Search

MgB 2 superconductor bulks were fabricated using Mg and B precursors. The physical state of Mg (solid, liquid, or gas) significantly influences the final product, MgB 2 bulk. In this study, the Solid-Solid, Liquid-Solid, and Gas-Solid methods were employed to fabricate MgB 2 bulks. The superconducting properties and microstructure of various samples were systematically investigated. Notably, for the first time, nano-CT was utilized to comprehensively and non-destructively analyze the microstructure of MgB 2 bulks, particularly the size and distribution of voids, which serve as the primary barrier affecting the superconducting properties. By examining the microstructure characteristics, the infiltration effect of Mg in different physical states during the reaction was analyzed, and a feasible reaction model was established. This research contributes to a better understanding of the reaction mechanism of MgB 2 , which may aid other researchers in enhancing the properties of MgB 2 superconductors. [ABSTRACT FROM AUTHOR]

MgB 2 superconductor pellets were synthesized through Mg gas infiltration method using nanosized- and microsized B powders. There was a marked difference in the superconducting properties of the two samples, particularly in the pinning force and dominant pinning mechanism. The microstructures of the samples were observed using HR-TEM and STEM-HAADF, and the results showed that the primary reason for the difference in the superconducting properties is the distribution of the nanosized second-phase particle MgO. Additionally, a feasible reaction model for the Mg gas infiltration method was established. Compared to the Mg liquid infiltration method, the gas infiltration showed better penetrability ability with a small amount of residual Mg. This study presents a novel synthesis process to fabricate an MgB 2 pellet with superior density and superconducting properties. This method can be used in multiple applications such as superconducting bearings, compact superconductor magnets, and magnetic shielding. [ABSTRACT FROM AUTHOR]

As the lightest metal, the reversible insertion/extraction properties of lithium have been key findings in lithium metal oxide chemistry. Lithium has been widely used in the oxygen evolution reaction (OER), and the reaction mechanism of lithium‐mediated metal oxides has both similarities and uniqueness compared to typical dual metal oxides. Notably, the insertion/extraction of lithium during the OER is also crucial for the construction of novel surface reconstruction models. This review aims to provide the concepts of general OER pathways and key features of dual metal oxides for the OER. As a comparison then the development of lithium metal oxides for the OER is introduced and the chemistry underlying lithium metal oxide catalysts is unveiled. This review also examines the challenges remaining for the relevant catalysts, with prospects for further improving their OER activities. [ABSTRACT FROM AUTHOR]

Doping of nanoparticles is one of the effective methods in order to obtain nanocomposite thin films with significantly improved performance. A complete understanding of nucleation and growth mechanism for nanosized doped particles and the orientation relationship between the particles and matrix material is essentially important for the enhanced functional properties of nanocomposite films. In this study, a two-dimensional X-ray diffraction (2D-XRD) technique was utilized to detect the orientation and phase evolution of Ba2YNbO6 (BYNO) doped particles within YBa2Cu3O7−δ (YBCO). The textured and untextured information about the doped particles was extensively visualized via 2D-XRD spots and rings in comparison to 1D-XRD analysis. A systematic investigation of the nucleation and growth mechanism for the BYNO-doped YBCO nanocomposite film revealed the same orientation for BYNO particles near the LaAlO3 (LAO) substrate, whereas the rest of the particles were detected with random orientation. The higher isotropic Jc with increased random orientation of the BYNO particles contributed significantly towards the improved superconducting properties of the thin films. Finally, a rich nucleation and growth model for the BYNO-doped YBCO nanocomposite film was established. This study aimed to analyze the orientation of the doped BYNO nanoparticles during the nucleation and growth of the YBCO film, with the main focus on demonstrating double perovskite-structured nanoparticles. [ABSTRACT FROM AUTHOR]

Face-centered cubic (FCC) metals were subjected to heavy rolling and two-step recrystallization annealing to form sharp cubic textures. The traditional theory states that the formation of recrystallized cubic-oriented grains originates from rolling cube grains. However, in our study, the Ni8W alloy underwent severe deformation during rolling, forming a typical brass-type rolling texture with almost no cubic-oriented grains. The quasi-3D electron backscatter diffraction results indicated that the newly generated cubic grains were not necessarily adjacent to the rolling cubic grains. Instead of growing from excited rolling cube grains, we found newly oriented recrystallized cubic grains generated from twin growth. Initially, most recrystallized grains undergo grain boundary migration or merging during low-temperature recrystallization annealing. Under such conditions, the initial recrystallized grains maintained the same orientation as the original matrix. However, it is also possible that the initially newly oriented recrystallized grains were generated through twinning. The {221}<122> orientation grains can cause cubic orientation by Σ3 boundaries. This twinning process reveals another pathway for generating initially recrystallized cubic grains in highly deformed FCC alloys. The recrystallized cubic-oriented grains ultimately evolved into cubic textures owing to their growth advantages, as described by the traditional theory. This discovery solves the puzzle of the recrystallization nucleation mechanism for cubic-oriented grains. It can help us better understand the evolution of the recrystallized cubic texture in heavily deformed FCC alloys. [ABSTRACT FROM AUTHOR]

We report a novel doping strategy for YBa 2 Cu 3 O 7-x (YBCO) superconducting films by using a positive mismatch, Ba 2 YNbO 6 (BYNO), and a negative mismatch, LaAlO 3 (LAO), simultaneously. Double doping can significantly reduce the c -strain in the YBCO film by canceling the strain between the two dopants. By systematically optimizing the doping amount of both BYNO and LAO, it was found that BYNO and LAO do not act equally. The microstructure and distribution of both BYNO and LAO were investigated with magneto-optic microscopy and scanning electron microscopy. The effect of BYNO and LAO on pinning was confirmed. The results of this study will help select appropriate positive mismatch and negative mismatch dopants, which is fundamental to the design and fabrication of pinning centers to fit different application scenarios. [ABSTRACT FROM AUTHOR]

The efficient performance of Solid Oxide Fuel Cell (SOFC) by utilizing safe and cost effective hydrocarbon fuels at low temperature is really a challenging task due to C –H activation and sluggish oxidation/reduction kinetics. In this study a novel [Sr 0.4 La 0.6 (Fe 0.75 Ti 0.25) 0.6 Ni 0.4 O 3-δ ] (SLFTNO) nanocomposite was synthesized via solid state reaction route and was evaluated electrochemically in presence of multifuels such as hydrogen, ammonia, methane and ethanol. Phase purity and structural analysis was carried out through X-Ray Diffractometer (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). The average crystallite size calculated was ranged from 60-100 nm. The electrical conductivity and power density was measured between (89–226) S/cm and (147–318) mW/cm2 respectively among different fuels. This study indicated the synthesized SLFTNO nanocomposite as stable and efficient multifuels candidate for SOFCs. Image 1 [ABSTRACT FROM AUTHOR]

