Ammoniation and nitridation of highly disperse silica

Silicon oxynitride glasses produced by ammonolysis from colloidal silica

“…Another method of preparation of nitrided and oxynitride materials is the treatment of colloidal silica, or materials obtained through the sol-gel method, in ammonia atmosphere [3,4]. In the nitridation under ammonia the specific surface area of the material plays an important role, therefore colloidal silica should be a suitable material for nitriding.…”

Gas phase nitridation of silicate fiber glass materials with ammonia:Three case studies

“…In nitridated REM-Si glass new absorption bands at 3282, 3373, 3424 and 3500 cm − 1 appeared in the spectra. The first two bands correspond to stretching vibrations of the hydrogen-bonded Si-NH 2 groups, whereas the low-intensive bands 3424 and 3500 cm − 1 are typical of isolated Si-NH 2 groups [22,23,35]. As seen from Fig.…”

“…Among these materials are zeolites [18][19][20][21][22][23], amorphous silica [24,25] and various mesoporous crystalline silicas [26][27][28][29]. The substitution of O for N results in acquisition of new properties like pronounced basicity of nitridated silicate materials which makes them as potential solid base catalysts.…”

Synthesis and characterization of non-crystalline mesoporous silicon oxynitride MCM-41 with high nitrogen content

“…The bulk consists of a network of Si(O,N) 4 subunits with a variety of O:N ratio. Some of the characteristic absorption frequencies taken from the literature [11,12] are shown in Table 2. The peak positions tabulated are taken from materials with long-range periodicity, such as, crystalline ceramics and relatively simple, linear polymers.…”

“…5. In the MCM-41 the band at $1100 cm À1 corresponds to an asymmetric stretching vibration and the band at $800 cm À1 corresponds to a Si-O-Si bending motion Table 1 Elemental composition, d spacing and textural properties a of studied MCM-41 materials Sample N content (wt%) Table 2 Characteristic infrared absorption frequencies for Si-N and Si-O moieties [11,12] Peak position (cm À1 ) Absorption mode…”