| Al N+Al2O3+cordierite composite ceramic was adopted to investigate the heat dissipation of LED lamp holder. Firstly, the effects of aluminum nitride content(10%~60%) on sintering properties and thermal conductivity properties were investigated. Then, the effects of different sintering processing(1375~1550℃) on sintering properties and thermal conductivity properties were investigated. The factors(phase composition, impurities, porosity, density, grain boundaries, etc.) on thermal conductivity of the ceramic were investigated. Finaly, the ceramic lamp holder was prepared by hot casting and the effects of removing binder technology and sintering processing on sintering properties were investigated.The experimental results showed that: Phase composition, density and microstructure of ceramic were affected by the sintering temperature and composition. When sintering temperature was 1375~1550℃, the samples generated Al6O3N4, Al8O3N6, Al5O6 N, Al7O3N5 and Al9O3N7 five new phases, and all the phases were lead-zinc structure. When aluminum nitride content was from 40% to 60% and sintering temperature was 1500℃, the thermal conductivity of ceramic slightly increased(41.9~43.5 W?m-1?K-1). When aluminum nitride content was 40%, ceramic could be sintered in 1500℃, When aluminum nitride content was 40% and sintering temperature was 1450~1550℃, the thermal conductivity range of ceramic was 32.8~41.9 W/(m?K). When sintering temperature was 1500℃ and aluminum nitride content was 20%~60%, the thermal conductivity range of ceramic was 22.7~43.5 W/(m?K). The body of ceramic was intact when useing upside down way to remove binder, buring powder from outside to inside. Removing binder at temperature 600℃ and 650℃ was better. Removing binder at the temperature 600℃ was the best. When the content of aluminum nitride was 40%, the lamp holder sintering in 1400℃ had poor porcelain effect, while the lamp holder sintering in 1500℃ had good porcelain effect, the lamp holder sintering in 1600℃ was over sintering. |
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