Alok Chaudhari | D.D.U. Gorakhpur University (original) (raw)
Papers by Alok Chaudhari
Journal of The Electrochemical Society, 2015
ChemistrySelect, Aug 27, 2018
Soft magnetic Ni−Fe/Ta2O5 nanocomposites were synthesized by electro‐codeposition on a copper sub... more Soft magnetic Ni−Fe/Ta2O5 nanocomposites were synthesized by electro‐codeposition on a copper substrate from an ethylene glycol bath. Formation of the composites, tantalum oxide particle content and structure evolution were investigated using X‐ray diffractometer (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM) and energy dispersive X‐ray analyzer (EDAX). Maximum particle content of the deposits was up to 5.7 wt% and clusters of Ta2O5 particles were found on the coating surface. This appears beneficial for improving the corrosion resistance of the coatings. With increasing current density, relative texture coefficient of the coatings shifted from (111) to (200) and followed (220) crystallographic plane. Although crystallite size was recorded approximately 15 nm in the entire current density range studied, remarkable enhancement in the microhardness of the Ni−Fe/Ta2O5 nanocomposite coatings was noticed (up to 870 HV) owing to reinforcement of ceramic particles.
![Research paper thumbnail of Erratum: Studies on Electrodeposition, Microstructure and Physical Properties of Ni-Fe/In2O3Nanocomposite [J. Electrochem. Soc.,162, D341 (2015)]](https://attachments.academia-assets.com/110592305/thumbnails/1.jpg)
](Journal of The Electrochemical Society, 2015
Journal of Alloys and Compounds, Jun 1, 2018
A review of fundamental aspects, characterization and applications of electrodeposited nanocrysta... more A review of fundamental aspects, characterization and applications of electrodeposited nanocrystalline iron group metals, Ni-Fe alloy and oxide ceramics reinforced nanocomposite coatings,
ChemistrySelect, Oct 1, 2020
Metal matrix composites with yttria as reinforcement are mostly produced because of it's improved... more Metal matrix composites with yttria as reinforcement are mostly produced because of it's improved mechanical properties while thermal stability, electrochemical and magnetic properties of the yttria based composites are rarely considered. In the present study, the feasibility of incorporating yttria nanoparticles into nickel matrix from ethylene glycol bath by electro-codeposition method is demonstrated. The particle content of the coatings was strongly influenced by current density i. e. the rate of metal deposition. Particle content, surface morphology and microstructural changes of the deposits were investigated by scanning electron microscope (SEM) equipped with energy dispersed X-ray analyzer (EDAX). A dense, compact and smoother composite surface with lower particle content was obtained at higher current densities. Crystallographic structure, texture and lattice strain have been evaluated using X-ray diffraction (XRD). Incorporation of yttria particles inhibits the grain growth and causes grain refinement of the nickel matrix. Annealed nanocomposite deposits revealed thermal stability up to 700°C. The comparative electrochemical corrosion behavior of the electrodeposited coatings in 3.5 % NaCl solution and their deposition potential were evaluated. Magnetic studies showed nearly complete absence of hysteresis i. e. soft magnetic nature of the coatings.
Arabian Journal of Chemistry, Dec 1, 2019
A new type of nanocomposite, Ni-Fe/CeO 2 ($40 nm) was prepared by cathodic codeposition at severa... more A new type of nanocomposite, Ni-Fe/CeO 2 ($40 nm) was prepared by cathodic codeposition at several current densities (1.0-5.0 A dm À2) from an ethylene glycol bath. Coatings obtained from optimized bath were characterized by field emission scanning electron microscope (FESEM), energy dispersed X-ray analyzer (EDAX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Electrochemical and physical properties of the coatings were studied as a function of variation in current density and in CeO 2 particle content. Compared to Ni-Fe alloy, these nanocomposites exhibited finer grains, higher microhardness, better electrical conductivity, improved corrosion resistance and enhanced soft magnetic properties. The effect of annealing temperature on surface morphology, microstructure, texture and microhardness was also studied. CeO 2 particles were found involved in managing textural evolution of Ni-Fe growth resulting in a shift in preferred orientation from (1 1 1) to (2 2 0) crystallographic plane with increasing current density. The incorporation of CeO 2 particles (up to 5 wt%) also results in improvement in surface smoothness, and physical and electrochemical properties.
