Fabrication and microstructure development of Yb:YAG transparent ceramics from co‐precipitated powders without additives

Abstract

Sintering additives are generally considered to be important for improving densification in fabrication of transparent ceramics. However, the sintering aids as impurities doped in the laser materials would decrease the laser output power and produce additional heat during laser operation. In this work, Yb:YAG ceramics were vacuum‐sintered without additives at different temperatures for various soaking time through using ball‐milled powders synthesized by co‐precipitation route. The densification behavior and grain growth kinetics of Yb:YAG ceramics were systematically investigated through densification curves and microstructural characterizations. It was determined that the densification in the 1500°C‐1600°C temperature range was controlled by a grain‐boundary diffusion. It is revealed that the volume diffusion is the main mechanism controlling the grain growth between 1600°C and 1750°C. Although SiO2 additives can promote densification during low‐temperature sintering, the optical transmittance of Yb:YAG ceramic with no additives, sintered at 1800°C for 15 hours, reaches a maximum of 83.4% at 1064 nm, very close to the measured transmittance value of Yb:YAG single crystal. The optical attenuation loss was measured at 1064 nm in Yb:YAG transparent ceramic, to be 0.0035 cm−1, a value close to that observed for single crystals.

Fabrication, microstructure, spectral properties, and laser performance of Yb:GdxY3−xAl5O12 ceramics

“…[7][8][9] For the laser ceramic hosts, the most widely studied garnet is the yttrium aluminum garnet Y 3 Al 5 O 12 (YAG). 10,11 The first significant breakthrough in the transparent ceramic is the Nd:YAG ceramics, which was first successfully fabricated by the solid-state reactive method by Ikesue et al in 1995. 12,13 In order to increase the bandwidth of the absorption and emission peaks of the Yb:YAG ceramics for the ultra-faster and broader tunable laser generation, the mixed garnets media were proposed and prepared.…”

“…For the laser ceramic hosts, the most widely studied garnet is the yttrium aluminum garnet Y 3 Al 5 O 12 (YAG) 10,11 . The first significant breakthrough in the transparent ceramic is the Nd:YAG ceramics, which was first successfully fabricated by the solid‐state reactive method by Ikesue et al.…”

Optimization of a TEOS addition on plasma resistance of YAG ceramics

“…Tetraethyl orthosilicate (TEOS) is a commonly used sintering additive to promote the densification of YAG ceramics. [19][20][21][22][23] Boulesteix et al 24 reported that the densification rate obtained by adding .3 wt.% SiO 2 was two orders of magnitude higher than pure YAG powder. A small amount of SiO 2 doping can significantly increase the densification rate of YAG ceramics, whereas SiO 2 doping exceeding a critical amount may result in the formation of a second phase abundant in Si, which is vulnerable to fluorine gas etching.…”

“…Tetraethyl orthosilicate (TEOS) is a commonly used sintering additive to promote the densification of YAG ceramics 19–23 . Boulesteix et al 24 .…”