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Metal-ceramic nanocomposite coatings have been applied to many industrial applications owing to their remarkable properties such as wear, corrosion and high temperature oxidation resistance than that of metals and alloys in high temperature environments. In this study, YSZ and Ni-YSZ nanocomposite coatings deposited by electron beam physical vapour deposition (EBPVD) for high temperature environments have been investigated. Initially friction and wear behaviour of YSZ coatings deposited at various substrate temperature were studied. Then the effect on wear response of Ni-YSZ nanocomposites with different Ni content were investigated using a ball-on-disc micro tribometer. The structural and tribochemical changes that occurred in the wear tracks of YSZ and Ni-YSZ coatings were investigated using field emission scanning electron microscopy and Raman spectroscopy. The results obtained on sliding wear and friction behaviour of these nanocomposite coatings suggest that 50 wt.% of Ni in YSZ nanocomposite provides good wear resistance behaviour than that of other coatings. Such an improvement in tribomechanical and wear performance of the nanocomposite coating could be attributed to the optimum amount of Ni which promotes the formation of NiO from Ni due to the frictional heat between nanocomposite coating and the sliding counter body in wear track as confirmed by Raman analysis.

Electrochemical supercapacitor fabrication using heterogeneous nanocomposite is one of the most promising pathways for energy storage technology. Herein, heterostructure based nickel-molybdenum (NiO@Ni(OH)2-α-MoO3) nanocomposites have been successfully prepared on nickel foil via hydrothermal route for supercapacitor application. The mixed phases of cubic, hexagonal, and orthorhombic crystal structure for NiO, Ni(OH)2, and α-MoO3, respectively were observed by X-ray diffraction. Heterostructures of nanosheet and nanosphere morphologies were confirmed by high resolution transmission electron microscopy. Impressively, the NiO@Ni(OH)2-α-MoO3 composite working electrode exhibits a high specific capacitance of 445 Fg-1 at current density of 1 Ag-1 and shows outstanding rate capability (97.3% capacity retention after 3000 cycles at 10 Ag-1), compared to that of NiO@Ni(OH)2 nanoparticles. Notably, two-electrode symmetric supercapacitor of NiO@Ni(OH)2-α-MoO3 working electrode shows a high specific capacitance of 172 Fg-1 at 0.5 Ag-1, excellent rate capability and good cycling stability. Also, an excellent cycling stability (capacity retention of 98% after 5000 cycles) is observed for NiO@Ni(OH)2-α-MoO3 as a working electrode in the symmetric two-electrode system. The obtained attractive results demonstrate that nanocomposite anode material can be used for development of a wide-range of energy storage devices.

Heterostructure nickel oxide (NiO) nanoparticles have been synthesized by a facile hydrothermal route. Structural, optical, and microstructural information were investigated using XRD, UV–vis, FT-IR, FT-Raman, SEM, HR-TEM, and XPS. The X-ray diffraction and HR-TEM analysis shows that the average size of the synthesized NiO is to be 12 nm. The X-ray photoelectron spectroscopic results revealed oxidation state and elemental composition of NiO. Electrochemical examination of NiO showed attractive performance with high specific capacitance of 1358 F g−1 at 1 A g−1 in 3 M KOH aqueous electrolyte. Moreover, the results showed superior energy density of 138 W Kg−1 and power density of 1041 Wh Kg−1. The NiO-modified electrode showed high capacitive execution with high specific capacitance and excellent cycle life. The attractive electrochemical result is attributed to the heterostructure morphology and good adherence of the NiO nanoparticle on the substrates, which reduce the particle diffusion length and significantly encourage the charge movement both at the contact interfaces and inside the anode materials during the electrochemical cycle.

Surface modifications have been applied to metal in order to improve the mechanical, chemical and physical properties, such as wear and hardness. Surface modification is found on the part surface of the automobile parts like turbochargers. Surface modification of stainless-steel alloy by plasma treatment is achieved using different gases such as air, nitrogen, argon and helium. The objective of plasma surface modification is to enhance the surface wettability, reduce surface friction, to reduce the wear rate and to avoid surface crack propagation on the components, to improve of surface properties against wear and other factors. In this project SS310 material is selected as the base material which is used for turbocharger. This SS310 material is machined and undergone plasma nitriding at a temperature of 450 °C for 4 h. The plasma nitrided specimens have undergone different tests such as roughness, wear and hardness From all the test results, it is concluded that the material undergone heat treated plasma nitriding exhibits better mechanical and tribological properties such as roughness, hardness and wear resistance for the automobile components. This brings better service life of mating components in a successful way.

In this present work, a one-step hydrothermal approach was employed for the synthesis of ternary metal sulfides (TMS) for the preparation of high performance electrochemical supercapacitor electrode materials. Powder X-ray diffraction confirmed the formation of rhombohedral structure of NiS, hexagonal structure of the CoS and cubic structure of Ni1-xCoxS. The peaks obtained in the Fourier transform infrared spectroscopy (FTIR) also confirmed the formation of NiS, CoS, Ni1-xCoxS (x = 0.1,0.2 & 0.3) compounds. Field emission scanning electron microscopy revealed severe agglomeration and spongy microstructure with decreasing Ni content, while fine distribution of particles with less porosity with low Ni content in Ni1-xCoxS.The electrochemical behaviour of the fabricated Ni0.8Co0.2S electrode exhibited high specific capacitance of 71.92F/g at 5 mV/s in a potential window range from 0.25 to −0.3 V in 0.1 M non-aqueous electrolyte of TEABF4 in acetonitrile (AN) at room temperature. An excellent cycling stability was obtained up to 5,000 cycles with 87% capacitance retention.

