Synthesis, densification and characterization of ultra-fine W-Al2O3 composite powder

W-Al2O3 composite powder was prepared via hydrothermal synthesis containing doping, annealing and reduction. The precursors WO3 and AlOOH were synthesized by the two sets of the hydrothermal reactions, respectively. The formation of Al2(WO4)3 from these two precursors in an aqueous solution is a key process, which is beneficial to improve the mixing uniformity of final powder to a molecular level. During subsequent reduction, nano-Al2O3 coated W particles were obtained, and inhibited the further deposition of reduced W atoms on the adjacent W particles, obtaining ultra-fine Al2O3/W composite powder. After sintering, the dense and fine-grained W-Al2O3 alloy was obtained due to the high sintering activity of ultra-fine powder. Compared with the pure tungsten, the W-Al2O3 alloy displays obvious higher values of both strength and plasticity especially when the Al2O3 content is 2 wt%.