Surface & Coatings Technology, Dec 1, 2016
The mechanical and magnetic properties of Ni-Fe alloy deposits may be controlled by compositional... more The mechanical and magnetic properties of Ni-Fe alloy deposits may be controlled by compositional tailoring and reinforcement by ceramics. The incorporation of high content of ceramic particles in the alloy matrix has, however, detrimental effect on electrical and magnetic properties of the nanocomposites. Here, electrodeposition of WO 3 nanoparticle (spheroidal shaped, 20-40 nm) doped Ni-Fe nanocomposites has been carried out in an organic bath at various current densities. The particle content in coating was found up to ~2.0 weight %. Field emission scanning electron microscope (FESEM), energy dispersed X-ray analyzer (EDAX) and atomic force microscopic (AFM) examinations revealed a distinct change in morphology of the deposit due to inclusion of the particles in the matrix. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies showed fcc lattice of the matrix and a shift in preferred orientation of the coating from (111) to (220) crystallographic planes with increasing current density. Significant enhancement in the microhardness of the coatings was observed on incorporation of only 1.25 wt% WO 3 particles due to solid solution hardening and dispersion hardening. An improvement in the conduction and corrosion resistance of the coatings over matrix has also been noticed due to dispersion of the ceramic particles in the matrix. Magnetic studies point to ferromagnetic behavior of the nanocomposite which also has the tendency of superparamagnetism.
Functional composites and structures, Nov 28, 2019
Ni-Fe/ZrO2 nanocomposite coatings were prepared by electrodeposition under direct current conditi... more Ni-Fe/ZrO2 nanocomposite coatings were prepared by electrodeposition under direct current condition from nickel sulfamate and ferrous sulphate bath with ZrO2 nanopowder using ethylene glycol as a solvent. Plating parameters like current density, concentration of ZrO2 particles and electrolytes, temperature and agitation were optimized in terms of particle incorporation, microhardness and brightness of the deposits. Morphology, composition, micro and crystallographic structures of the coatings were investigated by SEM, EDAX, XRD and TEM. The iron content in the deposit varies from 38.2% to 19.1% showing fcc lattice by the Ni-Fe alloy matrix. Due to incorporation of ZrO2 particles in Ni-Fe matrix average crystallite size of the deposit reduces to ≈11 nm. The effect of current density and annealing temperature on microstructure, texture and microhardness was studied. With increasing current density from 1.0 to 5.0 A/dm 2 there is shifting of preferred orientation from (111) to (220) cr...
Materials Research Express, 2018
Functional Composites and Structures, 2019
ChemistrySelect, 2018
Soft magnetic Ni−Fe/Ta2O5 nanocomposites were synthesized by electro‐codeposition on a copper sub... more Soft magnetic Ni−Fe/Ta2O5 nanocomposites were synthesized by electro‐codeposition on a copper substrate from an ethylene glycol bath. Formation of the composites, tantalum oxide particle content and structure evolution were investigated using X‐ray diffractometer (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM) and energy dispersive X‐ray analyzer (EDAX). Maximum particle content of the deposits was up to 5.7 wt% and clusters of Ta2O5 particles were found on the coating surface. This appears beneficial for improving the corrosion resistance of the coatings. With increasing current density, relative texture coefficient of the coatings shifted from (111) to (200) and followed (220) crystallographic plane. Although crystallite size was recorded approximately 15 nm in the entire current density range studied, remarkable enhancement in the microhardness of the Ni−Fe/Ta2O5 nanocomposite coatings was noticed (up to 870 HV) owing to reinforcement of ceramic ...