The structural, nanomechanical and corrosion properties of TiC and TiN thin films prepared by pulsed dc sputtering under similar processing conditions were investigated. X-ray diffraction, scanning electron microscopy and atomic force microscopy techniques were used to investigate the phase formation, surface morphology, and surface roughness of the films, respectively. Nanoindentation technique revealed that the TiC films had superior indentation hardness and Young’s modulus of 18.61GPa, and 196.57 GPa, respectively than that of the TiN films. Electrochemical impedance spectroscopy measurements carried out in natural seawater and 3.5% NaCl solution indicated that TiC coating with low surface roughness has shown a superior passivation and better corrosion protection for the M−50 steel substrate than that of TiN coatings.

Two series of samarium co-doped in 10 mol% Gd doped ceria Ce0.90Gd0.1O1.95(GDC10) formulated as Ce0.9-xSmxGd0.1O2-δ(CS) and Ce0.9Gd0.1-xSmxO2-δ(GS) (x = 0.0, 0.03, 0.05 0.10) were synthesized by glycine nitrate auto combustion method. The structural effects of Sm substitution in the GDC10 solid solution have been studied by X-ray diffraction (XRD) and Raman spectroscopy techniques. An increased lattice constant (5.407 A to 5.414 A) with decreasing crystallite size (28.6 nm 22.5 nm) was observed in both the Ce substituted by Sm (CS) and Gd substituted by Sm (GS) in GDC10 crystal system. The highest oxygen vacancy concentration ( V O ⋅ ⋅ = 2.65 × 1021 cm−3) was found for 10 mol % Sm and 10 mol % Gd doped ceria (Ce0.8 Sm0.1Gd0.1O1.90) composition (CS10) evaluated by spatial correlation model from Raman spectroscopy. The microhardness of the sintered pellets was investigated by Vickers hardness measurement. The highest fracture toughness was found to be 1.85 ± 0.27 MPa m1/2 for Ce substituted by 3 mol% Sm composition (CS3) among the overall compositions. The surface morphology and elemental composition of the CS and GS compositions were analyzed by FESEM. The morphology and composition of optimized electrolyte (CS10) was further analyzed by HRTEM and XPS respectively. AC impedance spectroscopy revealed that CS10 composition has an improved ionic conductivity (σ800 = 0.147 × 10−3 S‧cm−1) with significantly reduced activation energy (0.85 eV) in the temperature range of 673–1073 K under air atmosphere. A mechanism for conductivity enhancement by oxygen vacancy for CS compositions has been proposed. The effect of Sm as a secondary co-dopant in the GDC10 electrolyte was studied in detail to establish a candidate electrolyte material for operating solid oxide fuel cells in the intermediate temperature range (673–1073 K).

The need for clean energy production and utilization is urgent and continues to grow due to the serious issues of human population growth and environmental pollution. The energy crisis is driving the demand for novel and innovative materials for the development of alternative energy sources and the fabrication of innovative energy storage devices. Supercapacitors are emerging electrochemical energy devices for future clean energy technologies. Supercapacitors have several distinctive features, such as rapid charging rates, high power densities, long cycle lives, and simple configurations. Thus, supercapacitors can serve as bridges to span the power gap between conventional capacitors and batteries or fuel cells. The current state of supercapacitor research is summarized in this review, and rapid progress in the basic development and practical application of supercapacitors is highlighted. A concise review of the technologies and working mechanisms of different supercapacitors is presented along with recent developments in the application of transition metal sulfide-based materials in electrochemical supercapacitors. Nanostructured transition metal sulfides have gained prominence as advanced electrode materials for an electrochemical supercapacitor due to their outstanding properties. These include good electrical conductivity, high specific capacity, low electronegativity, unique crystal structures, and high redox activity. The electrochemical performance of transition metal sulfides is superior to that of transition metal oxides which is attributed to the replacement of oxygen atoms with sulfur atoms. In this context, special emphasis is placed on nickel, cobalt, molybdenum, tin, manganese, and tungsten metal sulfides and their composites as advanced electrode materials for supercapacitor applications. Finally, the benefits and challenges of using transition metal sulfide-based electrode materials for future clean energy storage are discussed.

Dielectric studies of sintered pellets of barium strontium titanate, BaxSr(1−x)TiO3 (BST) with different compositions (x = 0.5, 0.6, 0.7) were carried out as a function of temperature in the range 35–297 K. The phase transformation temperature of cubic (paraelectric), tetragonal (ferroelectric), rhombohedral (ferroelectric), and orthorhombic (ferroelectric) phases of the BST ceramics with different strontium contents has been determined. The dielectric properties of the BaxSr(1−x)TiO3 pellets have revealed that Curie temperature decreased on replacing Ba by Sr. The Curie temperatures of Ba0.5Sr0.5TiO3, Ba0.6Sr0.4TiO3, and Ba0.7Sr0.3TiO3 were found to be 245 K, 260 K, and 285 K, respectively. Further, cubic, tetragonal, orthorhombic, and rhombohedral phases were observed for the BST pellets with x = 0.5, 0.6, 0.7 in the low temperature range of 35–297 K. The dielectric studies revealed higher dielectric constant and low dielectric loss for Ba0.6Sr0.4TiO3 sample than that of other compositions of the BST. Polarization–electric field (P–E) hysteresis loop measurements for Ba0.6Sr0.4TiO3 ceramic pellet was carried out with different applied electric fields in the range 1.39 to 4.86 kV/cm and in the temperature range of 108–323 K to study the variation in remanent polarization (Pr), saturated polarization (Ps), and coercive field (Ec). The saturated polarization and remanent polarization were found to increase steadily up to the temperature of 165 K and to decrease drastically at about 323 K as a consequence of ferroelectric to paraelectric transition.

