Microwave heating characteristics of bulk metallic materials and role of oxides
In the present work, microwave heating characteristics of a few selected bulk metallic materials were studied in the ambient environment using 1400 W input microwave power at 2.45 GHz. Interactions of microwaves with the three target metallic materials—aluminum, copper and stainless steel and their effects were elucidated using the time–temperature profiles monitored during microwave hybrid heating. Metal oxides formed at different stages of the exposure were characterized using scanning electron microscopy and other X-ray-based techniques; role of the oxides in the heating behavior has been explained. The results revealed that heating of the target materials get influenced by the metallic oxides formed on the exposed surfaces of the metallic materials. The oxide layer reduces heat transfer between the susceptor and metallic material at initial stages of heating; however, it assists microwave absorption in the metallic materials depending upon its electromagnetic properties at elevated temperatures during irradiation. The oxide particles act as tiny susceptors initially, which, however, turn into secondary sources of conventional heating in the target material during hybrid heating.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- 17.Agrawal D (2006, August) Microwave sintering, brazing and melting of metallic materials. In: Sohn international symposium advanced processing of metals and materials volume 4: new, improved and existing technologies: non-ferrous materials extraction and processing, vol. 4, pp 183–192Google Scholar
- 18.Ripley EB, Oberhaus JA (2005) Melting and heat treating metals using microwave heating. Ind Heat 72(5):65–70Google Scholar
- 20.Moore AF, Schechter DE, Morrow MS (2006) U.S. Patent No. 7,011,136. U.S. Patent and Trademark Office, Washington, DCGoogle Scholar
- 24.Gupta M, Wong WLE (2007) Microwave heating. Microw Metals 67:43–63Google Scholar
- 27.Cullity BD (1956) Elements of X-ray diffraction. Addison-Wesley Publishing Company, ReadingGoogle Scholar
- 29.Keil P, Lützenkirchen-Hecht D, Frahm R (2007, February) Investigation of room temperature oxidation of Cu in air by Yoneda-XAFS. In: AIP conference proceedings, vol 882, No. 1. AIP, pp 490–492Google Scholar
- 36.Peng Z, Hwang JY, Andriese M, Zhang Y, Li G, Jiang T (2015) Microwave power absorption characteristics of iron oxides. In: Carpenter JS, Bai C, Escobedo JP, Hwang J-Y, Ikhmayies S, Li B, Li J, Monteiro SN, Peng Z, Zhang M (eds) Characterization of minerals, metals, and materials 2015. Springer, Cham, pp 299–305. https://doi.org/10.1007/978-3-319-48191-3_37 CrossRefGoogle Scholar