Nitrided glasses

Insulator (dielectrics) Alumina Silicon oxide Silicon nitride Glass Bound to nucleus 1012 to 1022... 

M-SiAlON systems contain a combination of M atoms. Glass formation is found to be easier, more the types of atoms present in the nitrided glasses. Several simple silicates and phosphates which are nitrided have provided much insight into the stmcture of oxynitride glasses. 

Nitridation in general is known to improve several properties. Tg has been found to uniformly increase in all nitrided systems (Hampshire et al, 1984). Variation of Tg by N substitution in phosphate glasses is shown in Figure 14.09. Nitrided glasses exhibit enhanced chemical durability. 

The first paper on the fabrication and characterisation of carbon fibre-reinforced glass matrix composites was published in 1969 [1], Major developments in these composite systems were carried out during the 70s and 80s, especially in USA, England and Germany [2,29,30,32,46], There are still considerable research efforts worldwide in this area [6,43, 47-54], A recent development is the use of nitride glass matrices, for example Y-Si-Al-O-N glass [42],... 

Increased glass transition temperatures, hardness and chemical durability are claimed for these nitrided glasses in which some of the O atoms have been replaced by N or NH. The N atoms are capable of three connections and may therefore participate in extra cross-linking (12.65b) or tighter bonding to neighbouring P atoms (12.65c). 

Later, it was realized that oxynitride glasses, which revealed themselves to be more resistant to high temperatures than the corresponding non-nitrided glasses, were of interest in their own right. Various systems, in particular the Y-Si-Al-O-N quinary system, were extensively investigated with the preparation and study of properties of a wide variety of bulk glass compositions. 

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