Highlights • The malonic acid was proved to be an effective carbon source. • The carbon atoms were released by the reaction of Mg and CO 2. • The x value in Mg(B 1-x C x) 2 increased with a higher amount of malonic acid addition. • A moderate amount of malonic acid addition resulted in grain refinement. • Bulk MgB 2 with 10 wt% malonic acid addition showed the highest J c value. Abstract In this paper, malonic acid was tested as a new carbon source and its effects on the structural and superconducting properties of bulk MgB 2 have been systematically investigated. The detailed pyrolysis process of malonic acid was analyzed to understand the possible doping mechanism of malonic acid added MgB 2 samples. The weight fraction of MgO phase and the actual carbon substitution level in bulk MgB 2 increased with a higher amount of malonic acid addition, which was proven to be mainly caused by the reaction of Mg and CO 2 gas. A moderate amount of malonic acid addition resulted in grain refinement and enhanced flux pinning. Bulk MgB 2 with 10 wt% malonic acid addition showed much higher J c values in the entire magnetic field range. Three different doping methods with the same amount of malonic acid addition were compared. MgB 2 samples using malonic acid and ethanol processed boron showed the highest J c value, which was 7.2 times larger than that of the pure MgB 2 at 20 K and 5 T. [ABSTRACT FROM AUTHOR]

The purpose of this study was to improve the critical current density (Jc) of YBa2Cu3O7−δ (YBCO) superconducting films at high magnetic fields. Thin Y1−xYbxBa2Cu3O7−δ (Y1−xYbxBCO) superconducting films on LaAlO3 substrates were prepared by modified low-fluorine metal organic deposition method (LF-MOD) in order to investigate the effect of Yb substitution on the microstructure and superconducting properties of a YBCO-coated conductor. In this study, single-phased, c-axial-aligned Y1−xYbxBCO films were obtained. Yb doping had a little effect on the critical temperature (Tc) and transition width (ΔT) values of Y1−xYbxBCO films. An abnormal phenomenon was observed that the Jc of Y1−xYbxBCO films at low field was smaller than that of the pure YBCO film, but the Jc of Y1−xYbxBCO films at high field was much greater than that of the undoped YBCO film. Compared to pure YBCO film, the Jc values of Y0.75Yb0.25BCO and Y0.25Yb0.75BCO films were enhanced by a factor of 8 at 8 T, 65 K, which meant that chemical substitution of Yb into the Y site could improve flux pinning significantly under the high magnetic field in Y1−xYbxBCO coated conductors. [ABSTRACT FROM AUTHOR]

• The 40 μm ultra thin Ni5W substrate having 97.6% cube texture is obtained. • Intermediate annealing at the appropriate deformation quantities is the key to cube texture. • All the samples have a RMS surface roughness around 10 nm. In this work, a series of studies have been carried out on ultra-thin Ni-5at%W (Ni5W) alloy substrates used for the coated conductors. The ultra-thin Ni5W alloy substrate can be fabricated for the large square REBCO film with a size of over 40 mm × 40 mm, which is normally used in scenarios to support a magnetic field in a specific area. To obtain a stronger recrystallized cubic texture, the intermediate annealing was added to optimize the rolling texture during the rolling process of the Ni5W alloy substrate. A typical copper-type rolling texture was obtained in the substrate which intermediate annealed at 96.25%, and the cube texture reached 97.6% after annealing recrystallization. Moreover, The deformation and recrystallization of 40 μm thick Ni-5at%W (Ni5W) alloy thin substrates were investigated by the quasi- in situ method. The fabrication of ultra-thin Ni5W substrates increases the potential of miniaturizing lightweight coated conductors, which helps to further promote and accelerate the manufacturing process of the entire coated conductor strip. [ABSTRACT FROM AUTHOR]

To achieve the approriate trade-off between the low charing delay and enough self-protection ability in the NI REBCO coil, the controllable Cu layer structure in REBCO tape is essential, which can cause required electrical and thermal properties in both the radial and circumferential direction. In this paper, the correlation between the material characteristics of the copper layer on the electrical and thermal properties of REBCO was explored by investigating the REBCO tape with different Cu layer thicknesses. The influence of charging decay, self-protection, and cold shrinkage stress on the REBCO coil performance was also evaluated based on three tapes. Three new findings showed the possible dominant factor on electrical and thermal properties in either radial or circumferential direction. Unlike the traditional electroplated layer, the Cu layer in the SP3 sample has piecemeal Cu grains, which may be the primary factor in significantly increasing the electrical resistivity and decreasing the thermal conductivity significantly. In the radial direction, the nonuniform top, bottom, and even side thickness of the Cu layer could increase the electrical resistivity and thermal conductivity. And the bad corner contact quality between the Cu and Ag/REBCO could be an important factor. Furthermore, the Cu layer purity may be significantly lower than previously thought. Using the electrical resistivity and thermal conductivity values of pure Cu as the Cu layer in the simulation could result in significant errors. This study provides possible directions for finding a method to control the properties of the Cu layer of REBCO commercial tape, which can better fit different application scenarios. • Geometry uniformity and bad corner contact is crucial to the radial direction properties. • Cu grain morphology and orientation dominate the circumferential direction properties. • The purity of Cu layer in REBCO is not as pure as expected, but only around 50%. [ABSTRACT FROM AUTHOR]

Two types of Cu–45 at%Ni alloy thin tapes with and without surface shear were obtained by different heavy cold rolling processes. The deformation and recrystallization textures of the two tapes were thoroughly investigated by electron back scattering diffraction technique. The results showed that a shear texture mainly covered the surface of the heavy deformed tapes because of the fraction between the surface of rolling mills and the thin tapes when the rolling force strongly reduced at high strain, which significantly reduced the fraction of rolling texture on the surface of the Cu–45at %Ni alloy thin tapes, retarded the cube grain growth during recrystallization and affected the strong cube texture formation after high temperature annealing. [ABSTRACT FROM AUTHOR]

In this study, the effects of stress-relief annealing (SRA) on the rolled texture of nickel-based alloys were extensively analysed. Biaxially textured Ni–W alloy substrates with strong cube textures were fabricated by cold rolling and recrystallisation annealing for coated conductor applications. The results indicate that the evolution of the rolled texture, and hence the annealed cube texture, were greatly influenced by the stress-induced by deformation. The stress and rolled texture were found to be significantly correlated. X-ray diffraction and electron backscattered diffraction analyses were used to explore the effect of SRA on the cold-rolled microstructure. The stress distribution was found to be associated with the copper texture. The addition of SRA effectively eliminated stress and strengthened the copper and S textures, thereby facilitating the formation of the final annealed cube texture. Finally, the mechanism by which stress influences the rolled texture of nickel-based alloys was elaborated in detail. • The quasi-in-situ method is used to analyze the effect of stress-relief annealing on rolled texture. • It is found that the grain orientation, stress distribution and grain morphology are closely related. • The mechanism by which stress influences the rolled texture is clarified in the nickel-based alloy. [ABSTRACT FROM AUTHOR]

