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The novel chemical composition of pristine Mn1/3Ni1/3Co1/3MoO4 (MNC) and Mn1/3Ni1/3Co1/3MoO4 dispersed in various percentages of reduced graphene oxide (MNC/rGO) composites were prepared via the one-step hydrothermal method. X-ray diffraction (XRD) patterns showed pure crystalline phase CoMoO4 for the heat treated powder at 350 °C. Fourier Transform Infrared (FT-IR) spectra showed that the chemical band structure of Mn1/3Ni1/3Co1/3MoO4 corresponds to the strong vibrational bands of Mo O, Mo O and Mo O Mo bonds. X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of Mn, Ni, Co, Mo, C and O elements and its valance in the MNC/rGO powder. Field Emission Scanning Electron Microscope (FE-SEM) images displayed the nanorods morphology of the MNC/rGO powders. High-resolution Transmission Electron Microscopy (HR-TEM) images showed the morphology of MNC nanorods wrapped with the reduced graphene oxide of the MNC/rGO composite. The MNC/rGO composite displayed the highest specific capacitances of 1750 F g−1 at 1 A g−1 in 3 M KOH. The MNC/rGO composite demonstrated a better cycling stability with a cycling efficiency of 85.5% after 5000 cycles at 10 A g−1. The high rate performances, good reversibility and capacity retention at a range of current densities were demonstrated the structural stability of the MNC/rGO composite. The high energy density of 38.8 W h kg−1 at a constant power density of 200 W kg−1was achieved for the MNC/rGO composite.

Infrared Imaging Video Bolometer (IRVB) measures the radiation from plasma in two-dimensions. IRVB uses a few micrometer thick metal foil as a radiation absorber. The foil being ultra-thin has several limitations. A new radiation absorbing module is proposed here that can effectively overcome the shortcomings of the foils used in IRVB. This module is developed by depositing carbon and metal thin films on an infrared transmitting substrate using magnetron sputtering. This patented module is termed Deposited Layer on a Substrate. A prototype is developed and laboratory tests are carried out using a laser source to demonstrate its feasibility as a radiation detector. The advantages of this module over conventional foils, its development, and experimental results validating the concept are discussed in this article.

Pristine α-MnMoO4 nanorods were facilely prepared via co-precipitation (Cp) and microwave hydrothermal (MH) methods. X-ray diffraction (XRD) patterns showed pure monoclinic crystalline phase α-MnMoO4 for the heat treated powder at 500 °C. Fourier Transform Infrared (FTIR) spectra showed that the chemical bond structure of α-MnMoO4 corresponds to the strong vibrational modes of Mo–O–Mo, Mo–O and MoO. Raman spectra showed the structural bonding and crystalline nature of α-MnMoO4. Field Emission Scanning Electron Microscope (FE-SEM) images exposed the nanorod shape of the α-MnMoO4 powder, with diameters of ∼200 nm and lengths of ∼1.6 μm. Electrochemical studies of the Cp- and MH-MnMoO4 nanorods with 2 M NaOH as the electrolyte showed specific capacitances of 143 F g−1 and 551 F g−1, respectively, at a 1 A g−1 constant discharge current density. Cyclic voltammetric (CV) studies of the MH-MnMoO4 nanorods at various scan rates revealed the presence of redox pairs, suggesting a pseudocapacitive nature. The structural stability at different current densities demonstrated the high rate performances and good reversible capacity retention of the calcined MH-MnMoO4 nanorods. A cycling life stability study of MH-MnMoO4 demonstrated a good capacity retention of 89% of the initial specific capacitance at 5 A g−1 after 1000 cycles.

Erbium oxide (erbia/Er 2 O 3 ) is one of the leading candidate coating types to address the issues of tritium permeation reduction and Magnetohydrodynamic (MHD) drag reduction in fusion reactor with liquid Lead–Lithium (Pb–Li) or molten salt Flibe (2LiF + BeF 2 ) as the coolant and breeder materials. The electrical resistivity, hydrogen/deuterium permeation reduction property, liquid metal corrosion, radiation effects and deposition techniques are major areas of research on erbia coating. Though it is having a single stable phase of cubic structure up to 2300 °C, it is known to develop metastable monoclinic phase especially in sputter coating methods. We grow erbia by reactive magnetron sputter coating method and study the phase formation, electrical, microstructural and optical dielectric properties. The effects of erbium metal pre-layer deposition, post annealing in oxygen rich vacuum and oxygen to argon gas feed ratio are studied keeping other parameters constant. The film grows in mixed phase of cubic and monoclinic structures when erbium metal pre-layer is deposited on the P91 steel substrate and in pure monoclinic phase in absence of the pre-layer. Post annealing seems to partially convert monoclinic into cubic phase in the mixed phase coating. Better crystallization and slightly more surface roughness is observed in the sample processed with higher oxygen to argon ratio. DC resistivity is found in 10 15 Ω * cm range and it is marginally more in the sample processed with more oxygen. The spectroscopic ellipsometry on these films to obtain optical dielectric properties gives encouraging results in terms of close match of the thickness and roughness values with those obtained from SEM and AFM respectively. Systematic study of optical dielectric property suggests a trend consistent with DC resistivity.

