FeSiCr Alloy Powder to Carbonyl Iron Powder Mixing Ratio Effects on the Magnetic Properties of the Iron-Based Alloy Powder Cores Prepared Using Screen Printing.

Hsing-I Hsiang,Kai-H Chuang,Wen-H Lee

doi:10.3390/ma14041034

Abstract

A screen printing process was used to substitute dry molding to solve the uneven compaction problem in the coil center column during molding in this study. FeSiCr alloy powders (FSC) with a large particle size were mixed with fine spherical carbonyl iron powder to increase the compaction density. FSC to carbonyl iron powder (CIP) mixing ratio effects on magnetic paste rheological behaviors and magnetic properties of the molding coil prepared using screen printing were investigated. A magnetic paste with the lowest viscosity can be obtained using 3C7F (30% CIP + 70% FSC) due to the small-sized CIP adsorbed onto the FSC surface. This process reduces the interlocked network formation resulting from the CIP. The toroidal core with 3C7F exhibited the highest relative density and highest inductance. The coils with pure CIP and higher CIP content exhibited the better DC superposition characteristic. The toroidal core loss increased rapidly as the FSC content was increased. A proper trade-off between the inductance, DC-bias superposition characteristic, and magnetic core loss can be reached by choosing a suitable powder mixing ratio.

Highlights

The dry molding of alloy magnetic powders directly onto enameled wire is used to prepare the molding coils
The FeSiCr alloy powders (FSC) with a large particle size were mixed with fine spherical carbonyl iron powder to increase the compacted density, and the FSC to CIP mixing ratio on the rheological behaviors of the magnetic pastes and magnetic properties of the molding coils prepared using screen printing were investigated in this study
The lowest viscosity was obtained in the 3C7F sample due to the small-sized CIP adsorbed onto the FSC surface

Summary

Introduction

The dry molding of alloy magnetic powders directly onto enameled wire is used to prepare the molding coils. The small space in the coil center column cannot be well filled with the granules composing of alloy magnetic powder and organic binder during molding the miniaturized coil. In this study the molding coils were fabricated by using a screen printing process of high-solid-content iron-based alloy magnetic paste. The compaction density of the molding coils can be enhanced by adding CIP into FSC owing to its large plastic deformation during pressing and can increase the inductance. The FSC with a large particle size were mixed with fine spherical carbonyl iron powder to increase the compacted density, and the FSC to CIP mixing ratio on the rheological behaviors of the magnetic pastes and magnetic properties of the molding coils prepared using screen printing were investigated in this study

Experimental Procedures

Results and Discussion

Conclusions