Authors:K. Dhoot, R. Tripathi, M. Jangid, and M. Chacharkar
Mössbauer spectroscopic studies were carried out on some synthesized iron complexes of Schiff's bases. The studies have evidenced that iron/II/ and iron/III/ species were formed, and no stereoisomers were found. However, the complex of bis/acetylacetone diethylene triamine/ had shown the geometric isomers, and only the Fe/III/ species formed. Immersion of the chelate of iron bis/salicylaldehyde ethylene diamine/ in aerated distilled water for a day had resulted in the conversion of the entire iron/II/ species into the iron/III/ complexes. The exposure to atmosphere had converted a part of iron/II/ into iron/III/ and resulted in distortion of the iron/II/ chelates. This leaves a room to think that oxygen transport or absorption may bring change in the oxidation number of the central metal ion or distortion in the structural arrangements.
Authors:A. Nigam, R. Tripathi, M. Jangid, and M. Chacharkar
The corrosion of mild steel as a result of interaction with various types of local natural water samples and distilled water is studied with the help of Mössbauer spectroscopy. The data are supplemented with the studies on IR and magnetic properties as and when required. Distilled water and potable water behave in almost similar fashion wherein ferrihydrite and FeOOH are observed to be the precursors of magnetite, the end corrosion product. In case of brakish water, the additional species, viz., FeCl2, FeOOH and an intermediate possibly FeOCl are accounted, and possible mechanisms are suggested.
Authors:A. Nigam, R. Tripathi, M. Jangid, M. Chacharkar, and Madan Lal
Tungsten ores from Degana, Rajashthan State, India are studied using Mössbauer spectroscopy. The low grade ore exhibits two types of mineral assemblages as per chemical states of iron. The relation between ferrous/ferric ratio and tungsten concentration also supports the existence of two types of mineral assemblages. The Mössbauer spectroscopy of concentrate ore samples has shown the absence of iron. The energy dispersive X-ray fluorescence spectroscopy on the contrary has evidenced the presence of iron in concentrate ore samples but at lower concentration on comparison with low grade ores. These differences in behaviour in the above spectroscopic studies may be additionally due to higher attenuation of -radiations and higher atomic weight material in the ore concentrates.
Authors:Praniti Dave, M. Roy, Shiv Barbar, and Sumit Jangid
The polycrystalline ceramic samples of general formula Pb1−XCaXTiO3 with X = 0.00, 0.1, 0.2 and 0.3 have been synthesized by standard high temperature solid state reaction method using high purity
oxide and carbonates. The formation of the single phase compounds have been checked by X-ray diffraction technique. The Modulated
Differential Scanning Calorimetry has been used to investigate the effect of substitution on the phase transition temperature
and the corresponding change on the enthalpy and other thermal parameters of the substituted compound/solid solutions. It
was observed that the phase transition temperature (Tc) decreases linearly with the increase of substitution concentration. The linear decrease in Tc with increase of substitution concentration may be useful for the eventual functionality of the materials for different ferroelectric
devices. The results are discussed in detail.
Authors:M. Roy, Praniti Dave, Shiv Barbar, Sumit Jangid, D. Phase, and A. Awasthi
The polycrystalline ferroelectric compounds of general formula Pb1−XBaXTiO3 with X = 0.00, 0.1, 0.2 and 0.5 were prepared by high temperature solid-state reaction technique using high purity oxides and carbonates.
The compounds formation was confirmed by X-ray diffraction and all the X-ray peaks were indexed with tetragonal structure
of space group P4mm. Morphology and particle size of the compounds were obtained using scanning electron microscopy. Ferroelectric phase transition,
enthalpy change, and specific heat of the compounds were obtained using modulated differential scanning calorimetry. It was
observed that the phase transition temperature decreased linearly with the increase of substitution concentration.