• Shows the different texture evolustion of CuNi alloy with different strain. • The key point is the recrystallized nuclea size and position of cube at 500 °C. • Reveals the different growth rate of the cube and the random after nucleation. In this study, the texture evolution of CuNi alloy fabricated by rolling and annealing processes with different von Mises strains was systematically investigated by electron backscatter diffraction (EBSD). All the samples with different strains exhibited a strong cube texture after annealing at high temperatures, but the texture evolution trace was apparently affected by the strains. The most significant effect of the strain was the recrystallization nucleation of the cube texture. The distinct nucleation causes a different growth rate of the cube texture and the random texture, which causes a large temperature difference of 550–700 °C between the samples with different strains. This investigation allows us to better understand the texture evolution in CuNi and other FCC alloys after the rolling and annealing processes. [ABSTRACT FROM AUTHOR]

Wedescribe and develop an example of the successful applicationof a broadly applicable biomimetic growth process to the crystal growthof the complex inorganic quaternary high-temperature superconductingceramic oxide YBa2Cu3O7−δ. By combining effective biopolymer mediation with established syntheticsingle crystal growth processes, we leverage a reduction in the requiredgrowth temperature from 1045 to 920 °C to enable the successfuluse of a molten salt synthesis technique in place of the high-temperaturesolution method commonly employed. Further, the influence of the biopolymeron the seed crystal nucleation provides for morphological controlof the synthesis product, offering the potential for designed macromorphologiesthrough biopolymer selection or customization. The method describedis directly applicable to other difficult-to-synthesize materialsthat presently rely on similar conventional techniques, or for whichsuch approaches have been found to fail, thereby providing a novelroute to the successful bulk synthesis of complex refractory materials. [ABSTRACT FROM AUTHOR]

Hydrogen energy, as a clean and renewable energy, has attracted much attention in recent years. Water electrolysis via the hydrogen evolution reaction at the cathode coupled with the oxygen evolution reaction at the anode is a promising method to produce hydrogen. Given the shortage of freshwater resources on the planet, the direct use of seawater as an electrolyte for hydrogen production has become a hot research topic. Direct use of seawater as the electrolyte for water electrolysis can reduce the cost of hydrogen production due to the great abundance and wide availability. In recent years, various high-efficiency electrocatalysts have made great progress in seawater splitting and have shown great potential. This review introduces the mechanisms and challenges of seawater splitting and summarizes the recent progress of various electrocatalysts used for hydrogen and oxygen evolution reaction in seawater electrolysis in recent years. Finally, the challenges and future opportunities of seawater electrolysis for hydrogen and oxygen production are presented. [ABSTRACT FROM AUTHOR]

This paper focused on the modification properties of the La2Zr2O7 (LZO) seed layers for the epitaxial growth of thick LZO buffer films on cube-textured Ni5%W (Ni5W) substrate by the metal organic deposition (MOD) method. The surface morphologies of the LZO seed layers with different precursor concentrations were described by SEM. The grain orientation and the crystallographic growth model of the LZO seed layer were characterized by the electron backscatter diffraction (EBSD). The XRD analyses reveal that the LZO buffer layers on the Ni5W substrates with and without seed layers were grown epitaxially. However, the uniformly distributed islanded LZO seed layers with highly (001)[110] rotated cube texture not only can improve the crystallinity of the subsequent LZO buffer films, but also can optimize the in-plan and out-plan orientations of the thick LZO buffer layers. [ABSTRACT FROM AUTHOR]

Abstract: The YBCO films with BaSnO3 (BSO) particles were prepared on LAO (001) substrates by metal organic deposition using trifluoroacetates (TFA-MOD) via introducing SnCl4 powders into the YBCO precursor solution. It was found that with the increase of the SnCl4 contents, the slower decomposition and higher temperature for nucleation during the reaction were requested compared to that of pure YBCO film. The YBCO films with different contents of Sn with dense surface and well c-alignment were obtained under optimized heat treatment, and the BaSnO3 phases were detected by XRD analysis. Litter effect of BSO particles on the Tc and Jc values of YBCO films was found. All YBCO films with BSO particles had Tc values over 90K and Jc values over 1MA/cm2. A significant enhancement of Jc was observed for YBCO films with BSO particles compared to that of pure YBCO film by the field dependence of Jc values. The best property was obtained for YBCO film with 6mol.% Sn at 77K under magnetic field. The results showed that the Jc value of YBCO film with 6mol.% Sn was enhanced by a factor of 2 in 2T, and over a factor of 10 beyond 4T compared to that of pure YBCO film. [Copyright &y& Elsevier]

Abstract: Thin, biaxially textured Ni5W/Ni12W/Ni5W composite substrates for coated conductor applications have been fabricated. The particularity of this three-layer composite configuration resides in the elemental diffusion between the outer layer and the core layer. Due to the migration of elemental W, the diffusion layer in the as-annealed substrate becomes broader than that of the as-rolled substrate. The obtained tape has a sharp cubic texture on the Ni5W outer layers, and the volume fraction of cubic grains exceeds 98.8% (<10°) at the outer surfaces. In situ electron backscatter diffraction strain–stress analysis shows that the high-quality cubic texture was stable until elongations as high as 2%. The yield strength of the composite substrate approaches 240MPa and its saturation magnetization at 77K has been strongly reduced with respect to pure Ni and Ni5W substrates. The present results demonstrate that this advanced three-layer substrate is suitable for the epitaxial growth of the LZO buffer layers. [Copyright &y& Elsevier]

CeO2 caped La2Zr2O7(LZO) buffer layers on cube-textured Ni5W substrates were fabricated by the method of chemical solution deposition(CSD). The orientation of both LZO film and CeO2 /LZO buffer layer was investigated using conventional XRD and X-ray four circle diffractometers, respectively. The results reveal that both the LZO film on Ni5W substrates and CeO2 film on LZO buffer layer are grown epitaxially. The value of Full Width at Half Maximum (FWHM) of (111) Phi scan of CeO2/LZO buffer layer is around 8°, and the FWHM of (200) w-scan of CeO2/La2Zr2O7 buffer layer is 6.5°, indicating a good in-plan orientation of the as obtained buffer layers. It was observed by the high resolution SEM that the surface of LZO buffer layer is crack-free and very dense. The surface result observed by AFM indicates a very smooth CeO2 surface with 5.9 nm of the root mean square roughness measured in an areas of 30 x 30 μm2. AES depth profile results of CeO2/LZO buffer layers shows that the deposited LZO film could effectively prevent the diffusion of Ni into the buffer layer. [ABSTRACT FROM AUTHOR]

