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Herein, Ag–Mo films were deposited on Si(100) substrates by magnetron co-sputtering. The phase evolution and microstructural investigation revealed that the pure Ag phase and no Ag(Mo) solid soluti...

Metallic nano multilayers were usually prepared by dual targets alternating deposition method. In this paper, a series of self-assembled Cu–W nano multilayers with different modulation periods were deposited on single crystal silicon substrate by dual targets confocal magnetron sputtering technique. The self-assembled film presented an alternation of W-rich layer and Cu-rich layer. The degree of coherence of the layered interface can be adjusted by controlling both the solid solubility of W-rich and Cu-rich layers. The film resistance increment of the self-assembled Cu–W multilayers is only 14% when the modulation period decreases from 68.2 nm to 5.3 nm, having less size effect compared to the film prepared by alternating deposition method. It noticed that the film resistance even decreased slightly when the modulation period decreased to below 5.3 nm. These results suggested that the coherence could weak the interface scattering ability to electrons, so the self-assembled Cu–W multilayers have lower resistance than the multilayer prepared by alternating deposition technique. This study presented a new pathway to enhance the conductivity of the multilayers.

Two-dimensional (2D) nanomaterials possessing a unique sheet structure, compared to correlative bulk materials, exhibit excellent properties, especially in the energy storage and energy conversion ...

Although nanocrystallization and carbon modification could improve the specific capacity of cathode materials, the deficiency of high voltage makes it difficult to satisfy the need of high-power thermal battery. Hence, the carbon coated NiCl2/NiS2 double active cathode materials are fabricated by the simple ball milling-sintering method. The NiCl2/NiS2@C cathodes have the excellent discharge performances (initial voltage with 2.78 V, specific capacity with 946.08 mAh g−1 and energy with 1497.11 Wh kg−1 in 0.1 A cm−2 at 500 °C under cut-off voltage of 0.5 V) when the quality ratio between NiCl2 and NiS2 is about 1:1. A prominently enhanced specific energy could be attributed to surface synergistic effects which from high voltage of NiCl2, high capacity of NiS2 and high conductivity of carbon. Especially, improving voltage and capacity of ball milling are superior to sintering and carbon coating through contrast experiments. Furthermore, the morphology of post-electrodes indicates that carbon coating could solve the structure collapse question of NiCl2/NiS2 cathodes in high temperature and current density. These findings open a new avenue for developing double active composites as high-power cathodes for thermal battery.

Polystyrene (PS) composites with silver nanoparticles (AgNPs)-decorated reduced graphene oxides (rGO) were prepared by electrostatic self-assembly and following a hot press process. Specifically, GO sheets were uniformly attached to positively charged PS microspheres through electrostatic absorption, and then, AgNPs were in situ reduced on the surface of PS/rGO composite microspheres. Followed by hot press, the sintering process of AgNPs induced bridge connection between the adjacent rGO sheets obviously, therefore, three dimensional (3D) rGO conductive frameworks featured by AgNPs adhesive was constructed in the composite. The synergistic effect of rGO and AgNPs in the frameworks contributed to significant enhancement of thermal conductivity. Thus, the thermal conductivity of the PS/rGO-AgNPs composite reached 0.54 W/(m K), about 2.38 times higher than that of pure PS material. This result suggests that AgNPs-decorated 3D rGO as a hybrid filler is an effective strategy for enhancing thermal conductive performance of polymer composites.

