Study On Fabrication And Properties Of Ti₃AlC₂Porous Ceramics

Automobile exhaust does harm to both environment and human health. Thus automobile exhaust purification and waste gas treatment have attracted wide attention right now. It is an effective way to install automobile gas catalyst purifier. The catalyst support used in the purifier is the key factor to determine purification. In order to improve the purification effects at the first few minutes when the auto start, preparing porous ceramics with certain conductivity for using as catalyst support may be a good idea. In this thesis, Ti3AlC2was used as matrix materials. Porous Ti3AlC2ceramics were fabricated by in-situ sintering method, foam-gelcasting method and adding pore forming method respectively. And the effects of processing parameters on the structure and properties of prepared porous Ti3AlC2ceramics have been studied.Using Al, TiC, Sn, Ti and TiH2as raw materials, porous Ti3AlC2ceramics could be fabricated by in-situ sintering method As TiH2/Ti increased from0to100%, porosity increased from30.4%to47.2%, bending strength decreased from120.3MPa to91.2MPa and resistivity increased from0.812×10-6Ω·m to1.21×10-6Ω·m. Using Ti3AlC2powder as raw materials, porous Ti3AlC2ceramics could be prepared by foam-gelcasting method. Solid content in original slurry affected the structure and properties of prepared materials. With the increasing of solid content from25vol.%to35vol.%, porosity declined from72.4%to67.1%, resistivity decreased from12.1×10-6Ω·m to8.1×10-6Ω·m. Using starch as pore former, porous Ti3AlC2ceramics could be manufactured from Ti3AlC2powder. Both starch content and sintering temperature had certain effects on phase composition, structure and properties. Sintered at1200℃, as starch content varied from0to30vol.%, porosity increased from35.6%to47.8%, bending strength decreased from145.6MPa to95.5MPa, resistivity increased from0.71×10-6Ω·m to3.22×10-6Ω·m. Porous Ti3AlC2ceramics could also be fabricated using NaCl as pore former and Ti3AlC2powder as raw materials. Both NaCl content and particle size had certain influence on the structure and properties. Sintered at1200℃, with the increasing of NaCl content from40vol.%to70vol.%, porosity increased from50%to70%, the resistivity increased from1.78×10-6Ω·m to4.22×10-6Ω·m, while bending strength declined from30.8MPa to9.9MPa. The size of NaCl particles had little effect on the porosity, but it affected resistivity greatly. The particle size of NaCl has a certain effect on the bending strength.