Silicon carbonitride covered SiC composites for enhanced thermal conductivity and electrical insulation

•Silicon carbonitride covered SiC is fabricated with polysilazane.•Surface-treated SiC composites result in an enhanced thermal conductivity.•The measured thermal conductivity is correlated with theoretical models.•Electrical conductivity results reveal the enhanced electrical insulation.

Surface-treated silicon carbide (SiC) particles were prepared with polysilazane (PSZ) and its amorphous silicon carbonitride (SiCNO) ceramic coatings on the SiC surface using a dip-coating method. Moisture-crosslinking of PSZ on the SiC produced PSZ–SiC particles, and heat treatment of the PSZ–SiC at 800 °C converted the PSZ–SiCNO. The surface treatment of the SiC particles enhanced interfacial adhesion with the silicone-based matrix. The thermal transport properties of these composites were investigated and then, interpreted with Agari's model. An analysis of the coefficients of this model indicated that the surface treatment of SiC particles facilitates the formation of conducting paths. The electrical properties of the composites also demonstrated the effect of the amorphous Si–C–N–O network on the SiC surface.

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