Alloy expansion actuator0301122-6
An actuator that uses volume change of alloy by gas storage /release.
When an alloy film is hydrogenated, the alloy expands because the
space between metal atoms is extended to a degree corresponding to the concentration of the occluded
hydrogen. This phe-nomenon can be utilized as an actuator. The alloy expansion actuator has
advantages such as 1) simple structure suitable for miniaturizing, 2) large force, and 3)
self-retention property holding the state when power is turned off. Its drawbacks are 1) poor
response and 2) small displacement. To compensate these drawbacks, a bimorph type actuator, which
warps the alloy films to amplify the displacement, is being studied. Popular materials are LaNi5
alloy, TiFe alloy, and so on. Use of a thin film prepared by vacuum deposition or sputtering, and
so on and an amorphous thick film formed by melt quenching is also studied.
Hydrogen storage alloy, Metal hydride actuator