| Microwave joining is a new technology in recent ten years. The polarization and dielectric loss coming from the intereaction of electromagnetism field and materials success in joining. Microwave heating is rapid, selective, uniform. So Joining can get many merits such as high joining strength on tie-in, be prone to control temperature, low energy waste. In this paper we mainly investigate on joining ceramics in TEios single mode resonance cavity. First we analysis the recent reseachs on microwave joining, difflcuities and several problems on this technique. Then discuss the mechanism of the intereaction between microwave and materials, the characters of dielectric loss and heating, compare the merits and the disadvantages between microwave joining and others joinings, consider microwave joining is in favor of diffuse joining .Then we clearly introduce the equipment, such as the structure of cavity, coincidence and resonance, manipulation rules, we analys is the physical and chemical characters of speciments, then analysis the stress on heating, so elicit the project on this paper. In succession, we discuss the joining of 95%alumina with NaO-SiO2 glass, direct diffuse joining of 75% alumina, 95% alumina direct diffuse joining by assistant heating. In addition study on joining Si with glass coat .We get the optimum parameters through fumbling on these different joining systems, for instance, temperature % pressure, heat preservation time, avoiding the phenomena of hotspot and thermal runaway. We enhance the efficiency, make the best use of the merits of microwave heating and find out the relation and differences of joining characters of these joining systems. At last we discuss the mechanism of microwave promoting diffusion. We can get: Vacancy can diffuse from high concentration to low concentration along thedirection of electric field, hastening the movements of vacancy and clearanceionic which paralleling the electric field direction, as a result enhancing diffusion, hastening joining.
|
PDF Full Text Request