In this study, hierarchical-structured Co3O4 nanocapsules and various rare earth metal (La, Nd, Gd, Sm)–doped Co3O4 materials were synthesized by a polymer-assisted combustion route. These rare earth metal–doped Co3O4 materials were tested as active electrode materials for high performance electrochemical supercapacitors. The Sm-Co3O4 electrode has shown an extraordinary electrochemical supercapacitor performance with high specific capacitance and exhibited a good cycling stability with the capacitance retention of 93.18% after 5000 cycles. The doping of rare earth metals in Co3O4 can reduce the charge transfer resistance and crystalline nature which are expected to improve the transfer of ions and electrons. Also, the large number of structural defects can promote the diffusion of electrolyte ion and electrochemical supercapacitance behavior. Furthermore, the antistructural modeling has shown that isovalent cation substitution leads to the formation of cation vacancies and interstitial defects, which enhance the electrochemical properties of doped Co3O4 materials.

This work reports the coprecipitation synthesis and characterization of single-phase Sm3+/Sr2+/Ca2+ codoped with Gd3+ in cerium oxide formulated as Ce0.8M0.1Gd0.1O2−δ (CMGO; M = Sm3+, Sr2+, Ca2) na...

Development of metal nitride-based thin film binder-free electrodes is a rapidly emerging area of research for the development of supercapacitors. The manganese nitride (Mn3N2) binder-free thin film electrodes were prepared using DC magnetron sputtering process. X-ray diffraction and the Raman spectroscopy characterization confirmed the formation of the tetragonal phase of Mn3N2 thin film. Field emission scanning electron microscopy revealed that the Mn3N2 particles are in nanoscale range and the particles with pyramidal shape are distributed uniformly on the surface of the film. Further, the Mn3N2 electrodes were examined by cyclic voltammetry and galvanostatic charge-discharge measurements to investigate the supercapacitive properties. The electrochemical measurements were performed on Mn3N2 deposited on conducting stainless steel substrates in different electrolytes (KOH, KCl and, Na2SO4 at 1 M concentration). The effect of various electrolytes on the areal capacitance, cycling stability, capacitance retention of the Mn3N2 electrodes was investigated. The Mn3N2 electrodes show high areal capacitance of 118 mF cm−2 for KOH, 68 mF cm−2 for KCl and 27 mF cm−2 for Na2SO4 at a scan rate of 10 mV/s. Moreover, the Mn3N2 electrodes indicated excellent cycling stability with capacitance retention of 98.5%, 89% and 83% for KOH, KCl, and Na2SO4, electrolytes respectively after 4,000 cycles. A comparative study on the electrochemical supercapacitive properties of the Mn3N2 electrode in different aqueous electrolytes is reported for the next generation electrochemical energy storage devices.

In the present study, structural properties of thermally treated thermal barrier coatings made of plasma sprayed NiCrAlY bond coat with single layered yttria (7 wt%) partially stabilized zirconia (PSZ) and bi-layered PSZ/gadolinium zirconate (GZ) (PSZ/GZ) as topcoat prepared by electron beam physical vapor deposition have been investigated. X-ray diffraction was used to understand the phase distribution, crystallite size, strain and preferred orientation in the as-deposited as well as thermally treated topcoat materials. SEM examination of the cross-sectional microstructure of the bond coat showed lamellar microstructure, while both the topcoats exhibited feathery columnar microstructure associated with fine pores. The single layered PSZ and bi-layered PSZ/GZ coatings were isothermally oxidized at 1273 K, 100 h to investigate the microstructure and crack distribution in these coatings. Mechanical properties of the as-deposited and isothermally oxidized single layered PSZ and bi-layered PSZ/GZ coatings were evaluated. The phase stability and lifetime of the TBCs were studied for the samples subjected to isothermal and cyclic oxidation tests. Results revealed that the coatings were thermally stable with no phase transformation and no spallation on both PSZ and PSZ/GZ coating subjected thermal cycling at 1273 K, 200 cycles. However, the bi-layered PSZ/GZ coatings performed better than single layered PSZ coatings subjected to thermal cyclic at 1473 K, 100 cycles. The reduced hardness obtained after thermal cycling of the PSZ/GZ suggests that the latter coatings are better than the single layered PSZ or GZ coatings as top coat material.

Two-dimensional nanostructured transition metal nitride-based thin film electrodes have been gaining importance in the electrochemical supercapacitor applications. In this work, Cr doped vanadium nitride (VN) thin films as an electrode material for high-performance supercapacitors have been demonstrated. In this study, reactive magnetron co-sputtering technique was adopted to fabricate phase pure VN as well as VN films doped with different Cr contents. These films were directly investigated as electrodes without using any additional binders. The phase purity and the surface chemistry of the Cr doped VN thin films were investigated using XRD and XPS techniques. Furthermore, EDS and X-ray elemental mappings were used to confirm the content of Cr and its distribution in these electrode films. The Cr −5.7 at. % doped VN thin film electrodes exhibited an extraordinary supercapacitor performance with the maximum areal capacitance of 190 mF/cm2 compared to the areal capacitance of 27 mF/cm2 for the un-doped VN at a scan rate of 10 mV/s. Moreover, the Cr-5.7 at. % doped VN thin film electrodes showed excellent electrochemical cycling stability and excellent reversibility with the capacitance retention of 92.4 %. It could be noticed that the incorporation of metal such as Cr could be a viable method to improve the electronic or ionic conductivity of the metal nitrides for supercapacitor applications.

