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

摘要

X-ray analysis, Mossbauer and Raman spectroscopies have been used to study mechanosynthesized ironfullerite powders with the initial fullerite C-60/70 content of 10, 25 and 75 at%. The structural changes of C-60/70 in mechanocomposites have been studied. It has been shown that in conditions of high-energy mechanosynthesis of iron-fullerite powders the disordering of fullerite C-60/70 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 C-60/70 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 C=C bonds disrupture. Amorphous carbon, C am , amorphous phase, Am(Fe-C), carbides, Fe3C3, Fe7C3 and a paramagnetic P-phase can be the end products of solid-phase reactions. At the initial stage of Fe-75C(60/70) 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 C-60/70 content 25 at% is higher than at 75 at%. (C) 2020 Elsevier B.V. All rights reserved.