Journal of Alloys and Compounds, 2018
A review of fundamental aspects, characterization and applications of electrodeposited nanocrysta... more A review of fundamental aspects, characterization and applications of electrodeposited nanocrystalline iron group metals, Ni-Fe alloy and oxide ceramics reinforced nanocomposite coatings,
![Research paper thumbnail of Erratum: Studies on Electrodeposition, Microstructure and Physical Properties of Ni-Fe/In2O3Nanocomposite [J. Electrochem. Soc.,162, D341 (2015)]](https://attachments.academia-assets.com/110592302/thumbnails/1.jpg)
](Journal of The Electrochemical Society, 2015
Journal of Applied Electrochemistry
Journal of The Electrochemical Society, 2017
Journal of The Electrochemical Society, 2015
Arabian Journal of Chemistry, 2016
A new type of nanocomposite, Ni-Fe/CeO 2 ($40 nm) was prepared by cathodic codeposition at severa... more A new type of nanocomposite, Ni-Fe/CeO 2 ($40 nm) was prepared by cathodic codeposition at several current densities (1.0-5.0 A dm À2) from an ethylene glycol bath. Coatings obtained from optimized bath were characterized by field emission scanning electron microscope (FESEM), energy dispersed X-ray analyzer (EDAX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Electrochemical and physical properties of the coatings were studied as a function of variation in current density and in CeO 2 particle content. Compared to Ni-Fe alloy, these nanocomposites exhibited finer grains, higher microhardness, better electrical conductivity, improved corrosion resistance and enhanced soft magnetic properties. The effect of annealing temperature on surface morphology, microstructure, texture and microhardness was also studied. CeO 2 particles were found involved in managing textural evolution of Ni-Fe growth resulting in a shift in preferred orientation from (1 1 1) to (2 2 0) crystallographic plane with increasing current density. The incorporation of CeO 2 particles (up to 5 wt%) also results in improvement in surface smoothness, and physical and electrochemical properties.
Surface and Coatings Technology, 2016
The mechanical and magnetic properties of Ni-Fe alloy deposits may be controlled by compositional... more The mechanical and magnetic properties of Ni-Fe alloy deposits may be controlled by compositional tailoring and reinforcement by ceramics. The incorporation of high content of ceramic particles in the alloy matrix has, however, detrimental effect on electrical and magnetic properties of the nanocomposites. Here, electrodeposition of WO 3 nanoparticle (spheroidal shaped, 20-40 nm) doped Ni-Fe nanocomposites has been carried out in an organic bath at various current densities. The particle content in coating was found up to ~2.0 weight %. Field emission scanning electron microscope (FESEM), energy dispersed X-ray analyzer (EDAX) and atomic force microscopic (AFM) examinations revealed a distinct change in morphology of the deposit due to inclusion of the particles in the matrix. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies showed fcc lattice of the matrix and a shift in preferred orientation of the coating from (111) to (220) crystallographic planes with increasing current density. Significant enhancement in the microhardness of the coatings was observed on incorporation of only 1.25 wt% WO 3 particles due to solid solution hardening and dispersion hardening. An improvement in the conduction and corrosion resistance of the coatings over matrix has also been noticed due to dispersion of the ceramic particles in the matrix. Magnetic studies point to ferromagnetic behavior of the nanocomposite which also has the tendency of superparamagnetism.
Journal of Physics D: Applied Physics, 2013
Metal matrix composites with yttria as reinforcement are mostly produced because of it's improved... more Metal matrix composites with yttria as reinforcement are mostly produced because of it's improved mechanical properties while thermal stability, electrochemical and magnetic properties of the yttria based composites are rarely considered. In the present study, the feasibility of incorporating yttria nanoparticles into nickel matrix from ethylene glycol bath by electro-codeposition method is demonstrated. The particle content of the coatings was strongly influenced by current density i. e. the rate of metal deposition. Particle content, surface morphology and microstructural changes of the deposits were investigated by scanning electron microscope (SEM) equipped with energy dispersed X-ray analyzer (EDAX). A dense, compact and smoother composite surface with lower particle content was obtained at higher current densities. Crystallographic structure, texture and lattice strain have been evaluated using X-ray diffraction (XRD). Incorporation of yttria particles inhibits the grain growth and causes grain refinement of the nickel matrix. Annealed nanocomposite deposits revealed thermal stability up to 700°C. The comparative electrochemical corrosion behavior of the electrodeposited coatings in 3.5 % NaCl solution and their deposition potential were evaluated. Magnetic studies showed nearly complete absence of hysteresis i. e. soft magnetic nature of the coatings.