In the present study, a nanocomposite cathode comprising Fe rich La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) based pervoskite semiconductor oxide and Sm-Gd co-doped ceria rich Ce 0.8 Sm 0.1 Gd 0.1 O 1.90 (CSGO) in the ratio of 1:1 has been successfully synthesized by a simple glycine nitrate auto combustion method. The structural properties of the two phase nanocomposite were evaluated by X-ray diffraction and Raman spectroscopy. A detailed electrical properties of co-doped LSCF-CSGO nanocomposites have been studied with a comparison of LSCF added with 10 mol% and 20 mol% Gd singly doped ceria (LSCF-GDC10 and LSCF-GDC20) nanocomposites as a function of temperature in the range of 673–1073 K at air atmosphere by AC impedance spectroscopy. The total electrical conductivity of the co-doped LSCF-CSGO nanocomposites has been found to be 0.043 S cm −1 at 973 K which is higher than that of the LSCF composite containing singly doped compositions. The Sm co-doping in GDC phase has effectively helped to reduce the undesired electronic conduction produced in the doped ceria as the electron concentration of LSCF-CSGO was found to be − 2.62 × 10 15 cm −3 which was lower than the electron concentration of LSCF containing singly doped nanocomposite (LSCF-GDC20, − 2 ×10 16 cm −3 ) estimated by Hall-Effect measurement. The activation energy of LSCF-CSGO nanocomposite has been found to be 0.05 eV for the oxygen reduction reaction by temperature dependent Arrhenius equation. The improved electrical properties in terms of high ionic conductivity and low activation energy have been achieved through the incorporation of Sm into GDC10 electrolyte phase in LSCF nanocomposite. The combustion synthesis method has also effectively helped to produce microstructure containing large grain size (~ 6 µm) which is beneficial for enlarging triple phase boundary (TPB) area of cathodes utilized in solid oxide fuel cells (SOFC) operated at reduced/intermediate temperature (673–973 K).

Electrochemical supercapacitor fabrication using heterogeneous nanocomposite is one of the most promising pathways for energy storage technology. Herein, heterostructure based nickel-molybdenum (NiO@Ni(OH)

This chapter explores the advancement in the development of ceramic nanocomposite coatings with a major emphasis on corrosion protection of metals and alloys. Examples on corrosion behavior of metal–ceramic nanocomposite coatings of Ni–SiO2, Ni–Al2O3, Ni–TiO2, and Ni–YSZ on corrosion are briefly presented from the corrosion point of view. The various contributing factors for corrosion mechanism such as choice of elements, grain size, texture, porosity, grain boundary, and concentration of ceramic oxide in nanocomposites are described. In addition, the development of compositionally graded Ni–YSZ coating and its corrosion behavior are illustrated to bring out the importance of material selection to reduce thermal expansion and lattice mismatch for the high-temperature corrosion applications. The new strategies and approaches toward corrosion protection at nanoscale are proposed based on the experimental results reported in the literature.

This chapter explains the emerging trends and development of cerium oxide–based material as a potential solid electrolyte for intermediate temperature solid oxide fuel cells (IT-SOFCs) application. The new strategies and approaches toward the enhancement in the ionic conductivity of the solid electrolyte in the current literature are discussed. The influence of structural and microstructural modifications on electrical properties of the solid electrolyte has been explained from the fundamental material aspect of IT-SOFCs. The various contributing factors for ionic transport such as grain and grain boundary effect in the bulk nanostructures are described. In addition, the importance of the oxide ionic conductivity to reduce the operational temperature of SOFCs is highlighted. The ongoing research in the development and requirements of thin layer of electrolytes using both chemical and physical methods are illustrated. This chapter highlights on the key development of interlayers which can be used in conjunction with doped ceria electrolytes for IT-SOFCs. The work also reviews the recent progress, advancements, and future directions in the ceria-based electrolytes for IT-SOFCs.

Supercapacitors (SCs) has gained an impressive concentration by the researchers due to its advantages such as high energy and power densities, long cyclic life, rapid charge–discharge rates, low maintenance and desirable safety. Hence it has been widely utilized in energy storage and conversion devices. Among the different components of SC, electrodes play a vital role in the performances of SCs. In this review, we present the recent advances in 2-D nanostructured metal nitrides, carbides, and phosphides based materials for SC electrodes. Finally, the electrochemical stability and designing approach for the future advancement of the electrode materials are also highlighted.

In this paper, phase pure cubic yttrium oxide (Y2O3) films deposited by electron beam physical vapor deposition technique on Inconel-718 substrate at different substrate temperatures (773–973 K) are investigated. The structure and phase evolution in the films of Y2O3 as a function of substrate temperature have been evaluated by X-ray diffraction. Atomic force microscopy and scanning electron microscopy were used to examine the surface roughness and morphology of the as-deposited Y2O3 films. The adhesion behavior of the Y2O3 film with Inconel-718 substrate was investigated using scratch indentation testing. The thermal expansion coefficient (TEC) of Inconel-718 substrate and Y2O3 film coated on Inconel-718 substrate were determined by high temperature X-ray diffraction (HTXRD) measurement in the temperature range of 298–1273 K with temperature interval of 100 K. The linear TECs of Inconel-718 and Y2O3 film at 1273 K were found to be 1.22 × 10−5 K−1 and 7.02 × 10−6 K−1, respectively. Thermal stability of the Y2O3 coated Inconel-718 substrate tested at 1273 K in air over a period of 100 h is also discussed.

