Effects of sintering additives on preparation of CaF2 transparent ceramics

Abstract

The effects of different sintering addictives on the preparation of CaF 2 transparent ceramics were studied. Transparent CaF 2 ceramics were fabricated by vacuum sintering and hot isostatic pressing (HIP) method, using CaF 2 nanopowders synthesized by chemical precipitation method as raw materials. The nanopowders and transparent ceramics were studied using X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and spectrophotometer. The experimental results indicated that the obtained nanopowders presented normal distribution with grain size about 30 nm; transmittance of CaF 2 transparent ceramics was 39% and 26% at 1100 nm for LiF and NaF as sintering addictives, respectively, with corresponding mean grain size 188 μm and 44 μm. Loss of transmission could be attributed to the residual closed porosity. Sintering mechanism was liquid-phase sintering at pre-stage, then solid-phase sintering at later stage, as well as solid solution of lithium ions and sodium ions in the CaF 2 lattice structure.

Effect of Yb concentration on the microstructures, spectra, and laser performance of Yb: CaF2 transparent ceramics

“…Until nanosized Yb: CaF 2 powders were synthesized by co‐precipitation method in 2009 and high optical quality of Yb: CaF 2 transparent ceramics were obtained by cold isostatic pressing (CIP) combined with hot isostatic pressing (HIP) method 14‐16 . The research on fluoride based transparent ceramics has aroused attention again 17‐21 …”

“…[14][15][16] The research on fluoride based transparent ceramics has aroused attention again. [17][18][19][20][21] At present, there are two methods for fabricating fluoride-based transparent ceramics. The first one is the hot-forming method in which the single crystals were pressed at high temperatures and pressure.…”