Processing of silicon added Fe-Cr-Co hard magnetic alloy by two stage thermomagnetic treatment technique

Abstract

Fe-Cr-Co is a typical spinodal decomposition type magnetic alloy. FeCrCo alloys being highly workable are important for slender feature designs and ductile applications. However, due to the rising prices of cobalt, research is increasingly being focused toward reducing the amount of cobalt in FeCrCo semi-hard magnetic alloys, without compromising on their magnetic properties. Silicon is ferrite stabilizer and therefore, can be utilized as a potential alloying element. Few researchers have reported work on addition of silicon in FeCrCo alloys, especially on the double isothermal magnetic field annealing. In this work, FeCrCo alloy with 2% silicon addition was produced and subjected to different heat treatments. An electromagnetic setup equipped with a tube furnace was designed based on Finite Element Method (FEM) analysis, and developed for thermomagnetic treatments. An increase in remanence for double thermomagnetic treatment was noted. This improvement could be attributed to the transformation of retained α phase into α1 phase. It was also observed that the squareness of the M-H curve improved with the double treatment.