Preparation of MgF2–CaF2 nanocomposite ceramics with high infrared transmittance

Currently, most infrared nanocomposite ceramics are based on oxides. In this study, a brand-new system of infrared nanocomposite ceramics is proposed and realized. The new infrared nanocomposite ceramics contain two phases, MgF2 and CaF2, in a one-to-one volume ratio. The nanocomposite powders were synthesized by co-precipitation and calcination. The characterization of the as-prepared powders by X-ray diffraction and scanning electron microscopy revealed the presence of phases of ultrafine nanostructured MgF2 and CaF2, with an average particle size less than 30 nm. The nanocomposite ceramics were fabricated by hot-pressing the constituent powders at 650 ℃ under 200 MPa, yielding ceramics with a grain size less than 100 nm. The resulting nanocomposite ceramics exhibit excellent transmittance in the mid-IR region, which reaches 90 % in the wavelength range of 3–5 µm. These results demonstrate the promising application potential of fluoride infrared nanocomposite ceramics.