YBa2Cu3O7-δ (YBCO) films with Zr doping have been prepared successfully by the trifluoroacetate metal-organic deposition (TEA-MOD) method through dissolving Zr acetylacetonate into the precursor solution. Yttria-stabilized zirconia(YSZ)nanoparticles were detected in the doped YBCO films by XRD. From the analysis of XRD ω and φ scans, the doped films have better out-of-plane and in-plane textures than those of the un-doped YBCO film. Although the doped YBCO films have lower Tc than that of the un-doped YECO film, a very significant enhancement of normalized Jc is displayed as compared to the undoped film at applied fields, indicating that an effective pinning force was created by Zr doping. [ABSTRACT FROM AUTHOR]

A sharp cube textured alloy substrates with high strength and low magnetism are required in coated conductors' applications. In this work, the cube textured Ni-7at.%W substrates, starting from advanced powder metallurgy ingots followed by Rolling Assisted Biaxially Textured Substrate (RABiTS) method, have been prepared. The fabrication processes of Ni-7at.%W tapes with sharp cube texture by spark plasma sintering(SPS) routes were described. By Electron Back Scattering Diffraction (EBSD) analysis, the percentage of the cube texture component in Ni-7at. %W tape surface is found to reach 99.4% within a misorientation angle smaller than 10°. Moreover, the formation mechanism of the cube texture in the Ni-7at. %W tape was also investigated by EBSD. Particular attention was focused on the difference of the texture components along the thickness of the partially recrystallized samples. [ABSTRACT FROM AUTHOR]

Abstract: One of the main challenges for coated conductor applications is to produce sharp cubic textured alloy substrates with high strength and low magnetism. In this work, the cubic textured Ni–7at.%W substrates were prepared from different powder metallurgy ingots by rolling-assisted biaxially textured substrate processing. The fabrication processes of cubic texture in the Ni–7at.%W tapes by two powder metallurgy routes are described in detail. Through the optimized process, full width at half maximum values of 6.7° and 5.0° were obtained, as estimated by X-ray (111) phi scan and (200) rocking curve in the textured Ni–7at.%W tape, respectively. By electron backscattering diffraction (EBSD) analysis, the percentage of the cubic textured component in the Ni–7at.%W tape surface was found to reach 97.0% within a tolerance angle smaller than 10°. Moreover, the formation mechanism of the cubic texture in the Ni–7at.%W tape were also investigated by EBSD. Particular attention was focused on the difference in the texture components along the thickness of the partially recrystallized samples. [Copyright &y& Elsevier]

Abstract: The development of reinforced and biaxially textured Ni5W/Ni9W/Ni5W composite substrate for coated conductor applications is presented. The configuration of this substrate is a thin, sharp cubic textured Ni5W outer layer on a Ni9W alloy core that provides the mechanical strength while decreasing the magnetization of the whole substrate. The key technique is to use thin Ag and Cu foils between initial Ni5W and Ni9W alloy pieces to bond them together, followed by cold-rolling and recrystallization. The obtained composite substrate has a very sharp cubic texture on the Ni5W outer layer and its yield strength approaches 200MPa, thus being 50MPa higher than commercially used Ni5W substrates. The saturation magnetization of this composite substrate at 77K was reduced by 75% and 40% compared with pure Ni and Ni5W substrates, respectively. The present results show that this new substrate is suitable for the epitaxial growth of the CeO2 buffer layers. [Copyright &y& Elsevier]

Abstract: A Ni-based tri-layer composite substrate designed as a substitute for traditional substrate architecture, was obtained by sintering together two Ni–5at.%W layers on both sides of a metallurgically prepared powder Ni–12at.%W inner layer. An advanced sparking plasma sintering technology was used, followed by cold rolling and annealing. The composite substrates obtained have a very sharp cube texture on the Ni–5at.%W outer layer and the yield strength exceeds 320MPa, while the magnetization behaviour was dramatically reduced. These properties render these tri-layer substrates suitable for the epitaxial growth of buffer layers for coated conductor applications. [Copyright &y& Elsevier]

Abstract: Biaxially textured Ni–5at.%W substrates have been prepared by cold rolling, followed by three different annealing routes. In this paper, the processes of melting Ni and W metals, flat rolling, various annealing methods are described in detail. The Ni–5at.%W tapes annealed under either high vacuum or flowing Ar (7% H2) gas were characterized by X-ray pole figures, ODF, EBSD as well as AFM analysis. The texture analysis indicated that as fabricated tapes have a sharp cube texture formed after annealing at a wide temperature range of 800–1100°C. The high quality of cube orientation on tapes was obtained after a two-step annealing (TSA), where the percentage of the cube texture component was as high as 93.5% within a misorientation angle smaller than 8° from EBSD analysis. Furthermore, it was also observed that the number of twin boundaries in this tape decreased with respect to that of tapes annealed both in vacuum and one-step gas annealing. From AFM on 1μm2 areas, it was concluded that the roughness (RMS) on the tape surface reached 0.98nm. [Copyright &y& Elsevier]

New, reinforced {1 1 0}〈1 1 0〉 textured Ag/Ni-alloys composite ribbons were developed as possible substrates for coated conductors without any buffer layer. The texture quality and tensile strength were investigated. A new technique to bond the Ag and Ni or alloy layers through a Cu foil was presented. The Ag/Ni-alloys composite ribbons were fabricated by choosing proper sintering processing to bond the different layers followed by cold rolling and recrystallization. A thin Cu foil was intercalated between the initial Ag and Ni or alloy pieces to get a tough bond. A unique and stable {1 1 0}〈1 1 0〉 annealing texture was obtained in 300 μm thick Ag/Ni composite ribbon after annealing. X-ray ODF analysis and EBSD measurements in the top Ag layer showed distribution of misorientation angles around 10–15°. A {1 1 0}〈1 1 0〉 texture was also found in ribbons as thin as 50 μm, which cannot be obtained with pure Ag ribbons. A pronounced reduction of Ag amount was obtained in 60 μm thick Ag/NiCrV ribbons, with a textured Ag top layer being as thin as 7 μm. The amount of Ag was decreased by 75% compared to pure Ag ribbons of the same thickness. A strong enhancement of the mechanical properties was observed. The yield strength σ0.2 at 77 K was 220 MPa for Ag/NiCrV ribbons, i.e. considerably higher than the 30 MPa for pure Ag ribbons. [Copyright &y& Elsevier]

