Preparation and Light Transmission Properties of AlON Ceramics by the Two-Step Method with Nanosized Al2O3 and AlN

Abstract

The single-phase aluminum oxynitride (AlON) powder used in this experiment was obtained at relatively low temperature by the solid-state-reaction method with nanosized AlN powder and nanosized alumina powder. The obtained powder was ground by ball milling and doped with Y 2 O 3 ; then, it was shaped into pellets. Transparent ceramics sintering was carried out at 2153 K (1880°C) for 5, 10, and 20 hours. Obtained samples for three duration times are all are transparent, and the light transmittance of samples increases with increasing the holding time at the sintering temperature. The transmittance of the sample with 20 hours holding time is 55 pct at near 5 lm. X-ray diffraction (XRD) measurement shows that all samples were single-phase AlON. The fracture surfaces of samples from scanning electron microscopy (SEM) analysis shows that with increasing the holding time, the grain size grows slightly, while the pore size and porosity decrease apparently, which bring about the transmittance increase. The pore size and the porosity are the main factors affecting the light transmitting properties of samples.

First‐Principles Study on Site Preference of Aluminum Vacancy and Nitrogen Atoms in γ–Alon

“…Spinel aluminum oxynitride (γ–alon) ceramics are well‐known as new armor materials and thermo mechanically stable windows and domes, for its outstanding optical transparent properties in the range from ultraviolet to mid–infrared light and excellent mechanical properties at high temperature . In addition, the rare earth or transition‐metal cations–doped γ–alon has also shown luminescent properties and high chemical stability, which makes it possible for it to find potential application in advanced phosphors for plasma display, fluorescent lamp, and in white LEDs .…”

Ethanol‐Water‐Derived Sucrose‐Coated‐Al2O3 for Submicrometer AlON Powder Synthesis

“…Single‐phase AlON is obtained at 1700°C, a temperature at which AlON, Al 2 O 3 and AlN coexists for S 23 E 100 . Our synthesis temperature for single‐phase AlON with sucrose‐coated‐Al 2 O 3 structured S 23 E 85 is lower than those with mechanical AlN/Al 2 O 3 , C/Al 2 O 3 , Al/Al 2 O 3 mixtures (generally 1750°C–1850°C), and even our own mechanical sucrose/Al 2 O 3 mixture of S 23 E 100 .…”

“…According to the weight loss after decarbonization, 23.2 wt% sucrose in precursor corresponds to 5.1 wt% carbon in derived C/Al 2 O 3 mixture, which is within the optimal value of 5.0-6.0 wt% widely employed by other investigators. 5,7,8,11,12 Figure 7 represents the XRD patterns for the final products synthesized at 1650°C-1700°C for 1.5 h after the pretreatment at 1550°C with S 23 E 85 and S 23 with sucrose-coated-Al 2 O 3 structured S 23 E 85 is lower than those with mechanical AlN/Al 2 O 3 , C/Al 2 O 3 , Al/Al 2 O 3 mixtures (generally 1750°C-1850°C), 3,4,[7][8][9][10][11]13…”

“…At present, widely employed methods for AlON powder synthesis include solid-state reaction, 3,4 carbothermal reduction and nitridation (CRN), [5][6][7][8][9][10][11][12] and direct nitridation. 13 Among them, CRN receives the most extensive investigations because of the low cost of the starting materials and the high quality of the final products.…”

Highly transparent AlON fabricated via SPS synthesized by Al2O3/C core–shell starting powder and CRN method

“…1,2 Transparency of AlON fully dense specimen is in the wavelength range of about 0.2-5 μm. 3 AlON is appropriate for phosphor-converted white LED, light-emitting devices, load-bearing orthopedic, and ceramic semiconductors because of its excellent optical properties besides high hardness and strength. AlON can be used instead of sapphire with a lower price, for applications that excellent mechanical and optical properties are needed.…”