Microwave sintering technology is the key to microwave heating, the principle is that the matter in the microwave action of the electron polarization, atom polarization, interface polarization, dipole steering polarization and other ways, the microwave electromagnetic energy into heat energy. Obviously, not all materials can be heated by microwave, according to the function of matter and microwave, the material can be divided into three categories:
(1) transparent type, mainly low loss insulator, such as most of the polymer materials and some non-metallic materials, microwave part of the reflection and partial penetration, very little absorption of microwave, this kind of material can be in the microwave field for a long time, the calorific value is very small, commonly used in the heating cavity body's permeable material, such as tetrafluoroethylene, can be used for microwave vacuum (2) Full reflective type, mainly conductive properties of good metal materials, the microwave reflectance of the material close to 1, only a small amount of incident microwave can penetrate, can be used as microwave heating equipment, the waveguide, microwave cavity body, stirrer and so on; (3) absorption type, mainly some dielectric material between metal and insulator, including textile fiber material, paper, wood, SIC, zirconia, fluorescent powder, ceramics, water, paraffin, etc. The Application object of microwave sintering technology is mainly ceramic material and metal powder material. Microwave sintering technology is characterized by its characteristics of wholeness, instantaneous, selectivity, environmental friendliness, safety and high efficiency and energy saving. Microwave as a clean energy, used in microwave sintering, has become a research hotspot in the material field, and has triggered a revolution in sintering technology.