Abstract: The key requirements for the substrates employed in coated conductors are using magnetic reduced and strengthening materials. In this work, Ni-based alloy composite tapes were designed and prepared in order to meet such needs through a hybrid route. A novel multi-layer of composite tapes was obtained by sintering two pieces of Ni–5at.%W (out layers) connected with Ni–12at.%W mixture powder together using sparking plasma sintering (SPS) technology. The high tungsten contents mixture powder after sintering not only played a role as a joint layer, but also performed high strength and reduced ferromagnetism as an inner layer at the same time. The sharp cube texture was obtained in the composite tapes after the optimized cold rolling and recrystallization. The FWHM values of (111) Phi-scans and (002) rocking curves of these tapes were around 9.45°and 5.48°, respectively, measured by X-rays. Extremely, the yield stress of this composite substrate exceeds 320MPa, the magnetization of the composite substrate being reduced to 10.9emu/g at 77K, only 41% in comparison with commercial Ni5W substrate. [Copyright &y& Elsevier]

Abstract: In-situ MgB2/Fe tapes were fabricated by powder-in-tube (PIT) technology using Mg and B powders. The tapes were sintered by advanced spark plasma sintering (SPS) technique. The effects of the annealing parameters on the properties of the MgB2 tapes were investigated by the analysis of XRD, SEM and the magnetic J c measurements. It was shown that at 10K, 0T, the J c value of the tape sintered using SPS machine at 800°C for 15min under 40MPa was close to 106 A/cm2, which was higher than that of the same tapes annealed by conventional method. It was supposed that the density and the homogeneity of the MgB2 core were strongly improved using fast SPS sintering process. Further enhancement of J c in the tapes is expected for the understanding of the SPS sintering mechanism. [Copyright &y& Elsevier]

We report on a novel technique of sparking plasma sintering to prepare Ni–W alloy composite substrates with strong cube texture, high yield strength and reduced magnetization for coated conductors. It was found that an outer Ni–5at.% W layer in as-obtained composite substrates has a sharp and pure cube texture, while the use of the Ni alloy with high W content in the core of the composite substrates not only enhances the mechanical property, but also degrades the ferromagnetism of the whole substrates. [Copyright &y& Elsevier]

A combination of an in-situ tensile technique and electron backscattering diffraction (EBSD) was used to investigate the changes in microstructure and texture during plastic deformation of nickel with a high cubic texture. Surprisingly, unlike most data in the literature, it was found that the grains in nickel with a high cubic texture tended to align rather than scatter under a large force; thus, a large tensile stress causes enhancement of the cubic texture. The in-situ tensile tests are allowable to observe the entire process in real-time, while the EBSD results are helpful to separate texture changes at individual-grain resolution and to uncover the regular progression. It was found that, except for tiny grains and twins, most of the recrystallized grains tended towards the <001> pole. The only difference was that grains with a soft orientation effortlessly joined in the activation of the slip system, with the movement of dislocations playing a significant role in these grains. Conversely, the hard-orientation grains maintained the coordination of plastic deformation by means of rotation. Our results validate the in-situ tensile technique combined with EBSD as a systematic research method applied to the study of texture transformation for pure nickel. [ABSTRACT FROM AUTHOR]

Biaxially textured super-high tungsten Ni–W alloy substrates have been fabricated through the composite substrate method in view of coated conductor applications. The tungsten content exceeds 10% in the obtained substrates. The excellent super-high tungsten substrate (Ni10W) had a strong cube texture consistent with commercial Ni5W and better than Ni8W or Ni9W substrate. Furthermore, yield strength ∼310 MPa (twice of Ni5W) and saturation magnetization of only 4% to that of Ni5W at the temperature of 77 K was calculated for Ni10W substrate. The novel Ni10W substrate with strong cube texture and negligible magnetization is best suited to be utilized for 2nd generation coated conductor REBCO. It can significantly improve the progress of using the RABiTS route in the fabrication of REBCO tapes. Meantime, the mechanisms of the cube evolution and elements diffusion in super high tungsten substrate are also studied. • The super high tungsten (the content of W exceeds 10%) Ni-W alloy substrates with sharp cube texture have been prepared.. • The fabricated super high tungsten substrates have extremely stability up to 0.2 % strain through in-situ analysis. • A CeO 2 buffer layer was successfully deposited on the super high tungsten substrates by the MOD method. • The mechanisms of the cube evolution and tungsten diffusion in super high tungsten substrate are studied. • The model between the growth of grains and elemental diffusion during the heat treatment process is established. [ABSTRACT FROM AUTHOR]

In the present work, Ag–Ni and Al–Ni nanoparticles (NPs) were synthesized via co-precipitation method and their structural, resistive response of humidity and photocatalytic degradation properties evaluated. The as prepared NPs were characterized by XRD, FTIR, TGA, DRS, BET, XPS, SEM and TEM. XRD patterns indicated well defined peaks for Ag, Al and Ni elements. SEM and TEM micrographs displayed nano size heterogeneous microstructures both for Ag–Ni and Al–Ni NPs along with some agglomeration. The average particle size calculated by XRD, SEM and TEM was ranged from 42 to 95 nm. FTIR and XPS investigated about various functional groups and elemental contents within the synthesized samples. TGA showed total weight loss of 14.93 and 39.29% whereas, surface area, pore volume and pore size were 18.63 m2/g, 0.2846 mL/g, 1.3277 nm and 8.52 m2/g, 0.0556 mL/g, 1.3678 nm for Ag–Ni and Al–Ni NPs respectively. Low band gap energies ~1.30 (for Ag–Ni) and 1.51eV (for Al–Ni) were calculated via DRS. Resistance was decreased from (879–240MΩ for Ag–Ni and 745 to 169MΩ for Al–Ni NPs) with increased humidity level (from 10 to 95%) due to surface adsorption of water by fabricated samples. Response time ~60s, 59s and recovery time ~39s, 20s with low hysteresis was measured for Ag–Ni and Al–Ni NPs respectively. Furthermore, photocatalytic degradation ability of the synthesized samples was also investigated against Methyl Orange (MO) dye. Ag–Ni and Al–Ni NPs showed 91 and 75% degradation during total time of 80 and 120 min respectively. Degradation ability of the samples was also evaluated for various factors such as catalyst loading, pH and different scavengers. Fast response/recovery time, low hysteresis, better catalysis and excellent stability indicated for both the samples categorize them well suited for resistive humidity sensing and photocatalytic degradation of MO dye from industrial effluents. Image 101298 • Ag–Ni & Al–Ni NPs. • Humidity/MO degradation. • Low hysteresis. • Recyclability. [ABSTRACT FROM AUTHOR]

