Interaction of microwave with materials and application of microwave heating

Microwave interacts with materials. And it is possible to heat various materials, if they are a good microwave absorber. The heating mechanism has been generally understood as the friction of molecules in their rotation under microwave electric field. In this paper, on the other hand, importance of heating effect by microwave magnetic field is pointed out, and microwave heating of metal powders is discussed, especially. Heating mechanisms of microwave was classified according to its interaction with materials, related to the difference in microwave penetration depth into materials. The heating mechanisms of materials are classified as the dielectric loss, the induction (eddy current) loss and the magnetic loss. Application of microwave heating to materials processing and environmental engineering fields is briefly discussed.