WEB Effect of transition metals on the evolution of polymer-derived SiOC ceramics
In this study, iron, cobalt, and nickel – modified silicon oxycarbides (SiOC) were synthesized at different temperatures in argon. The presence of transition metals in the polymeric precursors induced the formation of the corresponding metal silicides, β-SiC, cristobalite silica, and graphitic carbon. The order of catalytic activity was iron > cobalt > nickel, which was in agreement with the activation energy calculation. Raman spectroscopy provided insight for the lateral growth of the turbostratic carbon followed by a 2D growth process, and the defect density was decreased due to the catalytic effect of the transition metals. The different phase compositions of the Fe, Ni, or Co activated SiOC materials were rationalized by in-depth understanding of the phase composition and crystallization of the SiOC systems.