Electroplating of CoNiMnP-based permanent magnet and its application in bidirectionally actuated micro-electro-mechanical systems

Abstract

This article reports the preparation and characterization of CoNiMnP-based permanent magnetic material using various sulphate and chloride solutions under different conditions. Five samples are under study, and all the five samples show vertical magnetic anisotropy, among which sample 5 electroplated from the low concentration chloride solution under external magnetic field demonstrates the best magnetic properties with coercivity of 2632 Oe, remanence of 0.2 T, and maximum magnetic energy density of 10.185 kJ/m³. Experiments indicate that an array structure rather than a monolithic plate can suppress the stress and enhance the adhesion between the electroplated layer and the seed layer. Furthermore, the resistivity of the electroplated CoNiMnP is measured as 160–200 μω cm. The low-stress electroplated CoNiMnP-based permanent magnetic material has potential for bidirectional actuators in micro-electro-mechanical system applications such as micropump, microswitch, and microgripper.