M-Si-Al-O-N systems

The extent of the glass forming regions in various M-Si-Al-O-N systems (M = Mg, Y, Ca, etc.) has been studied previously and represented using the Janecke prism with compositions... 

Redington Keely W, Redington M, Hampshire S (2000) Liquid Formation in the Y-Si-Al-O-N System. In Hampshire S, Pomeroy MJ (eds) Nitrides and Oxinitrides. Mater Sci Forum 325-326. Trans Tech Publications Ltd, Switzerland, p 237... 

More recent studies have involved the formation, composition, and microstructure of B-phase in much more detail [54] - especially in the Y- and Er-sialon systems. The composition is variable, both in cation and O N ratios, depending to some extent on the starting composition, with the simplest whole number M Si Al ratio being 4 3 2, and a nitrogen content of approximately 10-15 eq%. It is apparent that the B-phase forms most readily from glasses close to this composition when heat-treated at low temperatures (1000-1100 °C). Although additional structural studies have been conducted on this phase, and appear to imply that B-phase has a chain [55] rather than... 

The a-sialon-forming area expands with decreasing size of the M ion in M3cSii2-(m-n)Al(m+n)0 N(i6- )- The maximum w-value is 1.0 for Nd, and approximately 1.2 for the other dopants. The m-value varies from 1.0 in all systems studied to a value of 2.75 in the Yb-a-sialon system, indicating that the substitution of Al-O units for Si-N in a-sialon is more restricted than the substitution of Al-N for Si-N. 

Polymer-derived ceramics have been investigated in the last two decades concerning their high temperature oxidation behavior (i.e., usually temperatures exceeding 1000 °C and oxidizing environments such as air or combustion atmosphere). Mainly ternary and multinary systems based on the Si-M-O-C and Si-M-C-N-O systems (M = B, Al, Zr) were tested and showed passive oxidation behavior. (Chollon, 2010) Within this context, they can be considered as behaving to some extent like silica formers (e.g., silicon, metal silicides, SiC or SijN ). 

Polymer pyrolysis appears to be a very promising processing route to advanced covalent ceramics. This process allows the formation of new amorphous covalent ceramic phases in the general system Si-M-C-N-O (with M = B, Ti, Al, Zr...) which show exceptional oxidation and creep resistance at high temperature up to... 

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