Investigation of Surface Electrical Resistance of Soft Magnetic Core Compacted with MgO Coated Powder

• Published in: European Congress and Exhibition on Powder Metallurgy. European PM Conference Proceedings pp. 1 - 5
• Main Authors: Kato, Kenichi, Kobayashi, Naoki, Miyahara, Masahisa
• Format: Conference Proceeding
• Language: English
• Published: Shrewsbury The European Powder Metallurgy Association 01.01.2016
• Subjects: Coating; Compacting; Converters; Core loss; Current loss; Eddy current testing; Eddy currents; Ejection; Electrical resistance; Flux density; Friction resistance; Heat resistance; Insulation; Investigations; Lubricants & lubrication; Magnesium oxide; Molding (process); Motors; Powder metallurgy; Voltage converters (DC to DC)

High density soft magnetic powder core are produced by compacting iron powder coated with a thin insulation. It is beginning to be applied to high-current reactor core for DC-DC converter for HEV traction motors because of its high saturation flux density and low iron loss,. Eddy current loss of soft magnetic powder core depends on its surface electrical resistance as well as its internal electrical resistivity. Surface electrical resistance of soft magnetic powder core has a tend to decrease in ejection process by sliding against molding die due to insulation coating is pealed off from the surface of the iron powder by friction between compacting and die. In this study, surface electrical resistance of soft magnetic core compacted with MgO-based oxide coated powder was investigated in some powder compaction conditions. As a result, the core compacted with MgO-based oxide coated powder shows high surface electrical resistance compared to that of core compacted with phosphate coated powder.