Vibrating Reed Internal Friction Apparatus for Films and Foils
by B. S. Berry, W. C. Pritchet
An apparatus is described which permits for the first time the resolution of anelastic relaxation effects in evaporated metallic thin films and ion-implanted surface layers of silicon. The composite samples consist of the film or layer of interest on a carrier substrate having the form of a thin cantilevered reed. Low external losses and an exceptionally good span of operating frequencies are obtained by integrally bonding the substrate to a supporting pedestal and by using electrostatic drive and detection for the transverse modes of vibration. The internal friction can be measured with relatively simply instrumentation, at pressures below 10-5 torr (1.33 × 10-3 Pa) and over the temperature range 190°C to 550°C. The apparatus has considerable versatility for work in a number of areas, including the investigation of metallic foils prepared by splat-cooling.