Influence of Ti content on magnetic and microstructural properties of Fe-28Cr-15Co-3.5Mo permanent magnets

Magnetic properties in Fe-28Cr-15Co-3.5Mo alloys were improved by optimizing the heat treatment conditions and titanium addition up to 3 wt%. The Fe-28Cr-15Co-3.5Mo-1.8Ti alloys have produced best magnetic properties as H-J(c) = 78.7 kA/m (990Oe), B-r = (11.2 kG) (1.12 T), B-s = 13.4 kG (1.34 T) and energy product, (BH)(max) = 6.6 M GOe (52.5 kJ/m(3)). The results show that both magnetic properties and microstructural features are sensitive to the heat treatment temperature and time. The microstructural studies revealed that the addition of titanium to the basic alloy affects the morphology of ferromagnetic alpha(1) phase by favoring elongation of alpha(1) phase in preferred < 0 0 1 > direction, which leads to enhancement of the magnetic properties. The titanium content above 1.8 wt% produced undesirable microstructure with deteriorated magnetic properties. (C) 2002 Elsevier Science B.V. All rights reserved.