Hu Zheng-Fei; Yao Chen; Mo Fan
Abstract
Metallurgical bonding aluminum foam sandwich (AFS) was fabricated by specially designed method of solder pre-coating via hot-dip and heat-press assisted with vibration. Peeling test and three-point bending test were performed to investigate the joints strength and flexural strength of the AFS. The results ...
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Metallurgical bonding aluminum foam sandwich (AFS) was fabricated by specially designed method of solder pre-coating via hot-dip and heat-press assisted with vibration. Peeling test and three-point bending test were performed to investigate the joints strength and flexural strength of the AFS. The results show that the joints have steady mechanical properties, and the joint fabricated with ultrasonic vibration has much higher peeling moment and flexural strength than that prepared only by hot-press. Microstructure observations of the joints indicate a good metallurgical bonding between Al face sheet and foam core was achieved. The seam of AFS fabricated by hot-press assisted with ultrasonic vibration looks more compact and the bonding interface fused together firmly. The bonding faces of aluminum sheet and foam core are obviously corroded by melt ZnAl alloy and an obvious interdiffusion took placed during hot-dip process and hot-press, so the chemical compositions in the diffusion transitional zone are continuous. However the seam of the AFS fabricated only by hot-press has visible macro-defects, and the worse is its bonding interface fused together partially, which severely degrades the bonding strength.
Amin Nakhi; Monireh Ganjali; Haji Shirinzadeh; Ali Sedaghat Ahangari Hossein Zadeh; Masoud Mozafari
Abstract
In this study, at first fluorapatite nanopowder (nfAp) was initially synthesized by sol-gel method and then deposited on Titanium alloys (Ti-6Al-4V) using laser cladding technique. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) equipped ...
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In this study, at first fluorapatite nanopowder (nfAp) was initially synthesized by sol-gel method and then deposited on Titanium alloys (Ti-6Al-4V) using laser cladding technique. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) equipped with electron dispersive spectroscopy (EDX), were applied to study the crystallite and particle size, phase and chemical structure and microstructure the powder and coating sample. The results of XRD analysis and FTIR showed the presence of fluorapatite phases and ions replacement of F with OH in the structure of apatite. The MTT cell viability assays were used to study the biocompatibility of the coating samples. The average size of the crystallites estimated from XRD patterns using the Scherrer equation was 44 nm. The prepared nfAp coating deposited on Ti6Al4V showed well-behaved biocompatibility properties.
Leon Shaw; Maziar Ashuri
Abstract
Layered lithium nickel manganese cobalt oxides, Li(NixMnyCoz)O2 where x + y + z = 1 (NMCs), have been studied extensively due to their higher capacity, less toxicity and lower cost compared to LiCoO2. However, widespread market penetration of NMCs as cathodes for Li-ion batteries (LIBs) is impeded by ...
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Layered lithium nickel manganese cobalt oxides, Li(NixMnyCoz)O2 where x + y + z = 1 (NMCs), have been studied extensively due to their higher capacity, less toxicity and lower cost compared to LiCoO2. However, widespread market penetration of NMCs as cathodes for Li-ion batteries (LIBs) is impeded by their poor capacity retention and low rate capability. Coatings provide an effective solution to these problems. This article focuses on review of the recent advancements in coatings of NMCs from the mechanism viewpoint. This is the first time that coatings on NMCs are reviewed based on their functionalities and mechanisms through which the electrochemical properties and performance of NMCs have been improved. To provide a comprehensive understanding of the functions and mechanisms offered by coatings, the following functions and mechanisms are reviewed individually: (i) scavenging HF in the electrolyte, (ii) scavenging water molecules in the electrolyte and thus suppressing HF propagation during charge/discharge cycles, (iii) serving as a buffer layer to minimize HF attack on NMCs and suppress side reactions between NMCs and the electrolyte, (iv) hindering phase transitions and impeding loss of lattice oxygen, (v) preventing microcracks in NMC particles to keep participation of most NMC material in lithiation/de-lithiation, and (vi) enhancing the rate capability of NMC cathodes. Finally, the personal perspectives on outlook are offered with an aim to stimulate further discussion and ideas on the rational design of coatings for durable and high-performance NMC cathodes for the next generation LIBs in the near future.
Arenst Andreas Arie; Joong Kee Lee
Abstract
In this work, LiCoO2(LCO) composite electrodes were coated by fullerene C60 thin film with different thickness of 60, 100 and 200 nm using a plasma thermal evaporation technique. The surface morphology of bare and coated samples was observed by scanning electron microscope (SEM). The electrochemical ...
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In this work, LiCoO2(LCO) composite electrodes were coated by fullerene C60 thin film with different thickness of 60, 100 and 200 nm using a plasma thermal evaporation technique. The surface morphology of bare and coated samples was observed by scanning electron microscope (SEM). The electrochemical characteristics of the coated electrodes as cathode materials in Lithium-Ion Batteries (LIB)were investigated by a galvanostatic charge-discharge test at various C-rates between 3.0 and 4.5 V and compared with those of uncoated samples. An improvement of the performances of the coated electrodes in terms of higher initial coulombic efficiency, higher capacity retention and better rate capability was shown by the 60 nm thick C60 coated LiCoO2 electrodes. It can be said that the thin C60 coating layer can minimize the dissolution of Co from the electrode to the electrolyte. As the thickness of coating layer was increased, the coated electrodes show a more severe capacity fade due to longer Li-ion diffusion path.
Sandra Rivero; Javier Lecot; Adriana Pinotti
Abstract
PLA coating on Kraft paper is very promising systems for food packaging, and has potential environmental advantages over conventional synthetic paper coatings. This work was focused on: (i) analyzing the physicochemical, thermal and microstructural properties of PLA films; (ii) developing and studying ...
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PLA coating on Kraft paper is very promising systems for food packaging, and has potential environmental advantages over conventional synthetic paper coatings. This work was focused on: (i) analyzing the physicochemical, thermal and microstructural properties of PLA films; (ii) developing and studying multilayer systems obtained by impregnation of Kraft paper with different layers of PLA solution; (iii) evaluating the influence of PLA layers on the support cellulosic properties. The PLA coating improves packaging material performance and hence the functional properties of Kraft paper. The impregnation of hygroscopic materials as the Kraft paper with PLA was an alternative interesting to obtain more hydrophobic matrices. The assembled materials attained were heat-sealed. Furthermore, the use of PLA adds to potential food applications, a renewable resource value obtained from sources agricultural. The design of this multilayer support also allows its extension to other media such as paperboard. Moreover, the addition of 4 or 5 layers favourably modified the assembled system properties. Increasing even further the number of PLA layers, system properties hardly underwent a significant improvement. Consequently, the selection of the number of PLA layers would be a response to a relationship of commitment between the increase in the cost and the enhancement of the properties.
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