The Fabrication Of Ti₃AlC₂ Ceramic Material By Self-propagating High Temperature Reaction Synthesis

New layered ternary Ti₃AlC₂ ceramic attracts increasing interest owing to its unique properties.Ti₃AlC₂ combines unusual properties of both metals and ceramics. Like metals,it is a good thermal and electrical conductor,relatively soft and can be easily machined with traditional drill without lubrication or cooling water.Like ceramics,it is elastically stiff:exhibits excellent high temperature mechanical properties.It is resistant to thermal shock and unusually damage tolerant,and exhibits excellent corrosion resistance.These excellent properties mentioned above make it another family of technically important materials.To date,many methods such as chemical vapor deposition(CVD),self-propagating high temperature reaction synthesis(SHS),hot pressing(HP),and hot-isostatic pressing(HIP)have been used for the synthesis of Ti₃AlC₂.However,it is difficult to be synthesized as a pure phase by elf-propagating high temperature reaction synthesis,being often accompanied by unacceptably large amounts of TiC and titanium aluminum(Ti-Al) intermetallics.So we conducted the research on the fabrication of single-phase Ti₃AlC₂ material by combustion synthesis.In the present research,two series of raw materials molar ratio of Ti:C=3:2 and Ti:C=2:1,the elemental Ti,Al and C powders,were used to fabricate Ti₃AlC₂ by self-propagating high temperature reaction synthesis.In order to find the ideal synthesis conditions,different raw materials ratios in molar and experimental parameters were investigated.X-ray diffraction(XRD)and scanning electron microscope(SEM)coupled with energy-dispersive spectroscopy(EDS)were utilized to investigate the phase composition and the morphology characteristics of the products.The experiment results show that the main phase of combustion products is high-purity Ti₃AlC₂ ceramic and Ti₃AlC₂ grains are well developed,when used element of powder as raw materials,with raw materials molar ratio of n(Ti):n(Al):n(C)=2:2:1,the mass ratio of steel balls to elemental powder is 15:1, with milling speeding of 120rpm,mixing time for 4-5 hours,under the Ar protection atmosphere in the milling,in the 150MPa of pressure to compacting a sample.When the molar ratio of titanium to carbon are equal to 1.5,regardless of how changes in process parameters,it is too difficult to be synthesized as a single phase of the ceramic materials of Ti₃AlC₂.In the same raw materials molar ratio,only a proper ratio of the ball and materials,milling speeds,mixing times and the pressure to compacting a sample are good at the results of combustion synthesis.