Abnormal Graphitization Behavior in Near-Surface/Interface Region of Polymer-Derived Ceramics

The in situ free carbon generated in polymer-derived ceramics (PDCs) plays a crucial role in their unique microstructure and resultant properties. This study advances a new phenomenon of graphitization of PDCs. Specifically, whether in micro-/nanoscale films or millimeter-scale bulks, the surface/interface radically changes the fate of carbon and the evolution of PDC nanodomains, promotes the graphitization of carbon, and evolves a free carbon enriched layer in the near-surface/interface region. Affected by the enrichment behavior of free carbon in the near-surface/interface region, PDCs exhibit highly abnormal properties such as the skin behavior and edge effect of the current. The current intensity in the near-surface/interface region of PDCs is orders of magnitude higher than that in its interior. Ultrahigh conductivity of up to 14.47 S cm(-1) is obtained under the action of the interface and surface, which is 5-8 orders of magnitude higher than that of the bulk prepared under the same conditions. Such surface/interface interactions are of interest for the regulation of free carbon and its resultant properties, which are the core of PDC applications. Finally, the first PDC thin-film strain gauge that can survive a butane flame with a high temperature of up to approximate to 1300 degrees C is fabricated.

Automated summary

This study investigates the phenomenon of the graphitization of free carbon in polymer-derived ceramics (PDCs) and uncovers the crucial role of surface/interface interactions in regulating carbon and its properties. Due to the enrichment behavior of free carbon in the near-surface/interface region, PDCs exhibit highly abnormal properties, such as the behavior of the current and the edge effect. These surface/interface interactions are of great significance for the applications of PDCs.