- Ei，ESCI收录期刊
- 中国科学引文数据库(CSCD)核心期刊
- 中文核心期刊
- 文摘与引文数据库(Scopus)
- 剑桥科学文摘(CSA)
MXene has a wide application prospect in energy storage, electromagnetic interference shielding, catalysis, medicine and other fields due to its unique layered structure, high electronic conductivity and rich surface chemical properties.Ti3C2Tx, as the earliest discovered MXene material, has the possibility to achieve both high energy density and power density in the field of sodium ion batteries because of its inherent metal conductive characteristics, wide layer spacing and abundant surface functional groups, which is attracted by many researchers. Based on this, the research progress of Ti3C2Tx based materials in sodium ion batteries in recent years was reviewed in this paper. Firstly, the structure and electrochemical properties of Ti3C2Tx materials with multi-layer and few-layer were summarized by introducing the preparation of Ti3C2Tx. Then, combined with the application trend of the study, the influences of layer spacing modification, doping modification and morphology regulation on the sodium storage behavior of the two kinds of Ti3C2Tx materials were summarized. The structural design ideas of the two kinds of Ti3C2Tx based composites applied to the anode of the sodium ion battery were also analyzed. It was pointed out that the reasonable structural design is vital to the battery performance. Finally, some suggestions for the problems and challenges faced by Ti3C2Tx based composites in the field of sodium ion batteries were given.
The flexible wearable pressure sensor has unique properties such as high comfort, strong braid ability and the ability to imitate human skin to sensitively perceive and respond to external stimuli. It can be used as the artificial electronic skin which will be widely applied in medical detections, disease diagnosis, human motion tracking and health monitoring, etc. In recent years, the design, construction, performance exploration and development of flexible wearable pressure sensors have attracted extensive attention from researchers. The nanofibrous membranes prepared by electrospinning have the advantages of high porosity, large specific surface area and easy to be functionalized, which make them have extensive applications in the field of flexible sensors. The research and progress of electrospun nanofibers in flexible wearable pressure sensors were reviewed in this paper. The major characteristics of the wearable pressure sensors were briefly introduced, and the advantages of electrospinning technology and electrospinning nanofibers in the preparation of flexible wearable pressure sensors were described. The types and applications of the flexible wearable pressure sensors based on electrospinning in different fields were emphatically discussed. Finally, the low-cost manufacture of flexible wearable pressure sensors with high resolution, high sensitivity and accurate response was briefly summarized and prospected.
As the core of electric energy conversion, power devices have been developed rapidly in new electronic fields such as spacecraft, renewable energy vehicles, high-speed trains and submarine communication cables. The new generation of power devices have put forward higher, faster and more efficient requirements for advanced electronic packaging. However, the significant reduction of the solder joint size of chip interconnection leads to a sharp increase in the formation of intermetallic compounds (IMCs) within the solder joint, which poses a challenge to the reliability of the solder joint. In packaging structure, diffusion barrier layer plays an important role in the generation of intermetallic compounds. Therefore, the development of high reliability diffusion barrier layer has become one of the research concerns in the field of advanced electronic packaging. Herein, the research progress of diffusion barrier in advanced electronic packaging field in recent years was summarized based on different materials including elementary substance, binary compound, ternary compound, composite material and multi-layers. On this basis, three diffusion blocking mechanisms were summarized, including grain refinement of IMCs, segregation of alloying elements and suppression of Kirkendall voids. In the meanwhile, the failure mechanism of the barrier layer was analyzed.The effect of diffusion barrier on solder joint reliability was discussed. Finally, it was pointed out that the existing diffusion barrier research is still in the stage of manufacturing process and material performance exploration, and in the future, in-depth and systematic research can be carried out on high-entropy alloys, multi-physics coupling effects, failure and diffusion barrier mechanism disclosure.
One-dimensional carbon materials were widely used in adsorption and purification, catalytic carriers, energy electronics and other fields because of their efficient mass transfer and diffusion efficiency, excellent mechanical properties and good chemical stability. Microwave heating met the requirements of current material processing and sustainable development by rapid treatment, improving energy efficiency and reducing equipment cost, and showed great application potential in the preparation of one-dimensional carbon materials. The development and application status of one-dimensional carbon materials and the unique advantages of microwave heating technology were introduced in this paper, the mechanism and characteristics of microwave heating were summarized, and the research and application status of microwave heating related to the preparation and performance optimization of biomass-based carbon nanotubes (CNTs), carbon nanofibers (CNFs) and polyacrylonitrile-based carbon nanofibers (PAN-based CNFs) were summarized. In addition, the action mode of microwave heating on biomass-based one-dimensional carbon materials during carbonization and the changes of structure and properties of PAN-based carbon fibers during microwave heating were emphatically analyzed. Finally, it was pointed out that accurate and reliable temperature measurement tools and corresponding microscopic characterization methods should be developed, the simulation and modeling tools should be used to innovatively design novel microwave reators, and the understanding of the interaction mechanism between materials and microwave through scientific research practice and basic research should be deepened, and to promote the extensive and in-depth application of microwave heating technology in the field of material processing.