We report on the preparation of dense monofilamentary MgB[sub 2]/Ni and MgB[sub 2]/Fe tapes with high critical current densities. In annealed MgB[sub 2]/Ni tapes, we obtained transport critical current densities as high as 2.3×10[sup 5] A/cm[sup 2] at 4.2 K and 1.5 T, and for MgB[sub 2]/Fe tapes 10[sup 4] A/cm[sup 2] at 4.2 K and 6.5 T. An extrapolation to zero field of the MgB[sub 2]/Fe data gives a critical current value of ∼1 MA/cm[sup 2], corresponding to a critical current value well above 1000 A. The high j[sub c] values obtained after annealing are a consequence of sintering densification and grain reconnection. Fe does not react with MgB[sub 2] and is thus an excellent sheath material candidate for tapes with self-field j[sub c] values at 4.2 K in excess of 1 MA/cm[sup 2]. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Among all the preparation methods, electrochemical exfoliation of graphite in neutral aqueous solution to prepare high-quality graphene is a hot research topic due to many advantages, such as high efficiency, environmental friendly, fewer defects, and convenient operation with simple equipment. In this work, the graphene was prepared by pre-intercalation assisted electrochemical exfoliation of graphite foil, in which one pre-intercalation stage was performed at the low voltage to moderately enlarge the interlayer distance of graphite foil, and then graphite electrode was electrochemically exfoliated to produce graphene nanosheets in an aqueous inorganic salt solution of (NH4)2SO4. Through comparing two pretreatment methods of graphite foil (pre-expansion with liquid nitrogen and pre-intercalation by electrochemical intercalation), the electrochemical pre-intercalation process was confirmed to avoid the serious loss of the graphite electrode during the liquid nitrogen pretreatment and facilitate electrochemical exfoliation. Meanwhile, the optimum parameters of pre-intercalation were determined. Subsequently, the effect of applied voltage on the quality of obtained graphene (such as the number of layers, defects, size, composition) during the exfoliation stage was investigated systematically, and especially the effect of applied voltage on the quality and yield of graphene was discussed in detail. The graphene nanosheets with a small number of layers (60% is less than 5 layers) were obtained through two stages of electrochemical pre-intercalation and exfoliation. The structure, morphology, and composition of the graphene were analyzed by using the XRD, SEM, TEM, AFM, and XPS. [ABSTRACT FROM AUTHOR]

This paper presents a novel two-step procedure for measuring the critical current (I c) properties as a function of tensile stress. The proposed method completely eliminates the possible negative effect of the voltage tap used during the tensile procedure, allowing the actual I c irreversible degradation stress to be clearly determined. Six different commercial REBCO tapes from five manufacturers were tested. The I c value does not degrade until the stress reaches the 'inflection area' in the tensile curve, which corresponds to the most pronounced transformation step from elastic to plastic deformation. This allows easy estimation of the stress corresponding to I c irreversible degradation by a simple and accurate cryogenic tensile curve instead of complicated in-situ I c tensile measurement. A feasible composite-material tensile model is established to explain the phenomenon. In addition, fatigue measurements on a commercial REBCO tape from Shanghai Superconductor technology show that the tape can withstand 10 000 cycles under 580 MPa and over 5000 cycles under 695 MPa, which also is consistent with the proposed composite-materials tensile model and is confirmed by the EBSD experiments on the Hastelloy substrate. This research provides better insight and tools for designing and fabricating extremely high-field magnets. [ABSTRACT FROM AUTHOR]

In depth and detailed study about various classes of aerosols over an urban city of Beijing has been carried out, with the help of cluster technique during the period from (2005–2017). Aerosol Robotic Network (AERONET), retrieved data for Aerosol Optical Depth (AOD), Angstrom Exponent (AE), Extinction Angstrom Exponent (EAE), Absorption Angstrom Exponent (AAE), Single Scattering Albedo (SSA), Real and Imaginary index of Refraction (RRI & IRI respectively), Asymmetry Parameter (ASY) has been utilized for discrimination of aerosols over the study site. Higher mean values of AOD and AE were found in winter and spring season as (0.86 ± 0.38, 0.85 ± 0.32) and (1.06 ± 0.36, 1.19 ± 0.21), while lower values (0.75 ± 0.33, 0.75 ± 0.33) and (0.97 ± 0.22, 0.85 ± 0.17) for summer and autumn season respectively, representing mixed anthropogenic aerosols over the site. Three main types of aerosol were reported in this study: Mixed Carbonaceous (MC), Biomass Residuals (BR), and coarse mode local and transported Dust Particles (DP). Various aerosol parameters and their inter-relationship were investigated in detail to analyze the dominant aerosol type and its seasonal variations. The EAE and AAE values ranged from (0.10–1.77 and 0.00–1.70 respectively), could mainly be attributed towards MC aerosols. Real and Imaginary parts of Index (RRI & IRI) were recorded in the range from (1.33–1.60 and 0–0.010) respectively. Similarly, the range for SSA and ASY was found as (0.79–0.99 and 0.43–0.78) respectively. Back-trajectories using Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model revealed transportation of air masses from Mongolian deserts, Gobi desert, and other neighboring regions (i.e. Russia and Kazakhstan). • Aerosols study of Beijing • AERONET • AOD • Carbonaceous aerosols [ABSTRACT FROM AUTHOR]

Thermal barrier coatings (TBCs) are widely used as insulating layers to protect the underlying metallic structure of gas turbine blades. However, the thermal cycling performance of TBCs is affected by their complex working environments, which may shorten their service life. Previous studies have shown that preparing a mesh structure in the bonding layer can relieve thermal stress and improve the bonding strength, thereby prolonging the service life of TBCs. In this paper, a micromesh structure was prepared on the surface of the bonding layer via wet etching. The microstructure and failure mechanism of the micromesh TBCs after CMAS (CaO-MgO-Al 2 O 3 -SiO 2) thermal erosion were investigated. Numerical simulation was combined with thermal shock experiments to study the stress distribution of the micromesh-structured TBCs. The results showed that the circular convex structure can effectively improve the CMAS corrosion resistance and thermal shock resistance of TBCs. [ABSTRACT FROM AUTHOR]

Abstract: A pronounced effect of overheating is observed on the thermal stability and mechanical properties of Cu36Zr48Ag8Al8 bulk metallic glass. Higher overheated temperature enhances the thermal stability of bulk amorphous alloys, corresponding to higher specific-heat capacity and the smaller initial defect concentration. And a threshold overheating temperature is found for the fully amorphous structure. Bulk amorphous alloys exhibit good compressive plasticity at small overheat levels, whereas the compressive fracture strength and micro-hardness exhibit a significant increase first and then a slightly decrease. Mechanical properties of BMGs can be tailored in certain extent by controlling the overheated level, which is correlated with free volume and residual stresses. [Copyright &y& Elsevier]

