Systematic optimization of ball milling for highly transparent Yb:YAG ceramic using co-precipitated raw powders

Abstract

Yb:YAG transparent ceramics were fabricated by vacuum sintering method using the co-precipitation synthesis of raw powders. These raw powders were mixed in ethanol doped with TEOS and ball milled for different time periods (0–20 h) and various solid contents of slurry (Sc = 7.8–38.5 wt%). The samples were vacuum sintered from 1350 °C to 1800 °C. Effects of ball-milling time and slurry concentrations on the morphology of powders, as well as densification, microstructure and transmittance of Yb:YAG ceramics were systematically evaluated. Results show that ball milling for 12 h can break the sintering neck of the particles and increase the optical transmittance to 81% at 1100 nm. For the Sc range of 38.5–20.3 wt%, decreasing slurry concentration improved the densification and in-line transmittance of Yb:YAG ceramics in the visible light region. When ball-milled for 12 h with 20.3 wt% slurry concentration, the Yb:YAG powders showed the most homogeneous particle distribution and highest densification rate, from which the ceramics prepared have the pore-free microstructure and the best transmittance. The highest optical transmittance of Yb:YAG ceramic sintered at 1750 °C for 15 h reaches up to 82% in the visible light region and 83.5% at 1100 nm, which is almost close to the theoretical transmittance.