Structural and Magnetic Properties of Mn-Al-C Alloy Powders by Mechanical Milling

When: Thursday, November 17, 2011 at 12:00 pm
Where: EG 306
Speaker: Dr. Ogheneyunume Obi
Organization: Department of Electrical and Computer Engineering, Northeastern University
Sponsor: Nanogroup Meeting

Mn-Al-C magnets are well known to posses hard magnetic properties without ferromagnetic elements due to their metastable ferromagnetic τ-phase, which has a relative large saturation magnetization of up to 7 kG and high anisotropy field of 40 kOe [1-3]. These materials have gained a lot of attention due to their less expensive component materials in contrast to the high cost of rare earth alloys such as Sm-Co and Nd-Fe-B etc., which makes them more practical in commercial applications as high-performance magnets.

 

In this work, we fabricated and investigated the structural and magnetic properties of Mn-Al-C (Mn0.53Al0.47-xCx) alloy powders by mechanical milling. The alloy powders were annealed in a tube furnace to form the ferromagnetic τ-phase with magnetic performance. The annealed powders exhibited a high percentage of τ-phases (39-57%), leading to a coercivity of up to 2.2 kOe and a maximum saturation magnetization of 3.3 kG. Magnetic properties were systemetically investigated with different annealing conditions.

 

 

Reference

 

  1. Q. Zeng, I. Baker, J.B. Qui, Z.C. Yan, Structural and magnetic properties of nanostructured Mn-Al-C magnetic materials, Journal of Magnetism and Magnetic Materials, 308 (2007), 214-226.
  2. T. Saito, Magnetic properties of Mn-Al system alloys produced by mechanical alloying, J. Appl. Phys., Vol 93, No. 10, Parts 2 & 3, 15 May 2003, 8686.
  3. T. Saito, Magnetic properties of Mn-Al-C alloy powders produced by mechanical grinding, Journal of Applied Physics 97, 10F304 (2005) .