Structure change in Fe4N powders by mechanical milling: a new aspect and correction of our previous reports

Mechanically induced phase transition in Fe4N during ball milling and shock compression of powders

“…Of particular interest in this study is the evaluation of thermal and mechanical stability of the ␥ -Fe 4 N phase. These results are compared with studies by Sumiyama et al [8] and Yao * Corresponding author.…”

Magnetic properties and thermal stability of γ′-Fe4N nanoparticles prepared by a combined method of reduction and nitriding

“…Many methods, such as solid-gas reaction [7,8], plasma nitriding [9] and ion nitriding have been developed, e.g. heating a-Fe in a mixed gas of NH 3 +H 2 [10], or evaporate Fe metal in an atmosphere of NH 3 gas [11], or mechanical milling Fe powders in a NH 3 gas atmosphere [12]. But some samples might have suffered from oxidation and must be protected in a high-purity inert gases atmosphere during the nitriding procedure [12,13].…”

“…heating a-Fe in a mixed gas of NH 3 +H 2 [10], or evaporate Fe metal in an atmosphere of NH 3 gas [11], or mechanical milling Fe powders in a NH 3 gas atmosphere [12]. But some samples might have suffered from oxidation and must be protected in a high-purity inert gases atmosphere during the nitriding procedure [12,13]. Reduction is a simple and convenient method widely used in preparing metal.…”

Mechanical Milling Process of High Nitrogen Austenite

“…With a hope to produce powders of bct iron nitride, mechanical alloying experiments have been carried out by some research groups. [4][5][6][7][8][9][10][11][12][13][14] Present author examined two different approaches, i.e., ball milling of elemental iron powders under NH 3 gas atmosphere 4) and milling of the a-Fe and gЈ-Fe 4 N in Ar gas. 5) Both experiments resulted in formation of metastable iron nitride exhibiting bcc-like diffraction spectra and no enhancement was observed in the magnetization.…”

“…Other research groups also reported essentially the same results. [4][5][6][7][8][11][12][13][14] It is well known that high nitrogen austenite undergoes martensitic transformation at room temperature when it is subjected to plastic deformation. Mechanical alloying is known to be accomplished by repeated kneading of starting powders utilizing kinetic energy of balls in a vial.…”