Abstract
The stresses induced by hydrogen absorption in Pd nanofilms were studied by the electrochemical quartz crystal microbalance (EQCM) and bending beam methods. In the EQCM method, hydrogen was charged electrolytically into a Pd nanofilm that was coated on an AT- or BT-cut quartz crystal. For Pd films in a thickness of 120-nm on the AT-cut and 158-nm on the BT-cut quartz crystal, compressive stresses of 1.07×10 3 MPa and 1.70×10 3 MPa, respectively, were measured. With the bending beam technique, the bending curvature of the Si substrate during gas-phase hydrogenation was monitored. The maximum compressive stress induced in a 50-nm Pd film on the Si substrate during hydrogenation at 0.2 MPa of hydrogen gas was 944 MPa. When hydrogen was desorbed from the film, a tensile stress of 708 MPa in the film was observed. When the thickness of the Pd film was increased to 130 nm, peeling of the Pd film from the substrate occurred.