X-RAY AND NEUTRON SMALL-ANGLE SCATTERING WITH SI-C-N CERAMICS USING ISOTOPIC-SUBSTITUTION

Using small angle neutron and X-ray scattering measurements, the tempe rature dependence of the medium range structure Of amorphous Si24.4C42 .4N33.2 ceramics was investigated. Contrast variation by the isotopic substitution method (N-nat and N-15) showed that the observed SAS sign al is caused by two separate phases of amorphous Si3N4 and amorphous c arbon within the material. The measured invariant remains constant ove r the whole observed temperature range, whereas the correlation volume increases with increasing temperature.