Hydrogen-induced actuation: a new active mechanism for MEMS

A novel electrochemical actuation based on the hydrogen aborbing-desorping of metal is presented. The hydrogen aborbing-desorping of metal was accompanying with the volume swelling and shrinking, which could be used to convert electrical energy into mechanical energy. This type of actuation not only has usual advantages of electrochemical actuation such as long travel distance and acoustical quiet, but also there was no the concerns of gas leakage of those electrochemical actuation driven by the gas pressure built up by electrolysis of an aqueous electrolyte solution. In this work, a mischmetal (Mm)-Ni based alloy film, MmNi5, was prepared by sputtering method. The MmNi5 film was studied by x-ray diffraction method (XRD) and electrochemical method. It was found that the metal film had undergone phase transformation during its hydrogen absorbing and desorbing cycle, which was first time to be observed for the metal hydride film prepared by sputtering method. The further results of surface micromaching and scanning electron microscope (SEM) indicated that the hydrogen-induced actuation was applicable in MEMS.