Highly Transparent Mg_(0.27)Al_(2.58)O_(3.73)N_(0.27) Ceramic Prepared by Pressureless Sintering

摘要

A novel aluminum magnesium oxynitride transparent ceramic with the chemical formula Mg_(0.27)Al_(2.58)O_(3.73)N_(0.27) was firstly prepared by pressureless sintering of fine single-phase powders at 1875℃ for 24 h in nitrogen atmosphere. The ceramic was fully dense with the average grain size of 57.5 urn. The sample showed excellent in-line transmission from the visible to middle-infrared wavelengths with the maximum transmittance of 84%, which could be attributed to rare pores in the sintering body. The material also exhibited good mechanical properties of Vickers hardness (13.39 ± 0.18 GPa), fracture toughness (2.46 ± 0.3 MPa/m~(1/2)), and flexural strength (274 ± 6 MPa).