CONTROL OF THE MECHANICAL-PROPERTIES OF METAL CERAMIC INTERFACES THROUGH INTERFACIAL REACTIONS

The use of interfacial reactions to control the structure and shear strength of metal-ceramic interfaces was studied in the NiO-Pt system. Interfaces were formed by hot1pressing together thin NiO single crystals and thick Pt polycrystalline films. Suitable choice of the annealing temperature, time and oxygen partial pressure allowed the introduction at the interface of a layer of either an intermetallic compound NiPt with thickness between 1 and 65 nm or a Ni-Pt solid solution.The shear strength of the NiO-Pt interface with and without the different interlayers present was measured by the periodic cracking method. Compared to its originally hot pressed state the shear strength of the NiO-Pt interface was increased by a factor of at least 4 by the presence of the NiPt and by ∼10 by the solid solution. The use of interfacial reactions to control interfacial strength may also be applicable in other metal-ceramic systems where the metal and the cation form intermetallic compounds, and where the oxidation potentials of the metal and the cation are significantly different. © 1990.