Combustion Synthesis of Ti_3SiC_2 in Air from 3Ti/Si/2C/0.2Al Powder Mixtures

Ti3SiC2 based material was successfully synthesized by self combustion in air using mechanically activated 3Ti/Si/2C/0.2Al powders as starting materials.Phase composition and microstructure of the material were characterized by means of XRD and SEM,the composition of sample was determined through EDX.Mechanical alloying of 3Ti/Si/2C/0.2Al powder mixtures may refine the powder particles and produce the severe lattice distortion,which significantly improves the reaction activities of the powders.When the powder mixture is exposed to the air,it self-ignited spontaneously and self-propagating high temperature synthesis(SHS) of titanium silicon carbide(Ti3SiC2) is induced.After cooling,a porous sample is obtained.The sample is composed of Ti3SiC2,TiC and tiny amounts of oxide.The content of Ti3SiC2 in the sample is about 83wt%.Surface of the sample is relatively uniform and dense,but the fracture is rough and porous.Surface layer of the sample consists mainly of Al2O3 and TiO2 grains with a size of 2-4μm.The oxidation film thickness is 5-10μm.The inner of the sample is a mixture of Ti3SiC2 and TiC.Lath Ti3SiC2 grains are 20-40μm in length and 2-4μm in width.TiC grains are about 3μm in dimension.