Preparation Of YAG Transparent Ceramics With Glass As Grain Boundary Phase

Yttrium aluminum garnet（YAG） transparent ceramics has been widely used in the laser field because of its high concentration, high output power, wide spectrum and so on. At present, all YAG transparent ceramics only has one single phase. Meanwhile, there are two major difficulties in the preparation process: Firstly, the requirements of the purity and particle size of the powder are very strict; Secondly, high sintering temperature and long time heat preservation are necessary. These difficulties seriously hinder the development of YAG transparent ceramics.It is generally believed that the second phase in the material is the main reason for the loss of light transmittance. However, according to the theory of light scattering, the difference between the two phases is the fundamental reason. Consequently, a new kind of YAG transparent ceramics with glass as the grain boundary phase has been proposed for the first time in this experiment. At the same time, a method of preparing YAG single crystal powder, which is used to make the YAG transparent ceramics, has also been invented. These haven’t been reported all over the world. The results show that:The YAG transparent ceramics with glass as the grain boundary phase can be successfully prepared by matching the refractive index of the dense flint glass to that of YAG.Dipping sintering was an effective method for the preparation of the YAG transparent ceramics with glass as the grain boundary phase. Compared with the single phase sintering, the sintering temperature of dipping sintering reduced 700 ℃ and the heat preservation decreased from tens of hours to 4 hours.YAG single crystal powder was successfully prepared by melt crystallization method. The best crystallization conditions were as follows: the crystallization temperature was 1100℃, the mass ratio of PbO-to-SiO₂ was 3.95, and the content of Al₂O₃ was 10.87wt%.