Effect Of Addition Of Al Component On The Microstructure And Properties Of Ti₃SiC₂ Material

Ti₃SiC₂ is a typical of 312 phase compounds with a hexagonal P63 / mmc structure, melting point higher than 3000℃, the density of 4.53 g/cm3. Thus, Ti₃SiC₂ material is widely used in high-temperature structural ceramics, electrode material, workability ceramics, self-lubricating materials and other fields. and therefore become an important field of materials research. However, single-phase Ti₃SiC₂ material is often difficult to obtain in synthesis process, often together with impurity phases carbide and silicide. It was found that highly pure dense Ti₃SiC₂ bulk materials can be got through adding aluminum powder. This study was carried out in two steps: firstly, mixtures of Ti powder, Si powder, and TiC powder were prepared introducing Al and Al-Si alloy, and then Ti3Si（Al） C2 is synthesized by reactive hot pressing method. After that, the influence of the introducing way and content of Al component on density, phase composition, mechanical properties and SEM of the Ti3Si（Al） C2 materials.Secondly, based on the Ti₃SiC₂ erosion caused by the aluminum and aluminum alloy the anti-slag experiments were designed. And then the anti-corrosion of Ti₃SiC₂ and Al₂O₃/Ti₃SiC₂ composite was observed according to X-Ray diffraction, and electron microscopy. The results show that:（1） The introduction of an appropriate amount of Al powder or Al-Si alloy powder can promote Ti₃SiC₂ generation by reactive hot pressing at 1500℃. With the increase of Al or Al-Si alloy powder introducing content, more Ti₃SiC₂ can be got. And the effect of the introduction of Al-Si alloy powder is more obvious, but the bulk density of Ti₃SiC₂ material decreases. The introduction of Al or Al-Si alloy powder helps Ti₃SiC₂ grow and improve the mechanical properties. When the amount of the introduction of a molar ratio is 0.3 of Al-Si alloy powder, the bending strength is to 352 MPa, fracture toughness is to 5.68 MPa ? m1/2.（2） As the temperature increases, the penetration of Al or Al-Si alloys to pure Ti₃SiC₂, Al₂O₃/Ti₃SiC₂ composites increases. Under the same temperature, the Al metal is easier to penetrate into pure Ti₃SiC₂, Al₂O₃/Ti₃SiC₂ composite than Al-Si alloy. Under the same conditions, the beginning temperature of Al infiltrate into pure Ti₃SiC₂ is 750℃, and Al-Si alloy is 800℃, the beginning temperature of Al infiltrate into pure Al₂O₃/Ti₃SiC₂ composite is 700℃, and Al-Si alloy is 800℃.Al or Al-Si alloy infiltrates Al₂O₃/Ti₃SiC₂ composite material through the Ti₃SiC₂ section.