Titanium and its alloys are promising biomedical metallic materials due to their high specific strength, low Young's modulus, nonmagnetic, excellent biocompatibility and corrosion resistance. A new generation of metastable β-type Ti alloys with non-toxic Nb, Mo, Ta, Zr and Sn alloying elements and low Young's modulus has become the key research direction of Ti alloys for biomedical applications. The basic characteristics and development history of biomedical titanium alloys were reviewed. Taking Ti-Nb based biomedical titanium alloys as an example, the composition design method, alloying principle, research status and preparation technology of new metastable β-type biomedical titanium alloys were introduced. Finally, it was pointed out that the further reduction of elastic modulus and improving the comprehensive properties including strength, fatigue performance, and functional properties are the key development directions of β-type Ti alloys for biomedical applications. In the future, in-depth research should be placed on the interaction mechanism of alloying elements, chemical composition design approach, microstructure and mechanical properties regulation methods, as well as micromechanical mechanisms.
Superhydrophobic surfaces offer a wide range of uses, including self-cleaning, oil-water separation, and underwater drag reduction. Conventional methods for producing superhydrophobic surfaces are frequently complicated, difficult to operate, and wasteful. Plasma spraying is a widespread surface modification technique, and using plasma spraying to produce superhydrophobic surfaces offers an advantage of simple preparation process and high preparation efficiency. Recent advances in the preparation of superhydrophobic surfaces using plasma spraying were summarized. Firstly, the basic principles of superhydrophobic surfaces and plasma spraying technique were introduced; then, the process evolution of two plasma spraying methods for the preparation of superhydrophobic surfaces, atmospheric plasma spraying and liquid phase plasma spraying was summarized, and the preparation characteristics of the two methods were described; finally, it was pointed out that the preparation of superhydrophobic surfaces using plasma spraying has the advantages of simple operation, low cost and excellent preparation performance, but also faces challenges such as complex exploration of process parameters and difficult balance between performance and preparation efficiency. It was expected that this paper would be useful in the surface modification of critical components used in aerospace, marine science, and military equipment.
Advanced oxidation process based on sulfate radical (SO4-·) is recognized as one of the effective methods to degrade organic wastewater. In recent years, as an economical and readily available carbon containing material, biochar has been gradually applied in the advanced oxidation field. Biochar and its composite activated persulfate have become a promising system for organic pollutants degradation. The latest research progress of different typical biochar-based catalysts for persulfate activation was analyzed, including pristine biochar, transition metal loaded biochar, non-metallic doping biochar, and metallic and non-metallic co-doping biochar. In addition, the synthesis methods and physicochemical properties were summarized. Furthermore, the activation performance and mechanism of biochar-based catalysts for persulfate and the degradation mechanism of organic pollutants were discussed, respectively. Finally, based on the current research progress, from the perspectives of different biomass sources, metallic and non-metallic co-modified biochar technology and the dynamic change of ecotoxicity in the degradation process, relevant discussions and future suggestions for biochar and its composites were put forward in terms of degradation mechanism exploration, potential catalyst development and practical catalytic system application.
FeCoNiAlCrx(x=0, 0.2, 0.4, 0.6, 0.8, atomic ratio) high-entropy alloy ingots were prepared by vacuum arc melting method, and the effect of Cr content on the microstructure and mechanical properties of the alloy was investigated. The phase structure, microstructure and the composition of the alloy were analyzed and characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS).The compression properties of the alloy were tested by universal testing machine. The results show that with the increase of Cr content, the microstructure of the alloy changes from a single-phase BCC structure to a BCC+FCC mixed structure; the microstructure of the alloy gradually changes from an equiaxed structure to a dendrite structure, and the grain size of the alloy is obviously refined. The five alloys prepared in this experiment have relatively good mechanical properties, and the compressive strength of the alloy increases greatly with the increase of Cr content. When x=0, the compressive strength and plastic strain of the alloy are the lowest, which are 1500 MPa and 13.56%, respectively; when x=0.8, the compressive strength and plastic strain of the alloy reach the maximum, which are 2460 MPa and 30.09%, respectively; the compressive strength of the alloy increases by 64%. It indicates that Cr addition plays an important role in the microstructure refinement, the improvement of compressive strength and ductility of FeCoNiAlCrx high-entropy alloys.
