Synthesis and Characterizationof CuAl₂O₄ Thin Films by Deposition and Thermal Oxidation of Cu-Coatings on Al₂O₃ Disc

The CuAl₂O₄ thin films were synthesized by thermal oxidation of the Cu coatings,grown by ion beam assisted deposition on 95%(wt)Al₂O₃ substrate.The influence of the oxidation temperature in air on the microstructures,phases-structures and properties of the CuAl₂O₄ coating was investigated with X-ray diffraction,scanning electron microscopy,energy dispersive spectroscopy and X-ray photoelectron spectroscopy.The results show that the thermal oxidation temperature had a major impact.As the oxidation temperature increased from 1000 to 1100℃,the emerging CuAl₂O₄ phase increasingly replaced the dominant CuO phase,accompanied by grain-size growth.At 1100℃,the highly pure CuAl₂O₄ phase dominates the coatings with fairly large grains and with an increase of Al-content on the surfaces.