The effect of metallic elements on the crystallization behavior of amorphous Fe-Si-B alloys
- PDF / 613,493 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 56 Downloads / 208 Views
I.
INTRODUCTION
IT is generally accepted that the Fe-based amorphous alloys, which exhibit a large saturation magnetization Bs, have high engineering potentiality as core elements for power transformers.[1,2] Less attention, on the contrary, has been paid to their application as inductive components for electronics, because the effective permeability me of these alloys is usually lower in comparison with that of Co-based amorphous alloys.[3,4] Recent trends toward the miniaturization of electronic components demand the development of soft magnetic materials that possess large Bs as well as high me at a higher frequency range;[5] therefore, great efforts have been made to improve the soft magnetic properties of Fe-based amorphous alloys. Recently, Yoshizawa and Yamauchi[6] have determined that an improvement in the soft magnetic properties is achieved for a crystallization-induced Fe(Si) solid solution (designated hereafter as the a-Fe phase) with nanoscale grains in the amorphous Fe-Si-B alloys that simultaneously contain Nb and Cu. Considering the result that no nanoscale a-Fe phase appears through the crystallization of amorphous Fe-B and Fe-Si-B alloys,[7,8] the simultaneous addition of Nb and Cu seems to play an important role in obtaining such a unique microstructure.[9] Suzuki et al., however, have reported that the formation of the ultrafine a-Fe phase and the concurrent achievement of an enhanced me are also observed for amorphous Fe-Zr-B alloys as a result of the crystallization.[10] Although the addition of metallic elements, such as Nb, Zr, or Cu, is thought to be indispensable for the nanocrystallization, the essential role of each metallic element has still remained unsolved. The aim of the present study is to investigate the effect of metallic elements, exemplified by Nb, Zr, V, or Cu, on T. NAOHARA, Lecturer, is with the Department of Materials Science and Engineering, Ehime University, Matsuyama 790, Japan. Manuscript submitted on October 9, 1995. 3424—VOLUME 27A, NOVEMBER 1996
the crystallization behavior of amorphous Fe-Si-B alloys. In addition, the present data have been interpreted with the aid of the structural model originally proposed by Dubois and co-workers.[11,12,13] II.
EXPERIMENTAL PROCEDURE
A. Specimen Preparation Mixtures of electrolytic Fe (99.9 pct pure), Si (99.999 pct pure), metallic B (99.8 pct pure), Nb (99.9 pct pure), Zr (99.9 pct pure), V (99.9 pct pure), and electrolytic Cu (99.8 pct pure) were melted in an induction furnace under a flowing Ar atmosphere. The melts were sucked into a quartz tube of about 5 mm in inner diameter and then allowed to solidify in air. From these alloy ingots with compositions of Fe842XSi6B10MX (M 5 Nb, Zr, V, or Cu), ribbon-shaped specimens approximately 20-mm thick and 2-mm wide were produced using a single-roller melt-spinning apparatus. A stream of molten alloy was ejected through a nozzle with a 0.4-mm hole onto the outer surface of a revolving steel roller (200 mm in diameter). The amount of the alloy melted in a run was about three gram
Data Loading...
