Fast fabrication of AlON ceramics with ultra-high transmittance by the assistance of hot isostatic pressing treatment

By employing hot isostatic pressing (HIP) technology, AlON ceramics having ultra-high transmittance up to 88.7% were successfully fast fabricated via dwelling 2.5 h pressureless sintering (PS) and subsequent 2 h in HIP treatment of AlON powder with Y2O3 as additive. Different dwelling durations of PS were conducted to study the mechanism of ultra-high transmittance induced by HIP treatment. The evolution of element distribution, pore size and distribution, relative density and transparency before and after HIP treatment was thoroughly explored. Y concentration in AlON ceramics was observed for the first time. It was found that it was high relative density, pore free (no large pores and much fewer small pores) and no Y concentration that led to the ultra-high transmittance for the fabricated AlON ceramics. Therefore, a rational design of PS and HIP treatment is an effective approach to fabricate AlON ceramics of high transmittance.