Abstract
Effects of manganese oxide (MnO) addition on the densification of Al2O3 during sintering were studied. Although MnO is commonly used as a sintering aid for Al2O3, it has not been used as a sintering aid to produce transparent alumina. High-density Al2O3 doped with slight MnO (> 99.5%) was obtained using a conventional powder processing method, with sintering at 1250°C for 24 h. The Al2O3- 0.05 mass%MnO exhibited optical total transmittance of 42% at 600 nm wavelength and three-point bending strength of 528 MPa. The transmittance was further improved to greater than 70% at 600 nm through hot isostatic pressing (HIP) after conventional sintering. The possibility of high-strength transparent alumina was demonstrated.
