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 Fe70.4Pd29.6/Ni bimorph layers. These cantilever-type actuators can be bent by applying magnetic field parallel to length. An actuator point displaced about 300 mu m 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 0 mL.min(-1) increasing the magnetic field to 40 kAm(-1). The response time to the applied magnetic field is below 0.15 s.