In the present work, gadolinium zirconate (Gd 2 Zr 2 O 7 ) coatings have been developed on Inconel-718 substrates by electron beam physical vapor deposition (EB-PVD) technique. The structural, morphological and mechanical properties as a function of substrate temperature have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), nanoindentation and scratch tests. XRD analysis revealed that the coatings showed cubic defect fluorite phase, and no secondary phase formation was observed in the coatings during deposition. The decrease in the lattice constant of the fluorite phase with increasing deposition temperature was explained on the basis of strain relaxation and vacancy concentration. Increased surface roughness of the coatings has been found with increasing substrate temperature as a result of increased crystallite size. An improved coating adhesion achieved for the coating deposited at higher substrate temperature of 973 K was confirmed by scratch test. Nanoindentation measurements indicated higher hardness (7.7 GPa) and resistance to plastic deformation and better capability to accommodate deformation energy for the coatings prepared at higher deposition temperature.

Nanostructured carbon based materials with unique and tunable properties make them to be utilized for various applications in different forms especially for energy and environmental applications. Carbon is a distinctive chemical element which has superior properties such as porous structure, low cost, resistance to basic and acidic conditions, easy accessibility, low density, good recycling properties, more abundant and ability to combine with other chemical elements in different ways. In this review, we have critically assessed the recent developments in carbon based heterostructures for their applications in energy and environment. Special consideration has been paid on the applications in dye-sensitized solar cells, hydrogen evolution reaction, oxygen evolution reaction, Li-ion battery, supercapacitor, photocatalysis for the degradation of organic pollutants, electrochemical/bio sensors and biomedical applications. Finally, the challenges and future developments of carbon based heterostructures for applications in energy and environment are also outlined.

Transition metal carbides (TMC) are known for their improved tribological properties and are sensitive to the tribo-atmospheric environment. Nanocrystalline molybdenum carbide (MoC) thin films were deposited by DC magnetron sputtering technique using reactive CH4 gas. The friction and wear resistance properties of MoC thin films were significantly improved in humid-atmospheric condition as compared to high-vacuum tribo-condition. A comprehensive chemical analysis of deformed contact interfaces was carried out by X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX) and Raman spectroscopy. XPS and Raman spectroscopy showed the formation of stable molybdenum-oxide (MoO), molybdenum carbide (MoC) and amorphous carbon (a-C) tribo-phases. Moreover, during the sliding in humid-atmospheric condition, these phases were extensively deposited on the sliding steel ball counter body which significantly protected against undesirable friction and wear.

In this study, planar heterojunction oxide solar cells (PHOSC) in both (p-i-n) and (n-i-p) configurations are fabricated using the radio frequency (RF) magnetron sputtered tin oxide (SnO2), copper (II) oxide (CuO) and nickel oxide (NiO) as n-type, absorber and p-type layers, respectively. XRD analysis confirmed the formation of tetragonal SnO2, monoclinic CuO, and cubic NiO phases. The cross-sectional SEM analysis showed the columnar growth for the sputtered metal oxide layers and XPS analysis revealed the valence states of metal oxides. Optical bandgap of n-type, absorber and p-type layers were found to be 3.7, 1.2 and 3.5 eV, respectively which leads to a staircase arrangement in the energy level alignment. The fabricated device with 600 nm thickness shows power conversion efficiency (PCE) (η) of 2.3% with enhanced open-circuit voltage (Voc) = 0.75 V, short-circuit current density (Jsc) = 5.73 mA/cm2 and fill factor (FF) of about 54% for (n-i-p) configuration. Similarly for (p-i-n) configuration, (η) of 0.4% is achieved with decreased Jsc. This new strategy paves the way for easier, stable and large scale fabrication of planar oxide solar cells.

In this work, supercapacitive properties of un-doped and Cu doped Mo3N2 thin films developed by reactive magnetron co-sputtering technique are reported. X-ray diffraction (XRD) investigation confirmed the cubic phase of Mo3N2 and the addition of Cu to Mo3N2 did not change the crystal structure. The presence of Cu in this Mo3N2 was further confirmed by energy dispersive spectroscopy (EDX). The electrochemical supercapacitive performance of the needle/cone shaped thin film electrodes were investigated using cyclic voltammetry and galvanostatic charge-discharge techniques. The measurements showed an areal capacitance of 173.4 mF cm−2 for the un-doped and 619.5 mF cm−2 for the Cu doped Mo3N2 at a scan rate of 5 mV s−1 in 1 M KOH and the excellent cycling stability of 80% capacitance retention over 2000 cycles. The results suggested that the prepared Mo3N2 based electrodes are excellent candidate materials for high-performance supercapacitors.

Cubic YSZ coating and compositionally graded Ni-YSZ nanocomposite coating have been developed on Inconel-690 using electron beam physical vapor deposition technique to act as a chemical diffusion barrier. The microstructure and chemical composition of the graded coating have been characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, electron probe microanalysis, X-ray photoelectron spectroscopy and secondary ion mass spectroscopy techniques. Electrochemical corrosion study was carried out in 3 M HNO3 medium and it was found that compositionally graded Ni-YSZ coating heat treated at 1273 K in air showed superior corrosion resistance than as-deposited compositionally graded Ni-YSZ and YSZ coatings on Inconel-690 substrate.