Abstract: A single Ce0.8Gd0.2O1.9 (CGO) buffer layer was successfully grown on the home-made textured Ni–5at.%W (Ni–5W) substrates for YBCO coated conductors by a simple metal–organic deposition (MOD) technique. The precursor solution was prepared using a newly developed process and only contained common metal–organic salts of both Ce and Gd dissolved into a propionic acid solvent. The precursor solution at 0.4M concentration was spin coated on short samples of Ni–5W substrates and heat-treated at 1100°C in a mixture gas of 5% H2 in Ar for an hour. X-ray studies indicated that the CGO films had good out-of-plane and in-plane textures with full-width-half-maximum values of 4.18° and 6.19°, respectively. Atomic force microscope (AFM) investigations of the CGO films revealed that most of the grain boundary grooves on the Ni–5W surface were found to be well covered by CGO layers, which had a fairly dense and smooth microstructure without cracks and porosity. These results indicate that our MOD technique is very promising for further development of single buffer layer architecture for YBCO coated conductors, due to its low cost and simple process. [Copyright &y& Elsevier]

In this study, a repeatable and widely applicable method for decreasing the turn-to-turn contact resistivity of REBa 2 Cu 3 O 7 -x (RE=rare earth, REBCO) tapes was demonstrated. By applying a solder without further connections, the contact resistivity can be significantly and consistently decreased to low values. Four solders and five REBCO tapes from various manufacturers were tested to demonstrate the wide applicability of this method. The lowest value achieved by using a combination of solder and surface cleaning procedure was around 3 μΩ cm2. Furthermore, a possible governing mechanism for the repeatable decrease method using solder is discussed. The Mikic elastic correlation was considered the most probable candidate. After carefully discussing the three factors of contact resistivity, namely surface roughness, surface conductance, and surface Young's modulus, surface Young's modulus was considered to have a much higher weight index than the surface roughness, and the surface conductance was negligible. This research can help us better understand the contact resistivity of REBCO and develop a method that can controllably adjust the contact resistivity. [ABSTRACT FROM AUTHOR]

Different films comprising pure chitosan (CS) and chitosan coated sodium zeolites composites films designated as CSZ1, CSZ2, CSZ3 and CSZ4 respectively are presented here for the sequestration of MO dye. The as-synthesized films were characterized by using FSESM, XPS XRD, and TGA analysis. The sequestration of methyl orange dye (MO) was studied under various adsorption parameters i.e. pH effect, reaction temperature, catalytic dosage, interaction period, and original dye concentration in batch experiments. The adsorption power of MO dye sequestration in the presence of CSZ3 was 287 mg g−1 higher than the fine CS (201 mg g−1), and lowest for CSZ4 (173 mg g−1). The experimental data is fitted in the pseudo-second order of chemical kinetics. The Freundlich and Langmuir adsorption models were used on behalf of the analysis of experimental data that revealed multilayered adsorption of MO dye. Kinetics, equilibrium and thermodynamic process were discussed in detailed, suggesting the endothermic and spontaneous process of the adsorption of MO dye on the exterior of films. The present work is general for the MO adsorption, however, it can be applied on large scale applications and can be easily adjustable in the water purification assemblies. Unlabelled Image • Synthesis of CS coated sodium zeolite films • Loading of different weight of sodium zeolite to CS film • Application in the adsorption of MO dye • Kinetics and thermodynamics studies [ABSTRACT FROM AUTHOR]

A series of iron-based nanocomposites such as Cu–Fe (CFNCs), Ni–Fe (NFNCs), Ag–Fe (SFNCs) and Al–Fe (AFNCs) were fabricated via sol–gel route. An extensive investigation about crystallinity, microstructure, electrical and optical properties was carried out by utilizing X-ray diffractometer (XRD), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) and scanning electron microscopy (SEM). The frequency-dependent AC conductivity, dielectric constant and dielectric loss were measured in the frequency range of 25 kHz–2 MHz at room temperature via an LCR meter. The highest conductivity ~ 2.85 × 10−7S/m was revealed by AFNCs as compared to other nanocomposites. The Maxwell–Wagner model for induced polarization and Koop's phenomenological theory of dielectrics were followed by all the fabricated nanocomposites in the temperature range of 30–600 °C. The maximum dielectric constant ~ 930 was measured for AFNCs at a temperature of 200 °C. Furthermore, the synthesized nanocomposites effectively degraded a toxic organic dye Rhodamine B (RhB) and the degradation (%) ~ 77, 85, 86, and 87 within the time of 50, 40, 50 and 70 min was recorded for CFNCs, NFNCs, SFNCs and AFNCs, respectively. [ABSTRACT FROM AUTHOR]

Due to the high growth rate and environmental‐friendly, fluorine‐free metal‐organic decomposition routes (FF‐MOD) have attracted more attention for growth of high‐quality YBa2Cu3O7‐δ (YBCO) films. Few works have been performed when using technical substrates. In this study, correlation among the sintering process, microstructure, and superconductivity of the YBCO was systematically established on the technical substrates capped with CeO2 layer. We found that the optimal process conditions are mainly related to the enhanced transient liquid phase and BaCeO3. Combined X‐ray diffraction and scanning electron microscopy analyses indicate that high‐quality growth of YBCO film is a trade‐off of two different competition phenomena during sintering: (a) the presence of enhanced transient liquid phase, (b) the formation of BaCeO3 at the interface. The former is beneficial to YBCO epitaxial growth/structure rearrangement, while the latter should be suppressed in view of minimizing YBCO partial decomposition triggered by the interfacial reaction. Moreover, we confirmed that both two aforementioned phenomena are somehow associated with the cross‐linkage between the sintering temperature and pO2 during the YBCO conversion. According to this systemic study, the key parameters are defined to avoid the BaCeO3 formation prior to the YBCO orientation nucleation. Structure and superconductivity of the YBCO film were also investigated. Remarkably, a high Jc value of 3.69 mA/cm2 (77 K, sf) was obtained in the YBCO film grown on the CeO2 technical substrate deposited under optimized deposition conditions, which is rather comparable with that on the LaAlO3 single crystal. TEM cross‐sectional observation reveals that the enhanced Jc (B) properties of the YBCO film are mainly contributed by high density of short stacking faults. This work demonstrates the feasibility of FF‐MOD to fabricate high‐performance YBCO films on the CeO2‐buffered technical substrate. [ABSTRACT FROM AUTHOR]

The hysteresis loss of Ni–5 at.%W (Ni5W) substrate contributes considerably to the alternating current (AC) loss of coated conductors (CCs) working at low transporting current or low-frequency field. In the present work, the evolution of texture and magnetic properties in Ni5W substrates is analyzed and also the relationship between magnetic properties and the extrinsic characteristics (evolved due to the processing techniques) is determined. By making the comparison, we discovered the magnetic domain structures of Ni5W substrates for the first time, achieving a strip/branched domain structures in the recrystallized substrates. The hysteresis loss has been decreased dramatically for the recrystallized substrates. Interestingly, we also observed that this loss is also related to the annealing temperature in the fully recrystallized substrates. The reduced loss can be mainly attributed toward the decrease of grain boundary, which proves the contribution of grain size toward the reduction of hysteresis loss. This result provides a new insight to tailor the hysteresis loss of Ni5W substrates used for coated conductors. [ABSTRACT FROM AUTHOR]

