By using physical vapor deposition(PVD)to grow metallic nanorods,the characteristic length is controllable,which can be identified by two different growth modes:Mode I and Mode II.In Mode I,the growth of metallic nano...By using physical vapor deposition(PVD)to grow metallic nanorods,the characteristic length is controllable,which can be identified by two different growth modes:Mode I and Mode II.In Mode I,the growth of metallic nanorods is dominated by the monolayer surface steps.Whereas in Mode II,the growth mechanism is mainly determined by the multilayer surface steps.In this work,we focused on the analysis of the physical process of Mode I,in which the adatoms diffuse on the monolayer surface at beginning,then diffuse down to the next monolayer surface,and finally result in the metallic nanorods growth.Based on the physical process,both the variations of the characteristic length and the numerical solutions were theoretically proposed.In addition,the twodimensional(2 D)lattice kinetic Monte Carlo simulations were employed to verify the theoretical derivation of the metallic nanorods growth.Our results pay a new way for modifying the performance of metallic nanorods-based applications and devices.展开更多
Two-dimensional(2D) PbI_2 flakes have been attracting intensive attention as one potential candidate for the modern optoelectronics. However, suffered from the instability of kinetics-driven growth, the fabricated 2D ...Two-dimensional(2D) PbI_2 flakes have been attracting intensive attention as one potential candidate for the modern optoelectronics. However, suffered from the instability of kinetics-driven growth, the fabricated 2D PbI_2 flakes have a wide dimensional distribution even under the same conditions. Herein, a novel facile space confined physical vapor deposition(PVD) process is provided to synthesize uniform triangle PbI_2 flakes with high quality. The confined space provides a relatively stable growth environment that renders more control on the growth kinetics, leading to highly uniform triangle PbI_2 flakes with the average size of 5 mm and thickness of 17 nm. Moreover, as-fabricated PbI_2-based photodetectors show promising stable and flexible optoelectronic performances to 470 nm light, including high responsivity(0.72 AW^(-1)), large on/off ratio up to 900, fast photoresponse speed(rise time of 13.5 ms and decay time of 20 ms) and high detectivity(1.04×10^(10) Jones). The well-controllable growth of the uniform triangle PbI_2 flakes and the detailed exploration of their optoelectronic properties are particularly valuable for their further practical applications.展开更多
Plasma spray–physical vapor deposition(PS–PVD)is a unique technology that enables highly tailorable functional films and coatings with various rare metal elements to be processed.This technology bridges the gap betw...Plasma spray–physical vapor deposition(PS–PVD)is a unique technology that enables highly tailorable functional films and coatings with various rare metal elements to be processed.This technology bridges the gap between conventional thermal spray and vapor deposition and provides a variety of coating microstructures composed of vapor,liquid,and solid deposition units.The PS–PVD technique serves a broad range of applications in the fields of thermal barrier coatings(TBCs),environmental barrier coatings(EBCs),oxygen permeable films,and electrode films.It also represents the development direction of high-performance TBC/EBC preparation technologies.With the PS–PVD technique,the composition of the deposition unit determines the microstructure of the coating and its performance.When coating materials are injected into a nozzle and transported into the plasma jet,the deposition unit generated by a coating material is affected by the plasma jet characteristics.However,there is no direct in situ measurement method of material transfer and deposition processes in the PS–PVD plasma jet,because of the extreme conditions of PS–PVD such as a low operating pressure of*100 Pa,temperatures of thousands of degrees,and a thin and high-velocity jet.Despite the difficulties,the transport and transformation behaviors of the deposition units were also researched by optical emission spectroscopy,observation of the coating microstructure and other methods.This paper reviews the progress of PS–PVD technologies considering the preparation of advanced thermal barrier coatings from the perspective of the transport and transformation behaviors of the deposition units.The development prospects of new high-performance TBCs using the PS–PVD technique are also discussed.展开更多
Physical vapor deposition method was employed to deposit antimony telluride (Sb2Te3) crystals in a dual-zone furnace. The microstructure, surface topography and composition of samples were characterized using X-ray ...Physical vapor deposition method was employed to deposit antimony telluride (Sb2Te3) crystals in a dual-zone furnace. The microstructure, surface topography and composition of samples were characterized using X-ray diffraction, atomic force and scanning electron microscopy. Seebeck coefficient (Sic), electrical conductivity (σ⊥c) as well as power factor (PF) were enhanced for pure Sb2Te3 samples upon annealing, and the samples annealed at 473 K exhibited the highest PF of 3.16 × 10^-3 W m-1K-2 with an enhancement of 22% in the figure of merit (Z). When the delivered dose of 60Co gamma radiation was increased from 0 to 30 kGy in the stoichiometric crystals, σ⊥c decreased due to the decrease in mobility. As a result of the increase in S, PF and Z improved by 12.11 and 13.7%, respectively, in the 30 kGy gamma- irradiated crystals. Both RH (BIIc) and S⊥c were positive, suggesting that the prepared Sb2Te3 crystals retained the p-type semiconductivity after these treatments.展开更多