Pristine α-MnMoO

Indian LLCB – TBM uses liquid Lead-Lithium (Pb-Li) as tritium breeder, neutron multiplier and coolant. Tritium bred in liquid PbLi stream has to be recovered by tritium extraction system. Therefore, a reliable sensor with quick response time for measurement of hydrogen isotope is essential. A hydrogen isotope sensor in liquid Pb-Li, based on permeation of hydrogen isotopes through metal (sensor material) is designed. The capsule shaped sensor, made of iron membrane coated with Pd from inside (downstream side), allow hydrogen isotope to permeate through it. The design work mainly includes the selection of proper material, its thickness and surface conditions, which is to be supported by numerical calculations for optimization of maximum permeation flux, fast response and fabricability. The numerical calculation utilizes a physical model having recombination of two hydrogen isotope atoms at the surface and atomic diffusion through the bulk. In this work, design calculations based on numerical simulation and fabrication procedure of the hydrogen isotope sensor are presented.

India has proposed to develop and test the Lead-Lithium–cooled Ceramic Breeder Test Blanket Module (In-LLCB-TBM) in ITER. This concept, unlike some others, may need a high-performance ceramic coati...

Plasma nitriding is widely used for the improvement of the mechanical/tribological properties of various steel components in many applications such as automobile parts, turbine parts, textile machinery parts, etc. However, plasma nitriding on components with welding joints have not been intensively studied so far. In this study, we attempted to study the welded region of AISI 304 stainless steel after carrying out the plasma nitriding process. The plasma nitriding of stainless steel welded joints has been done with a H 2 :N 2 (4:1) gas mixture at 570 and 450 °C for different time durations. The parent and the welded regions were characterized using a microhardness tester, a scanning electron microscope (SEM) and an X-ray diffractometer (XRD) for surface hardness, case depth and phase formation respectively. The results show that the nitrided layer formed on the welded region consists of Fe 4 N and Fe 3 N, CrN and γ phases. Also, welded joints using the multiple pass technique gave better nitriding properties compared with that of the single pass technique. There is an improvement in the hardness by 3 times which could be correlated with structural changes and process parameters.

Tungsten is being considered as a front runner choice for the plasma facing component material of next generation fusion reactor because of its superior thermophysical and mechanical properties. Therefore, it is essential to study the ion material interaction of this material for its response to severe conditions of fusion reactor. In this work, we have used an ingenious ion source a namely plasma focus to study the effect of proton irradiation on tungsten under various experimental conditions. Exposed and reference tungsten samples were analyzed using optical microscope, scanning electron microscope, atomic force microscope, grazing incidence X-ray diffraction and Vickers hardness tester. Surface analyses confirm the formation of microcracks, bubbles, blisters, holes, etc. X-ray diffraction pattern confirms the development of compressive stress on the sample due to thermal load and formation of other phases or some expanded phases. A slight reduction in hardness values is observed in case of the exposed sample than the reference sample.

For magnetron sputter deposited coatings, the structure development during growth mostly depends on the mobility of the adatom over the substrate. The mobility is significantly affected by the orientation of the substrate with respect to the direction of the incident flux of sputtered atoms. The structural properties like crystallite size, crystallographic structure, column orientation, etc., are therefore influenced. This is relevant as the real work pieces over which the overlay functional coatings has to be applied are three dimensional in nature with the surfaces being off-normal to the incident flux. In the present investigation, the effect of incident angle on the various aspects of the structure development of Titanium Nitride coatings, having wide tribological applications, deposited on Si substrates by reactive magnetron sputter deposition was studied. A planar magnetron, with cathode diameter 75 mm and mounted with pure Ti target was used and TiN was deposited in a mixture of argon and nitrogen gas. The deposition was done for different durations. The deposited coatings were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results indicate the formation of well defined columnar microstructure in the coatings. The column inclination is compared with the well known ‘Tangent rule’.

