Corrosion and fatigue in micro-sized Ni cantilever beams

The Ni microcantilevers were fabricated by femtosecond laser. The corrosion behavior of the micro-sized Ni cantilever beams was studied by electrochemical noise and a newly developed fatigue testing method. The results show that the micro-sized specimens exhibit general corrosion behavior under the studied corrosion condition,whereas the ordinary-sized plates exhibit the localized corrosion behavior. The critical load amplitude of the micro-sized Ni specimens under corrosion fatigue status was determined to be 15 mN. The maximum bending loads,which were measured by fatigue tests,decrease gradually prior to final fracture. Corrosion fracture first occurs in the range of notch with a higher tensile bending stress,and exhibits clear evidence of trans-columnar fracture. The variation of maximum bending loads with time agrees with that creep deformation of the micro-sized Ni specimens can easily occur at room temperature,which implies that the micro-sized Ni specimens appear to have an improved resistance towards total crack as compared with the ordinary-sized Ni specimens.