Preparation of silicon oxynitrides by the reaction of ammonia with high disperse silica

• Autorzy: Truckenbrodt B. , Breitbarth F. W. , Vogelsberger W.
• Języki publikacji: EN

Abstrakty

EN

Nanosized silica is nitrided at different temperatures up to 1200° C by the reaction with gaseous ammonia. The nitridation degree of silica is determined as a function of time. After a nitridation time of 119 h and a temperature of 1200° C the mass fraction of nitrogen in the nitrided sample was found to be 35.4%. This corresponds to the stoi-chiometric formula SiO(18)Ni (1.21). It could be shown that the progressive nitridation of the samples is accompanied by a decrease of the specific surface area. The different degree of nitridation can be followed by IR spectroscopical investigations. Several absorption bands of silica and the nitrided species can be detected in dependence of nitridation time. EPR spectroscopical investigation of irradiated samples provide information about the bonding in the samples. Furthermore, a relation between the concentration of defect centers and the degree of nitridation is found. The process of nitridation is also determined by X-ray diffraction measurements. It was shown to be possible to separate the diffraction patterns of SiO(2)2, Si(2)ON(2) and Si(3)N(4). This separation could be established by NMR spectroscopy. Thus it was possible to follow the development of the mentioned three species in dependence of nitridation time. A phenomenological consecutive reaction scheme describes the time dependent appearance of the three species well.

Słowa kluczowe

EN

silica; nitridation; ammonia; kinetic

PL

krzemionka; azotowanie; amoniak; kinetyka

• Wydawca: Centrum Upowszechniania Nauki PAN
• Czasopismo: Bulletin of the Polish Academy of Sciences. Chemistry
• Rocznik: 2002
• Tom: Vol. 50, No. 1
• Strony: 77--92
• Opis fizyczny: Bibliogr. 32 poz.

Twórcy

autor

Truckenbrodt B.

autor

Breitbarth F. W.

autor

Vogelsberger W.

• Friedrich-Schiller-University Jena, Chemistry and Earth Science, Institute of Physical Chemistry, Lessingstrasse 10, D-07743 Jena, Germany