Corrosion and oxidation resistance behaviour has been studied after reactive ion beam mixing (RIBM) treatment of 316 SS. The RIBM treatment was carried out on 28 nm Al- or 34 nm Si-deposited 316 SS using 30 keV N 2 + ions, at room temperature, at different doses ranging from 4 × 10 16 to 2 × 10 17 ions/cm 2 . Structural characterization was done using the GXRD technique. Potentiodynamic polarization studies in 0.5 N H 2 SO 4 solution were carried out to determine the corrosion resistance. Oxidation studies were done using the weight gain method. The RIBM-treated 316 SS show the increase in corrosion and oxidation resistances with the dose. The weight gain curves of the RIBM-treated 316 SS follow the logarithmic law indicating the formation of protective oxide film, which helps in preventing further oxidation. The improvements in corrosion and oxidation properties have been concluded to be due to the presence of AlN or Si 3 N 4 in the near-surface region of 316 SS. The potentiodynamic polarization studies indicate that 316 SS containing Si 3 N 4 has relatively better corrosion resistance than that containing AlN.

Experiments were performed with an aim of studying an effect of initial surface roughness with different gas compositions in plasma nitriding, using pulse D.C. glow discharge plasma in presence of nitrogen and hydrogen gas mixtures. Samples were prepared with different mechanical treatments: polishing, rough polishing, machining and grinding. Plasma nitriding was carried out on AISI 304 stainless steel at 560 °C under 4-mbar pressures for 24 h in presence of N 2 : H 2 in 20 : 80 and 80 : 20 ratios. After plasma nitriding, surface roughness, micro hardness, case depth and phase formation were evaluated by using stylus profilometer, Vickers micro hardness tester, optical microscope and X-ray diffraction techniques, respectively. After plasma nitriding, hardness and case depth variation are observed with variation in surface roughness as well as gas compositions. Maximum hardness i.e. 1325 HV and case depth i.e. 110 μm are achieved on mirror polished samples at 80N 2 : 20H 2 . The diffraction patterns show the most dominant phase formation of CrN, Fe 4 N and Fe 3 N which is responsible for this increase.

The objective of the present work is to study and develop a suitable structural material for the Accelerator Driven Subcritical System (ADSS), which can withstand extreme conditions of irradiation in corrosive environment. Effects of radiation damage on corrosion resistance are evaluated and a possible solution is attempted by adding alloying elements such as Al or Si. Aqueous corrosion studies were carried out in 0.5 N H 2 SO 4 solution on 316 SS, Ar + implanted 316 SS, Al ion-beam-mixed 316 SS and Si ion-beam-mixed 316 SS. At a low dose 30 keV Ar + implantation, the martensitic phase transformation was observed in 316 SS. Corrosion potential reduced to very low negative values after Ar + implantation, indicating the reduction in corrosion resistance. As the dose was increased further, the corrosion resistance marginally improved. This correlates with the reduction in martensitic phase, as observed using glancing angle X-ray diffraction (GXRD). Si ion-beam-mixed 316 SS displayed good corrosion resistance with higher corrosion potential, higher pitting potential and large passive region, whereas Al ion-beam-mixed 316 SS displayed no passive region but had a higher corrosion potential.

Soft x-ray energy-dependent angle-resolved photoemission measurements are performed on the heavy-fermion superconductor CeIrIn5 to study the Fermi surface (FS) and the electronic structure near the Fermi level in the ΓMZA plane. The non-dispersive band designated as the Ce 4f7/21 final state is found at 280 meV along with the main body of the valence band consisting of highly dispersive In 5p bands, which are in good qualitative agreement with the band structure calculation based on the itinerant 4f electron model. Furthermore, we found two electron-like and one hole-like cylindrical FSs at the M (A) and Γ (Z) points. The Fermi momenta of the observed FSs are consistent with the de Haas–van Alphen experiment, while they contradict the stronger anisotropy of the FS along the kz direction predicted by the band calculation. The results suggest stronger two-dimensionality of the electronic structure of CeIrIn5 and point to the need for its theoretical verification.