A facile approach involving electrochemical deposition method was utilized to coat ITO substrate with zinc selenide thin films at different rare earth metal (Eu3+, Sm3+ and Gd3+) ions. The characteristics of deposited films were studied in relation with the doped metal ions. The structure of the coating was confirmed to be hexagonal wurtzite in (101) plane by X-ray analysis. The new antistructural modeling shows that the doping of ZnSe lattice by rare earth cations increases the concentration of the surface active centers such as $${\text{Gd}}_{{{\text{Zn}}}}^{\cdot },\,{\text{Eu}}_{{{\text{Zn}}}}^{\cdot },\,{\text{Sm}}_{{{\text{Zn}}}}^{\cdot },\,{\text{and}}\,{\text{V}^{\prime\prime}_{{\text{Zn}}}}$$, which are located in the cationic sublattice. XRD data revealed that the average crystallite size of ZnSe and ZnSe:Eu, ZnSe:Sm, and ZnSe:Gd was 63, 54, 47, and 49 nm, respectively. The morphological results by scanning electron microscopy indicate that the spherical-like structure with agglomeration of grains and a slight increase in the particle size. Energy dispersive X-ray, UV–Visible and photoluminescence spectroscopy were used to study the composition and optical properties of the films. A blue-shift was observed in ZnSe thin films. The bandgap energy of undoped ZnSe and ZnSe:Eu, ZnSe:Sm, and ZnSe:Gd were found to be 2.28, 2.44, 2.68 and 2.75 eV, respectively. Among the different coated films, the Gd3+ ion doped ZnSe thin film exhibited a lesser charge transfer resistance of 25.5 Ω as analyzed from the electrochemical impedance measurement. The photoelectrochemical studies reveal that the rate of photoinduced charge carriers was higher in Gd3+ ion doped thin film. The present studies suggested that the Gd3+ ion doped ZnSe thin film can be a promising material for electrochemical device applications.

Nuclear vitrification components used in melter pot made of Ni-base superalloys degrade prematurely due to alloy-waste glass interaction and the formation of secondary precipitates. Deposition of cubic yttria stabilized zirconia (c-YSZ) coating has been recommended as a diffusion barrier material to delay or reduce the failure of the alloy and to enable an extended life. In the present work, c-YSZ films have been deposited on Inconel-690 substrate by electron beam evaporation technique at various substrate temperatures from 673 K to 973 K. The residual stress in the film surface and at the film/substrate interface was measured using grazing incidence x-ray diffraction (GIXRD) with various incidence angles. It was observed that the residual stress at the film/substrate interface region changes from tensile to compressive when the substrate temperature was increased from 673 K to 973 K during deposition. Furthermore, the thermal expansion coefficient (TEC) of Inconel-690 substrate and YSZ film coated Inconel-690 substrate were determined by high temperature (HTXRD) measurement in the temperature range of 298–1273 K with 100 K interval. The linear TECs of Inconel-690 and YSZ coated Inconel-690 at 1273 K were found to be 1.53 × 10 −5 K −1 and 6.04 × 10 −6 K −1 , respectively.

In this study, a systematic investigation on in-situ sintering behavior of Ni-YSZ (50: 50wt. %) pellets of density of 4.2 (low density) and 4.9 g/cm3 (high density) in ambient and oxygen environment by impedance spectroscopy is presented. X-ray diffraction indicated the formation of cubic phases of NiO and YSZ. The low density pellet sintered for 16 h showed low content of monoclinic phase when compared to high density pellet. The microstructure of the high density pellet revealed finer and homogenous distribution of Ni in YSZ matrix due to longer sintering duration when compared with the low density pellet. AC impedance spectra were recorded for both low and high density pellets during sintering in ambient and oxygen environment in the temperature range 873-1173 K. The results indicate that for both the pellets, the impedance values decreased when sintering temperature increased from 873 to 1173 K in both ambient and oxygen environment. However, the impedance was low while sintering in oxygen atmosphere than in ambient. Besides these observation, impedance of the high density pellet was much lower than that of the low density pellet at all sintering temperature in both ambient and oxygen atmosphere. While the impedance decreased with increasing sintering temperature, the capacitance increased slowly in both the ambient and oxygen atmosphere. The change in the impedance behavior due to grain interior and grain boundaries is explained in relation with the microstructural changes that occur during sintering in different environments.

In this paper, NiO-Gadolinia Doped Ceria (10 mole % Gadolinia) NiO-GDC10 composite with Nickel varying from 50 to 65 wt.% has been prepared by conventional solid state reaction method. The structural and microstructural properties have been evaluated by X-ray diffraction and scanning electron microscopy, respectively. The electrochemical behavior of the composites with varying concentration of Ni has been investigated by AC impedance spectroscopy. Both the grain and grain boundary conductivities have been determined as a function of temperature in the range of 773-973 K. The highest total electrical conductivity (σGi+σGb) have been achieved as 0.28 x10-3 Scm-1 at 973 K with activation energy of 0.40 eV for composition of GDC10 with 65 wt % of NiO (NiO-GDC-65:35 wt.%). The influence of microstructure on electrical properties of the composites has been analyzed and the conductivities have been compared with the conventional NiO-YSZ (50:50) composite in order to fabricate Ni-GDC based anode material of better performance.

