A Study on Solution Combustion Synthesis of Aluminum Nitride Coated Carbon

• Main Authors: Yun Pin Ou, 歐允斌
• Other Authors: 李文熙
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/74175511954491861195

碩士 === 國立成功大學 === 電機工程學系 === 102 === Great electric insulation, high thermal conductivity, low dielectric constant, and low thermal expansion coefficient make AlN a very promising material for electric applications. Due to the high cost of the material, it is hard to be popular. In the study, we sintered the precursor-coated AlN powder at 800°C、900°C and 1000°C by SHS in order to obtain carbon-coated AlN powder for lower-cost synthesis use and further applications. We add sucrose in the 70% nitric acid solution first, wait until it was fully dissolved, then add AlN powder in the solution. After two steps of drying, it was sintered under Ar atmosphere for 2 hours. At last, we studied the density, grain, microstructure, dielectric properties and thermal conductivity with the product. We found that although the density and shrinkage rate increase as the sintered temperature increases, but it was not apparent. The X-ray patterns showed as we add more carbon precursor, the more carbon atom will substitute the “N” atom in the AlN crystal structure during the whole combustion process which will result in peak shift. The SEM also showed pores and defects from breaking plane of the product. For dielectric properties, we found as we increased the carbon precursor concentration, the dielectric properties didn’t get improved. We obtained the best dielectric constant 13.17 and dielectric loss 0.314 with 25wt% precursor concentration sintered at 800°C. At last, we obtained the thermal conductivity 1.048 W/m•K from the sample synthesized at 800°C. with 35wt% precursor added.