In this work an effort has been made to study the effect on the performance of the plasma nitrided AISI H13 hot-forging dies and punches in two different forging service conditions –namely, fully-automatic and semi-automatic processes. The plasma nitriding is performed to increase the surface properties like –wear resistance and surface hardness of these components. After plasma nitriding the surface hardness of these materials has increased typically from ~500 HV0.01 to ~1200 HV0.01. In the plasma nitriding process high-voltage electrical energy is used to form plasma through which nitrogen ions are accelerated to impinge on the workpiece. The ion bombardment heats the workpiece, cleans the surface, and provides active nitrogen to make iron-nitride compounds. The iron-nitride compounds then diffuse to the workspace to harden the surface. In these two service conditions the plasma nitrided hot-forging dies and punches have shown typically 2.5 to 4 times increment during the performance. It is observed that the increment in the performance of the dies and punches depends on the forging service conditions, i.e., temperature of the dies and punches, shot repetition time and effective cooling of dies and punches in service conditions. Four times increment in the performance of dies and punches is found in the semi-automatic process, whereas two and half times increment in performance of dies and punches is observed in the fully-automatic process.

We study the electronic structure of $\mathrm{Eu}{\mathrm{Ni}}_{2}{({\mathrm{Si}}_{0.2}{\mathrm{Ge}}_{0.8})}_{2}$, which exhibits a temperature dependent mixed valence transition, using $4d\text{\ensuremath{-}}4f$ resonant photoemission spectroscopy (RESPES), x-ray absorption spectroscopy (XAS) and temperature-dependent ultraviolet photoemission spectroscopy (UPS). The RESPES studies identify the divalent and trivalent Eu $4f$ character density of states (DOS) which participate in the valence transition. Using the photoionization cross section variation as a function of photon energy, we discuss the Eu, Ni, and $\mathrm{Ge}\ensuremath{-}\mathrm{Si}$ partial DOS in the valence band. The bulk divalent Eu $4f$ character states are centered at a binding energy of about $0.75\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$, significantly away from the Fermi level. While the surface divalent feature is negligibly affected, the spectra obtained using He $II\ensuremath{\alpha}$ UPS exhibit temperature dependent bulk Eu $4f$ character states. The bulk divalent spectral weight is transferred to the high energy trivalent states, across the valence transition temperature, ${T}_{v}\ensuremath{\sim}80\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The He $I\ensuremath{\alpha}$ UPS also exhibit spectral intensity changes across ${T}_{v}$. The non-$f$ character conduction band states at and near the Fermi level exhibit spectral weight changes up to $350\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$ with a small energy $(\ensuremath{\sim}25\phantom{\rule{0.3em}{0ex}}\mathrm{meV})$ temperature dependent pseudogaplike feature. The results suggest an increase in effective hybridization strength between the conduction and $4f$ electrons in the low temperature nearly trivalent phase. While the $4f$ character changes across ${T}_{v}$ are qualitatively consistent with change in valence configurations, the temperature dependent spectral changes in the non-$f$ character DOS indicate direct participation in the valence transition in $\mathrm{Eu}{\mathrm{Ni}}_{2}{({\mathrm{Si}}_{0.2}{\mathrm{Ge}}_{0.8})}_{2}$.

CeOs(4)Sb(12) and CeFe(4)P(12) are classified as Kondo semiconductors, which show coupled changes in electrical transport, thermodynamic and magnetic properties with a low-temperature semiconductor-like electrical resistivity. We have carried out core level and valence band photoemission spectroscopy on single crystal CeOs(4)Sb(12) and CeFe(4)P(12) to study their electronic structure and the evolution of states at the Fermi level as a function of temperature (∼10-300 K). The Ce 3d core level spectra show the presence of f(0), f(1) and f(2) final states with very different relative intensities in the two compounds. Single-impurity Anderson model calculations provide f electron counts of n(f) = 0.97 and 0.86 per Ce atom, suggestive of a low- and high-T(K) (= single ion Kondo temperature) for CeOs(4)Sb(12) and CeFe(4)P(12), respectively. The high-resolution temperature-dependent near-Fermi level spectra show pseudogaps of energy ∼ 50 meV and ∼ 110 meV in the valence band density of states (DOS) of CeOs(4)Sb(12) and CeFe(4)P(12), respectively. The temperature dependence of the DOS at the Fermi level follows the change in effective magnetic moment estimated from magnetic susceptibility for both materials, confirming the Kondo nature of the pseudogap in CeOs(4)Sb(12) and CeFe(4)P(12). A compilation of measured pseudogaps using photoemission and optical spectroscopy identifies the charge gaps Δ(C) for Ce-based Kondo semiconductors and provides a direct relation with T(K) given by Δ(C) ∼ 2k(B)T(K). In conjunction with the known behaviour of the spin gaps Δ(S) ∼ k(B)T(K), the results establish the coupled energy scaling of the spin and charge gaps in Kondo semiconductors.