Formation and properties of NdFeB prepared by mechanical alloying and solid-state reaction

Abstract

Magnetically isotropic Nd15Fe77B8 powder is prepared by mechanical alloying and a solid-state reaction from the elemental powders. Due to the extremely short reaction time (for example, 10 min at 700 °C) the magnetically isotropic particles have a very fine microstructure comparable to rapidly quenched samples, show a pinning-type behavior and possess excellent magnetic values such as IHC up to 13 kOe and BHmax up to 12.8 MGOe. Details on the development of the microstructure during milling, the reaction kinetics, and the magnetic properties are reported.

Mechanochemical Synthesis of Fe–S Materials

“…In this metallurgical process, powder particles are subjected to severe mechanical deformation during collisions with balls and vial and are repeatedly deformed, cold welded, and fractured, so that solid-state reactions and/or mechanochemical reactions in powder blends can be generated. Although the principles governing these reactions in many cases are incompletely understood and are also undoubtedly system specific, the formation of many compounds prepared by mechanochemical reactions, for example, borides (7), carbides (8,9), and silicides (10,11), has been reported in the literature. However, relatively few studies of synthesis of metal sulfides have been published (12)(13)(14)(15)(16)(17)(18)(19)(20)(21).…”

Some kinetic and microstructural aspects during hydrogen-induced phase transformations in alloys

“…There have been proposed several methods to improve magnetic properties, such as powder metallurgy [2], rapid quenching [3], mechanical alloying [4], hot working [5], sintering, etc. However, these methods have some disadvantages [6].…”

Effect of mechanical alloying on the formation of Sm2Fe17Nx compound

“…Mechanical alloying (MA) has been recognized as a new technique for synthesizing ultra-fine powder materials through solid-state diffusion under intense mechanical deformations [5][6][7][8][9]. In particular, it has been shown that the MA process may prove to be a useful and cost effective method for the production of isotropic polycrystalline permanent magnetic powder materials [10][11][12][13][14].…”