Cathodic arc evaporation is a well-established physical vapor deposition technique which is characterized by a high degree of ionization and high deposition rate. So far, this technique has been mainly used for the de...Cathodic arc evaporation is a well-established physical vapor deposition technique which is characterized by a high degree of ionization and high deposition rate. So far, this technique has been mainly used for the deposition of tribological coatings. In this study, anti-corrosive and electrical conductive carbon-based coatings with a metallic interlayer were prepared on stainless steel substrates as surface modification for metallic bipolar plates. Hereby, the influence of the deposition temperature during the deposition of the carbon top layer was investigated. Raman spectroscopy revealed differences in the microstructure at 200°C compared to 300°C and 100°C. Measurements of the interfacial contact resistance showed that the deposited coatings significantly improve the electrical conductivity. There are only minor differences between the different carbon top layers. The corrosion resistance of the coatings was studied via potentiodynamic polarization at room temperature and 80°C. Experiments showed that the coating with a carbon top layer deposited at 200°C, considerably reduces the current density and thus corrosion of the substrate is suppressed.展开更多
Physical vapor deposition(PVD)can be used to produce high-quality Gd_(2)O_(3)-doped CeO2(GDC)films.Among various PVD methods,reactive sputtering provides unique benefits,such as high deposition rates and easy upscalin...Physical vapor deposition(PVD)can be used to produce high-quality Gd_(2)O_(3)-doped CeO2(GDC)films.Among various PVD methods,reactive sputtering provides unique benefits,such as high deposition rates and easy upscaling for industrial applications.GDC thin films were successfully fabricated through reactive sputtering using a Gd_(0.2)Ce_(0.8)(at%)metallic target,and their application in solid oxide fuel cells,such as buffer layers between yttria-stabilized zirconia(YSZ)/La0.6Sr0.4Co0.2Fe0.8O_(3−δ)and as sublayers in the steel/coating system,was evaluated.First,the direct current(DC)reactive-sputtering behavior of the GdCe metallic target was determined.Then,the GDC films were deposited on NiO-YSZ/YSZ half-cells to investigate the influence of oxygen flow rate on the quality of annealed GDC films.The results demonstrated that reactive sputtering can be used to prepare thin and dense GDC buffer layers without high-temperature sintering.Furthermore,the cells with a sputtered GDC buffer layer showed better electrochemical performance than those with a screen-printed GDC buffer layer.In addition,the insertion of a GDC sublayer between the SUS441 interconnects and the Mn-Co spinel coatings contributed to the reduction of the oxidation rate for SUS441 at operating temperatures,according to the area-specific resistance tests.展开更多
A Y2O3 dispersion strengthened nickel-based superalloy sheet(0.15 mm thick) was prepared by electron beam physical vapor deposition(EB-PVD) technology.Different heat treatments were used to improve the mechanical ...A Y2O3 dispersion strengthened nickel-based superalloy sheet(0.15 mm thick) was prepared by electron beam physical vapor deposition(EB-PVD) technology.Different heat treatments were used to improve the mechanical properties of the alloy sheet.Differential thermal analysis(DTA) was used to examine the thermal stability of the as-deposited sheet.Element contents,phase composition and microstructure investigations on as-deposited and heat treated specimens were performed by X-ray fluorescence spectrometer(XRF),X-ray diffraction(XRD) and scanning electron microscopy(SEM).Tensile tests were conducted at room temperature on specimens as-deposited and heat treated.The results show that the as-deposited sheet is composed of equiaxed grains on the substrate side and columnar grains on the evaporation side.The as-deposited sheet shows poor ductility due to micropores between columnar grains.The strength and ductility can be improved effectively by annealing at 800°C for 3 h.For samples treated at 1100°C,the strength drops down due to the precipitates of Y3Al5O12(YAG).展开更多
Monolayer and bilayer coatings of TiAlN, AlCrN, and AlCrN/TiAlN were deposited onto tungsten carbide inserts using the plasma enhanced physical vapor deposition process. The microstructures of the coatings were charac...Monolayer and bilayer coatings of TiAlN, AlCrN, and AlCrN/TiAlN were deposited onto tungsten carbide inserts using the plasma enhanced physical vapor deposition process. The microstructures of the coatings were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The SEM micrographs revealed that the AlrN and AlCrN/TiAlN coatings were uniform and highly dense and contained only a limited number of microvoids. The TiAIN coating was non-uniform and highly porous and contained more micro droplets. The hardness and scratch resistance of the specimens were measured using a nanoindentation tester and scratch tester, respectively. Different phases formed in the coatings were analyzed by X-ray diffraction (XRD). The AlCrN/TiAlN coating exhibited a higher hardness (32.75 GPa), a higher Young's modulus (561.97 GPa), and superior scratch resistance (LcN = 46 N) compared to conventional coatings such as TiAlN, A1CrN, and TiN.展开更多
Poly (para-xylylene) hollow fibers with inner diameters can be prepared via template fibers electrospun from solutions. The PPX is deposited from the vapor phase and the template fiber is selectively removed by heat t...Poly (para-xylylene) hollow fibers with inner diameters can be prepared via template fibers electrospun from solutions. The PPX is deposited from the vapor phase and the template fiber is selectively removed by heat treatment or solvent extraction. The PPX is partially crystalline and the crystal modification depending on the route is used to extract the template fiber. The thermal stability of the hollow fibers is only slightly reduced relative to the bulk material and the same holds for the UV-stability.展开更多
Li-doped ZnO thin films had been grown by radio frequency magnetron sputtering and then annealed under various annealing temperatures. The characteristics of ZnO films were examined by XRD, FESEM, Hall measurement and...Li-doped ZnO thin films had been grown by radio frequency magnetron sputtering and then annealed under various annealing temperatures. The characteristics of ZnO films were examined by XRD, FESEM, Hall measurement and optical transmission spectra. Results showed that p type conduction was observed in Li doped ZnO films annealed at 500-600 ℃ and thep type ZnO films possessed a good crystalline with c-axis orientation, dense surface, and average transmission of about 85% in visible spectral region.展开更多
