The stability upon air-annealing of uncapped Au-Co thin films is investigated. The analysis focuses on the modifications of the crystalline fraction of the films produced by physical vapor deposition. The film with the highest Au concentration exhibits the strongest diffraction signal, corresponding to a Au-rich fcc AuxCo1−x solid solution alloy, with nanocrystals which have a rod-like shape. Air annealing induces a progressive de-alloying which is complete at 500 °C, as shown by X-ray Absorption Spectroscopy and X-ray diffraction. The film, that is directly exposed to the oxidizing atmosphere, undergoes a de-wetting process, likely triggered by Au. X-ray nanoimaging mapping enlightens the presence of interpenetrating sub-μm Au and Co3O4 domains. This peculiar annealed nanostructured system can have interesting applications in the field of catalysis.

研究了未封端的Au-Co薄膜在空气退火后的稳定性。分析着重于通过物理气相沉积产生的膜的结晶部分的改性。Au浓度最高的薄膜显示出最强的衍射信号，相当于富Au的fcc Au x Co1- x固溶体合金，具有棒状纳米晶体。如X射线吸收光谱和X射线衍射所示，空气退火引起在500℃下完成的渐进脱合金。直接暴露在氧化气氛中的薄膜经历了可能由金触发的去湿过程。X射线纳米成像制图启发了亚微米Au和Co3O4互穿域的存在。这种特殊的退火纳米结构系统可以在催化领域中具有有趣的应用。