The δ-TaN films were fabricated through reactive magnetron sputtering deposition technique onto WC-Co substrate. The texture of δ-TaN films can be tuned by adjusting the sputtering power and working gas pressure to vary the ion energy and mobility of particles. The underdense structure observed on film with (111) texture was formed at high work gas pressure and lower power due to large ion motion resistance and low driving force, respectively. Increasing ion mobility by decreasing pressure would lead to a fully dense δ-TaN (200) film with the lowest surface energy. The scratch test was used to measure the bond strength of the film to the substrate and how the film fails. The wear resistance of δ-TaN presented a strong correlation with texture. δ-TaN film with (200) texture possessed of lowest wear rate (2.4 × 10−6 mm3/N·m) far below that of WC-Co (4.0 × 10−6 mm3/N·m) and δ-TaN film with (111) texture (4.3 × 10−6 mm3/N·m). δ-TaN film with (200) texture or no obvious texture had a hardness above 30 GPa, which was much higher than that of (111) texture. In addition, the lowest surface energy of (200) texture induced the mild adhesion between δ-TaN film and AISI52100 steel counterpart. So δ-TaN film with (200) texture had the best wear resistance among these films. Further study on the machinability behavior of δ-TaN films has been found to lead to more remarkable loss of wear volume of steel ball comparing with the WC-Co substrate. This film especially with (200) texture can be expected as an excellent candidate for cutting tools.

Two-dimensional (2D) nanomaterials possessing a unique sheet structure, compared to correlative bulk materials, exhibit excellent properties, especially in the energy storage and energy conversion field. In this case, NiCl

To unravel the underlying causes of the opposite variation tendency in theoretical and experimental thermal conductivity of copper/diamond composites as the increasing thickness of nanoscale interface layer, WC layers with 70–400 nm thickness were prepared by magnetron sputtering W layers on the diamond substrates and following vacuum annealing treatment. The interface structure of the WC coated diamond was studied by TEM, and the density (ρ) of the WC layers was measured by the relative peaking intensity of the coating phase using the X-ray scattering strength method. Nanoindentation and four-point probe experiments were also carried out for indirectly characterizing average phonon velocity (ν) and thermal conductivity (KWC) of the WC layers. Interfacial thermal conductance (ITC) of the composites was calculated by the actual experimental ρ, ν and KWC of the WC nanoscale layers. Meanwhile, corresponding copper/diamond composites were fabricated by pressure-assisted infiltration method. The maximum thermal conductivity (TC) of the composite achieved 943 W·m−1·K−1. The variation trend of the actual TC in the composites was agreed with that of the calculated ones which were calculated by the ITC and differential effective medium (DEM) model. Based on the above quantitative analysis, the thermal boundary conductance of WC/Cu and diamond/WC interface is the main factor that leads to the variation of TC of the composites with the increase of the WC interlayer thickness. Optimizing a higher thermal boundary conductance by regulating the interlayer thickness is a crucial factor for enhancing the TC of the composite.

The F-doped ZrO2−x nanotubes are synthesized by anodic oxidization in a F-containing electrolyte and following a low temperature annealing process. The F-doped ZrO2−x nanotubes exhibit a dramatic increase in visible light absorption and efficient visible light photocatalytic activity which are not possessed to normalized ZrO2. The fluorine in anodic ZrO2 nanotubes plays a vital role in the formation of abundant anion vacancies during the annealing. Combining the doping effect of the residual fluorine element, the band gap of the F-doped ZrO2−x nanotubes reduced from 5.13 to 2.35 eV. Moreover, the transient photocurrent response plots and the photocatalytic experiments reveal the highly effective electrons–holes separation of the F-doped ZrO2−x nanotubes and enhanced visible-light photocatalytic degradation for RhB. The degradation rate of RhB in the presence of the F-doped ZrO2−x nanotubes catalyst has reached up to 83% under 2 h low-power LED light irradiation. In addition, the possible photocatalytic mechanism of the F-doped ZrO2−x nanotubes has been proposed via studying the band structure. It is believed that the F-doped ZrO2−x nanotubes will have a bright future for sustainable energy sources and cleaning environment.

Iron fluorides have drawn much attention in Li-ion batteries due to high theoretical capacity. However, its application progress is hampered by the inferior electrode cyclability and rate capability. The main issue in this work is to find effective ways to improve the electrochemical activity of iron fluoride (FeF3), and enhance the electrochemical properties. Herein, carbon wrapped FeF3 nanocomposite has been synthesized progressively by carbon coating and fluorination. This structure not only keeps the grain size of FeF3 about 60 nm, but also immerses the electrode in the electrolyte fully. So the electrode shows excellent electrochemical activity. This nano-composite exhibits an initial discharge capacity of ∼166.4 mAh g−1 in the voltage of 2.0–4.5 V at 20 mA g−1. After 100 cycle, the discharge capacity keeps about 126.3 mAh g−1, with the fading rate of ∼0.24%. Furthermore, the EIS of carbon winded FeF3 indicates that the transmission ability of lithium ion improved greatly. This structure is very meaningful to provide a synthetic approach to prepare the cathode material.

