Fabrication and characterization of transparent ceramics for solid state laser applications

• Main Author: Wang, Shengming
• Other Authors: School of Materials Science and Engineering
• Format: Final Year Project
• Language: English
• Published: 2016
• Subjects: DRNTU::Engineering::Materials::Ceramic materials
• Online Access: http://hdl.handle.net/10356/67052
• Institution: Nanyang Technological University

Transparent ceramics have been known to be one of the best materials for solid state lasers application. Known for its flexibility to be doped with different elements with excellent transmittance, it has been used widely as a host for solid state lasers. This work consists of the fabrication of Holmium-doped Yttria (Ho:Y2O3) transparent ceramics via co-precipitation process followed by vacuum sintering to produce the final transparent ceramic samples. The samples are then polished and characterized using tools like Scanning Electron Microscope and UV-vis Spectroscopy. Parameters that were investigated include the heating rate of during vacuum sintering and alternative routes for rapid rate sintering method. Based on the microstructure of the samples, we determined the porosity, relative density as well as the in-line optical transmittance of the samples, which are factors considered when producing a high quality transparent ceramic product. It was found out that a higher heating rate will yield differences in densification between the near center and near surface regions of the sample, resulting in inhomogeneous densification. This results in pores trapped in the center of the sample due to the formation of a hard shell near the surface of the samples, which ultimately inhibit the full densification of the samples and hence a lower optical transmittance value. A two-step rapid rate sintering was used and investigated and proved to yield decent results.