| The effects of Zr content and heat treatment on the distribution of alloy elements, magnetic domain and magnetic properties in Sm(Co, Fe, Cu, Zr)z alloy have been investigated. A new magnetic alloy with a low temperature coefficient of intrinsic coercivity (Hci) was designed by adjusting the value of z, lowering the content of Fe, increasing the content of Cu and optimizing Zr content. In addition, by using suction casting method, the Hci of this alloy at room temperature was improved considerably. On the basis of the optimization of component and the improving of fabrication process, an excellent 2:17 type SmCo permanent magnetic alloy was developed for high temperature up to 550~600℃. The Y(Fe, Co)B alloy with nano-layered structure was prepared by suction casting method. The controlled preparation of the nano-layered structure with different sizes could be achieved by changing the solicitation process. The hard magnetic property was achieved in this alloy replacing part of the Y by Nd element.The ingot, rod and ribbon of Sm(CobalFe0.08-0.10Cu0.08-0.10Zr0.02-0.03)7.5~7.6 alloy were prepared by arc-melting, suction casting and melt quenching methods, respectively. Results show that magnetic property of the fast-cooling alloy rod is remarkably enhanced and is much higher than that of the ingot and ribbon samples. The fast-cooling alloy rod with size of ?6 shows the most stable property and its Hci reach 16.47kOe at room temperature in Sm(CobalFe0.08Cu0.10Zr0.025)7.45 alloy. The Hci of ?6 sample does not show an evident decline until 500℃and its remains 70% of the value at room temperature when temperature was increased to 600℃, which is better than the results reported in the literatures. The critical temperatures at which the Hci of sample start to decrease obviously in ingot and ribbon with the same composition, are ~450℃. The more excellent magnetic property at room temperature of ?6 sample than that of the ingot and ribbon maybe due to grain refinement, change in the lattice parameters and misfits of 2:17 phase and 1:5 phase caused by suction casting. The substitution of Sm by the heavy rare-earth elements has been also investigated. (Sm0.5Ho0.5)(CobalFe0.10Cu0.08Zr0.025)7.55 ingot sample shows an excellent magnetic property and its Hci can exceed 12 kOe at room temperature. Its Hci is less than that of the sample without Ho element when the temperature exceeds 250℃. But its saturation magnetization (Ms) is much more than that of the sample without Ho element with the temperature above 300℃.The Y6(FeCo)72B22 alloy samples with the diameter of ?2mm ~ ?9mm and size of 2×10mm were prepared by suction casting method, which shows soft magnetic properties. The sample with size of ?2 is almost amorphous. With the increasing of sample size, in other words, the decreasing of the cooling rate, some nano-scale phases start to precipitate in the amorphous matrix and eventually forming the two phases nano-layered structure. It has been found that with lowering of cooling rate, the period of nano-layered structure increases from 40 to 400 nm in ?2.5 and ?9 alloys, respectively. The EDX result shows that the concentration of Fe and Y elements are enrichment regarding their own layers over each other. The presence of Co element does not show any significant change in both layers. XRD and SAED investigations also confirm that there are two phases (Fe,Co)2B and Fe (Co,Y) or Fe (Co,Y,B) in the nano-layered structure. The alloy replacing of Y by Nd element has been prepared by suction casting under the magnetic field (~1kOe) and its magnetic measurements show a significant enhancement in Hci (1.1kOe) and Mr/ Ms (0.3).
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