Alloy expansion actuator


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.


[Related Terms]
Hydrogen storage alloy, Metal hydride actuator