The dielectric properties of carbon imply that heating with microwave energy should not be significant at elevated temperatures. It has been demonstrated, however, that temperatures in excess of 1900°C can be achieved with low powers. The effect of particle size on the heating rate will be presented and a heat absorption mechanism is postulated to explain the high temperatures observed.
Under controlled conditions, conventional and microwave heating has been used to observe growth of the carbon crystallite size up to a temperature of 1400°C. Under these conditions, no enhanced crystal growth was observed for microwave heating.