Journal of The Electrochemical Society, 2015
ChemistrySelect, Aug 27, 2018
Soft magnetic Ni−Fe/Ta2O5 nanocomposites were synthesized by electro‐codeposition on a copper sub... more Soft magnetic Ni−Fe/Ta2O5 nanocomposites were synthesized by electro‐codeposition on a copper substrate from an ethylene glycol bath. Formation of the composites, tantalum oxide particle content and structure evolution were investigated using X‐ray diffractometer (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM) and energy dispersive X‐ray analyzer (EDAX). Maximum particle content of the deposits was up to 5.7 wt% and clusters of Ta2O5 particles were found on the coating surface. This appears beneficial for improving the corrosion resistance of the coatings. With increasing current density, relative texture coefficient of the coatings shifted from (111) to (200) and followed (220) crystallographic plane. Although crystallite size was recorded approximately 15 nm in the entire current density range studied, remarkable enhancement in the microhardness of the Ni−Fe/Ta2O5 nanocomposite coatings was noticed (up to 870 HV) owing to reinforcement of ceramic particles.
Journal of The Electrochemical Society, 2015
Journal of Alloys and Compounds, Jun 1, 2018
A review of fundamental aspects, characterization and applications of electrodeposited nanocrysta... more A review of fundamental aspects, characterization and applications of electrodeposited nanocrystalline iron group metals, Ni-Fe alloy and oxide ceramics reinforced nanocomposite coatings,
ChemistrySelect, Oct 1, 2020
Metal matrix composites with yttria as reinforcement are mostly produced because of it's improved... more Metal matrix composites with yttria as reinforcement are mostly produced because of it's improved mechanical properties while thermal stability, electrochemical and magnetic properties of the yttria based composites are rarely considered. In the present study, the feasibility of incorporating yttria nanoparticles into nickel matrix from ethylene glycol bath by electro-codeposition method is demonstrated. The particle content of the coatings was strongly influenced by current density i. e. the rate of metal deposition. Particle content, surface morphology and microstructural changes of the deposits were investigated by scanning electron microscope (SEM) equipped with energy dispersed X-ray analyzer (EDAX). A dense, compact and smoother composite surface with lower particle content was obtained at higher current densities. Crystallographic structure, texture and lattice strain have been evaluated using X-ray diffraction (XRD). Incorporation of yttria particles inhibits the grain growth and causes grain refinement of the nickel matrix. Annealed nanocomposite deposits revealed thermal stability up to 700°C. The comparative electrochemical corrosion behavior of the electrodeposited coatings in 3.5 % NaCl solution and their deposition potential were evaluated. Magnetic studies showed nearly complete absence of hysteresis i. e. soft magnetic nature of the coatings.
Arabian Journal of Chemistry, Dec 1, 2019
A new type of nanocomposite, Ni-Fe/CeO 2 ($40 nm) was prepared by cathodic codeposition at severa... more A new type of nanocomposite, Ni-Fe/CeO 2 ($40 nm) was prepared by cathodic codeposition at several current densities (1.0-5.0 A dm À2) from an ethylene glycol bath. Coatings obtained from optimized bath were characterized by field emission scanning electron microscope (FESEM), energy dispersed X-ray analyzer (EDAX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Electrochemical and physical properties of the coatings were studied as a function of variation in current density and in CeO 2 particle content. Compared to Ni-Fe alloy, these nanocomposites exhibited finer grains, higher microhardness, better electrical conductivity, improved corrosion resistance and enhanced soft magnetic properties. The effect of annealing temperature on surface morphology, microstructure, texture and microhardness was also studied. CeO 2 particles were found involved in managing textural evolution of Ni-Fe growth resulting in a shift in preferred orientation from (1 1 1) to (2 2 0) crystallographic plane with increasing current density. The incorporation of CeO 2 particles (up to 5 wt%) also results in improvement in surface smoothness, and physical and electrochemical properties.
