Ferromagnetic Nanomaterials Obtained by Thermal Decomposition of Ferrocene

Abstract

Ferromagnetic micro and nano particles that are chemically resistant have been obtained by thermal decomposition of ferrocenes in a tightly closed chamber at high pressures. The investigation is focused on the influence of decomposition temperature, work atmosphere, temperature-change rate and process duration. According to the conditions, Fe3C, Fe3O4 and pure α-Fe particles have been created. Their composition and structure have been studied by Mössbauer spectroscopy, Scanning and Transmission Electron Microscopy, Electron Probe X-ray Micro Analysis and Energy Dispersive X-ray Spectrometry. In a tightly closed chamber, all components obtained during the decomposition process remain there. This difference to the widely-used Chemical Vapor Deposition method is very important. It inhibits the decomposition process and growth of ordered structures, preventing the end materials to be separated from each other. During the process, iron is liberated from the ferrocene molecule. Experiments have shown that it is highly chemically active to carbon and oxygen. For example, creation of carbide occured in conditions that are not allowed according to the iron-carbon phase diagram valid for bulk iron. Parallel to the reaction of iron with carbon (according to work atmosphere), the surplus of carbon atoms causes emerging of carbon nanoparticles.

Thermal Decomposition Study of Ferrocene [(C5H5)2Fe]

“…The activation energy * values for the single-step thermal decomposition of ferrocene obtained by all methods discussed so far are shown as a function of the extent of conversion in Figure 3. It is noticeable that the * values thus calculated by the three different methods given by (7), (8), and (13) are remarkably identical and are also close to that obtained by (1). At this point it should be recalled that de Souza et al [7] observed three activation energies for the single-step thermal decomposition of ferrocene using Freeman-Carroll method which are 66.7, 71.2, and 86.5 kJ mole −1 .…”

“…In recent times, the organometallic compound ferrocene, [(C 5 H 5 ) 2 Fe], has become an important precursor material for preparing iron oxide nanostructures through thermal decomposition, for example, ferromagnetic micro/ nanoparticles [1][2][3], iron oxide thin films [4], and singlewalled/ferromagnetic-filled carbon nanotube [5,6]. Taking leaf out of these works, we undertake to study the thermal decomposition of ferrocene materials in the presence of guest molecules of various kinds leading to iron oxides and to investigate the correlation among the thermal decomposition reaction kinetics, morphology/physical characteristics of the reaction products, and the nature of the guest molecules.…”

Using the Atomic-Layer-Deposited method to obtain LiFePO4 fi lm: The infl uence of process conditions on the phase composition of the fi lm

“…However, with all the positive moments, the use of ferrocene as a precursor in atomic-layer-deposited method is not possible, because at heating it sublimes and decomposes to form a mixture of products consisting not only of compounds of iron(II) but iron (III) compounds of iron mixed-valence and metallic iron [18][19][20][21][22]. Use of precursor FeCl 2 has allowed receiving iron in the necessary oxidation state, namely FeО.…”

Kinetic Analysis of Nonisothermal Decomposition of Acetyl Ferrocene

“…The properties of the end decomposition product depend on the chemical nature of the precursor used, temperature, and reaction atmosphere. Thermal decomposition of organic iron precursors, in particular ferrocene materials, has been demonstrated to be very successful in the preparation of iron oxide nanoparticles with controllable size and high quality . In this light, in a recent study we have found that an organoiron precursor acetyl ferrocene on thermal decompositionin inert atmosphere produces hematite nanoparticles and the yield and the size of the product are significantly affected by the presence of a coprecursor .…”