Highlights • The cube texture has been realized by consuming other orientation grains. • A perfect domain structure formed because of larger grain size and more SAGBs. • Higher hysteresis loss caused by complex domain structure and sharp cube texture. • There is a discrepancy between sharp cube texture and reduction of AC loss. Abstract The metallic Ni–5 at.%W (Ni5W) substrate with sharp cube texture is found as one of the promising candidates used for fabrication of coated conductors. However, the alternating current (AC) loss, partly contributed by the ferromagnetic Ni5W substrate is unavoidable. In this work, we analyzed the evolution of magnetic properties of Ni5W substrates via the cube texture development. The results revealed that the cube texture has an important impact related to size advantage during recrystallization, leading towards the consumption of the deformation and other orientational grains, and hence giving rise to form a sharp cube texture. Increasing the annealing temperature, the grain size is found to be increased. In the fully developed cube-textured substrate, the grain boundary was replaced by small angle grain boundaries (SAGBs). Also the magnetic domain structure was transformed from 180°-structure to a branched one with the increasing annealing temperature. This transformation is dependent on the increase of grain size, particularly, the SAGBs plays an important role in the formation of perfect domain structure. Increased coercivity and hysteresis loss in the fully textured substrate can be attributed towards the ideal cube texture and perfect complex domain structure. Therefore, a potential solution has been proposed to resolve this limitation of the sharp cube texture and increased hysteresis loss in Ni5W substrates. [ABSTRACT FROM AUTHOR]

[Display omitted] • BaHfO 3 doped Eu 1 Ba 2 Cu 3 O 7-δ films was fabricated by an ultra-fast pulsed laser deposition. • The periodic change of growth conditions during the multi-turn dynamic deposition results a distinct lamellar structure in doped film. • A strong correlation between dopant content and BaHfO 3 self-assembly mechanism was established. • The predominant pinning mechanism transforms form random pinning to correlated pinning with the increase of dopant content. Structure modulation of rare-earth barium cuperates (REBCO) superconducting films plays an essential role in the flux pinning behaviors. In this paper, nano-composite EuBa 2 Cu 3 O 7−δ -BaHfO 3 (EuBCO/BHO) films were deposited by the ultra-fast pulsed laser deposition technique. All nano-composite films exhibited high-quality orientation under the growth rates up to 100 nm/s. TEM cross-sectional analysis reveals that the EuBCO/BHO films have a distinct lamellar structure, which is related to the periodic change of growth conditions during the multi-turn dynamic deposition. In addition, the morphology of BHO varies with dopant content, which suggests a strong correlation between dopant content and the BHO self-assembly mechanism. Consequently, the vortex behavior shifts from giant-flux creep to vortex-glass formation at the thermally activated flux flow region as the dopant content increases. The primary flux pinning behaviors change from random to correlated pinning with the increase of dopant content at 4.2 K. Due to the larger contribution of the correlated pinning machinimas, the 8% BHO-doped EuBCO film exhibits the highest J c value at 4.2 K, with moderate fields (below 8 T) among all the three films. At 4.2 K and 14 T, the 6% BHO doped EuBCO film has the highest F p value attributing to the predominate random pinning mechanism. [ABSTRACT FROM AUTHOR]

In this present work, Al–Sr and Al–Cd nano-materials (NMs) were fabricated trough co-precipitation route. The synthesized NMs were subjected to various advanced techniques such as XRD, XPS, SEM, DRS and BET. XRD patterns showed prominent peaks for Al, Sr and Cd elements within the synthesized samples. SEM images depicted nano size agglomerated particles for Al–Sr and tubular layered structure for Al–Cd-NMs with the average particle size in the range from (40–45) nm. The elemental content within the fabricated samples was investigated in detail via XPS technique. Surface area adsorption (SAA) parameters obtained from BET analysis were ∼122.32 m2/g, 162.41 m2/g (surface area), 0.1231 cm3/g, 0.4312 cm3/g (pore volume) and 0.8996, 0.9982 nm (pore size) for Al–Sr and Al–Cd-NMs. Energy band gaps ∼2.58 (for Al–Sr) and 2.53eV (for Al–Cd) were obtained through DRS. Furthermore, the fabricated samples were tested for humidity sensing ability. The NMs were indicated with decreased resistance as (987–344) MΩ and (924–290) MΩ for Al–Sr and Al–Cd respectively. Response/recovery time ∼60s/44s for (Al–Sr) and ∼29s/45s for (Al–Cd) was calculated. Both the samples were found highly stable for a longer period of 105 days (with the time gap of 20 days) with the variation in resistance less than 2%. Stable microstructure, quick response-recovery behaviour and low hysteresis categorize these two NMs well suited for resistive response of humidity sensing at industrial level. [Display omitted] • Al–Sr and Al–Cd nano-materials. • Surface area adsorption. • Humidity sensing. • Response/recovery time. [ABSTRACT FROM AUTHOR]

A 10-m-long homemade textured Ni-5at.%W (Ni5W) long tape with a CeO buffer layer has been prepared successfully by means of rolling-assisted biaxially textured substrate (RABiTS) route followed by a chemical solution deposition method in a reel-to-reel manner. Globally, the Ni5W substrate and CeO film exhibit high homogeneity in terms of biaxial texture over the tape. The average values of full width at half maximum of in-plane and out-of-plane texture are 7.2° and 6.1° in Ni5W substrate, 7.6° and 6.1° in CeO buffer layer, respectively, all of those with a small standard deviation. On a microlevel, the CeO film epitaxially grows well on top of the Ni5W tape. A continuous, smooth, and crack-free morphology was observed on the CeO film and the fraction of low-angle grain boundaries (≤ 10°) is about 98 %. This process is a potential possibility for producing long-length textured CeO/Ni5W tapes for coated conductors with a low cost. [ABSTRACT FROM AUTHOR]

A co-precipitation process was used to recover composite powders from a NdFeB slurry. The most appropriate concentration of HCl and a v/w ratio were obtained in the leaching process. The optimum pH range for the co-precipitation process was determined by the log[Me(Nd, Fe, Co, Pr)]–pH curve simulated using a thermodynamics model. Fe 2 O 3 , Fe 2 O 3 ·Nd 2 O 3 , and Pr 2 CoO 4 phases were detected in the final composite powders after firing the co-precipitated products at 1273 K for 2 h. The content of the valuable metals (Nd, Pr, Co, Fe) in the obtained composite powders was greater than 99.4%, which meets the raw material requirements for preparing recycled NdFeB magnetic powders. The main advantages of the co-precipitation process are that it is efficient, low-cost, and environmentally friendly. [ABSTRACT FROM AUTHOR]