Synthese und Herstellung von hochreinen Yttriumvanadat-Keramiken für optische Anwendungen

摘要

Yttriumorthovanadate (YVO_4) single crystal is an excellent polarizer as well as laser host material with high optical transparency in the region 400-5000 nm. High-tech applications of YVO_4 are still limited due to different crystal growth difficulties, so an alternative production method is required. Therefore high purity YVO_4 with a small grain size of approx. 100 nm was synthesized by a wet chemical precipitation via a continuously working micro-jet reactor technique. After freeze-drying the precipitation-solution and calcination, the powder was uniaxially pressed and pressureless sintered in air at different temperatures up to 1450 °C. High densities >98.5 % of the theoretical density were achieved. To further increase the densities the samples were hot isostatically pressed followed by an annealing process. Thus, translucent samples with densities >99.5 % of the theoretical density could be obtained.