Effect of pyrolysis atmospheres on the morphology of polymer-derived silicon oxynitrocarbide ceramic films coated aluminum nitride surface and the thermal conductivity of silicone rubber composites

摘要

Amorphous silicon oxycarbide (SiOC) and silicon oxynitrocarbide (SiONC) ceramic films coated aluminum nitride (AlN) were prepared by using preceramic-polysilazane (PSZ) with dip-coating method, followed by pyrolysis at 700℃ in different (air, Ar, N_2 and NH_3) atmospheres to converted PSZ into SiOCair and SiONC_((Ar.N_2 and NH_3)) ceramic. The existence of amorphous SiOC_(air) and SiONC_((Ar,N_2 and NH_3)) ceramic films on AlN surface was characterized by FTIR, XRD and XPS. The interfacial adhesion between silicone rubber and AlN was significantly improved after the introduction of amorphous SiOC_(air) and SiONC_((Ar，N_2 and NH_3)) ceramic films on AlN surface. It can be observed from AFM that the pyrolysis of PSZ at different atmosphere strongly affected to films morphology on AlN surface as SiOC_(air) and SiONC_(NH_3) ceramic films were more flat and smooth than SiONC_(N_2) and SiONC_(Ar) ceramic films. Besides, the enhancement of the thermal conductivity of silicone rubber composites was found to be related to the decrease in the surface roughness of SiOC_(air) and SiONC_((Ar，N_2 and NH_3)) ceramic films on AlN surface. This present work provided an alternative surface modification of thermally conductive fillers to improve the thermal conductivity of silicon rubber composites by coating with amorphous SiOC_(air) and SiONC_((Ar，N_2 and NH_3)) ceramic films.