Fabrication and Mechanical Properties of Al₂O₃/LaPO₄ Composite

Al₂O₃/LaPO₄ ceramic composites were prepared from lanthanum nitrate hexahydrate, diammonium hydrogenphosphate and Al₂O₃ mixed in aqueous solution. Prepared powders were in-situ reaction sintered by hot-pressing at 1400°C for 1 h. The conventional reaction sintering using simple powder mixture of α-Al₂O₃, lanthanum carbonate and aluminum dihydrogenphosphate was also carried out for the comparison of the microstructure and mechanical properties. X-ray diffraction analyses showed that the sintered bodies were composed of only α-Al₂O₃ and LaPO₄. The more fine-grained composites fabricated by using aqueous solution process indicated the enhanced mechanical properties compared with the composites from reaction synthesis process.