A new class gear and bearing steel with ultrahigh strength and high heat-resistant has excellent strength and toughness. The steel was austenitized at different temperatures, combined with a variety of mechanical property tests and micro-analysis techniques to study the changes in microstructure and mechanical properties of the steel. The results show that M6C carbides are undissolved, then the impact energy and fracture toughness decrease respectively when the steel is austenitized at 1060 ℃; the M6C carbides are dissolved, then the impact energy and fracture toughness increase respectively when the steel is austenitized at 1080-1100 ℃. There is little change in tensile strength and plasticity, and the specified plastic elongation strength decreases slightly with the increase of austenitizing temperature, when the steel is austenitized at 1060-1100 ℃. The initiation and propagation of crack is accelerated by M6C carbides, resulting in decrease in toughness. The steel has an excellent combination of strength and toughness when the steel is austenitized at 1080-1100 ℃, and the tensile strength is not less than 2000 MPa, the proof strength of specified plastic extension is not less than 1800 MPa, and the fracture toughness is not less than 100 MPa·m1/2.
Metal-matrix composites with high damping capacity and excellent energy absorption properties have extensive application requirements. Porous TiNi shape memory alloys with a three-dimensional connected structure were firstly prepared by powder metallurgy technology consisting of "uniform-mixing, compaction, dissolution and sintering" four stages. Then, the novel Acrylic/TiNi composites were manufactured in light of vacuum negative pressure infiltration technology. The damping properties were characterized by internal friction. It was found that Acrylic/TiNi composites exhibit a much higher damping capacity than that of corresponding TiNi porous materials, especially in around room temperature zone. It was rationalized that the great improvement of the damping capacity is originated from the intrinsic high-damping of Acrylic phase as well as induced massive interface damping between TiNi porous matrix and Acrylic phases. The quasi-static compressive mechanical measurement shows that Acrylic/TiNi composites can achieve energy absorption efficiency similar to that of TiNi porous alloy, the reason of which is confirmed to be associated with the longer and smoother compression plateau area of TiNi composites. In addition, the full penetration of the Acrylic reinforced phase greatly enhances the energy absorption capacity and yield strength of the composites. Deformation mechanism analysis of the TiNi composites indicates that the mutual compensation and coupling between porous matrix and Acrylic fillings during the compressive process can be considered to account for the improved energy absorption characteristics.
In order to further expand the application of magnesium alloy, and improve its corrosion resistance and wear resistance in an environmentally-friendly way, Ni-P-nano SiCP deposition coating was prepared on the surface of AZ91D magnesium alloy by direct chemical deposition without chromium and fluorine. The effects of SiCP addition on the morphology, composition, phase and properties of the deposited coating were studied by SEM, EDS, XRD, hardness tester and electrochemical workstation. The results show that with the increase of SiCP addition, the deposition amount of particles on the surface of the deposition coating first increases and then decreases, the size of cellular structure gradually decreases and then increases, and the hardness and corrosion resistance first increase and then decrease. When the addition amount of SiCP is 1.2 g/L the deposition amount of particles is the largest, the dispersion strengthening and fine grain strengthening effect are the best, and the deposition coating is both uniform and dense, with a thickness of about 36 μm, which has good bonding with the matrix; the hardness of the deposited coating is 682HV, which is significantly higher than that of the magnesium alloy matrix. The corrosion potential is -0.397 V, which is 75% higher than that of magnesium alloy matrix. The corrosion current density is 6.18×10-7 A·cm-2, which is 4 orders of magnitude lower than the matrix.
WO3 nanosheet films were prepared on the conductive glass substrate. WO3/BiVO4 composite film samples with different thicknesses were successfully synthesized on WO3 nanosheet films by changing the number of spin coating of BiVO4. X-ray diffraction and scanning electron microscopy were used to characterize samples. WO3/BiVO4 composite film samples were tested for absorption spectrum, photocurrent, photoelectrocatalysis and alternating current impedance. The results show that the photocurrent density and photocatalytic degradation efficiency of the WO3/BiVO4 composite film sample are improved compared with pure WO3 nanosheet films, and it has better photoelectrochemical property. Meanwhile, WO3/BiVO4 composite film sample with twice spin coating of BiVO4 has the highest photocurrent density (1.79 mA/cm2) and photoelectric degradation efficiency (about 60.5%), which is increased by 27.4% than the photocurrent density of pure WO3films (1.30 mA/cm2), the photoelectric degradation efficiency is also 26.3% higher than pure WO3 films (approximately 47.9%), and has the most excellent photoelectrochemical property.
Porous layered g-C3N4 was selected as base material via direct calcination method to synthesize g-C3N4/CeO2/BiOBr ternary composite photocatalytic materials with heterogeneous structure, while CeO2/BiOBr composites were introduced by ultrasonic stirring method. The composition, structure and optical properties of g-C3N4/CeO2/BiOBr were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis DRS and photoluminescence analysis, and so on. The results show that the g-C3N4/CeO2/BiOBr has sandwich layered stacking structure, good interface contact structure and excellent light response performance due to the uniform phase distribution and high degree of crystallization. When the molar fraction of Ce∶Bi is 1∶1 and the mass fraction of g-C3N4 is 15%, the obtained three-phase composite shows the highest photocatalytic degradation property for RhB. The degradation rate for RhB is 99%, which is 86 times that of pure CeO2 and 3 times that of pure BiOBr. In addition, the composite has good stability with the RhB degradation efficiency of 89% after four cycles.
