;含铝和不含铝试样的三点抗弯强度分别为221.0、231.7 MPa.

Synthesis of SiC/Ti_3SiC_2 Composites by Spark Plasma Sintering

Ti,C and Si powders were adopted to synthesize Ti_3SiC_2 based composite containing 20%of SiC using spark plasma sintering(SPS)method.Effect ofadding Al powder as sintering aid on the properties of composites was studied.X-ray diffraction was utilized in phase identification;scanning electron microscopy Was used for the analysis of microstmcture and fracture surface.Density,hardness and three point bending strengths were measured.The results show that by sintering samples with nominal compositions of Ti_3Si_(1.2)C_2-20%SiC and(Ti_3Si_(1.2)C_2-20%SiC)+2wt%Al,respectively,high purity SiC /Ti_3SiC_2 composites with a small amount of graphite as impurity can be obtained.While,samples without Al have some TiSi_2 as impurity;the hardness of the sample containing Al is lower than that of the sample without Al,there is no significantdifference between their densities.The three point bending strength of the samples with and without Al are 22 1.0 MPa and23 1.7 MPa.respectively.