Densification, microstructure and optical properties of YAG transparent ceramics prepared by dry-pressing and gelcasting

The effects of dry-pressing and gelcasting on the densification, microstructure and optical properties of YAG transparent ceramics were researched. The gelcasting samples had smoother and more uniform surface without agglomeration, but its average pore size was larger than that of the dry-pressing samples. The dynamic densification curves showed three continuous transition stages. The initial temperature of densification for the gelcasting samples was higher than that for the dry-pressing samples, but the initial temperature of obvious grain growth for the gelcasting samples were relatively lower. After being sintered at 1750 °C for 10 h, the transmittances at 1064 nm of samples (thickness of 1 mm) prepared by dry-pressing and gelcasting were about 77.79% and 81.26%, respectively. These two forming methods had difference influences on the microstructure, the dynamic shrinkage curves and the microstructure evolution of green bodies or ceramics, which could further impact the properties of YAG transparent ceramics. In a word, the gelcasting had certain advantages over the dry-pressing in preparing YAG transparent ceramics.