Highly transparent AlON fabricated via SPS synthesized by Al 2 O 3 /C core–shell starting powder and CRN method

Two types of starting powders were used to synthesis AlON powder via the carbothermal reduction and nitridation (CRN) route, the Al 2 O 3 and C mixture, and the Al 2 O 3 /C core–shell. Al 2 O 3 /C core–shell resulted in lower carbon content and lower synthesis temperature for CRN method. AlON powder was synthesized using Al 2 O 3 and C then was sintered via SPS at 1500, 1600, and 1700°C for 10‐30 min in a vacuum atmosphere. A sample with the highest transmittance was annealed at 1250°C for 2, 4, and 8 h in air. The characteristics of AlON powder and bulk samples were investigated by XRD, DLS, FT‐IR, elemental analysis of carbon and sulfur, SEM, EDS, and UV–Vis spectroscopy analyses. The annealing process for 2 h improved the transmittance from 31% to 58% at the wavelength of 600 nm. AlON powder synthesized using Al 2 O 3 /C core–shell, was SPSed at 1700°C for 15 min and annealed at 1250°C for 2 h was used to make a sample of 1.7 mm thickness whose transmittance was found to be 81%.