Everydaya lot of machineries, involves various relative motions between the mating parts and there is a need to improve the surface to make it to face the severe working conditions. The ductile materials are soft in nature and it is no longer good enough to meet friction and the associated wear. Hence it is recommended to go for surface improvement so as to increase hardness on the surface only and retaining the core material hardness as unaltered. For improving surfaces, Nitriding processes gives promising results. In Nitriding process the objective is to diffuse nitrogen into the metal surface to make the surface hardened. The three methods of Nitriding is available in the literature and in this paper an attempt has been made to emphasize the processes in brief for Gas Nitriding, Liquid bath Nitriding and Plasma Nitriding. Also 40Cr4Mo3 material has been nitrided and checked for energy consumed in Charpy V-notch test method. Also SEM results have been presented for confirming nitrided dispersion. Conclusions are made in favour of Plasma Nitriding for its desired environmental friendly process characteristics, stability with low temperature applications.

Cu2O-Cu(OH)2 nanocomposite was successfully synthesized by a facile one step chemical precipitation method. The structure, morphology and optical properties of the Cu2O-Cu(OH)2 nanocomposites were investigated using X-ray diffraction, SEM, TEM and UV–vis absorption spectroscopy. The visible-light driven photocatalytic activity was evaluated by the decolouration of crystal violet (Cv) using Cu2O-Cu(OH)2 nanocomposites. This durable nanocomposite catalyst, with its excellent combination of Cu2O and Cu(OH)2 nanoparticles is a promising catalyst for Cv degradation under visible-light irradiation.

The present paper reports on the measurement of coating adhesion with Inconel 718 as a function of substrate temperature in order to qualify the coatings for application in nuclear vitrification furnace. In the present study, the scratch indentation has been used to determine the critical loads and the friction coefficient offered by the coatings as a function of the substrate temperature. It is noticed that as the substrate temperature increases from 673 to 973 K, the critical load also increases from 2.5 N to 6.1 N, while the friction coefficient remains almost constant. Initially at lower loads, nested micro cracks which form in the coating open in the direction of the scratch track. As the scratch length increases with increasing load, the tensile cracking of YSZ gets transformed to conformal cracking. For the coatings deposited at higher temperature, chipping formation gets reduced as a consequence of improved adhesion of the coating with the substrate. This coating with an improved adhesion finds its application as diffusion barrier coating in nuclear vitrification furnace. This will reduce the faster degradation or premature failure of the components of vitrification furnace made up of Ni based super alloy. The use of YSZ diffusion barrier coating increases the durability and efficiency of the component. Copyright © 2016 VBRI Press.

Biogenic calcium carbonate/phosphate were isolated and characterized from oral bacteria (CPOB). The crystalline nature and morphology of calcium carbonate/phosphate were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. XRD analysis revealed the cubic phase of YSZ coating as well as biogenic calcium carbonate (rhombohedral) and calcium phosphate oxide (hexagonal) was observed from CPOB. FESEM confirmed the extracellular synthesis of calcium compounds. Bacterial adhesion result reveals that YSZ coating drastically reduce bacterial invasion than titanium substrate.

The ability to control matter at the range of micron as well nanometer is crucial for material science and engineering. In the domain of material science, the transition metal (TM) nitrides find a unique place owing to their excellent properties such as wear resistance, high hardness and etc. These excellent properties recommended TM nitrides to be used as hard and protective coatings. Further improvements of the mechanical properties were reported by using either ternary compounds such as TiSiC, TiSiN, TiAlN, multilayer or bilayers structures. Here we report the preparation of of multilayer with no of layers of 2,4,10 of titanium nitride (TiN)/zirconium nitride (ZrN) thin films on single crystal Si(100) substrate by using pulsed laser deposition with Nd-YAG laser operating at a wavelength of 1064 nm, pulsed duration 6 ns and repetition rate 10 Hz. The multilayers are grown by ablating from the targets of Zr and Ti in reactive DC nitrogen plasma at a substrate temperature of 673 K at a nitrogen partial pressure of 2x10 -3 mbar. We investigated the mechanical properties and roughness analysis by Nanoindentation and Atomic force microscopy. Grazing incidence X ray diffraction was used to identify the phase presence in multilayers of TiN/ZrN and cross sectional scanning electron microscopy was used to examine the microstructures and thickness of bilayers. The nanoindentation results showed that peak in hardness was observed in (TiN/ZrN) 2 about 18 Gpa and young’s modulus 250 Gpa

In this work, ZnS:Cu thin films were synthetized by RF magnetron co-sputtering using ceramic ZnS and metallic Cu targets. The power applied to Cu target was changed to vary the Cu content in the films while other experimental parameters remain constant. Whatever the copper content, only the hexagonal ZnS phase was detected by X-ray diffraction and the films are oriented along the c-axis. For films with a Cu content higher than 10.6 at%, the a and c lattice parameters of the crystal cell decrease leading to a shrinkage of the ZnS:Cu cell. Changes in the microstructural, optical and electronic properties of the films are also observed. Regarding the optical properties, the energy bandgap determined by optical absorption decreases with the Cu content. Moreover, an absorption in the near infrared region appears probably due to a plasmon resonance coming from an increase of the holes carrier concentration. From electrical measurements it was found that above a copper concentration of 10 at%, the films are conductive and exhibit a p-type behavior. These results were discussed taking into account the substitution of Zn atoms by Cu ones. Finally, electron energy loss spectrometry measurements clearly showed that copper atoms are present in the ZnS lattice with an oxidation state of +I.

