Mechanical alloying of iron-fullerite system. Correlation between fullerite content, its structural state and end products

• Published in: Journal of alloys and compounds 2020-07, Vol.829, p.154528, Article 154528
• Main Authors: Larionova, N.S., Nikonova, R.M., Ul’yanov, A.L., Lad’yanov, V.I., Mikheev, K.G.
• Format: Article
• Language: English
• Subjects: Alloy systems; Carbon; Cementite; Crystal structure; Destruction; Fullerenes; Iron carbides; Mechanical alloying; Metal matrix composites; Mössbauer spectroscopy; Phase composition; Reaction kinetics; Solid phases; X ray analysis; X-ray diffraction
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.154528

X-ray analysis, Mössbauer and Raman spectroscopies have been used to study mechanosynthesized iron-fullerite powders with the initial fullerite С60/70 content of 10, 25 and 75 at%. The structural changes of С60/70 in mechanocomposites have been studied. It has been shown that in conditions of high-energy mechanosynthesis of iron-fullerite powders the disordering of fullerite С60/70 crystalline structure takes place followed by the total fullerene molecules destruction with the formation of amorphous carbon. At content 75–90 at% iron serves as a catalyst of С60/70 destruction. It has been stated that the phase composition of mechanocomposites depends on the amount of fullerite and its structural state. Carbides formation takes place only after the destruction of fullerene molecules as a result of C–C and CC bonds disrupture. Amorphous carbon, Сam, amorphous phase, Am(Fe–C), carbides, Fe3C, Fe7C3 and a paramagnetic P-phase can be the end products of solid-phase reactions. At the initial stage of Fe–75C60/70 mechanosynthesis, while fullerene structure is preserved, it is possible to obtain iron-fullerene composite. The kinetics of carbide formation in the samples has been analyzed. It has been shown that the speed of solid-phase reactions at С60/70 content 25 at% is higher than at 75 at%. [Display omitted] •During mechanosynthesis of Fe-С60/70 partial or complete destruction of C60/70 take place.•The phase composition of Fe–C60/70 depends of C60/70 content and its stability.•End products can be СAm, Am(Fe–C), Fe3C, Fe7C3 and paramagnetic phase.•The 75–90 at.% Fe content acts as a catalyst for the С60/70 destruction.•After complete destruction of C60/70 the phase composition is similar to that for Fe-graphite.