ZrN/TiZrN multilayers are deposited by using the cathodic vacuum arc method with different substrate bias(from 0 to 800 V),using Ti and Zr plasma flows in residual N 2 atmosphere,combined with ion bombardment of sam...ZrN/TiZrN multilayers are deposited by using the cathodic vacuum arc method with different substrate bias(from 0 to 800 V),using Ti and Zr plasma flows in residual N 2 atmosphere,combined with ion bombardment of sample surfaces.The effect of pulsed bias on the structure and properties of films is investigated.Microstructure of the coating is analyzed by X-ray diffraction(XRD),and scanning electron microscopy(SEM).In addition,nanohardness,Young's modulus,and scratch tests are performed.The experimental results show that the films exhibit a nanoscale multilayer structure consisting of TiZrN and ZrN phases.Solid solutions are formed for component TiZrN films.The dominant preferred orientation of TiZrN films is(111) and(220).At a pulsed bias of 200 V,the nanohardness and the adhesion strength of the ZrN/TiZrN multilayer reach a maximum of 38 GPa,and 78 N,respectively.The ZrN/TiZrN multilayer demonstrates an enhanced nanohardness compared with binary TiN and ZrN films deposited under equivalent conditions.展开更多
The influence of the hysteretic behaviour in reactive sputtering with a pure aluminium target in the presence of argon and oxygen plasma on transmittance and surface free energy of aluminium oxide films was investigat...The influence of the hysteretic behaviour in reactive sputtering with a pure aluminium target in the presence of argon and oxygen plasma on transmittance and surface free energy of aluminium oxide films was investigated by plasma optical emission spectroscopy technology. The evolutions of aluminium, and aluminium oxide emission lines as functions of oxygen flow rate at constant power and pressure were studied. A steep transition from the metallic sputtering to the compound sputtering was observed upon increasing the oxygen flow rate from 0.0 SCCM to above 2.0 SCCM. Then an optimal deposition zone was obtained through analyzing the hysteretic curves of aluminium and aluminium oxide emission lines. The evolution of crystal structures of samples was discerned by X-ray diffraction spectra data. Energy dispersive X-ray spectroscopy data also demonstrate the relationship between the chemical compositions of aluminium oxide films and the hysteretic behaviour. The film deposited between 1.5 SCCM and 2.0 SCCM oxygen flow rate displays an optimal and stoichiometic atomic ratio of O to Al and mass ratio of O to Al. The changes in the transmittance of samples were discovered to depend on the oxygen flow rate by UV-VIS transmittance spectra, and the changes in surface free energy were studied by contact angle measurement.展开更多
Vectored non-covalent interactions—mainly hydrogen bonding and aromatic interactions—extensively contribute to(bio)-organic self-assembling processes and significantly impact the physicochemical properties of the as...Vectored non-covalent interactions—mainly hydrogen bonding and aromatic interactions—extensively contribute to(bio)-organic self-assembling processes and significantly impact the physicochemical properties of the associated superstructures.However,vectored non-covalent interaction-driven assembly occursmainly along one-dimensional(1D)or three-dimensional(3D)directions,and a two-dimensional(2D)orientation,especially that of multilayered,graphene-like assembly,has been reported less.In this present research,by introducing amino,hydroxyl,and phenyl moieties to the triazine skeleton,supramolecular layered assembly is achieved by vectored non-covalent interactions.The planar hydrogen bonding network results in high stability,with a thermal sustainability of up to about 330°C and a Young’s modulus of up to about 40 GPa.Upon introducing wrinkles by biased hydrogen bonding or aromatic interactions to disturb the planar organization,the stability attenuates.However,the intertwined aromatic interactions prompt a red edge excitation shift effect inside the assemblies,inducing broad-spectrum fluorescence covering nearly the entire visible light region(400–650 nm).We show that bionic,superhydrophobic,pillar-like arrays with contact angles of up to about 170°can be engineered by aromatic interactions using a physical vapor deposition approach,which cannot be realized through hydrogen bonding.Our findings show the feasibility of 2D assembly with engineerable properties by modulating vectored non-covalent interactions.展开更多
All-solid-state thin-film lithium batteries(TFLBs)are the ideal wireless power sources for on-chip micro/nanodevices due to the significant advantages of safety,portability,and integration.As the bottleneck for increa...All-solid-state thin-film lithium batteries(TFLBs)are the ideal wireless power sources for on-chip micro/nanodevices due to the significant advantages of safety,portability,and integration.As the bottleneck for increasing the energy density of TFLBs,the key components of cathode,electrolyte,and anode are still underway to be improved.In this review,a brief history of TFLBs is first outlined by presenting several TFLB configurations.Based on the state-of-the-art materials developed for lithium-ion batteries(LIBs),the challenges and related strategies for the application of those potential electrode and electrolyte materials in TFLBs are discussed.Given the advanced manufacture and characterization techniques,the recent advances of TFLBs are reviewed for pursuing the high-energy-density and long-termdurability demands,which could guide the development of future TFLBs and analogous all-solid-state lithium batteries.展开更多
AlN thin films were deposited on c-,a-and r-plane sapphire substrates by the magnetron sputtering technique.The in-fluence of high-temperature thermal annealing(HTTA)on the structural,optical properties as well as sur...AlN thin films were deposited on c-,a-and r-plane sapphire substrates by the magnetron sputtering technique.The in-fluence of high-temperature thermal annealing(HTTA)on the structural,optical properties as well as surface stoichiometry were comprehensively investigated.The significant narrowing of the(0002)diffraction peak to as low as 68 arcsec of AlN after HTTA implies a reduction of tilt component inside the AlN thin films,and consequently much-reduced dislocation densities.This is also supported by the appearance of E2(high)Raman peak and better Al-N stoichiometry after HTTA.Furthermore,the in-creased absorption edge after HTTA suggests a reduction of point defects acting as the absorption centers.It is concluded that HTTA is a universal post-treatment technique in improving the crystalline quality of sputtered AlN regardless of sapphire orienta-tion.展开更多