A series of Cu-W films with the W content higher than 17.2 at% were prepared by magnetron sputtering focused co-deposition technology. The micro-structures and nanoidentation hardness of the films were investigated. Except for the fcc, amorphous and bcc phases, a novel multilayered structure has been observed at the range of about 17.2–90 at% W. Within the multilayered structure, the high-density interfaces can inhibit the motion of dislocations, which resulted in the hardness at least 2 GPa higher than that of the mixing rule. Depending on different microstructures, the hardness curve of the Cu-W films can be divided into three regions instead of the linear increase with the W content. From 17.2–40 at% W, the hardness increased slowly due to lots of amorphous phase. Within 40–65 at% W, the hardness increased linearly, which was caused by the gradually obvious multilayered structure and decreasing amorphous content. Above 65 at% W, single-phase body-centered cubic (bcc) films were observed. In this region, the upward trend of hardness slowed down due to the porous columnar structure and gradually disappeared multilayered structure.

The microstructure, electrical resistivity and thermal conductivity of the sputtering deposited Cu-Ta films were investigated as a function of Ta content. The results showed that the amorphous phase formed between 20 at.% and 60 at.% Ta, and out of this range α-Cu(Ta) and β-Ta(Cu) solid solutions formed. Because the lattice distortion and β-Ta structure could significantly increase the probability of electron scattering, the electrical resistivity of the Cu-Ta films shows a ‘N’ type change with the increase of Ta content, and the inflection point appears at 50 at.% Ta and 60 at.% Ta respectively. As the thermal conductance is also dominated by electrons in metals films, an opposite variation tendency is found in the thermal conductivity of the Cu-Ta films. According to our knowledge, this is the first time to measure the thermal conductivity of Cu-Ta thin films.

Large scale, highly-ordered and vertically aligned lanthanum hexaboride (LaB6) nanotube arrays were prepared by DC magnetron sputtering deposition LaB6 on ultra-thin anodic aluminum oxide (AAO) substrates. The LaB6 nanotube arrays that were 210 nm in diameter and 620 nm in height haven’t collapsed and aggregated after the AAO templates have been removed by wet etching. After that, LaB6 nanotube arrays were bombarded by low energy Ar ion, which was used to further optimize its field emission property. X-ray diffraction measurement shows that LaB6 nanotube arrays are uniform polycrystalline phase without preferred orientation. SEM analysis shows that ion bombardment is an effective method for adjusting the micro-morphology of nanotube arrays. The cap-end nanotube arrays are turned into open-end, and the B/La atoms on its surface are decreased after ion bombardment. The formation of the open-end nanotube arrays with sharp edges and the enrichment of La atoms on the surface play an important role in enhancing the field emission property. The open-ended LaB6 nanotube arrays with sharp edges have the lowest turn-on field (6.8 V µm−1) and the highest current density (2.3 mA cm−2 at 11 V µm−1).

A new pretreatment process, namely, Ar+ ion beam bombardment and following deposition of a tungsten coating layer on diamond particles for fabricating diamond/copper composites is proposed in this paper. The composites are fabricated by infiltration method, and exhibited excellent thermal properties. Composition of the tungsten coated diamond particles is characterized by the Micro-XRD to investigate the effect of ion beam bombardment on the selectivity of interfacial reaction between the diamond planes and the coating layer. Scanning electron microscopy (SEM) is used to investigate the effect of the ion beam bombardment on interface structure and composition of the composites. A good interfacial adhesion without micro-gaps or cracks in the interfacial region is obtained. In addition to that, the phenomenon of selective interfacial reaction in the composite is no longer taking place, and the metal matrix uniformly adheres to all diamond planes. Therefore, the further enhancing thermal conductivity of the composites reach up to 896 W m−1 K−1, and coefficient of thermal expansion is only 5.9 × 10−6 K−1. The excellent performance can be attributed to the regulated interfacial adhesion and the optimized effective interfacial thermal conductance.

