陶瓷添加物对Ti_3SiC_2基复合材料抗氧化性的影响

为研究陶瓷添加物对Ti3SiC2基复合材料性能的影响,首先,采用反应热压烧结法制备了Ti3SiC2材料及陶瓷添加物含量均为30wt%的SiC/Ti3SiC2、Al2O3/Ti3SiC2和MgAl2O4/Ti3SiC2复合材料。然后,测试了材料的力学性能和导电性,在1 373~1 773K温度范围内对Ti3SiC2基复合材料的抗氧化性进行了研究,并对其烧结试样的物相组成和显微结构等进行了表征。结果表明:Ti3SiC2在高温氧化后的主要产物为TiO2和SiO2;氧化层分为内外2层,内层由TiO2与SiO2这2相混合组成,外层为TiO2;氧化层中存在大量显气孔,结构较为疏松,导致抗氧化性较差。与Al2O3/Ti3SiC2和MgAl2O4/Ti3SiC2复合材料相比,SiC/Ti3SiC2复合材料具有更好的抗氧化性。

Effects of ceramic additives on oxidation resistance of Ti3SiC2 matrix composites

In order to investigate the effects of ceramic additives on the properties of Ti₃SiC₂ matrix composites, Ti₃SiC₂ material as well as SiC/Ti₃SiC₂, Al₂O₃/Ti₃SiC₂ and MgAl₂O₄/Ti₃SiC₂ composites whose ceramic additive contents were 30wt% were fabricated by reactived hot pressing sintering method firstly. Then, the mechanical properties and conductivities of the materials were tested, the oxidation resistance of Ti₃SiC₂ matrix composites was investigated in the temperature range of 1 373-1 773 K, and the phase compositions and microstructures of sintering samples were characterized. The results show that the main products of Ti₃SiC₂ after high temperature oxidation are TiO₂ and SiO₂. The oxidation layer can be divided into two layers of inner and outer, the inner layer consists by two-phase mixture of TiO₂ and SiO₂, and the outer layer is TiO₂. A large number of apparent pores exist in oxide layers and the structure is relatively loose, which leads to the poor oxidation resistance. Comparing with Al₂O₃/Ti₃SiC₂ and MgAl₂O₄/Ti₃SiC₂ composites, SiC/Ti₃SiC₂ composite has better oxidation resistance.