Microwave heating behavior in SiC Fiber-MO₂ mixtures (M = Ce, Zr)-selective heating of micrometer-sized fibers facilitated by ZrO₂ Powder

SiC fiber-MO₂ (M= Ce, Zr) mixtures with various compositions were heated by applying an 80 W microwave electric field, to investigate their heating rate, maximum temperature, and dielectric constant. For the SiC fiber-CeO₂ mixture, all three parameters continued to increase as the weight ratio of the SiC fiber increased; in contrast, for the SiC fiber-ZrO₂ mixture, these parameters reached a maximum value at a certain composition. A thermal gradient of 500 °C was observed at a microlevel in the SiC fiber-ZrO₂ mixture, and hot spots were located in regions with a certain composition. This result not only contributes to designing a novel good microwave absorber but also presents new aspects with regard to high-temperature microwave processing, including the mechanism behind the high-temperature gradients on the order of micrometers as well as engineering applications that utilize these high-temperature gradients.