Electrochemical Deposition of CoP and CoNiP as Hard Magnetic Scales in a Position Measurement System

The fabrication and design of hard magnetic materials for micro-electro-mechanical system applications by electrochemical deposition has to consider not only the intrinsic material properties but also the shape anisotropy of the micro-devices. Within the scope of the present work, an as-plated proce...

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Bibliographic Details
Main Authors: Martin Theis, Tobias Bill, Heiko Knoll, Peter Starke, Monika Saumer
Format: Article
Language:English
Published: MDPI AG 2022-01-01
Series:Metals
Subjects:
Online Access:https://www.mdpi.com/2075-4701/12/2/235
Description
Summary:The fabrication and design of hard magnetic materials for micro-electro-mechanical system applications by electrochemical deposition has to consider not only the intrinsic material properties but also the shape anisotropy of the micro-devices. Within the scope of the present work, an as-plated process for hard magnetic Co-based materials was developed, with the products intended to be used as magnetic scales in a positioning system with a resolution within the nanometer range. First, the process–material correlations are investigated in a laboratory-scale process. The CoP and CoNiP show a maximum coercivity of <i>H<sub>C</sub></i> = 28 and 45 kA/m, respectively, as well as maximum remanence polarizations of <i>J<sub>R</sub></i> = 0.65 and 0.40 T, respectively. The CoP process is transferred to a specially developed 20 L plating cell with paddle convection capabilities and a passive bezel to deposit 50 µm wide scales with different thicknesses of up to 55 µm in an integrated process. The in-plane magnetization of the scale bars shows higher remanence polarization than for the out-of-plane direction. Magnetic field-assisted electrochemical deposition promotes the vertical magnetization component resulting in a remanence polarization of 205 mT (out-of-plane) for a scale thickness of 25 µm.
ISSN:2075-4701