Effect of reactive raw materials and pre-loading pressure on the microstructure and transmittance of pure CaF2 transparent ceramics

We reported an efficient way of fabricating pure CaF2 transparent ceramics using hot-pressing (HP) method. The effects of different reactive raw materials and pre-loading pressures on the microstructure and transmittance of pure CaF2 transparent ceramics were investigated. It was demonstrated that the optical quality of CaF2 ceramics was highly dependent on the reactive raw materials for synthesis of powders and pre-loading pressure. FESEM results manifested that the pre-loading pressure caused significant changes in the average grain size of pure CaF2 ceramics. With the pre-loading pressure increasing from 0 MPa to 15 MPa, the in-line transmittance of the obtained ceramics was obviously improved at all wavelength in the spectra. This work provides insight into mechanistic understanding of the sintering process of the fluoride-based ceramics and provides a reference value for improvement the optical quality of CaF2 transparent ceramics.