Surface & Coatings Technology, Dec 1, 2016
The mechanical and magnetic properties of Ni-Fe alloy deposits may be controlled by compositional... more The mechanical and magnetic properties of Ni-Fe alloy deposits may be controlled by compositional tailoring and reinforcement by ceramics. The incorporation of high content of ceramic particles in the alloy matrix has, however, detrimental effect on electrical and magnetic properties of the nanocomposites. Here, electrodeposition of WO 3 nanoparticle (spheroidal shaped, 20-40 nm) doped Ni-Fe nanocomposites has been carried out in an organic bath at various current densities. The particle content in coating was found up to ~2.0 weight %. Field emission scanning electron microscope (FESEM), energy dispersed X-ray analyzer (EDAX) and atomic force microscopic (AFM) examinations revealed a distinct change in morphology of the deposit due to inclusion of the particles in the matrix. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies showed fcc lattice of the matrix and a shift in preferred orientation of the coating from (111) to (220) crystallographic planes with increasing current density. Significant enhancement in the microhardness of the coatings was observed on incorporation of only 1.25 wt% WO 3 particles due to solid solution hardening and dispersion hardening. An improvement in the conduction and corrosion resistance of the coatings over matrix has also been noticed due to dispersion of the ceramic particles in the matrix. Magnetic studies point to ferromagnetic behavior of the nanocomposite which also has the tendency of superparamagnetism.
Functional composites and structures, Nov 28, 2019
Ni-Fe/ZrO2 nanocomposite coatings were prepared by electrodeposition under direct current conditi... more Ni-Fe/ZrO2 nanocomposite coatings were prepared by electrodeposition under direct current condition from nickel sulfamate and ferrous sulphate bath with ZrO2 nanopowder using ethylene glycol as a solvent. Plating parameters like current density, concentration of ZrO2 particles and electrolytes, temperature and agitation were optimized in terms of particle incorporation, microhardness and brightness of the deposits. Morphology, composition, micro and crystallographic structures of the coatings were investigated by SEM, EDAX, XRD and TEM. The iron content in the deposit varies from 38.2% to 19.1% showing fcc lattice by the Ni-Fe alloy matrix. Due to incorporation of ZrO2 particles in Ni-Fe matrix average crystallite size of the deposit reduces to ≈11 nm. The effect of current density and annealing temperature on microstructure, texture and microhardness was studied. With increasing current density from 1.0 to 5.0 A/dm 2 there is shifting of preferred orientation from (111) to (220) cr...
Materials Research Express, 2018
Functional Composites and Structures, 2019
ChemistrySelect, 2018
Soft magnetic Ni−Fe/Ta2O5 nanocomposites were synthesized by electro‐codeposition on a copper sub... more Soft magnetic Ni−Fe/Ta2O5 nanocomposites were synthesized by electro‐codeposition on a copper substrate from an ethylene glycol bath. Formation of the composites, tantalum oxide particle content and structure evolution were investigated using X‐ray diffractometer (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM) and energy dispersive X‐ray analyzer (EDAX). Maximum particle content of the deposits was up to 5.7 wt% and clusters of Ta2O5 particles were found on the coating surface. This appears beneficial for improving the corrosion resistance of the coatings. With increasing current density, relative texture coefficient of the coatings shifted from (111) to (200) and followed (220) crystallographic plane. Although crystallite size was recorded approximately 15 nm in the entire current density range studied, remarkable enhancement in the microhardness of the Ni−Fe/Ta2O5 nanocomposite coatings was noticed (up to 870 HV) owing to reinforcement of ceramic ...
