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Surface metallization of aluminum nitride is performed by a reactively thick film method. A layer of copper film is deposited on the surface of AlN ceramics. The morphology and composition of the metalized copper layer on ceramic substrate were investigated via scanning electron microscope (SEM) and X-ray diffraction (XRD). The interface layer between copper film and AlN substrate was examined through SEM, XRD and EDS. Reaction phases, Cu 2 O and intermediate phases (CuAlO 2 and CuAl 2 O 4 ), were detected at the interface layer. Subsequently, the formation process of these phases at the interface layer was discussed. And consequently, the relation within reaction phases and bonding strength was observed. Reaction phases play a key role in increasing bonding strength. The effect of these phases such as Cu 2 O and intermediate phases (CuAlO 2 and CuAl 2 O 4 ) on the mechanical property was discussed. Results show that the presence of Cu 2 O particles are detrimental to bonding strength. However, spinel CuAl 2 O 4 and isolated CuAlO 2 laminates at the interface layer can increase the bonding strength. The experimental results suggest that this thick film method is a useful technology for various metal-ceramics bonding. [ABSTRACT FROM AUTHOR]

Dense AlN ceramics with a thermal conductivity of 180W/m·K were obtained at the sintering temperature of 1750 °C using CaF2 and YF3 as additives. At temperatures below 1650 °C, the shrinkage of AlN ceramics is promoted by liquid (Ca,Y)F2 and Ca12Al14O32F2. Liquid CaYAlO4 mainly improves the densification of the sample when the sintering temperature increases to 1750 °C. The formation of liquid (Ca,Y)F2 at a relatively low temperature results in homogeneous YF3 distribution around the AlN particles, which benefits the removal of oxygen impurity in the AlN lattice, and thus a higher thermal conductivity. [Copyright &y& Elsevier]