| Summary: | 碩士 === 國立成功大學 === 化學工程學系碩博士班 === 101 === Aluminum nitride(AlN) is a promising material for electric substrate applications because of its good electric resistance and high thermal conductivity. The study revealed ceramic materials sintered by microwave possessed of good property including high-speed、energy saving、high relative density and excellent microstructure because microwave have a lot of merit inclusive of fast heating、no limit to thermal resistance and high energy efficiency. This paper continued the research in the lab for microwave sintering of Aluminum nitride, and sintered by using singe-mode microwave equipment. This paper discussed sintered property influenced by different sintering factor, including shrinkage、relative density、crystal phase composition、microstructure and thermal conductivity. This paper discussed sintering factor including different source of powder(synthesized from lab or from Tokuyama)、 different average particle size and content of oxygen、amount of sinterind aid、powder surface treatment and added redox. This paper also try to sinter at low temperature(〈1600。C) by addind different sintering aid. The result discovered Aluminum nitride have higher thermal conductivity if powder have lowder average particle size and lower content of oxygen. By using Aluminum nitride powder from lab(D50=2.2μm、content of oxygen=1.3wt%) with 5wt% yttria, then microwave sintering at 1830。C under nitrogen atmosphere and sintered 2hr, the thermal conductivity can reach 151W/mk. Although Aluminum nitride had anti-hydrolysis ability by surface treatment and reduce content of oxygen by adding redox, both of above methods resulted in yittrium remaining, then reduced relative density and thermal conductivity. Adding low temperature sintering aid(Li2CO3、CaF2) is necessary, because it can produce liquid and sinter at low temperature. But both of relative density and thermal conductivity are not very good (60W/mK). If the thermal conductivity can increase much more, it will have more applicability in the future.
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