Nanodomain growth in amorphous Si–C–N

Abstract

Polymer‐derived amorphous Si–C–N ceramics are phase separated into amorphous nanodomains after thermolysis. These nanodomains are expected to have a crucial importance for the extraordinary high temperature stability of these materials. We investigated nanodomain growth during isothermal annealing at 1400 °C using small angle X‐ray scattering. The as‐thermolyzed sample shows a domain radius of about 5 Å as determined from Guinier plots. During annealing, fast nanodomain growth up to 9 Å is observed for times up to 30 h while for longer annealing times up to 165 h the growth considerably slows down, resulting in a domain size of 11 Å. The experimental data can be fitted by a model based on diffusion controlled domain growth and simultaneous slow‐down of diffusion due to structural relaxation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Decomposition‐Coarsening Model of SiOC/HfO2 Ceramic Nanocomposites Upon Isothermal Anneal at 1300°C

“…Polymer‐derived ceramics (PDCs), namely silicon carbonitride (SiCN) and silicon oxycarbide (SiOC), have been extensively studied in recent years . Time‐ and temperature‐dependent investigations, using complementary techniques such as small‐angle X‐ray scattering, neutron diffraction, as well as transmission electron microscopy (TEM), were widely employed. Ternary and multi‐component glasses were shown to undergo a phase‐separation process at elevated temperature.…”