Sialons and related nitrogen ceramics

Abstract

Although silicon nitride is at present a leading contender for gas turbines and other hightemperature engineering applications, it is only the first of a wide field of nitrogen ceramics, other members of which offer better prospects for technological exploitation. "Sialons" are phases in the Si-AI-O-N and related systems and are comparable in variety and diversity with the mineral silicates. They are built up of one-, two-, and threedimensional arrangements of (Si, AI)(O, N)4 tetrahedra in the same way that the fundamental structural unit in the silicates is the SiO4 tetrahedron. These new oxynitrides include structure types based upon e and ~ silicon nitrides, silicon oxynitride, aluminium nitride and silicon carbide, eucryptite, spinel, melilite and apatite. They are being explored for their thermal, mechanical, chemical and electrical properties.

Preparation of Eu-doped β- and 15R-SiAlONs by ammonia nitridation of the precursor obtained using aluminum glycine gel

“…-SiAlON is isostructural with -Si 3 N 4 and has the chemical composition Si 6-z Al z O z N 8-z with 0 < z ≤ 4.2 [10,11]. The hexagonal -SiAlON lattice is in either space group P6 3 or P6 3 /m.…”

“…Several kinds of SiAlON compounds have been reported in addition to the -phase in the quaternary phase diagram of SiO 2 -Si 3 N 4 -AlN-Al 2 O 3 [10]. There are compounds named as SiAlON polytypoids, such as 8H, 15R, 12H, and so on, at the AlN-rich corner in the phase diagram.…”

Fabrication of mixed α/β-SiAlON powders via salt-assisted combustion synthesis

“…The effect of salts additives on the phase compositions and microstructures of the products was also investigated. The merits of selecting NaCl and MgCl 2 as the salts candidates in this study are expected to be the following; (1) …”

Reaction characteristics of combustion synthesis of β-SiAlON using different additives

“…They are attractive materials for application in high-temperature engineering systems because of their high strength and hardness, good thermal and chemical stability, and superior wear and thermal shock resistance [1][2][3]. Recently, rare-earth-doped β-SiAlONs have been recognized as potential phosphors for application to white light-emitting diodes (LEDs) because of their intense photoluminescence and high thermal stability [4][5][6].…”