Hydrogen generation material is a new kind of energy material that can supply hydrogen by reacting with water and is drawing more and more attention with the development of hydrogen economy. In this study, a novel nan...Hydrogen generation material is a new kind of energy material that can supply hydrogen by reacting with water and is drawing more and more attention with the development of hydrogen economy. In this study, a novel nanoporous magnesium-lithium material prepared by a physical vapor deposition method exhibits an excellent hydrogen generation property. It generates hydrogen efficiently and quickly with saltwater, reaching a hydrogen generation amount of 962 mL g^(-1) and hydrogen generation rates of 60 mL g^(-1)min^(-1), 109 mL g^(-1)min^(-1),256 mL g^(-1)min^(-1) and 367 mL g^(-1)min^(-1) at 0 ℃, 25 ℃, 35 ℃ and 50 ℃, respectively. The nanoporous magnesium-lithium material is composed of a solid solution phase with a magnesium-lithium atomic ratio of 17:3. By synchrotron radiation analysis, the sizes of the nanopores are in the range of 100 nm ~ 600 nm with an average size of 280 nm, and the porosity is calculated to be ~42.4%. The improved hydrogen generation property is attributed to the nanoporous structure with a high specific surface area, and the addition of lithium element which acts as active sites in hydrogen generation process.展开更多
A synergy of computer simulations, analytical formulations, and experiments proves very effective in research and development. Using nanorod growth as an example, this letter presents the synergy of the three compleme...A synergy of computer simulations, analytical formulations, and experiments proves very effective in research and development. Using nanorod growth as an example, this letter presents the synergy of the three complementary approaches in research, and demonstrates its effectiveness. Through this synergy, a theoretical framework of nanorod growth emerges; through the direction of the theories, experimental realization of smallest well-separated nanorods becomes reality; through the realization of such nanorods, metallic glue in ambient environments becomes technical reality and commercial possibility.展开更多
The YSZ coatings are prepared by the plasma spray-physical vapor deposition(PS-PVD)technology based on a specific experimental design.The structure,thickness and growth angle of YSZ coatings on the entire circumferent...The YSZ coatings are prepared by the plasma spray-physical vapor deposition(PS-PVD)technology based on a specific experimental design.The structure,thickness and growth angle of YSZ coatings on the entire circumferential surface of the cylindrical sample are studied.The results indicated that the structure,thickness and deflection growth angle of YSZ coatings are related to the orientation of deposition location.The numerical simulation of the multiphase mixed fluid near the substrate is carried out and the deposition regularity and mechanism of YSZ coatings prepared by PS-PVD is deduced.The growth rate is related to the local characteristics of the plasma flow field,and is directly proportional to the field pressure and inversely proportional to the field velocity.The growth angle of the coating is generally affected by the flow direction of the plasma jet.Especially,the normal component of velocity vector,V_(norm),mainly affects the speed at which the coating grows vertically upwards.The tangential component of velocity vector,V_(tan),determines the degree that the coating growth direction deviates from the vertical direction.When V_(tan)≠0,the coating forms a fine column with a certain deflection angle and finally develops into an oblique columnar structure.展开更多
β-NiAl is a potential oxidation-resistant coating material to be operated at temperatures above 1 150 ℃. In this paper,β-NiAl coatings with 0-0.5 at% Dy are prepared by electron beam physical vapor deposition (EB-...β-NiAl is a potential oxidation-resistant coating material to be operated at temperatures above 1 150 ℃. In this paper,β-NiAl coatings with 0-0.5 at% Dy are prepared by electron beam physical vapor deposition (EB-PVD). Transient oxidation behavior of the coatings is investigated. At 1 200 ℃, only stable α-Al2O3 phase is observed on the 0.05 at% doped coating, whereas the phase transfomlation from θ-Al2O3 to α-Al2O3 occurs in the 0.5 at% Dy doped coating during 1 h oxidation. At 1 100 ℃, all the coatings reveal the transient transformation of θ-α in the early 15 min and the transformation for the 0.05 at% Dy doped coating is completed within 45 min, much earlier than that for the 0.5 at% Dy doped coating. Overdoping of Dy retards the transformation of θ-α. The undoped and overdoped coatings reveal the whisker structure of θ-Al2O3 even after 20 h oxidation at 1 100 ℃, while the 0.05 at% Dy coating reveals typical granulated structure of α-Al2O3.展开更多
文摘By using physical vapor deposition(PVD)to grow metallic nanorods,the characteristic length is controllable,which can be identified by two different growth modes:Mode I and Mode II.In Mode I,the growth of metallic nanorods is dominated by the monolayer surface steps.Whereas in Mode II,the growth mechanism is mainly determined by the multilayer surface steps.In this work,we focused on the analysis of the physical process of Mode I,in which the adatoms diffuse on the monolayer surface at beginning,then diffuse down to the next monolayer surface,and finally result in the metallic nanorods growth.Based on the physical process,both the variations of the characteristic length and the numerical solutions were theoretically proposed.In addition,the twodimensional(2 D)lattice kinetic Monte Carlo simulations were employed to verify the theoretical derivation of the metallic nanorods growth.Our results pay a new way for modifying the performance of metallic nanorods-based applications and devices.