Nano-multilayered film is usually prepared by the arrangement deposition of different materials. In this paper, a self-assembled nano-multilayered film was deposited by simultaneous sputtering of Cu and W. The Cu/W nano-multilayered film was accumulated by W-rich layer and Cu-rich layer. Smooth interfaces with consecutive composition variation and semi-coherent even coherent relationship were identified, indicating that a spinodal-like structure with a modulation wavelength of about 20 nm formed during co-deposition process. The participation of diffusion barrier element, such as W, is believed the essential to obtain the nano-multilayered structure besides the technological parameters.

In this paper, Ta and TaCu films were deposited by using magnetron sputtering, and the tribological properties of the films against Si3N4 balls were investigated under the loads of 2 N and 5 N. The average grain sizes of both films are below 25 nm. Ta and TaCu films have approximate hardness. While the wear rate of TaCu film is much smaller than that of Ta film. Post-wear testing XRD, Raman and XPS revealed the formation of tantalum oxide on the worn surface of both Ta and TaCu films. Tantalum oxidation is effectively lubricating to reduce friction coefficient. So the friction coefficient of both Ta and TaCu film is about 0.45 under different applied loads. Meanwhile, the addition of Cu could increase the toughness of the film, and avoid the generation of wear debris, resulting in a significant increase in wear resistance.

The wear behavior of Ag implantation GH4169 alloy by ion beam assisted bombardment was measured under lower applied load and sliding speed. The wear rate of GH4169 alloy decreased from 2.58 × 10−4 mm3·m−1 to 6.25 ×10−5 mm3·m−1 after Ag implantation. The friction coefficient had not mostly been changed. After Ag implantation, Ag and Ag2O were detected on the worn surface of GH4169 alloy, which benefits the formation of continuous lubrication and protected layers. The predominant wear mechanism changed from abrasion and adhesion wear to oxidation and adhesion wear. In addition, the hardness increased. So, the wear resistance of GH4169 alloy under lower applied load and sliding speed can be improved with Ag implantation by ion beam assisted bombardment.

Low energy Ar+ ion beam bombardment is adopted as a pretreatment process of diamond particles for fabricating diamond/aluminum composite. We demonstrate that the combined effects of higher defect density and concentration of oxygen functional groups on diamond {100} plane lead to a selective interfacial bonding in the raw diamond/aluminum composites. It limits the thermal transfer performance of the composite. With the help of ion implantation and cleaning effects, similar diamond surface states are obtained by a conversion of sp3 C to sp2 C which occurs on both the diamond {100} and {111} planes simultaneously. The similar surface states are beneficial for the aluminum matrix adhered to the bombarded diamond surface uniformly during the interfacial reaction. Furthermore, the mean interfacial thermal conductance between the bombarded diamond particles and the matrix reaches up to 9.3 × 107 W·m− 2·K− 1. The thermal conductivity of the diamond/aluminum composite is improved significantly to 713 W·m− 1·K− 1, indicating that low energy ion beam bombarded is a promising approach for further improving the interfacial bonding and the thermal conductivity of the diamond/aluminum composite.

Nanocrystallization is widely used to improve the discharge performances of LIBs. While its lower thermal stability limits the operating time, especially for the thermal battery system, which discharges at high temperatures (usually 500–550 °C). In this paper, NiS2 particles were coated with amorphous carbon. Then they accumulated into submicron particles and were connected/fixed by a carbon network. The initial decomposition temperature of nano-NiS2 increased from 400 °C to 590 °C after this hierarchical carbon modification. The hierarchical carbon modified nano-NiS2 cathode revealed excellent discharge performances in thermal batteries at high temperatures. Specifically with 0.1 A cm−2 at 500 °C, the specific capacity and energy reach 610 mA h g−1 and 1082 W h kg−1, respectively, at a cut-off voltage of 1.4 V. The specific energy retains about 503 W h kg−1 even at 700 °C. The multiple protective effects of hierarchical carbon modification not only effectively improve the conductivity and thermal stability, but also inhibit the dissolution and shuttling of products. So, hierarchical carbon modification makes nano-NiS2 more suitable for high specific energy and long operating life thermal batteries.

