Research On Microstructure And Evolution Of Tib₂-al₂o₃ Composite Ceramics Synthesyzed By Shs

TiB2 powder and TiB2-Al2O3 ceramic materials were prepared by Self-propagating High-temperature Synthesis (SHS) technology. The reaction process was studied, in which the effects of diluents content and compacting pressure on reaction process and material performance were also analyzed.TiB2-MgO ceramic materials were prepared by Self-propagating High-temperature Synthesis technology with the B2O3-TiO2-Mg reaction system. Then the TiB2-MgO ceramic materials and 17% H2SO4 acid solution were mixed together. TiB2 powder was prepared by pickling and drying the mixed solution. The results of X-ray diffraction analysis of TiB2 powder shows that the main phase of the ceramic powder is TiB2 with a small amount of MgO phase. The results of Scanning Electron Microscopy observation shows that the size of TiB2 particles are small and non-agglomeration.The TiB2 powder prepared by SHS and pickling method added in the B2O3-TiO2-Mg system as diluent to produce TiB2 ceramic materials. The effects of TiB2 content on SHS process were analyzed. The result shows that the adiabatic temperature and combustion temperature of the reaction decrease with the TiB2 content increasing, and the size of TiB2 particles increases.TiB2-Al2O3 ceramic materials were prepared by Self-propagating High-temperature Synthesis technology with the B2O3-TiO2-Al reaction system. The results of X-ray diffraction analysis of ceramic materials show that the main phase of the ceramic powder is TiB2 and Al2O3 without impurity phase. The products were observed by the Scanning Electron Microscopy, and the microstructure was characterized. The results show that the size of TiB2 particles has little to do with the compacting pressure. However, the size of TiB2 particles in products decreases obviously with the diluent TiB2 added.TiB2-Al2O3 ceramic material prepared by Self-propagating High-temperature Synthesis technology with the B2O3-TiO2-Al reaction system was observed by the Scanning Electron Microscopy. The morphology of TiB2 particles shows in granular, rod-like, sheet and other forms. The formation mechanism of TiB2 particles was analyzed. It is indicated that the morphology of TiB2 particles mainly depends on its intrinsic crystal habits and the external environment of system.High density of TiB2-Al2O3 composite ceramics were prepared by hot pressed sintering technology with TiB2-Al2O3 ceramic as raw materials prepared by Self-propagating High-temperature Synthesis. The property variation law of TiB2-Al2O3 ceramic with different TiB2 content was discussed. The results show that with the content of TiB2 increasing, the mechanical property of TiB2-Al2O3 composite ceramics increases firstly and then decreases slowly. So the TiB2 content can be adjusted to get TiB2-Al2O3 composite ceramics with high mechanical property. The optimum ratio of TiB2 and Al2O3 is 49.31 to 50.69.