基金supported by the National Natural Science Foundation of China (51472097, 91622117, 21501060, and 51727809)the National Key Research and Development Program (2016YFB0401100)+1 种基金the National Basic Research Program of China (2015CB932600)the Fundamental Research Funds for the Central University (2017KFKJXX007, 2015ZDTD038)
文摘Two-dimensional(2D) PbI_2 flakes have been attracting intensive attention as one potential candidate for the modern optoelectronics. However, suffered from the instability of kinetics-driven growth, the fabricated 2D PbI_2 flakes have a wide dimensional distribution even under the same conditions. Herein, a novel facile space confined physical vapor deposition(PVD) process is provided to synthesize uniform triangle PbI_2 flakes with high quality. The confined space provides a relatively stable growth environment that renders more control on the growth kinetics, leading to highly uniform triangle PbI_2 flakes with the average size of 5 mm and thickness of 17 nm. Moreover, as-fabricated PbI_2-based photodetectors show promising stable and flexible optoelectronic performances to 470 nm light, including high responsivity(0.72 AW^(-1)), large on/off ratio up to 900, fast photoresponse speed(rise time of 13.5 ms and decay time of 20 ms) and high detectivity(1.04×10^(10) Jones). The well-controllable growth of the uniform triangle PbI_2 flakes and the detailed exploration of their optoelectronic properties are particularly valuable for their further practical applications.
基金financially supported by the National Key R&D Plan(No.2017YFB0306103)the Fundamental Research Funds for the Central Universitiesthe National Program for Support of Top-notch Young Professionals。
文摘Plasma spray–physical vapor deposition(PS–PVD)is a unique technology that enables highly tailorable functional films and coatings with various rare metal elements to be processed.This technology bridges the gap between conventional thermal spray and vapor deposition and provides a variety of coating microstructures composed of vapor,liquid,and solid deposition units.The PS–PVD technique serves a broad range of applications in the fields of thermal barrier coatings(TBCs),environmental barrier coatings(EBCs),oxygen permeable films,and electrode films.It also represents the development direction of high-performance TBC/EBC preparation technologies.With the PS–PVD technique,the composition of the deposition unit determines the microstructure of the coating and its performance.When coating materials are injected into a nozzle and transported into the plasma jet,the deposition unit generated by a coating material is affected by the plasma jet characteristics.However,there is no direct in situ measurement method of material transfer and deposition processes in the PS–PVD plasma jet,because of the extreme conditions of PS–PVD such as a low operating pressure of*100 Pa,temperatures of thousands of degrees,and a thin and high-velocity jet.Despite the difficulties,the transport and transformation behaviors of the deposition units were also researched by optical emission spectroscopy,observation of the coating microstructure and other methods.This paper reviews the progress of PS–PVD technologies considering the preparation of advanced thermal barrier coatings from the perspective of the transport and transformation behaviors of the deposition units.The development prospects of new high-performance TBCs using the PS–PVD technique are also discussed.
文摘Physical vapor deposition method was employed to deposit antimony telluride (Sb2Te3) crystals in a dual-zone furnace. The microstructure, surface topography and composition of samples were characterized using X-ray diffraction, atomic force and scanning electron microscopy. Seebeck coefficient (Sic), electrical conductivity (σ⊥c) as well as power factor (PF) were enhanced for pure Sb2Te3 samples upon annealing, and the samples annealed at 473 K exhibited the highest PF of 3.16 × 10^-3 W m-1K-2 with an enhancement of 22% in the figure of merit (Z). When the delivered dose of 60Co gamma radiation was increased from 0 to 30 kGy in the stoichiometric crystals, σ⊥c decreased due to the decrease in mobility. As a result of the increase in S, PF and Z improved by 12.11 and 13.7%, respectively, in the 30 kGy gamma- irradiated crystals. Both RH (BIIc) and S⊥c were positive, suggesting that the prepared Sb2Te3 crystals retained the p-type semiconductivity after these treatments.
文摘Cathodic arc evaporation is a well-established physical vapor deposition technique which is characterized by a high degree of ionization and high deposition rate. So far, this technique has been mainly used for the deposition of tribological coatings. In this study, anti-corrosive and electrical conductive carbon-based coatings with a metallic interlayer were prepared on stainless steel substrates as surface modification for metallic bipolar plates. Hereby, the influence of the deposition temperature during the deposition of the carbon top layer was investigated. Raman spectroscopy revealed differences in the microstructure at 200°C compared to 300°C and 100°C. Measurements of the interfacial contact resistance showed that the deposited coatings significantly improve the electrical conductivity. There are only minor differences between the different carbon top layers. The corrosion resistance of the coatings was studied via potentiodynamic polarization at room temperature and 80°C. Experiments showed that the coating with a carbon top layer deposited at 200°C, considerably reduces the current density and thus corrosion of the substrate is suppressed.
