Effect of Al2O3 on sinterability and transmittance of Lu2O3 ceramics

• Main Author: Lim, Hui Xin
• Other Authors: School of Materials Science and Engineering
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/56090
• Institution: Nanyang Technological University

The development of laser gain medium has been the most engaging area in application of high- power solid-state laser. In addition, it is a vital component in laser as the operation wavelength is dependent on the types of gain medium materials used. Research has begun working on sesquioxides metal such as yttrium oxide (Y2O3), scandium oxide (Sc2O3) and lutetium oxide (Lu2O3). Lu2O3 is considered one of the excellent choices as it has highest Yb doping concentration. In this work, the Lu2O3 ceramics were doped in different amount of aluminium oxide (Al2O3) and were fabricated using solid-state reaction process with ball milling method. The samples were subjected to vacuum sintering between 1800°C to 1870°C for various hours. After which, the samples were analyzed in terms of relative density, microstructure, crystal structure to meet the criteria for transparent ceramic for laser gain medium. Visual observations show that Lu2O3 ceramic sintered at 1870°C for 11 hours with 273 ppm of doped Al2O3 has the highest transparency. Besides that, other results also show that the grain size of the Lu2O3 ceramic enhanced significantly with increasing doping level. Furthermore, the average grain sizes calculated show cubic grain growth kinetics. There is no change in crystal structure with acceptable relative density and transmittance. It is important to understand the optimum sintering temperature and hours for Lu2O3 transparent ceramic. In addition, using suitable sintering additives would significantly reduce the residual pores within the samples. Therefore, different sintering additives need to be conducted to investigate the most desirable for Lu2O3 ceramic.