6819.1:
Transparent Polycrystalline Alumina From Nanosized Powders
Abstract
Transparent alumina sought after for many years has seen recent progress with high in-line transmittance of 70% (cf single crystal sapphire, 86%). To further improve on this, grain sizes have to be <100nm. This project aims to produce transparent nanocrystalline alumina from 20nm powders by spark plasma sintering (SPS). Controlled powder characteristics will be combined with colloidal processing to produce preforms to be sintered by SPS, which has the advantage of rapid sintering cycles, limiting grain growth. Applications are firstly watch glasses and will be of great economical importance for Swiss industry.