The resistive switching layer of CeO2-x-TiO2 film was prepared on the FTO substrate by the sol-gel method and spin coating technique, and the Al/CeO2-x-TiO2/FTO resistive switching device was fabricated by depositing thin Al top electrode on the surface of the CeO2-x-TiO2 film. The crystal phase composition and crystal structure of CeO2-x-TiO2 thin films were characterized by XRD and XPS. The results show that the resistive switching layer is mainly composed of TiO2 and CeO2-x. Compared with Al/CeO2/FTO devices, the electrical performance of Al/CeO2-x-TiO2/FTO device is improved. I-V test shows that Al/CeO2-x-TiO2/FTO device has bipolar resistance variation characteristics without forming process. The resistive behavior with different CeO2-x-TiO2 thicknesses was carried out. The results show that the low resistance state of Al/CeO2-x-TiO2/FTO device shows ohmic conduction mechanism under different CeO2-x-TiO2 film thicknesses. As the thickness of CeO2-x-TiO2 increases, the essential change of resistance mechanism occurs in high resistance state. The resistance mechanism of the device changes from oxygen vacancy conductive filament mechanism to charge trapping/releasing mechanism by defect controlled. It was found that the AlOxlayer at the Al/CeO2-x-TiO2 interface is critical to the transformation of resistance mechanism, and the thickness of AlOx layer changes the device from "digital type" to "analog type".
BN and BN/SiC coatings were deposited on the surface of two typical domestic SiC fibers by CVI process, and the composition of coatings was analyzed. The tensile strength of monofilaments was evaluated by Weibull distribution, and the tensile fracture failure behaviors of the fiber before and after depositing coatings were studied. The results show that the carbon-rich layer with appropriate thickness (15 nm) can heal the defects on the surface of SiC fiber and reduce the possibility of fiber failure from the surface. The thickness of the coating prepared by the CVI process is uniform and the composition is stable. After depositing BN and BN/SiC coatings, the tensile strength and elastic modulus of the two kinds of SiC fibers are decreased. BN coatings can also repair the surface defects of the fiber, so that the fiber strength distribution tends to be concentrated. Different from the uncoated fibers, the tensile fracture failure sources of coated fibers are the surface defects of BN and SiC coatings, respectively.
MoS2 nanosheets with different sizes were prepared by ultrasonic liquid phase stripping and used as additives in lithium grease. The morphology, composition and structure of MoS2 nanosheets were characterized by electron microscopy, Raman spectroscopy, X-ray diffractometer and thermogravimetric analyzer; the tribological properties of lithium MoS2 grease were investigated by using four-ball friction and wear testing machine. The wear surface morphology of steel ball under MoS2 grease lubrication was analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy, and the lubrication mechanism of MoS2 grease was preliminarily explored. The results show that MoS2 nanosheets show excellent wear resistance and friction reduction performance. When the diameter of the added sheet is 80 nm and the amount is 1.0%(mass fraction), the tribological performance of lithium grease is the best, the maximum no-bite load and sintering load are increased by 55.4% and 61.2% respectively compared with the base grease, and the friction coefficient is decreased by 23.15%. The maximum diameter of wear scar diameter is decreased by 21.13%.The improvement of its tribological properties is mainly related to the tribological protective film composed of various oxides of Fe, FeOOH, MoS2 and related organic matter.
Octadecyltrichlorosilane (OTS) and dodecanoic acid (LA) were used as modifiers to conduct hydrophobic modification of waste activated carbon by liquid impregnation and heat treatment. The non-polar organic carbon chains in siloxane and saturated fatty acid were grafted onto the surface of activated carbon by chemical bonds to improve its hydrophobic properties, and the blocked pores of activated carbon were recovered by thermal regeneration. The results show that the regenerated-hydrophobic activated carbon has a high specific surface area (834.75 m2·g-1), good hydrophobic performance (water contact angle is 135°) and acid/alkali resistance. The adsorption and separation efficiency of regenerated-hydrophobic activated carbon for toluene-in-water emulsion increases from 42.58% (unmodified activated carbon) to 92.07%. The purification and separation efficiency of water-in-toluene emulsion increases from 51.76% (unmodified activated carbon) to 91.44% by the hybrid filter membrane composed of regenerated-hydrophobic activated carbon and nylon organic filter membrane, and the separation efficiency is still higher than 91% after 10 cycles.
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