Surface nanocrystallization and adjusting chemical compositions are anticipated to be effective strategies for exploring potential applications of diamond in physics, chemistry and biology. In this paper, the morphology evolution of a polycrystalline chemical vapor deposition diamond (PCD) under Ar+ ion beam bombardment was studied. Nano ripple was formed on the substrate. The characteristic sizes, including amplitude (A) and wavelength (W), of ripples could be adjusted by changing ion energy. Meanwhile, chemical compositions of the diamond surface after the bombardment were investigated by Raman spectrum and XPS. Amounts of lattice damage or defects appeared on the surface region of PCD due to a conversion of sp3 C to sp2 C during the ion bombardment. Moreover, high temperature annealing in vacuum was adopted to remove the damage layer. It was proved to be an effective means to restore diamond structure here and the ripple pattern could be still preserved after the thermal treatment. In addition, the variations of the sheet resistance of the PCD, which significantly increases as the increasing annealing time, offer a direct evidence to reveal the extent of restoration of diamond structure.

Garnet-type Ta-doped Li7La3Zr2O12 (LLZTO) solid electrolyte has been widely investigated for secondary Li ionic or metal batteries at ambient temperature. Because of the increasing ionic conductivity of LLZTO with temperature, we applied the LLZTO solid electrolyte to thermal battery working at 550 °C. The LLZTO presents ultrahigh specific energy as the discharge specific energy and specific power is 605 W h kg−1 and 2.74 kW kg−1 at 100 mA cm−2 with a cut-off voltage of 1.8 V, respectively. This is larger than the LiF–LiCl-LiBr electrolyte which is commonly used in thermal battery with a specific energy of 514 W h kg−1. The internal resistance of the single cell reaches 0.65 Ω, but the specific energy remains at about 400 W h kg−1 as the current density increases to 400 mA cm−2. We report the application of LLZTO in thermal battery with high specific energy, large current, and high voltage discharge for the first time, broadening the application range of solid electrolytes.

The Cu-48at.%Cr film was prepared by magnetron co-sputtering deposition technique with working pressure from 0.2 Pa to 1.5 Pa. The microstructure and nanoindentation hardness were investigated. When the working pressure decreased to 0.2 Pa, the consecutive layered structure formed. The formation of layered structure was attributed to the diffusion barrier ability of Cr element and the uphill diffusion of Cu atoms. While at higher working pressure, the sputtering particles energy near the substrate was not enough to promote the Cu diffusion. Therefore, the layered structure became indistinct as the working pressure increased. Owing to the interface strengthen, this layered structure made the nanoindentation hardness increase markedly from 4.2 GPa to 9.3 GPa as the working pressure decreased from 1.5 Pa to 0.2 Pa. This study could provide a good basis for preparing the film with specific microstructure in Cu–Cr system, even in other immiscible systems.

Comprehensive knowledge of the thermal stability of films is essential from the perspective of design and application. In this case, TaCu amorphous nano-multilayers with a Ta nominal content of 68 at.% were prepared by magnetron co-sputtering deposition technique. Nano-multilayers with a modulation period of 12.8 nm are constituted of equal-thickness sublayers both exhibiting pronounced Ta-rich amorphous phase. The Ta content presents an obviously sinusoidal fluctuation along the growth direction. The relatively intuitive processes of phase separation and layered structure destruction were obtained through isothermal annealing in the temperature range of 450–700 ℃ for 1 h. The high interfacial energy produced by co-sputtering deposition drives the thermally-activated Cu atoms to diffuse uphill, leading to the amorphous sublayers with the higher Cu content crystallizing initially at 450 ℃. Upon annealing at 480 ℃ for 1 h, the formation of the thermal groove between adjacent Cu grains and the diffusion of Ta atoms along the Cu grain boundaries synergistically induce the sublayers to fracture. Nanoindentation experiments showed that the hardness of the annealed films increases due to the clearer interface by uphill diffusion, but the enhancement only remains until the layered structure disappears. This study provides a good basis for the design and application of TaCu amorphous nano-multilayers, even in other immiscible systems.

