ESR INVESTIGATION OF MOSI2 POWDERS USED AS REACTIVE FILLERS IN POLYMER-DERIVED CERAMICS

Citation
B. Hahn et al., ESR INVESTIGATION OF MOSI2 POWDERS USED AS REACTIVE FILLERS IN POLYMER-DERIVED CERAMICS, Colloids and surfaces. A, Physicochemical and engineering aspects, 115, 1996, pp. 291-295
Citations number
17
Categorie Soggetti
Chemistry Physical
ISSN journal
09277757
Volume
115
Year of publication
1996
Pages
291 - 295
Database
ISI
SICI code
0927-7757(1996)115:<291:EIOMPU>2.0.ZU;2-U
Abstract
An electron spin resonance (ESR) and thermal rheology study is carried out on novel ceramic composites made by pyrolysis of polysiloxane-MoS i2 mixtures, which show potential for high temperature applications wi th their excellent oxidation stability and creep resistance up to 1500 degrees C, but for which injection moulding of the precursor mixture is strongly affected by catalytic effects of MoSi2 on the crosslinking reaction of the polymer phase. ESR showed that the surface of MoSi, w as oxidized during grinding, resulting in an active oxide layer of SiO 2 and MoxOy with Mo5+ centres. The Mo5+ signal is correlated with the MoSi2 grain size and the lowering of the thermosetting temperature. Bo th the Mo5+ signal and the catalytic effect can be suppressed by remov ing this mixed oxide layer with dilute acids.