Regensburg 2004 – scientific programme

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MA: Magnetismus

MA 26: Mikro- und nanostrukturierte Materialien

MA 26.1: Talk

Thursday, March 11, 2004, 15:15–15:30, H10

MAGNETIC PROPERTIES OF BULK AMORPHOUS Fe-Cr-Mo-Ga-P-C-B ALLOYS — •Mihai Stoica¹, Stefan Roth¹, Jürgen Eckert^1,2, and Ludwig Schultz¹ — ¹IFW Dresden, Institut für Metallische Werkstoffe, Postfach 270016, D-01171 Dresden, Deutschland — ²TU Darmstadt, FG Physikalische Metallkunde, Petersenstrasse 23, D-64287 Darmstadt, Deutschland

The Fe_65.5Cr₄Mo₄Ga₄P₁₂C₅B_5.5 bulk amorphous alloy exhibits good soft magnetic properties. However, the maximum achievable diameter of these Fe-based alloys is limited to only a few millimeters. Amorphous rods with diameters of 1.5-3 mm and discs with 10 mm diameter and 1 mm thickness were prepared by copper mold casting. The coercivity of as-cast rods and disc is around 5 A/m, decreasing up to less than 1 A/m upon annealing. The coercivity is expected to depend on the volume fraction of crystalline inclusions. The saturation polarization is around 0.8 T and the magnetostriction constant λ = 9 ppm.

On the other hand, bulk amorphous samples with larger sizes or various shapes can be prepared by powder metallurgical methods, i.e. mechanical alloying or ball milling combined with subsequent consolidation of the resulting powders. The aim of present work is to compare the magnetic properties of as-cast amorphous samples obtained by copper mold casting with samples prepared by hot pressing of ball milled melt-spun ribbons.