Behaviour of Microwave-Heated Al₄SiC₄ at 2.45 GHz

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.