LAUSR

Abstract The present work investigates the influence of pyrolysis temperature on the microstructure and thermal conductivity ( λ ) of polymer-derived SiC ceramics. For the study, both monolithic thin ceramic disks and highly porous reticulated foams were considered. The λ of the polymer-derived SiC disks were measured, in the temperature range 100 °C -1000 °C, to amount between 0.5 W.m-1. K-1 and 47 W.m-1. K-1, depending from the maximum pyrolysis temperature. While, the λ measured at RT on the SiC foams pyrolyzed at 1200 °C (porosity 79.5% - 99.0%), ranges between 0.03 W.m-1. K-1 and 0.19 W.m-1. K-1. The thermal transport in polymer-derived SiC ceramics was observed to be more significantly governed by the nanocrystalline to crystalline transition which occurs at pyrolysis temperatures above 1200 °C as compared to mesopore formations or the nature and amount of free carbon.