Hghly coercive melt-spun Sm(Co,Fe,Cu,Zr)/sub z/ magnets prepared by simple processing

Summary form only given. It is known that high coercivity in Sm(Co,Fe,Cu,Zr)/sub z/ magnets is obtained after a lengthy and complex heat treatment, which consists of solid solution and isothermal aging treatments, followed by slow cooling. In this work, a new simple method was developed for magnetic hardening of melt-spun Sm(Co,Fe,Cu,Zr), alloys. A coercivity of 2.8 T and a uniform cellular and lamellar microstructure were obtained only by slow cooling the as-spun Sm(Co/sub 0.74/Fe/sub 0.1/Cu/sub 0.12/Zr/sub 0.04/)/sub 7.5/ ribbons from 850/spl deg/C to 400/spl deg/C without the standard solid solution and isothermal aging, which are required for the bulk precipitation hardened 2:17-type SmCo alloy. A high density of lamellar phase with large width was observed by transmission electron microscopy (TEM) in the ribbons subjected to slow cooling. This leads to the fast development of an uniform and fine cellular microstructure, which gives rise to a strong domain wall pinning and therefore to high coercivity. The effect of processing parameters such as temperature range for the cooling regime on magnetic properties at room and high temperatures, microstructure and microchemistry of the phases is discussed.