The intermediate phase of NiS2 is thought to be a bottleneck currently to improve the overall performance of Li/NiS2 thermal batteries because of its low conductivity and close formation enthalpy between NiS2 and the intermediate phase (NiS, Ni3S2, etc). For improving the discharge performances of Li/NiS2 thermal batteries, the nano NiS2 with an average size of 85 ± 5 nm is designated as a cathode material. The electrochemical measurements show that the specific capacity of nano NiS2 cathode is higher than micro NiS2. The nano NiS2 cathode exhibits excellent electrochemical performances with high specific capacities of 794 and 654 mAh g−1 at current density of 0.1 and 0.5 A cm−2 under a cut-off voltage of 0.5 V, respectively. These results show that the rapid intermediate phase evolution from the nanocrystallization can obviously enhance use efficiency of NiS2 and improve discharge performances of thermal batteries.

The microstructure, nanoindentation hardness of the sputtering deposited Cu-Ta films were investigated. Because of high hardness of Ta, the hardness of Cu-Ta films increases with Ta content, except for a platform in the range of 20 at.% ∼60 at.% Ta that being related to the amorphous structure. This abnormal behavior presents that the hardness of Cu-Ta films is independent of alloy elemental content in the amorphous structure. The Ta addition inducing to Cu-Ta hardening is counteracted by the increase of inter-atomic distance in the amorphous structure with increasing of Ta. So this opposite effect makes the hardness platform.

The tribological properties of martensite steel with different grain sizes in vacuum was studied. The surface nanocrystalline martensite steel exhibited lower wear rate but higher friction coefficient than corresponding coarse grained steel in vacuum. The results presented that the tribo-oxidation has been effectively restricted in vacuum. Therefore the mechanical behavior was the main factor of the wear rate variety of martensite steel with different grain sizes. The surface film of martensite steel formed easier as the hardness increased and ductility weakened. So the wear mechanisms of the martensite steel in vacuum changed from plastic deformation and adhesion to adhesion and fracture as the grain size decreased.

A novel Cu–6.5Ni–1Al–1Si–0.15Mg–0.15Ce alloy with super-high strength was designed and its corrosion behavior in 3.5% NaCl solution at 25 °C was investigated by the means of SEM observation, TEM observation and XPS analysis. The alloy after solution treatment, 80% cold rolling and aging at 450 °C for 1 h had the best comprehensive properties with hardness of HV 314, electrical conductivity of 19.4% IACS, tensile strength of 1017 MPa, and average annual corrosion rate of 0.028 mm/a. The oxides and chloride products formed at first, followed by the formation of dyroxides products. The alloy showed super-high strength, good electrical conductivity and corrosion resistant because Ni 2 Si hindered the precipitation of large NiAl at the grain boundary and the denickelefication of the alloy.

The high solubility in molten salt and low conductivity of NiCl2, compared with traditional FeS2 and CoS2, have become the restrictions for its extensive application in cathode materials of thermal batteries. In this study, carbon coated NiCl2 cathode is successfully fabricated by the carbonization of stearic acid. The high specific energy of 641 Wh kg−1 at current densities of 0.5 A cm−2 are observed for the carbon coated NiCl2 thermal batteries, which is higher than the pure NiCl2 with 475 Wh kg−1. The high specific energies and high-current discharge ability are attribute to the graphite and amorphous carbon layers on the surface of NiCl2 crystalline, which were detected by TEM after carbonization. The graphite layers can improve the conductivity of NiCl2. Meanwhile the coated carbon structure could reduce the solubility of NiCl2 in molten salt.