Effect of Iron Substitution on the High-Temperature Properties of Sm(Co,Cu,Ti)z Permanent Magnets
Abstract
Recently, Ti-substituted Sm-Co permanent magnets have attracted renewed attention due to their interesting high-temperature coercivity. Our presentation deals with the effect of iron substitutions on the magnetic properties of the materials. X-ray diffraction shows that the investigated Sm(Co,Fe,Cu,Ti)(sub z) materials (z = 7.0 - 7.6) are two-phase magnets, consisting of 1:5 and 2:17 regions. The iron content affects both the coercivity and the magnetization. Depending on composition and heat treatment, some samples show a positive temperature coefficient of the coercivity in the temperature range from 22 deg C to 550 deg C. Moderate amounts of iron enhance the room-temperature coercivity. For example, the room-temperature coercivity of Sm(Co(6.0)Fe(0.4)Cu(0.6))Ti(0.3) is 9.6 kOe, as compared to 7.6 kOe for Sm(Co(6.4)Cu(0.6)Ti(0.3)). At high temperatures, the addition of Fe has a deteriorating effect on the coercivity, which is as high as 10.0 kOe at 500 deg C for Sm(Co(6.4)Cu(0.6)Ti(0.3)). The room-temperature magnetization increases on iron substitution, from 73 emu/g for Sm(Co(6.4)Cu(0.6)Ti(0.3)) to 78 emu/g for Sm(Co(6.0)Fe(0.4)Cu(0.6)Ti(0.3)). The observed temperature dependence is ascribed to the preferential dumbbell-site occupancy of the Fe atoms.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2001
- Accession Number
- ADP012287
Entities
People
- David J. Sellmyer
- George C. Hadjipanayis
- Jian Zhou
- Ralph Skomski
- Wei Tang
Organizations
- University of Delaware