Magnetic composite electrodeposition of micro-array magnets for MEMS actuators

This paper reports a new magnetic composite material deposition technique called magnetic composite electrodeposition (MCE). Thin films and micro-arrays of a composite matrix consisting of magnetic particles and a ferromagnetic alloy have been fabricated based on composite electroplating techniques. The magnetic particle selected is a barium ferrite magnet (BaFe₁₂O₁₉) and the ferromagnetic matrix is a pulse-reverse electrodeposited CoNiP alloy. The embedded particle fraction (w.t.%) directly affects magnetic properties and is experimentally determined by its energy dispersive spectrum (EDS). The effect of applied current and electrolyte pH on the embedded particle fraction is also experimentally investigated. The MCE deposited micro-arrays of BaFe₁₂O₁₉-CoNiP exhibit a coercivity of 1.6-2.2 KOe and a (BH)_max of 6.5-8.6 KJ/m³. These magnetic properties are particularly well suited for MEMS actuators.