Measuring Magnetic Susceptibility of Undercooled Co-Based Alloys with a Faraday Balance

Abstract

Co-based melts embedded by glass flux in a crucible can be undercooled nearly as strong as samples processed containerlessly by electromagnetic levitation. This allows to measure magnetic susceptibility on undercooled melts while combining the Faraday method with undercooling technique. The magnetic susceptibility of Co and Co-based alloys will be analysed as a function of temperature from superheated to undercooled state. This will be performed by measuring the change of magnetic force F Z on a sample in a constant magnetic field H 0 and an additional gradient field by means of a Faraday balance. When liquid Co-based alloys are undercooled the magnetisation steeply rises if temperature approaches the Curie temperature. The magnetisation is measured for some Co-based alloys in liquid state as function of alloy system and its concentration. The results show that the magnetic susceptibility of the liquid undercooled samples follows a Curie-Weiss behaviour, from which Curie temperature is inferred.