Donghai Ding

Self-Propagating High-Temperature Synthesis of ZrB2-Al2O3 Composite Powders: The Roles of Raw Material Ratios

ZrB2-Al2O3 composite powders were prepared by self-propagating high-temperature synthesis (SHS) using different raw material ratios. The phase constituents and microstructure of the final product were examined by X-ray Diffraction (XRD) and Field-Emission Scanning Electron Microscopy (FESEM) with Energy Dispersive Spectrometry (EDS). The results showed that ZrB2 and Al2O3 are only contained in the final product and the content of ZrB2 is the highest when the raw material mole ratio of ZrO2: B2O3: Al is 3 : 3 : 11.5. Unreacted ZrO2 remains in products prepared using raw materials with stoichiometric ratio and with excessive B2O3. The ZrB2 content decreases and then increases with increasing B2O3, while crystal grain diameter (D) and distance of crystal face (d) behaves in the opposite manner. A eutectic structure was formed in the local region of product prepared with a stoichnometric ratio.