Fabre Arnaud, Finot Eric, Demoment Jérôme, Contreras Serge
Laboratoire de Physique, UMR CNRS 5027, Université de Bourgogne, B.P. 47870, 9 rue A. Savary, F-21011, Dijon Cedex, France.
Ultramicroscopy. 2003 Oct-Nov;97(1-4):425-32. doi: 10.1016/S0304-3991(03)00070-6.
The reactivity of the palladium shaped as a microcantilever is investigated as a function of the hydrogen stoichiometry. A small cell holding the microcantilever is designed to monitor the deflection and the flexural resonance response from high vacuum to a hydrogen gas pressure of several bars. The measurements show that the Young's modulus is accurate if the cantilever is thick enough to be described by a continuum mechanics approach. The orientation distribution function of the palladium grains determined by X-ray diffraction enables to correlate Young's modulus measured using microcantilevers with the elastic constant tensor issued from the literature. The surface stress induced by the dissociation of H(2) in palladium surface depends mainly on the cantilever cross-section. Cantilever response was found to be extremely sensitive to both the palladium lattice expansion induced by the insertion of hydrogen atoms into octahedral sites of palladium and the electronic affinity between palladium and hydrogen.
研究了微悬臂梁形状的钯的反应性与氢化学计量比的关系。设计了一个容纳微悬臂梁的小室，用于监测从高真空到几巴氢气压力下的挠度和弯曲共振响应。测量结果表明，如果悬臂梁足够厚，可以用连续介质力学方法描述，那么杨氏模量是准确的。通过X射线衍射确定的钯晶粒的取向分布函数，能够将使用微悬臂梁测量的杨氏模量与文献中给出的弹性常数张量联系起来。钯表面H₂解离引起的表面应力主要取决于悬臂梁的横截面。发现悬臂梁响应对氢原子插入钯的八面体位置引起的钯晶格膨胀以及钯与氢之间的电子亲和力都极其敏感。
