Development of magnetic-field-driven micro-gas valve

Giant magnetostrictive Fe-Pd and Fe-Ga alloys are promising as actuator/sensor materials with high respective velocity and stress created by magnetostriction. To apply them to a micro-gas valve, we developed magnetostrictive actuators, that is, Fe₈₀Ga₂₀/Ni and Fe_70.4Pd_29.6/Ni bimorph layers. These cantilever-type actuators can be bent by applying magnetic field parallel to length. An actuator point displaced about 300 μm under a low magnetic field of 37 kAm ^-1. Small and large actuators were applied to a micro-gas valve. The opening and closing action of a gas valve consisting of magnetostrictive bimorph layers can be controlled remotely by magnetic fields. Gas flow rate can be driven from 50 to OmL-min^-1 by increasing the magnetic field to 40 kAm^-1. The response time to the applied magnetic field is below 0.15s.