Preparation of Transparent AlON Ceramics and Their Properties

Abstract

Transparent AlON ceramics were prepared with the powder mixture of AlN and Al₂O₃ powder. The raw materials include commercial AlN and Al₂O₃ powder. The AlN content in the powder mixture was varied from 10 to 45 mol%. Only AlON phase was found in the range of 20 to 35 mol% AlN after sintering at 1900 °C for 120 min. Transparent AlON ceramics were prepared by conbined sintering technique; the pressureless sintering followed by hot-pressing or HIP sintering. The optimum condition was pressing (HIP) at 1850 °C under 180 MPa after pressureless sintering. The transparency was achieved by HIP at 1850 °C under 180 MPa after pressureless sintering. Specimen of 3.0 mm thickness had in-line transmittance of 35 to 45 % in visible resion and 45 to 80 % in infrared resion.