Tailoring magnetic properties in 60Fe-27Cr-10Co-2Mo-1Ti magnetic alloy by Ni and Hf additive

Abstract

Present work describes the manufacturing of Ni and Hf doped 60-xFe-27Cr-10Co-2Mo-1Ti-xM (M = Ni, Hf and 0.3 ≤ x ≤ 1.8 wt%) magnets produced through casting, magnetic aging and multistage tempering. Structural, magnetic and thermal properties of materials were systematically evaluated and discussed. Experimental results deduced that micro addition of nickel and hafnium elements tend to modify the morphology of magnetic phases in 60Fe-27Cr-10Co-2Mo-1Ti alloy leading to increase both magnetic and structural properties. Nickel improved intrinsic coercivity (Hcj) and magnetic induction (Br) for 60Fe-27Cr-10Co-2Mo-1Ti alloy. Hafnium addition to 58.8Fe-27Cr-10Co-2Mo-1Ti-1.2Ni alloy refines the microstructure and substantially improves coercivity (76.5kA/m) without insignificant change in magnetic induction. Optimal magnetic microstructure comprised nanostructured and 〈001〉 textured Fe-Co-Hf phase embedded in Cr-Mo-Ni-Ti as a matrix phase. Henkel plot evidenced existence of strong interphase magnetization interactions between Fe-Co-Hf and Cr-Mo-Ni-Ti phases. Magnetic measurements showed optimum magnetic properties such as Hcj = 51.8 kA/m Br = 1.18 T, Bs = 1.28 T and (BH)max = 38.8 kJ/m3 for 58.8Fe-27Cr-10Co-2Mo-1Ti-1.2Ni alloy which were remarkably enhanced to Hcj = 76.5 kA/m, Br = 1.2 T, Bs = 1.34 T, and (BH)max = 46 kJ/m3 for 57.9Fe-27Cr-10Co-2Mo-1Ti-1.2Ni-0.9Hf alloy.