Orientation relationship and interfaces in Ni and Co-YSZ cermets prepared from directionally solidified eutectics

摘要

Textured Ni-YSZ and Co-YSZ (YSZ: cubic yttria stabilized zirconia) cermets prepared by reduction of direc_tionally solidified NiO-YSZ and CoO-YSZ oxide eutectics respectively display a self-organized microstucture formed by __400 nm wide alternating lamellae of YSZ and porous metal suitable for electrochemical applica_tions. The electrochemical properties of the cermets depend on their microstructure. We have analyzed the orientation relationships and interfaces both of the oxide composites and cermets using Scanning Electron Microscopy, Transmission Electron Microscopy, X-ray pole figures and Electron Back-Scattering Diffraction. In spite of the similar crystal structure, growth habits and orientation relationships of NiO-YSZ and CoO_YSZ are different. Also the crystallographic behaviour, when cermets are produced, differs. However the metal-YSZ interfaces are about the most stable ones giving good metal-ceramic adhesion. Due to their lamellar microstructure and good metal-ceramic adhesion these composites present long-term stability at working conditions, which makes them good candidates to be used as anodes in solid oxide fuel cells or electrolyzers.