Chromium concentration profiles in vacuum-sintered Fe–Cr–Co alloys

Resumo

Magnetically hard Fe–Cr–Co alloys doped with molybdenum and tungsten are prepared using powder metallurgy technology. It is found that chromium evaporation from the specimen surface occurs during sintering, which results in mass losses and nonuniform chemical composition and has a negative impact on the functional properties of the sintered material. A mathematical model describing the diffusional mass transfer and evaporation of chromium in a sample being sintered is presented. The modeled chromium concentration profiles are in qualitative agreement with the corresponding experimental profiles of the sintered specimens obtained via energy-dispersive X-ray analysis, performed using an electron microprobe. The evaporation of chromium is found to be the most intense in the first few minutes of sintering.