Improvement of Soft Magnetic Properties by Cr Addition for Fe-(34∼46)mass%Ni Alloys

Abstract

It is generally understood that the soft magnetic properties of Permalloy, especially permeability, decrease with decreasing Ni content. Many investigations have been carried out to improve the soft magnetic properties of Permalloy containing less than 50 mass%Ni. For example, the effects of addition of various elements on the soft magnetic properties have been reported. Main purpose of the present paper is to study the mechanism on improvement of soft magnetic properties of Fe-(34∼46)mass%Ni alloys by the addition of Cr. The results obtained are summarized as follows: μ_i and μ_L are improved by increasing Cr content. Especially, the effect of Cr addition is remarkable for Ni content between 35 and 38 mass%. The improvement of soft magnetic properties by the addition of Cr is contributed to the decrease in K₁ and λ with increasing Cr content. Moreover, it is considered that the remarkable improvement of μ_i and μ_L by the addition of Cr more than 8 mass% for Ni content between 35 and 38 mass% is due to Hopkinson effect, because T_c of the alloys are just above room temperature.