Gelcasting and Pressureless Sintering of Translucent Alumina Ceramics

Abstract

Gelcasting is a very useful technique for producing ceramic parts with complex shapes. In this work, gelcasting in air and pressureless sintering in hydrogen were applied to manufacture translucent alumina ceramics. A stable suspension with 75 wt% solids was prepared by ball milling. Trapped bubbles were removed completely before casting to obtain homogeneous green bodies. Final sintering was carried out in a hydrogen furnace at 1850°C for 3 h. Homogeneous microstructures of both calcined and sintered bodies were obtained. The in‐line transmission of the sample with a thickness of 0.5 mm increased gently from 9% to 10% in the wavelength range of 190–1100 nm.