基金financially supported by the National Key R&D Program of China (No. 2018YFB1502203-1)the Guangdong Basic and Applied Basic Research Foundation (No. 2021B1515120087)the Stable Supporting Fund of Shenzhen, China (No. GXWD20201230155427003-202007 28114835006)
文摘Physical vapor deposition(PVD)can be used to produce high-quality Gd_(2)O_(3)-doped CeO2(GDC)films.Among various PVD methods,reactive sputtering provides unique benefits,such as high deposition rates and easy upscaling for industrial applications.GDC thin films were successfully fabricated through reactive sputtering using a Gd_(0.2)Ce_(0.8)(at%)metallic target,and their application in solid oxide fuel cells,such as buffer layers between yttria-stabilized zirconia(YSZ)/La0.6Sr0.4Co0.2Fe0.8O_(3−δ)and as sublayers in the steel/coating system,was evaluated.First,the direct current(DC)reactive-sputtering behavior of the GdCe metallic target was determined.Then,the GDC films were deposited on NiO-YSZ/YSZ half-cells to investigate the influence of oxygen flow rate on the quality of annealed GDC films.The results demonstrated that reactive sputtering can be used to prepare thin and dense GDC buffer layers without high-temperature sintering.Furthermore,the cells with a sputtered GDC buffer layer showed better electrochemical performance than those with a screen-printed GDC buffer layer.In addition,the insertion of a GDC sublayer between the SUS441 interconnects and the Mn-Co spinel coatings contributed to the reduction of the oxidation rate for SUS441 at operating temperatures,according to the area-specific resistance tests.
文摘A Y2O3 dispersion strengthened nickel-based superalloy sheet(0.15 mm thick) was prepared by electron beam physical vapor deposition(EB-PVD) technology.Different heat treatments were used to improve the mechanical properties of the alloy sheet.Differential thermal analysis(DTA) was used to examine the thermal stability of the as-deposited sheet.Element contents,phase composition and microstructure investigations on as-deposited and heat treated specimens were performed by X-ray fluorescence spectrometer(XRF),X-ray diffraction(XRD) and scanning electron microscopy(SEM).Tensile tests were conducted at room temperature on specimens as-deposited and heat treated.The results show that the as-deposited sheet is composed of equiaxed grains on the substrate side and columnar grains on the evaporation side.The as-deposited sheet shows poor ductility due to micropores between columnar grains.The strength and ductility can be improved effectively by annealing at 800°C for 3 h.For samples treated at 1100°C,the strength drops down due to the precipitates of Y3Al5O12(YAG).
文摘Monolayer and bilayer coatings of TiAlN, AlCrN, and AlCrN/TiAlN were deposited onto tungsten carbide inserts using the plasma enhanced physical vapor deposition process. The microstructures of the coatings were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The SEM micrographs revealed that the AlrN and AlCrN/TiAlN coatings were uniform and highly dense and contained only a limited number of microvoids. The TiAIN coating was non-uniform and highly porous and contained more micro droplets. The hardness and scratch resistance of the specimens were measured using a nanoindentation tester and scratch tester, respectively. Different phases formed in the coatings were analyzed by X-ray diffraction (XRD). The AlCrN/TiAlN coating exhibited a higher hardness (32.75 GPa), a higher Young's modulus (561.97 GPa), and superior scratch resistance (LcN = 46 N) compared to conventional coatings such as TiAlN, A1CrN, and TiN.
文摘Poly (para-xylylene) hollow fibers with inner diameters can be prepared via template fibers electrospun from solutions. The PPX is deposited from the vapor phase and the template fiber is selectively removed by heat treatment or solvent extraction. The PPX is partially crystalline and the crystal modification depending on the route is used to extract the template fiber. The thermal stability of the hollow fibers is only slightly reduced relative to the bulk material and the same holds for the UV-stability.
基金Funded by the Natural Science Foundation of Liaoning,China(No.201204916)Training Programme Foundation for the Talents by the Education Bureau of Liaoning Province,China(No.LJQ2013068)+1 种基金Key Program of Ministry of Education,China(No.212031)Liaoning College Creative Team(No.LT2013014)
文摘Li-doped ZnO thin films had been grown by radio frequency magnetron sputtering and then annealed under various annealing temperatures. The characteristics of ZnO films were examined by XRD, FESEM, Hall measurement and optical transmission spectra. Results showed that p type conduction was observed in Li doped ZnO films annealed at 500-600 ℃ and thep type ZnO films possessed a good crystalline with c-axis orientation, dense surface, and average transmission of about 85% in visible spectral region.
