Effect of sintering temperature on microstructure and flexural strength of alumina borate whiskers

Abstract

Aluminium borate whiskers have been synthesized by hydrolysis route using Alumina (Al2O3) and boric acid (H3BO3). The effect of sintering temperature was studied in the range of 950 to 1400 °C on the formation of microstructures and associated mechanical strength of the synthesized whiskers. The microstructural evolution has been characterized using Differential Thermal Analysis (DTA-TGA), X-ray Diffraction Analysis (XRD), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (EDS) and Transmission Electron Microscopy was utilized to ascertain the formation of whiskers. The optimum temperature for whisker formation was found to be 1300 °C and around 1400 °C whiskers are about to lose the microstructure as the formation of glassy phase of Alumina borate start at this temperature. The room temperature and high temperature mechanical properties have been evaluated by cold modulus of rupture (CMOR) and hot modulus of rupture (HMOR) strengths. The results showed that highest HMOR and CMOR values reached 42 and 51 MPa respectively at sintering temperature of 1300 °C. © 2019 IOP Publishing Ltd.