Title :
Magnetic and structural properties of amorphous and nanocrystalline FeNi-based alloys
Author :
Willard, Matthew A. ; Claassen, John H. ; Harris, Vincent G.
Author_Institution :
Naval Res. Lab., Washington, DC, USA
Abstract :
Nanocrystalline soft magnetic ribbons, with a composition of (Ni 0.78Fe0.22)89-xZr7B4 Cux (where x is 0 or 1), were synthesized by melt spinning and subsequent crystallization. The best magnetic properties coincided with the development of a single nanocrystalline phase at annealing temperatures just above the primary crystallization. Differential thermal analysis indicates a 60°C difference between primary and secondary crystallization temperatures. This makes the nanocrystallization process for these materials more difficult than similar alloy systems. The alloy containing Cu exhibited good soft magnetic properties after annealing at 550°C for one hour. X-ray diffraction indicated a face-centered cubic phase with an average grain diameter of 8 nm, and vibrating sample magnetometry indicated a coercivity of 13 Oe and a normalized magnetic moment of 71 emu/g. The alloy without Cu showed improved properties for an annealing temperature of 475°C. A small value of 3.7 ppm for the saturation magnetostrictive coefficient was measured in the optimally annealed Fe 19.36Ni68.64Zr7B4Cu1 alloy
Keywords :
X-ray diffraction; amorphous magnetic materials; annealing; boron alloys; coercive force; copper alloys; crystallisation; differential thermal analysis; ferromagnetic materials; grain size; iron alloys; magnetic moments; magnetostriction; melt spinning; nanostructured materials; nickel alloys; soft magnetic materials; zirconium alloys; 475 C; 550 C; Fe19.36Ni68.64Zr7B4Cu 1; X-ray diffraction; amorphous alloy; annealing; coercivity; crystallization; differential thermal analysis; grain size; magnetic moment; magnetostrictive coefficient; melt spinning; nanocrystalline alloy; soft magnetic properties; structural properties; vibrating sample magnetometry; Amorphous magnetic materials; Amorphous materials; Annealing; Copper alloys; Crystallization; Magnetic properties; Magnetostriction; Saturation magnetization; Soft magnetic materials; Temperature;
Conference_Titel :
Nanotechnology, 2001. IEEE-NANO 2001. Proceedings of the 2001 1st IEEE Conference on
Conference_Location :
Maui, HI
Print_ISBN :
0-7803-7215-8
DOI :
10.1109/NANO.2001.966392