基金Project supported by the National Magnetic Confinement Fusion Science Program of China (Grant No. 2009GB106004)
文摘ZrN/TiZrN multilayers are deposited by using the cathodic vacuum arc method with different substrate bias(from 0 to 800 V),using Ti and Zr plasma flows in residual N 2 atmosphere,combined with ion bombardment of sample surfaces.The effect of pulsed bias on the structure and properties of films is investigated.Microstructure of the coating is analyzed by X-ray diffraction(XRD),and scanning electron microscopy(SEM).In addition,nanohardness,Young's modulus,and scratch tests are performed.The experimental results show that the films exhibit a nanoscale multilayer structure consisting of TiZrN and ZrN phases.Solid solutions are formed for component TiZrN films.The dominant preferred orientation of TiZrN films is(111) and(220).At a pulsed bias of 200 V,the nanohardness and the adhesion strength of the ZrN/TiZrN multilayer reach a maximum of 38 GPa,and 78 N,respectively.The ZrN/TiZrN multilayer demonstrates an enhanced nanohardness compared with binary TiN and ZrN films deposited under equivalent conditions.
基金supported by the Fundamental Research Funds for the Central Universities of China(N110403011)Science and Technology Plan of Shenyang City(F12-028-200),China
文摘The influence of the hysteretic behaviour in reactive sputtering with a pure aluminium target in the presence of argon and oxygen plasma on transmittance and surface free energy of aluminium oxide films was investigated by plasma optical emission spectroscopy technology. The evolutions of aluminium, and aluminium oxide emission lines as functions of oxygen flow rate at constant power and pressure were studied. A steep transition from the metallic sputtering to the compound sputtering was observed upon increasing the oxygen flow rate from 0.0 SCCM to above 2.0 SCCM. Then an optimal deposition zone was obtained through analyzing the hysteretic curves of aluminium and aluminium oxide emission lines. The evolution of crystal structures of samples was discerned by X-ray diffraction spectra data. Energy dispersive X-ray spectroscopy data also demonstrate the relationship between the chemical compositions of aluminium oxide films and the hysteretic behaviour. The film deposited between 1.5 SCCM and 2.0 SCCM oxygen flow rate displays an optimal and stoichiometic atomic ratio of O to Al and mass ratio of O to Al. The changes in the transmittance of samples were discovered to depend on the oxygen flow rate by UV-VIS transmittance spectra, and the changes in surface free energy were studied by contact angle measurement.
基金supported by the Fund for Creative Research Groups of National Natural Science Foundation of China (No. 51821093)the National Natural Science Foundation of China (Nos. 52175551, 52075484)(KT and DM)+2 种基金the National Key Research and Development Program (SQ2021YFE010405)(KT)Science Foundation Ireland (SFI) through awards Nos. 15/CDA/3491and 12/RC/2275_P2 (DT)computing resources at the SFI/Higher Education Authority Irish Center for High-End Computing (ICHEC)(SG and DT)
文摘Vectored non-covalent interactions—mainly hydrogen bonding and aromatic interactions—extensively contribute to(bio)-organic self-assembling processes and significantly impact the physicochemical properties of the associated superstructures.However,vectored non-covalent interaction-driven assembly occursmainly along one-dimensional(1D)or three-dimensional(3D)directions,and a two-dimensional(2D)orientation,especially that of multilayered,graphene-like assembly,has been reported less.In this present research,by introducing amino,hydroxyl,and phenyl moieties to the triazine skeleton,supramolecular layered assembly is achieved by vectored non-covalent interactions.The planar hydrogen bonding network results in high stability,with a thermal sustainability of up to about 330°C and a Young’s modulus of up to about 40 GPa.Upon introducing wrinkles by biased hydrogen bonding or aromatic interactions to disturb the planar organization,the stability attenuates.However,the intertwined aromatic interactions prompt a red edge excitation shift effect inside the assemblies,inducing broad-spectrum fluorescence covering nearly the entire visible light region(400–650 nm).We show that bionic,superhydrophobic,pillar-like arrays with contact angles of up to about 170°can be engineered by aromatic interactions using a physical vapor deposition approach,which cannot be realized through hydrogen bonding.Our findings show the feasibility of 2D assembly with engineerable properties by modulating vectored non-covalent interactions.
基金financial support from the National Key R&D Program of China (Grant No. 2016YFA0202602)the National Natural Science Foundation of China (Grant Nos. 51931006, 51871188, and 51701169)+2 种基金the Natural Science Foundation of Fujian Province of China (No. 2019J06003 and 2020J05014)the Fundamental Research Funds for the Central Universities of China (Xiamen University: Nos. 20720200080, 20720200068, and 20720190007)the “Double-First Class” Foundation of Materials Intel igent Manufacturing Discipline of Xiamen University
文摘All-solid-state thin-film lithium batteries(TFLBs)are the ideal wireless power sources for on-chip micro/nanodevices due to the significant advantages of safety,portability,and integration.As the bottleneck for increasing the energy density of TFLBs,the key components of cathode,electrolyte,and anode are still underway to be improved.In this review,a brief history of TFLBs is first outlined by presenting several TFLB configurations.Based on the state-of-the-art materials developed for lithium-ion batteries(LIBs),the challenges and related strategies for the application of those potential electrode and electrolyte materials in TFLBs are discussed.Given the advanced manufacture and characterization techniques,the recent advances of TFLBs are reviewed for pursuing the high-energy-density and long-termdurability demands,which could guide the development of future TFLBs and analogous all-solid-state lithium batteries.
