Behaviour of Microwave-Heated Al4SiC4 at 2.45 GHz.

Takashi Fujii,Akio Oshita,Keiichiro Kashimura

doi:10.3390/ma14174878

Abstract

The ongoing development of high-temperature processes with the use of microwaves requires new microwave absorbers that are useful at these temperatures. In this study, we propose Al4SiC4 powders as important and efficient microwave absorbers. We investigated both the behavioural microwave heating and electrical permittivity characteristics of Al4SiC4 powders with various particle sizes at 2.45 GHz. The TE103 single-mode cavity indicated that Al4SiC4 powder samples yielded different heating behaviours and dielectric constants for each particle size compared with SiC. By microwave heating ∅50 mm × 5 mm disks of Al4SiC4 and SiC, we demonstrate that for specific sizes, Al4SiC4 can be heated at a higher temperature than SiC. Finally, the results of the two-dimensional two-colour thermometer show that an energy concentration appears at the interface of the microwave-heated Al4SiC4. These phenomena, which are inconsistent in individual physical property values, can be explained without contradicting microwave heating physics.

Highlights

High-temperature processes employing microwave heating have not been demonstrated by many researchers, despite the report by Roy et al on microwave-based metal sintering [1]
The results showed that Al4 SiC4 is an efficient microwave absorber
The irradiation time was set to 10 min to provide sufficient time for the temperature of the heated materials to stabilize to a constant value

Summary

Introduction

High-temperature processes employing microwave heating have not been demonstrated by many researchers, despite the report by Roy et al on microwave-based metal sintering [1]. Leonelli et al used microwaves to provide heat for high-temperature processes in order to detoxify asbestos-containing materials [6,7]. Given that such materials have high-heat insulation properties, they can be heated more rapidly by employing microwave heating than conventional heating methods. By using microwaves to heat the inner parts of the refractory to attain high temperatures [8], the microwaves rapidly detoxify the asbestos fibres. Microwave heating technology will continue to expand into the high-temperature-processing region

Methods

Results

Conclusion