Vacuum-sintered Al2O3:Cr3+ transparent ceramics as cost-effective alternatives to single-crystal ruby†

Abstract

Al₂O₃:Cr³⁺ ruby is one of the most popular materials for lasers because it has unique optical and physical properties. How to obtain Al₂O₃:Cr³⁺ efficiently and economically remains a challenge. In this study, Al₂O₃:Cr³⁺ transparent ceramics were prepared through a traditional solid-state process in a vacuum environment. A high transmittance of 76.8% at 1200 nm, approaching that of single crystals, can be reached in the pure Al₂O₃ transparent ceramic. The photoluminescence, micromorphology, thermal conductivity, and mechanical characteristics of Al₂O₃:Cr³⁺ transparent ceramics were studied. A ruby with a thermal conductivity of about 38 W m⁻¹ K⁻¹ and a high hardness of 1859 HV was prepared. These results indicate that Al₂O₃:Cr³⁺ transparent ceramics have broad prospects to serve as a substitute for Al₂O₃:Cr³⁺ single crystals in certain fields.