Highly transparent LiAlON ceramic prepared by reaction sintering and post hot isostatic pressing

摘要

A highly transparent polycrystalline LiAlON ceramic with the size of Φ57?mm?×?6?mm was successfully fabricated by reaction sintering (1750?°C, 20?h) and post hot isostatic pressing (HIP, 1850?°C, 3?h, 180?MPa) using AlN, Al2O3and LiAl5O8powders. Related mechanism on the reaction sintering and densification were studied via the analysis of phase and microstructural evolution. High transparency was resulted from full elimination of Al2O3secondary phase and residual pores. It has excellent optical transparency from the visible to middle infrared (IR) bands with the maximum transmittance of ～ 85.5%. The flexural strength and Vikers hardness reach ～303?MPa and ～15.0?GPa, respectively.