Development of Actuator Utilizing Hydrogen Storage Alloys

Abstract

The actuators utilizing hydrogen storage alloys (HSAs) have been developed. In order to convert a volume expansion of HSA accompanied by hydrogen absorption into a bending motion, the actuators have a bimorph structure which consists of sheet-shape HSA and non-HSA. Pd-Ni and V-Ti based HSAs, which have high pulverization resistance on hydrogen absorption - desorption cycles and enough ductility to form into sheet, are used for the actuators. The shape change behavior of the V-Ti alloy actuators was improved by the sputtered Pd layer which would act as a catalyst and a protective layer against oxidization. Pd-Ni alloy actuators exhibited cyclic bending motion accompanied by hydrogen absorption- desorption cycles. The shape change behavior of the actuators could be controlled by controlling the hydrogen pressure. By forming the sample shape into the “L” shape, the rotational motion could be achieved without modifying the basic bimorph structure of the actuator.