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High performance of Fe-based soft magnetic composites coated with novel nano-CaCO3/epoxy nanocomposites insulating layer
No full textIn this paper, a novel type of nano-CaCO3/epoxy nanocomposites insulating layer for the FeSiCr/carbonyl-iron soft magnetic composites (SMCs) has been successfully developed. The novel inorganic/resin nanocomposites can greatly reduce the core loss of the SMCs while maintain other excellent magnetic properties. By optimizing the content of insulating layer, the FeSiCr/carbonyl-iron SMCs exhibits the lowest core loss of 466.5 mW/cm(3) at a maximum magnetic induction of 50 mT and frequency of 100 kHz, which is greatly reduced by 24.2%, compared with the sample only coated by epoxy resin. Meanwhile, the effective permeability and quality factor remains high. In addition, the production process of the novel nano-CaCO3/epoxy nanocomposites insulating layer exhibits the advantages of simplicity, convenience and low cost compared with other ceramic coatings (Al2O3, MgO, SiO2, etc.) and surface nitride coatings, which is more suitable for the industrialization of molded inductors, and therefore has a variety of industrial application prospects
Microstructure and corrosion behaviour of 316 L-IN625 functionally graded materials via laser metal deposition
No full textIn this work, the microstructure of gradient regions and the corrosion behaviour of transition interfaces for 316 LIN625 functional graded materials fabricated using laser metal deposition are investigated. The microstructure in gradient regions along the build direction such as celluar dendrites, columnar grains, coarse dendrites, and nearly equiaxed grains. When the composition of 316 L is less than or equal to 40%, the over passivation zone appears, resulting in the Mixed Cr (III/VI) oxide as the final corrosion products which consists of surviving Cr (III) oxide and generated Cr (VI) oxide. The composition gradient of 316 L-IN625 can effectively improve the corrosion resistance
Theoretical study on W-Co3O4(111) surface: Acetone adsorption and sensing mechanism
No full textVolatile organic compounds are highly toxic, and need advanced sensing technology for detection. The morphology, composition and surface characteristics are critical parameters to enhance the gas sensing of metal oxide-based sensors. However, the experimental results only reflect macroscopic phenomena, but cannot explain the sensing mechanism in depth. In this study, the acetone sensing performance of pristine and W modified Co3O4 (111) surface have been studied using DFT methods. Various adsorption sites have been investigated on top of the clean and O adsorped W-Co3O4 (111) surfaces. Our results show the decorated W atom in direct vicinity of pre-adsorbed oxygen is the best site for acetone adsorption. The modification of W atom makes energy band-gap narrower, alters the electronic properties, and enhances the number of transferred electrons. Our study provides a theoretical basis for finding better modified p-type semiconductor sensors toward acetone
Construction of Bionic Porous Polyetherimide Structure by an In Situ Foaming Fused Deposition Modeling Process
No full textThe biological hierarchical porous structures have excellent properties that are unmatched by artificial fabrication and have great potential for applications in catalysis, adsorption, energy and biomedicine. However, the traditional fabrication methods are difficult to mimic finely hierarchical porous structures and involve complex solution handling and residues. 3D printing is limited by materials and resolution, making it difficult to achieve microporous preparation. Herein, an in situ foaming fusion deposition modeling (FDM) technology using environmentally friendly CO2 as blowing agent to fabricate polyetherimide bionic hierarchical porous structures is applied. The macroscopic pores are obtained by 3D design, while the microporous structure is regulated by changing foaming parameters such as saturation pressure, desorption time, and nozzle temperature. The cell size of the microextruded fibers by FDM nozzle vary from 1.3 to 5.3 mu m and the cell density vary from 7.3 x 10(8) to 1.0 x 10(10) cell cm(-3) with the change of parameters. In addition, the deposited hierarchical porous scaffold with density of 0.89 g cm(-3) possess a compressive strength of 78.9 MPa at 15% strain and a compressive modulus of 1454.3 MPa, which exhibits comparable mechanical property with that of bone
Scalable fabrication of a large-area lithium/graphene anode towards a long-life 350 W h kg(-1) lithium metal pouch cell
No full textVolume expansion and dead Li accumulation in the Li anode forbid the development of practical pouch-cell type Li metal batteries (pLMBs). Thus, development of highly reversible and long-life Li metal anodes is of great importance in this area. Herein, a facile thermally initiated conversion method is proposed to fabricate a Li/graphene composite anode (Li@G) by a heating induced local reaction among Li powder, graphene and PVDF. Using simple mixing-coating-drying-heating procedures, a large-area Li@G anode can be prepared in a roll-to-roll way with a film casting machine. The detailed morphology and functions of the LiC6 skeleton in this composite anode on alleviating dead Li accumulation are confirmed. Failure analysis and morphology characterization demonstrate the improvement in reducing cell resistance and concentration polarization by using this novel Li anode. As a result, a 0.55 A h pLMB (Li@G/NCM811) strictly following practical conditions can cycle stably 140 times due to the improved reversibility of Li stripping/plating. Moreover, a 2.6 A h pLMB (Li@G/NCM811) delivers a high energy density of 356 W h kg(-1) (based on the whole cell) with a high capacity retention of 70% for 100 cycles. The scalable preparation method of the advanced Li@G anode presented in this paper makes promising progress in design and fabrication of Li composite anodes for practical pLMBs
Novel environment-friendly grease-infused porous surface exhibiting long-term cycle effective antifouling performance
No full textWith the increasingly strict requirements for marine environmental protection, the demand for antifouling coatings that can replace organotin is becoming more urgent. Here, environmentally friendly lubricants were infused into porous surfaces to obtain antifouling coating. The stability of the coating was evaluated by the contact angle and sliding angle tests. The antifouling performance was intuitively represented by the adhesion quantity of three marine algae. The adhesion experiment showed that a lubricating oil of suitable viscosity balanced stability and lubricity, so that the silicone oil (PMX200-100)-infused surface showed the best antifouling effect. However, it was covered by Navicula exigua (N. exigua) after a long time of immersion. In our work, the grease-infused surface displayed outstanding stability in water. In addition, the grease-infused porous surface showed another state of algae attachment after a period of immersion in algae solution. Algae adhered to the surface and congregated to form a layer of biofilm, but it could be easily removed and re-expose the new grease-infused surface. The requirement of lubricating grease for porous surface structures is not as high as that of lubricating oil. The grease-infused surface has a long-term circulation antifouling effect on algae