Electrical Transport and Joule Heating of ZrB2 Network in SiC Matrix

To control the electrical properties of a SiC heating element, we sintered SiC-ZrB2 composites by using the spark plasma sintering method. The addition of ZrB2 particles with lower electrical conductivity to the SiC matrices with comparatively higher electrical resistivity lowers the electrical resistivities of the composite material. The ZrB2 particles aggregate to form large particles and 3-1, 3-2, and 3-3 networks, i.e., conduction paths. In our study, about 1-mu m-sized ZrB2 powders start to form the conduction path at about 10 vol.% of addition, namely the threshold volume. The Joule heating experiment shows that 20 vol.% ZrB2-added SiC heating element has outstanding heating efficiency.