Magnetic and thermomagnetic studies of the formation of the Rhometal powders by high energy mechanical milling

Abstract

Nanocrystalline Rhometal (36Ni64Fe, wt. %) powders have been obtained by mechanical alloying under argon atmosphere. The initial mixture was milled up to 20 h. In order to eliminate internal stresses and to improve the solid state reaction annealing at 350°C was performed for 4h. The alloy formation is obtained after 8 h of milling. A mean crystallite size of 10 ± 4 nm is obtained after 20 hours of milling. The magnetization values for the as-milled samples are between that of the starting sample and that of the as cast one. The evolution of the magnetization versus the milling time is discussed. The thermomagnetic analysis shows the Curie temperatures confirming the alloy formation by milling. As a result of the solid state reaction by milling means, a continuous decrease of the magnetization with increasing the temperature is recorded, similarly to the behaviour of the classical cast alloy.