Journal of Alloys and Compounds, 2018
A review of fundamental aspects, characterization and applications of electrodeposited nanocrysta... more A review of fundamental aspects, characterization and applications of electrodeposited nanocrystalline iron group metals, Ni-Fe alloy and oxide ceramics reinforced nanocomposite coatings,
Journal of The Electrochemical Society, 2015
Journal of Applied Electrochemistry
Journal of The Electrochemical Society, 2017
Journal of The Electrochemical Society, 2015
Arabian Journal of Chemistry, 2016
A new type of nanocomposite, Ni-Fe/CeO 2 ($40 nm) was prepared by cathodic codeposition at severa... more A new type of nanocomposite, Ni-Fe/CeO 2 ($40 nm) was prepared by cathodic codeposition at several current densities (1.0-5.0 A dm À2) from an ethylene glycol bath. Coatings obtained from optimized bath were characterized by field emission scanning electron microscope (FESEM), energy dispersed X-ray analyzer (EDAX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Electrochemical and physical properties of the coatings were studied as a function of variation in current density and in CeO 2 particle content. Compared to Ni-Fe alloy, these nanocomposites exhibited finer grains, higher microhardness, better electrical conductivity, improved corrosion resistance and enhanced soft magnetic properties. The effect of annealing temperature on surface morphology, microstructure, texture and microhardness was also studied. CeO 2 particles were found involved in managing textural evolution of Ni-Fe growth resulting in a shift in preferred orientation from (1 1 1) to (2 2 0) crystallographic plane with increasing current density. The incorporation of CeO 2 particles (up to 5 wt%) also results in improvement in surface smoothness, and physical and electrochemical properties.
Surface and Coatings Technology, 2016
The mechanical and magnetic properties of Ni-Fe alloy deposits may be controlled by compositional... more The mechanical and magnetic properties of Ni-Fe alloy deposits may be controlled by compositional tailoring and reinforcement by ceramics. The incorporation of high content of ceramic particles in the alloy matrix has, however, detrimental effect on electrical and magnetic properties of the nanocomposites. Here, electrodeposition of WO 3 nanoparticle (spheroidal shaped, 20-40 nm) doped Ni-Fe nanocomposites has been carried out in an organic bath at various current densities. The particle content in coating was found up to ~2.0 weight %. Field emission scanning electron microscope (FESEM), energy dispersed X-ray analyzer (EDAX) and atomic force microscopic (AFM) examinations revealed a distinct change in morphology of the deposit due to inclusion of the particles in the matrix. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies showed fcc lattice of the matrix and a shift in preferred orientation of the coating from (111) to (220) crystallographic planes with increasing current density. Significant enhancement in the microhardness of the coatings was observed on incorporation of only 1.25 wt% WO 3 particles due to solid solution hardening and dispersion hardening. An improvement in the conduction and corrosion resistance of the coatings over matrix has also been noticed due to dispersion of the ceramic particles in the matrix. Magnetic studies point to ferromagnetic behavior of the nanocomposite which also has the tendency of superparamagnetism.
Journal of Physics D: Applied Physics, 2013
Metal matrix composites with yttria as reinforcement are mostly produced because of it's improved... more Metal matrix composites with yttria as reinforcement are mostly produced because of it's improved mechanical properties while thermal stability, electrochemical and magnetic properties of the yttria based composites are rarely considered. In the present study, the feasibility of incorporating yttria nanoparticles into nickel matrix from ethylene glycol bath by electro-codeposition method is demonstrated. The particle content of the coatings was strongly influenced by current density i. e. the rate of metal deposition. Particle content, surface morphology and microstructural changes of the deposits were investigated by scanning electron microscope (SEM) equipped with energy dispersed X-ray analyzer (EDAX). A dense, compact and smoother composite surface with lower particle content was obtained at higher current densities. Crystallographic structure, texture and lattice strain have been evaluated using X-ray diffraction (XRD). Incorporation of yttria particles inhibits the grain growth and causes grain refinement of the nickel matrix. Annealed nanocomposite deposits revealed thermal stability up to 700°C. The comparative electrochemical corrosion behavior of the electrodeposited coatings in 3.5 % NaCl solution and their deposition potential were evaluated. Magnetic studies showed nearly complete absence of hysteresis i. e. soft magnetic nature of the coatings.