Papers by Keyword: Nickel Foam

Abstract: This work is devoted to the development and research of functional and physico-chemical parameters of electrodes based on nanocomposite metals for water electrolysis. As a functional matrix support the nickel foam was chosen. The synthesis of bimetallic nanoparticles of nickel-platinum with further application to nickel foam was carried out. Particle sizes were investigated by electron microscopy methods. Resource tests of electrolysis cells constructed on the basis of the obtained electrodes were carried out.

Abstract: Metal foams, having a great of specific surface areas and three-dimensional open cell structures, can be used for electromagnetic shielding and thermal management in electronics, battery electrodes in new energy, catalyst carriers in chemical engineering and lightweight structure in aerospace. The key performance indicators of these open cell metal foams are how to effectively control their pore structures such as pore diameter distribution and porosity and how to make it thinner that can meet different requirements for the component preparation. Summarized about three manufacturing processes are usually used to build metal foams. The first is well-known as physical process. The second is chemical or electrochemical method. The third is a combined process between physical and chemical processes. No matter what kind of process is selected to manufacture open cell metal foam, the specific surface area directly related to the microstructure of the foam is an important parameter in a material selection and design for its application.This paper will introduce a special powder composite plus manufacture process that is developed by Jiangsu Green Materials Hi-Tech. Co. Ltd. The leading manufacture process is a new one that is combined by powder metallurgy, casting, deformation and physical-chemical synthesis. It is environmentally friendly and recyclable from raw material selection, manufacturing process to thermal-mechanical treatment. This paper will also focus on the introduction of the microstructure characterization of open-cell metal foams such as copper, nickel, iron, silver and their alloying foams that we manufactured and give some examples to demonstrate their potential applications in the field of new energy, such as being an electrode for lithium-ion battery, membranes for fuel cell and super-capacitor, in the field of electronic engineering such as thermal management and electromagnetic shielding, in the field of chemical engineering such as separation and catalysts. These examples show their lead roles of these open-cell metal foams and different applications by our developed process.

Abstract: The relationship between temperature of sintering in neutral atmosphere and compression strength has been investigated for nickel foams produced by electrodeposition on an organic foam. The as-plated nickel foams are sintered at 600and 1000 in order to eliminate polyurethane and enhance ductility. The results show that the compression strength is significantly influenced by sintering temperature. The most ductile sample is gained by sintering at 600. In addition, samples sintered at this temperature have the higher energy absorbing capability. EDX analyses show that oxygen element raised from oxidation in high temperature presents in specimen sintered at 1000. Hollow struts are obvious in SEM image of treated foams. Keywords: Nickel foam, electrodeposition, EDX, Compression test

Abstract: Ni foam with 3D porous structure has attracted attention in the field of catalysis. Expanding the specific surface area of Ni foam is an important method to enhance its chemical properties. In this study, the Cu-Ni/Ni foam were obtained by electroless plating copper on Ni foam and then heat treatment for homogenizing at 750°C. The dealloying of the Cu-Ni/Ni foam was carried out by electrochemical etching for obtaining the Ni foam with hierarchical pore structure. The microstructure, phase and electrochemical performance were characterized by SEM, XRD and electrochemical testing. The results showed that the optimized temperature of electroless plating Cu on Ni foam is 60oC. Ni-Cu alloy can be obtained by counter diffusion above 750°C. With prolonging time of etching, the content of Cu component decreased and the size of pores on the sturts of the Cu-Ni/Ni foam changed from nano to micro scale. The electrochemical properties of the alloywere significantly higher than that of the pure nickel foam.

Abstract: In the paper the methods of designing and manufacturing of the metals foam with regular cells are researched. The software models of metals foam are designed by CAD. The models are transmitted into 3D printing machine to manufacture foam framework. The metal foams with regular cells and fixed porosities are manufactured by chemical plating, electric plating and investment cast. According to the applications the structures of metal foams can be designed to control sizes, shapes and distribution of pores, porosities, density and to control the properties of metals foam, which can satisfy various demands of applications. Nickel foam with regular cells is designed and manufactured by this method.

Abstract: Nickel oxide/Ni foam composite was studied as an electrode for electrochemical capacitors. The material has been processed by a simple, green and cost-effective electrophoretic deposition (EPD) method directly from the post-reaction medium in an one-pot synthesis and its later heat treatment.NiO films were obtained after calcination (325 and 450ᵒC) of β-Ni(OH)₂ deposits. β-Ni(OH)₂ nanoplatelets were produced by chemical precipitation of Ni precursors and the aid of ultrasound, free of modifiers. The stabilization of the hydroxide powder in suspension in different mixtures of Ethanol:Water (4:1, 9:1 and 19:1) and the optimization of the EPD parameters allowed coating the commercial Ni foams via colloidal processing.Electrochemical properties of the electrodes were evaluated by cyclic voltammetry (CV) showing significant differences in terms of specific capacitance of 192 and 79 F/g for the electrodes calcined at 325 and 450ᵒC, respectively.

Abstract: Unique NiO and Co₃O₄ nanostructures were successfully deposited on nickel foam (NF) substrate by a hydrothermal process. Both of them are highly dispersed on the surface of NF, showing a unique nanoporous film structure. They exhibit excellent electrochemical performance due to their effective porous structure which introducing facile electrolyte penetration and fast proton exchange. The highest specific capacitance of 231 and 493 F g^-1 are achieved for NiO and Co₃O₄ electrodes at a current density of 0.5 A g^-1, respectively.

Abstract: The dyeing wastewater is processed by photoelectric catalytic oxidation with nickel foam electrode of titanium dioxide， which is prepared with ion liquid. The main influence factors including electrode distance, electrolysis voltage, pH and electrolytic time were studied in processing waste. Results show the optimal operating condition is the electrode gap of 1.0 cm, pH value of 4.4, electrolysis voltage of 5.0V and 100 mg∙L-1 dosages of Na2SO4 in 120 minutes electrolysis time under the irradiation of ultraviolet light . The effect of processing the wastewater with catalytic electrolysis can be greatly improved in water cycle system with continuous air, flocculent and activated carbon. Consequently the removal rate of the Chemical Oxygen Demand (COD)is 78.69%, and the decolored rate is 97.02%. The COD of the processed wastewater is within 100.0 mg∙L-1, and meets the first national emission standards. It is expected that the method will have good prospect in protecting the water resources and environment.

Abstract: In the present study, porous nickel foam samples with pore sizes of 20 μm and 150 μm and porosities of 60 % and 70 % were fabricated by the space-holding sintering method via powder metallurgy. Electron scanning microscopy (SEM) and Image-Pro Plus were used to characterise the morphological features of the porous nickel foam samples. The anisotropic mechanical properties of porous nickel foams were investigated by compressive testing loading in different directions, i.e. the major pore axis and minor pore axis. Results indicated that the nominal stress of the nickel foam samples increases with the decreasing of the porosity. Moreover, the foam sample exhibited significantly higher nominal stress for loading in the direction of the major pore axis than loading in direction of the minor pore axis. It is also noticeable that the nominal stress of the nickel foams increases with the decreasing of the pore size. It seems that the deformation behaviour of the foams with a pore size in the micron-order differs from those with a macro-porous structure.

Abstract: Nickel foam reinforced AZ91 magnesium alloy was fabricated by using melt infiltration and water quenching methods. The mechanical properties were measured in compressive and tensile deformation modes. Fracture surfaces were examined by scanning electronic microscopy. The results show that addition of nickel foam results in a significant increase in elastic modulus, yield strength of the composite material. However, ductility of the composite was adversely affected when compared to the unreinforced monolithic counterpart.