Fabrication of a Portable Magnetic Microcantilever Using Fe₄₀Ni₃₈Mo₄B₁₈ Amorphous Ribbon and Its Application as a Humidity Sensor by Coating with TiO₂ Nanotubes

Microcantilevers (MCs) are highly sensitive sensors capable of detecting mass changes on the surface at the nanogram and even picogram scale. In this study, microcantilevers were fabricated for the first time using the Sodick AP250L Wire electrical discharge machining (EDM) from amorphous 2826MB (Fe40Ni38Mo4B18) ferromagnetic ribbons. This method is advantageous because it allows for the simultaneous production of a large number of microcantilevers, with about 100 MCs being produced in a single manufacturing process. Additionally, a straightforward and cost-effective measurement system was developed to measure the resonance frequency and frequency shift of the MC entirely through magnetic means, a technique not previously reported in the literature. To evaluate the performance of the MC, we employed it as a humidity sensor. For the TiO2-NT-coated MC, a frequency shift of approximately 202 Hz was observed when the humidity level changed from 5% to 95% relative humidity (RH).