Furnace and laser methods of bonding metals to ceramics: interface investigation

Furnace and laser methods of direct bonding copper to industrial alumina in nearly inert atmospheres are investigated. Of specific interest is the interface and its characterization. Lasers of different wavelengths are employed to heat the metal component for a sufficient time to create a metal–metal oxide eutectic melt at the metal–ceramic interface. X-ray diffraction, transmission electron microscopy and high-resolution transmission electron microscopy are used to investigate metal–ceramic interfaces. Samples heated in a furnace and by laser beam were found to have a diffuse metal ceramic interface. The electron diffraction patterns indicate the phase at the interface (Cu/α-Al2O3) is cubic with the CuAl2O4 crystallographic structure. Samples heated by an excimer laser have a nano-sized grain structure in the top copper layer.