Hot-pressing of zinc sulfide infrared transparent ceramics from nanopowders synthesized by the solvothermal method

Abstract Hot-pressing of infrared transparent ZnS ceramics from nanopowders calls for proper particle size of the raw nanopowders to avoid the size-induced low-temperature sphalerite-to-wurtzite phase transition during calcination and sintering. In this paper, ZnS precipitate was solvothermally treated at 180 °C for 10–50 h. After solvothermal treatment, the particle size increased from 4 nm of the as-prepared precipitate to more than 10 nm, which results in better sphalerite phase stability. Even after calcination at 800 °C for 2 h, the major phase of the solvethermally synthesized powders kept as sphalerite phase. Due to the optically isotropic sphalerite phase, as well as the less organic impurities, the hot-pressed ceramic showed much better optical quality than that from the precipitated powders.