Electrodeposition of magnetic coatings for a magnetoelastic strain sensor

The goal of this work is to develop inexpensive strain sensors by electrodepositing "strain sensitive" magnetic thin films on polycrystalline copper wires. This paper will discuss the fabrication of the stress sensitive wires. A direct current, galvanostatic electrodeposition process, utilizing an aqueous sulfate-chloride electrolyte, was used to deposit the soft-magnetic, NiFe alloy thin films onto 0.125-mm diameter wires. This current investigation focused on elucidating the deposition parameters required for obtaining suitable NiFe thin films. A photolithographic technique was used for masking the wires and selectively depositing the NiFe films. Electrodeposition parameters were established that yielded extremely fine crystallites that were strain sensitive in the operational load range intended for the sensors.