Aluminium nitride (AlN) is an ideal substrate and packaging material applied in high-power devices,circuits and modules due to high thermal conductivity.

    ALN ceramic and thick film substrates with high thermal conductivity are prepared by adding Y₂O₃,CaO and Y₂O₃-CaO sintering agents and influences of composition,tape casting process,pressureless sintering on microstructure and physical properties are inverstigated.

    Surface metalization of the covalent-bonded AlN ceramics have two ways:CaO-B₂O₃-SiO₂-BaO glass-bonded and TiB2 reaction-bonded Ag pastes.Phase compositions,hot processing procedures and microstructures of AIN ceramics with and without metalization are characterized by XRD,DTA-TG,SEM.