Studies on lactobionic acid introduced as a synergist in the presence of phosphonobutane-1,2,4-tricarboxylic acid （PBTC） and zinc ions for corrosion control of carbon steel in aqueous environment are presented. The ...Studies on lactobionic acid introduced as a synergist in the presence of phosphonobutane-1,2,4-tricarboxylic acid （PBTC） and zinc ions for corrosion control of carbon steel in aqueous environment are presented. The investigations revealed that lactobionic acid （LBA） acts as an excellent synergist in corrosion inhibition. Optimum concentrations of all the three components of the ternary formulation are established by gravimetric studies. Potentiodynamic polarization studies indicate that the new ternary system is a mixed inhibitor. Impedance studies show that a protective film is formed on the metal surface in the presence of the inhibitor formulation. The film is found to exhibit its protective nature even at higher temperatures up to 60 ~C. Analysis of the protective film by X-ray photoelectron spectroscopy （XPS） and reflection absorption Fourier transform infrared （FTIR） spectroscopy infers the presence of Zn（OH）2, oxides and hydroxides of iron and the inhibitor molecules in the surface film probably in the form of a complex, [Zn（II）-PBTC-LBA]. The morphological studies by scanning electron microscopy （SEM） and the topographical studies by atomic force microscopy （AFM） also indicate the presence of protective film on the metal surface. A plausible mechanism of corrosion inhibition is proposed.展开更多
Dielectric studies were carried out on a lead free Sodium Bismuth Titanate,NBT,(Na_(0.5)Bi_(0.5)TiO_(3))composition.The material was synthesized by conventional ceramic method(CS)and microwave sintering(MS).The presen...Dielectric studies were carried out on a lead free Sodium Bismuth Titanate,NBT,(Na_(0.5)Bi_(0.5)TiO_(3))composition.The material was synthesized by conventional ceramic method(CS)and microwave sintering(MS).The presence of single phase has been confirmed by X-ray diffraction and scanning electron microscopy of NBT ceramic.The later technique(MS)resulted in material with high density,dielectric properties and improved microstructure.The transition temperature was observed slightly higher for microwave sintered(MS)material.Longitudinal modulus measurements are very sensitive property to identify the phase transitions in ceramics.Longitudinal modulus(L)measurements were also employed on these samples in the frequency 136 kHz and can be studied in the wide temperature range 30℃to 400℃.The elastic behavior(L)showed a break at two temperatures(~200℃and 350℃)in both the conventional and microwave sintered ceramics.In NBT ceramics,permittivity anomalies are connected to modulus anomalies.The results are correlated with the dielectric measurements.This behavior explained in the light of structural phase transitions in the ferroelectric ceramics.展开更多
文摘Studies on lactobionic acid introduced as a synergist in the presence of phosphonobutane-1,2,4-tricarboxylic acid （PBTC） and zinc ions for corrosion control of carbon steel in aqueous environment are presented. The investigations revealed that lactobionic acid （LBA） acts as an excellent synergist in corrosion inhibition. Optimum concentrations of all the three components of the ternary formulation are established by gravimetric studies. Potentiodynamic polarization studies indicate that the new ternary system is a mixed inhibitor. Impedance studies show that a protective film is formed on the metal surface in the presence of the inhibitor formulation. The film is found to exhibit its protective nature even at higher temperatures up to 60 ~C. Analysis of the protective film by X-ray photoelectron spectroscopy （XPS） and reflection absorption Fourier transform infrared （FTIR） spectroscopy infers the presence of Zn（OH）2, oxides and hydroxides of iron and the inhibitor molecules in the surface film probably in the form of a complex, [Zn（II）-PBTC-LBA]. The morphological studies by scanning electron microscopy （SEM） and the topographical studies by atomic force microscopy （AFM） also indicate the presence of protective film on the metal surface. A plausible mechanism of corrosion inhibition is proposed.
文摘Dielectric studies were carried out on a lead free Sodium Bismuth Titanate,NBT,(Na_(0.5)Bi_(0.5)TiO_(3))composition.The material was synthesized by conventional ceramic method(CS)and microwave sintering(MS).The presence of single phase has been confirmed by X-ray diffraction and scanning electron microscopy of NBT ceramic.The later technique(MS)resulted in material with high density,dielectric properties and improved microstructure.The transition temperature was observed slightly higher for microwave sintered(MS)material.Longitudinal modulus measurements are very sensitive property to identify the phase transitions in ceramics.Longitudinal modulus(L)measurements were also employed on these samples in the frequency 136 kHz and can be studied in the wide temperature range 30℃to 400℃.The elastic behavior(L)showed a break at two temperatures(~200℃and 350℃)in both the conventional and microwave sintered ceramics.In NBT ceramics,permittivity anomalies are connected to modulus anomalies.The results are correlated with the dielectric measurements.This behavior explained in the light of structural phase transitions in the ferroelectric ceramics.
