Metallization of Al2O3 ceramic with Mg by friction stir spot welding

Abstract The surfaces of Al2O3 ceramic plates were metallized with by a friction stir spot welding method. Tensile tests revealed that the adhesive strength between the Mg film and Al2O3 ceramic plate was 23.3 MPa. To investigate the origin of this strong adhesion, the interface structure was examined by X-ray diffraction, scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy, and transmission electron microscopy. The results indicated the formation of a microcrystalline MgO layer at the interface. Furthermore, the surfaces of two metallized Al2O3 ceramic plates separated by Ni foil were bonded together by hot pressing at 1100 °C for 180 min under vacuum. The resulting cross tensile strength of the bonding was 2.1 MPa, indicating strong adhesion between the Al2O3 ceramic plates.