Home – Home – Jornals – Chemistry for Sustainable Development 2017 number 6

With a view to optimizing conditions for preparation of promising high magnetic nanomaterials, the dimensional peculiarities of which find the increasing use, the work explored mixed iron, cobalt, and nickel hydroxides, i.e. intermediate products of synthesis by the method of reduction of precursors that refer to this class of nanostructured Fe-Co-Ni powders using methods of X-ray diffraction and mass spectrometry. Precipitation of hydroxides was carried out under conditions of preparation of a polymetallic but with a lack of a reducing agent, both in coprecipitation mode and separately. As established by crystal lattice parameters, iron in coprecipitated mixed hydroxides is largely oxidized to Fe³⁺, which is probably due to their nanoscale dimensionality determined using XPA.The composition of the resulting oxide-hydroxide phases (OHP) canbe expressed by a formula of w Fe(OH)₂ · x Co(OH)₂ · y Ni(OH)₂ · z FeOOH that crystallochemically corresponds to a structural type of brucite. When mixing suspensions of separately precipitated oxides, there occurs recrystallization in two phases, such as macrocrystalline, rich with iron, and superfine, with its lower amount and oxidized to a lesser degree. In addition to OHP, a spinel phase in fine dispersion is generated. Liberation of significant amounts of CO₂ at elevated temperatures points to the presence of carbonates in samples. Since they are not detected by means of X-rays, one may assume that the carbonate anion is embedded into oxygen layers of the structure of brucite of OHP.