Transparent aluminum oxynitride (AlON) ceramics have attracted more attentions as a ceramic material for IR/visible window, transparent armor, and other extremely durable optics due to its excellent optical and mechanical properties, especially superior mechanical properties and producibility. AlON components can be formed into near-net shapes, save energy and significantly reducing machining costs in comparison with single-crystal sapphire components.

Recently, the research group headed by Prof. ZHOU Youfu at Fujian Institute of Research on the Structure of Matter (FJIRSM), Chinese Academy of Sciences, has manufactured highly transparent AlON ceramics by the traditional ceramic process.

Starting powder with very high purity was synthesized at competitive cost by novel direct nitridation with domestic raw materials firstly. Through ball milling, shaping and pressureless sintering processes, AlON transparent ceramic (53 mm diameter) with in-line transmittance of 80.6% at 1100 nm and above 77.1% at 400 nm was manufactured successfully with the aid of sintering additives. This work helps to develop optical components in large sizes and complex geometries for a broader range of cost-sensitive applications.

This work is supported by the National Natural Science Foundation of China, CAS Priority Research Program, and the Natural Science Foundation of Fujian Province. FJIRSM has applied for patents for this work, and some results have been published in J. Eur. Ceram. Soc., 2015,35, 1173–1178.

                The in-line transmission spectra of the AlON ceramic (a), and the photograph, being 20 m behind the ceramic, of the statue to the FJIRSM founder Academician LU Jiaxi (b).(Image by Prof. ZHOU’s Group)