Fe-Cr-Si and Fe-Cr-Si-Mo Soft Magnetic Alloys Produced by MIM Process

In recent years, metal injection molding (MIM) has been adopted as a manufacturing method for solenoid valves which are parts of electronic fuel injectors, and PB permalloy parts have been commercialized. However, Ni, a constituent element of PB permalloy, is an expensive material, making it difficult to produce fuel injector parts at low cost. To solve this problem, the use of inexpensive Fe-Cr alloys has been considered. However, its properties are insufficient as a material for solenoid valves, which require improved magnetic properties, reduced core loss, and improved corrosion resistance, and these requirements have been increasing year by year. As a solution to this problem, we studied magnetic and material properties of Fe-Cr-Si and Fe-Cr-Si-Mo alloys produced by MIM process. These results revealed that magnetic properties were improved by reducing the amount of Cr, and that corrosion resistance was improved by adding Mo even if the amount of Cr was reduced. In this review, we describe the magnetic and material properties of Fe-Cr-Si and Fe-Cr-Si-Mo alloys produced by MIM process. © 2023 Journal of the Japan Society of Powder and Powder Metallurgy. All rights reserved.