Review article: RE-SiAlONa¤b- composites. Formation, thermal stability, phase relationships, reaction densification

Abstract

In view of the considerable progress that has been made over the last several years on the fundamental understanding of phase relationships, microstructural design, and tailoring of properties for specific applications of rare-earth doped SiAlONs, a clear review of current understanding of the basic regularities lying behind the processes that take place during sintering of SiAlONs is timely. Alternative secondary phase development, mechanism and full reversibility of thea«btransformation in relation with the phase assemblage evolution are elucidated. Reaction sintering of multicomponent SiAlONs is considered with regard of wetting behavior of silicate liquid phases formed on heating. Regularities of SiAlON’s behavior and stability are tentatively explained in terms of RE-element ionic radii and acid/base reaction principle.

New Deep-Blue-Emitting Ce-Doped A4–mBnC19+2mX29+m (A = Sr, La; B = Li; C = Si, Al; X = O, N; 0 ≤ m ≤ 1; 0 ≤ n ≤ 1) Phosphors for High-Color-Rendering Warm White Light-Emitting Diodes

“…M–Si–Al–O–N (sialon) materials, where M is usually an alkaline earth or rare earth element, have been extensively investigated as ceramics for several decades because of their excellent high-temperature mechanical properties and thermal shock resistance. , The good chemical and thermal stability and high structural flexibility make sialons hot candidates as host materials for white light-emitting diode (LED) phosphors. Several oxynitride phosphors that developed from sialon phase materials turned out to have good photoluminescence properties, promising for phosphor-converted white LED (pc-wLED) application.…”

Dense and near-net-shape fabrication of Si3N4 ceramics

“…The sintering of silicon nitride is very difficult because of the low self-diffusivity of this covalent material [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Doping pure Si 3 N 4 with of some oxides provides the formation of intergranular liquid phase which aids the further densification of the silicon nitride during different sintering routes [3][4][5][6][7][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. These oxides, however, remain as grain boundary glassy phase, which deteriorate the high temperature properties of the ceramics such as creep and high temperature strength [17,32,33].…”

“…These techniques can be summarized: i) Reaction Bonding Silicon Nitride (RBSN), ii) Hot Pressing Silicon Nitride (HPSN), iii) Sintering Silicon Nitride (SSN), iv) Sintering Reaction Bonding Silicon Nitride (SRBSN), v) Hot Isostatic Pressing Silicon Nitride (HIPSN), vi) Hot Isostatic Pressing Reaction Bonding Silicon Nitride (HIPRBSN), vii) Hot Isostatic Pressing Sintered Silicon Nitride (HIPSSN) and viii) Hot Isostatic Pressing Sintered Reaction Bonded Silicon Nitride (HIPSRBSN) [20,[22][23][24][25][26][27][28][29][30][31][32][33][34]. It is very difficult to produce pure dense silicon nitride ceramics by means of conventional sintering (simple heating of powder compacts) due to the high degree of covalent bonding between silicon and nitrogen [35].…”

Investigation of Production of Fine-grained SiAlON Ceramics from Nanopowders

“…As a result, the sialon material contains more oxygen-containing compounds than it should be necessary according to the phase diagram. Due to this more glass phase forms during sintering stimulating the transition of αsialon phase into the βsialon [7]. Therefore also the hardness of material (Tab.…”