Comparison of magnetic and mechanical properties of powder Fe-Cr-Co alloys with different cobalt content obtained at various sintering temperatures

Abstract

In present work, we studied the effect of sintering temperature and thermomagnetic treatment (TMT) on the magnetic hysteresis characteristics of the Fe-30Cr-8Co, Fe-30Cr-12Co and Fe-30Cr-16Co (wt. %) powder alloys. All investigated powder alloys, sintered at temperature range of 1100-1400 °C have a high level of magnetic properties ensuring their technical application. The highest values of magnetic properties for all three investigated powder alloys are observed after sintering at 1350 °C: Br = 1,28 T, Hc = 44,3 kA/m, BH(max) = 39 kJ/m3-for Fe-30Cr-8Co alloy; Br = 1,28 T, Hc = 48,2 kA/m, BH(max) = 39,2 kJ/m3-for Fe-30Cr-12Co alloy and Br = 1,23 T, Hc = 54,9 kA/m, BH(max) = 37,6 kJ/m3-for Fe-30Cr-16Co alloy. For Fe-30Cr-8Co alloy it was observed that additional annealing at 500 and 480 °C slightly increases the magnetic properties. For Fe-30Cr-12Co and Fe-30Cr-16Co alloys, there is no clear tendency regarding the effect of additional annealing on the magnetic properties. Compression tests of powder alloys Fe-30Cr-8Co and Fe-30Cr-16Co sintered in the temperature range 1100-1400 °C have shown that the yield strength σ0.2 of the Fe-30Cr-16Co alloy samples (970 – 1080 MPa) are higher compared to the Fe-30Cr-8Co alloy (710 – 930 MPa) throughout the entire sintering temperature range but Fe-30Cr-8Co alloy have a better ductility compared with Fe-30Cr-16Co alloy. Maximum values of σ0.2 were obtained on samples sintered at 1100 °C.