基金supported by the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2020298)National Key Scientific Instrument and Equipment Development Projects of China(YJKYYQ20190074)+2 种基金National Natural Science Foundation of China(61974149)Primary Research and Development Plan of Zhejiang Province(2020C01145)the Natural Science Foundation of Zhejiang Province(LQ21F040004)。
文摘AlN thin films were deposited on c-,a-and r-plane sapphire substrates by the magnetron sputtering technique.The in-fluence of high-temperature thermal annealing(HTTA)on the structural,optical properties as well as surface stoichiometry were comprehensively investigated.The significant narrowing of the(0002)diffraction peak to as low as 68 arcsec of AlN after HTTA implies a reduction of tilt component inside the AlN thin films,and consequently much-reduced dislocation densities.This is also supported by the appearance of E2(high)Raman peak and better Al-N stoichiometry after HTTA.Furthermore,the in-creased absorption edge after HTTA suggests a reduction of point defects acting as the absorption centers.It is concluded that HTTA is a universal post-treatment technique in improving the crystalline quality of sputtered AlN regardless of sapphire orienta-tion.
基金supported by National Natural Science Foundation of China [grant No.51271021]Natural Science Foundation of Beijing Municipality [grant No. 2162025]。
文摘Hydrogen generation material is a new kind of energy material that can supply hydrogen by reacting with water and is drawing more and more attention with the development of hydrogen economy. In this study, a novel nanoporous magnesium-lithium material prepared by a physical vapor deposition method exhibits an excellent hydrogen generation property. It generates hydrogen efficiently and quickly with saltwater, reaching a hydrogen generation amount of 962 mL g^(-1) and hydrogen generation rates of 60 mL g^(-1)min^(-1), 109 mL g^(-1)min^(-1),256 mL g^(-1)min^(-1) and 367 mL g^(-1)min^(-1) at 0 ℃, 25 ℃, 35 ℃ and 50 ℃, respectively. The nanoporous magnesium-lithium material is composed of a solid solution phase with a magnesium-lithium atomic ratio of 17:3. By synchrotron radiation analysis, the sizes of the nanopores are in the range of 100 nm ~ 600 nm with an average size of 280 nm, and the porosity is calculated to be ~42.4%. The improved hydrogen generation property is attributed to the nanoporous structure with a high specific surface area, and the addition of lithium element which acts as active sites in hydrogen generation process.
基金the sponsorship of the US Department of Energy Office of Basic Energy Science (DE-SC0014035)the US National Science Foundation (NSF 1506966)
文摘A synergy of computer simulations, analytical formulations, and experiments proves very effective in research and development. Using nanorod growth as an example, this letter presents the synergy of the three complementary approaches in research, and demonstrates its effectiveness. Through this synergy, a theoretical framework of nanorod growth emerges; through the direction of the theories, experimental realization of smallest well-separated nanorods becomes reality; through the realization of such nanorods, metallic glue in ambient environments becomes technical reality and commercial possibility.
基金the financial support from National Natural Science Foundation of China(51771059)R&D Program in Key Fields of Guangdong Province of China(2019B010936001)+2 种基金National Science and Technology Major Project of China(2017-VI-0010-0081)Science and Technology Project of Guangdong Province of China(2017A070701027,2014B070705007)Sciences Project of Guangdong Academy of China(2019GDASYL-0104022)。
文摘The YSZ coatings are prepared by the plasma spray-physical vapor deposition(PS-PVD)technology based on a specific experimental design.The structure,thickness and growth angle of YSZ coatings on the entire circumferential surface of the cylindrical sample are studied.The results indicated that the structure,thickness and deflection growth angle of YSZ coatings are related to the orientation of deposition location.The numerical simulation of the multiphase mixed fluid near the substrate is carried out and the deposition regularity and mechanism of YSZ coatings prepared by PS-PVD is deduced.The growth rate is related to the local characteristics of the plasma flow field,and is directly proportional to the field pressure and inversely proportional to the field velocity.The growth angle of the coating is generally affected by the flow direction of the plasma jet.Especially,the normal component of velocity vector,V_(norm),mainly affects the speed at which the coating grows vertically upwards.The tangential component of velocity vector,V_(tan),determines the degree that the coating growth direction deviates from the vertical direction.When V_(tan)≠0,the coating forms a fine column with a certain deflection angle and finally develops into an oblique columnar structure.
基金National Natural Science Foundation of China (50771009, 50731001) National Basic Research Program of China (2010CB631200) Research Fund for the Doctoral Program of Higher Education of China (20070006017)
文摘β-NiAl is a potential oxidation-resistant coating material to be operated at temperatures above 1 150 ℃. In this paper,β-NiAl coatings with 0-0.5 at% Dy are prepared by electron beam physical vapor deposition (EB-PVD). Transient oxidation behavior of the coatings is investigated. At 1 200 ℃, only stable α-Al2O3 phase is observed on the 0.05 at% doped coating, whereas the phase transfomlation from θ-Al2O3 to α-Al2O3 occurs in the 0.5 at% Dy doped coating during 1 h oxidation. At 1 100 ℃, all the coatings reveal the transient transformation of θ-α in the early 15 min and the transformation for the 0.05 at% Dy doped coating is completed within 45 min, much earlier than that for the 0.5 at% Dy doped coating. Overdoping of Dy retards the transformation of θ-α. The undoped and overdoped coatings reveal the whisker structure of θ-Al2O3 even after 20 h oxidation at 1 100 ℃, while the 0.05 at% Dy coating reveals typical granulated structure of α-Al2O3.