Uniform and fine Mg-gamma-AlON powders prepared from MgAl2O4: A promising yes precursor material for highly-transparent Mg-gamma-AlON ceramics

摘要

High-purity and sinterability Mg-gamma-AlON (Mg0.1Al1.53O1.89N0.27) powders were synthesized by gas pressure sintering (GPS) of mixed powders of commercial Al2O3 and AlN, and lab-made MgAl2O4. The Mg-gamma-AlON powders exhibited a uniform particle morphology and a small particle size of d(50)( )= 3.4 mu m, owing to the use of MgAl2O4 as the Mg source. Highly-transparent Mg-gamma-AlON ceramics were fabricated using the synthesized Mg-gamma-AlON powders by spark plasma sintering (SPS) at 1800 degrees C for 5 min under an axial pressure of 80 MPa, followed by hot isostatic pressing (HIP) at 1800 degrees C for 2 h under a nitrogen gas pressure of 190 MPa. The ceramics showed a high in-line transmittance of similar to 80.5% at 450 nm, ascribed to the high sinterability of the MgAl2O4 raw powder that leads to a pore-free and fully densified microstructure. This indicates that MgAl2O4 as sintering additive is superior over MgO and MgF2 in the fabrication of Mg-gamma-AlON transparent ceramic.