Microwave Heating Behavior in SiC Fiber-MO2 Mixtures (M = Ce, Zr)—Selective Heating of Micrometer-Sized Fibers Facilitated by ZrO2 Powder

Abstract

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.

Manufacturing carbon storage sintered body using microwave-selective and high-speed heating techniques

“…Thus far, several researchers have reported that microwave-heated materials behave differently than materials heated via conventional methods 33 – 36 . In recent years, research has clarified that the inhomogeneity of the material creates a mesoscale superheat point on the object to be heated 16 – 18 ; further, a superheat point is observed in this system.…”

“…Many researchers have investigated microwave heating in the field of ceramic sintering because it allows the rapid heating of objects 12 – 15 . In addition, research in the last few years has confirmed that microwaves create a temperature gradient of several hundred degrees in a narrow region ranging from 4.7 to 60 nm of the mixture 16 – 18 . Thus, materials other than CaCO 3 powder can be selectively heated by employing these two characteristics well, and the mixture can be sintered before CaCO 3 decomposes.…”