STRUCTURE AND MAGNETIC PROPERTIES OF NANOCRYSTALLINE (Fe₅₀Co₅₀)_73.5Cu₁Nb₃Si_13.5B₉ ALLOYS

Abstract

( Fe 50 Co 50)73.5 Cu 1 Nb 3 Si 13.5 B 9 amorphous ribbons, a type of Co doped Finemet alloy, were prepared by melt-spinning and annealed at 440–560°C for 30 min. Influences of heat treatment and Co content on the crystallization were analyzed through differential scanning calorimetric (DSC) and X-ray diffractometry (XRD). The microstructure was analyzed by atomic force microscopy (AFM). The magnetic properties of ( Fe 50 Co 50)73.5 Cu 1 Nb 3 Si 13.5 B 9 and Finemet ribbons were tested by an alternating current soft magnetic properties measurement system. A comparative study of frequency dispersion properties between ( Fe 50 Co 50)73.5 Cu 1 Nb 3 Si 13.5 B 9 and Finemet was conducted. Results indicate that the optimal magnetic property has been achieved when ( Fe 50 Co 50)73.5 Cu 1 Nb 3 Si 13.5 B 9 ribbons were annealed at the temperature range of 480°C–520°C, after which the grain size became between 10 nm and 20 nm. Although the permeability of ( Fe 50 Co 50)73.5 Cu 1 Nb 3 Si 13.5 B 9 is not as high as that of Finemet, this Co -doped Finemet amorphous alloy presents better high frequency properties, and therefore is a promising candidate for the high frequency field applications.

Stability of nanocrystalline metals: The role of grain-boundary chemistry and structure

“…6,7 Abnormal grain growth was also often found to occur with a few grains rapidly expanding to the micron scale. 7 Although many of these early experimental nanocrystalline materials were unstable, work on them substantially increased our understanding of their exceptional properties: enhanced strength, 1,8-10 hardness, [11][12][13][14] wear, 9,15,16 magnetic properties, [17][18][19][20][21] thermoelectricity, [22][23][24][25][26][27][28][29][30][31] and others. [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] They established a strong value proposition driving further interest in nanocrystalline materials for a variety of engineering applications.…”

Effect of heat treatment conditions on microstructure and magnetic property of Fe77Co2Zr9B10Cu2 alloy

“…Numerous systematic studies on annealing condition such as temperature and period have been made to obtain a fine grain size of α-Fe(Co). [11][12][13] W. Q. Yu et al The initial crystallization product of Fe-based amorphous alloy is generally body-centered cubic (b.c.c.) α-Fe phase (lattice constant a = 2.866 nm).…”