Metal/ceramic interfaces play a crucial role in materials science and for various industrial purposes. In technical applications these interfaces are often exposed to high temperatures and different atmospheres. This often results in a change of the mechanical stability via the morphology and electronic structure of the interfaces. We present a comprehensive analytical electron microcopy (AEM) and fracture mechanics study of this connection on a metal/ceramic-interface model system: Cu/ α-Al2O3.
The specimens were produced by UHV diffusion bonding of bulk Cu to (α-Al2O3 single crystals. Two different Cu materials were used, either pure Cu (noted: Cu) or Cu containing 83±12 ppm oxygen (noted: Cu(O)). After bonding the interfaces were annealed in an oxygen partial pressure at 1000°C between 20 and 120 h. Four point bending tests showed an increase of the fracture energy for the Cu(O)/α -Al2O3-interfaces compared to the Cu(O)/α-Al2O3-interfaces by a factor of 5±2.