Formamidinium lead tri-iodide (FAPbI3) perovskite is a promising photovoltaic material due its narrow band gap and superior thermal stability. Herein, ligand-free high quality α-phase FAPbI3 perovskite prepared by a facile hydrothermal method is reported. The phase purity, morphology, size and optical absorption were controlled by different anti-solvents, namely chlorobenzene, diethyl ether and toluene. The FAPbI3 exhibits band gap of 1.39 eV and it is considerably narrower than its polycrystalline counterparts. This solution processed low temperature method revealed that it can be used for preparation of room temperature stable well-crystalline α-FAPbI3 perovskites for photovoltaic and optoelectronic applications.

Thin film electrolytes of Sm and Gd doubly co-doped ceria, namely, Ce0.8Sm0.1Gd0.1O1.90 (CSGO) deposited by pulsed laser deposition (PLD) technique have been investigated. The influence of oxygen partial pressure (pO2) on structural and morphological properties of CSGO thin films deposited on Si (111) substrate was studied by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM) techniques. The XRD and FESEM results showed that the films were polycrystalline cubic structure with (111) oriented columnar structure. The co-doping strategy has strongly helped to stabilize the Ce4+ state as the lattice parameter of the films did not show any significant change under the influence of pO2 in the range of 2 × 10-4-3 × 10-2 mbar. The electrical conductivity and activation energy of CSGO thin film supported on NiO-GDC10 anode were found to be 0.48 mS.cm−1 and 0.5 eV respectively. Determination of significantly lower Ce3+ concentration (27%) in CSGO film by X-ray photon electron spectroscopy (XPS) suggests that Sm-Gd co-doping has strongly suppressed the conversion of Ce4+ to Ce3+ in the overall composition.

Tribochemical analysis of monolithic TaN, TiAlN, and TaAlN coatings deposited by reactive magnetron sputtering onto 316LN stainless steel (SS) substrates are described. Tribology experiments were carried out in ambient atmospheric and high-vacuum sliding conditions to investigate the tribo-atmospheric dependent friction and wear characteristics of these coatings. The lower friction coefficient and improved wear-resistant properties were observed for TaN and TiAlN coatings in the humid atmosphere than in high-vacuum testing condition. Interestingly, lower friction and wear resistance properties of TaAlN coated SS are significantly enhanced in atmospheric as well as high-vacuum sliding conditions because of their highly dense and fine-grained microstructure with stable cubic B1 TaAlN phase. Energy dispersive X-ray spectroscopy elemental mapping and micro-focused X-ray photoelectron spectroscopy were carried out on the wear tracks to explore the comprehensive tribo-environment dependent tribochemistry. Formations of alumina (Al2O3) rich tribolayer reduced the friction and enhanced the wear resistance of TaAlN/SS sample tested in atmospheric condition; whereas this coating is highly stable in the high-vacuum condition with higher wear resistance.

Single layer aluminium oxide (Al2O3), zirconium oxide (ZrO2) and Al2O3/ZrO2 nano multilayer films were deposited on Si (100) substrates at room temperature by pulsed laser deposition. The development of Al2O3/ZrO2 nanolayered structure is an important method used to stabilize the high temperature phase (tetragonal and cubic) of ZrO2 at room temperature. In the Al2O3/ZrO2 multilayer structure, the Al2O3 layer was kept constant at 5 nm, while the ZrO2 layer thickness varied from 5 to 20 nm (5/5, 5/10, 5/15 and 5/20 nm) with a total of 40 bilayers. The X-ray diffraction studies of single layer Al2O3 indicated the γ-Al2O3 of cubic structure, while the single layer ZrO2 indicated both monoclinic and tetragonal phases. The 5/5 and 5/10 nm multilayer films showed the nanocrystalline nature of ZrO2 with tetragonal phase. The high resolution transmission electron microscopy studies indicated the formation of well-defined Al2O3 and ZrO2 layers and that they are of uniform thickness. The atomic force microscopy studies revealed the uniform and dense distribution of nanocrystallites. The nanoindentation studies indicated the hardness of 20.8 ± 1.10 and 10 ± 0.60 GPa, for single layer Al2O3 and ZrO2, respectively, and the hardness of multilayer films varied with bilayer thickness.

Transition metal nitride based materials have attracted significant interest owing to their excellent properties and multiple applications in the field of electrochemical energy conversion and storage devices. Herein we synthesize 3D nanorhombus nickel nitride (Ni3N) thin films by adopting a reactive radio frequency magnetron sputtering process. The as-deposited 3D nano rhombus Ni3N thin films were utilized as cost-effective electrodes in the fabrication of supercapacitors (SCs) and dye-sensitized solar cells (DSSCs). The structure, phase formation, surface morphology and elemental composition of the as-deposited Ni3N thin films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS) and atomic force microscopy (AFM). The electrochemical supercapacitive performance of the Ni3N thin films was examined by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) techniques, in 3 M KOH supporting electrolyte. The areal capacitance of the Ni3N thin film electrode obtained from CV analysis was 319.5 mF cm−2 at a lower scan rate of 10 mV s−1. Meanwhile, the Ni3N thin film showed an excellent cyclic stability and retained 93.7% efficiency of its initial capacitance after 2000 cycles at 100 mV s−1. Interestingly, the DSSCs fabricated with a Ni3N CE showed a notable power energy conversion efficiency of 2.88% and remarkable stability. The prominent performance of the Ni3N thin film was ascribed mainly due to good conductivity, high electrochemically active sites with excellent 3D nano rhombus structures and high electrocatalytic activity. Overall, these results demonstrate that the Ni3N electrode is capable of being considered for efficient SCs and DSSCs. This investigation also offers an essential directive for the advancement of energy storage and conversion devices.