Fabrication of transparent ZnS ceramic by optimizing the heating rate in spark plasma sintering process

Transparent ZnS ceramics were fabricated at a lower temperature (840 °C) by optimizing the heating rate in the spark plasma sintering (SPS) process. The phase composition, microstructure and the optical properties of the ceramics were investigated by XRD, SEM and FTIR. Under the optimized heating rate of 5 °C/min, ZnS ceramics with the best optical qualities was obtained, and the transmittance reached above 60% in the range of 5.0–12.0 μm and it was higher than 40% in the range of 2.0–3.0 μm. Meanwhile, the content of hexagonal phase was controlled to be lower than 7.5%.