Fabrication technology, based on MEMS processes, for constructing components for use in switched-mode power supplies are developed and presented. Capacitors, magnetic cores, and inductors based on sacrificial multilayer electroplating are designed, fabricated, and characterized. Characterization of the produced inductors' core losses at high frequency and high flux is presented, confirming the aptness of the featured microfabrication processes for reducing eddy current losses in magnetic cores. As well, the demonstration of the same inductors in DC/DC converters at high switching frequencies, up to 6 MHz, is presented. Initial work addressing the top-down development of a fully-integrated DC/DC converter is presented. As well, the comprehensive advancement of the central process - sacrificial multilayer electroplating - is presented, including the development of a second-generation automated multilayer electroplating system. The advanced sacrificial multilayer plating process is applied to produce microfabricated capacitors, which achieved in excess of 1.5 nF/mm² capacitance density, The fabrication of highly-laminated magnetic cores and power inductors based on sacrificial multilayer electroplating is presented, along with the design and development of a system for characterizing inductor behavior at high-frequency, high-flux conditions. The design and operation of both buck and boost DC/DC converters, switching at up to 6 MHz, built around these highly-laminated-core inductors are presented.

This thesis presents various aspects of polishing the electroplating wastewater in constructed wetlands: analysis of the performance, study on the operation and configuration effects, effects of various carbon sources, analysis of the substrate (bed media), analysis of plants, and design issues.The goals of the experiment were to: (i) study the feasibility of polishing electroplating effluent, (ii) study the effect of operating schemes, plants, bed media and wastewater strength, (iii) to elucidate metal removal mechanisms in the CW microcosms.This study furnished new information and expanded the existing knowledge on industrial wastewater treatment in constructed wetlands. In fact, this is, to the best knowledge, the first publication studying the removal of metals and cyanide from electroplating wastewater in subsurface flow constructed wetlands. The aim of this study was to study the polishing of the electroplating wastewater pretreated using physical-chemical methods.

The aim of this research proj ect was to produce compositionally modulated zincnickel and zinc-nickel-manganese coatings usi ng a single bath process by variation of the applied electroplating current density. These could then be considered as possible replacements for electroplated cadmium. Zinc-nickel electrodeposits from both a simple bath and one containing the complexant tris(hydroxymethyl)methylamine (TRIS) were produced using either bath or by selective electroplating onto mild steel, 2014-T6 aluminium and 2000 series aluminium alloy connector shells. Zinc-nickelmanganese coatings were electroplated onto mild steel, using both DC and pulse electroplating from sulphate based baths containing either the complexant TRIS or sodium citrate. The coatings and the various electrodeposition processes were evaluated by thickness measurements, cun'ent efficiency calculations, composition detennination using energy dispersive X-ray anal ys is and SEM to examine the morphology. Corrosion characteristics were investigated by neutral salt fog exposure, alternate immersion, atmospheric trials, and electrochemical immersion tests including potential monitoring, galvanic and polarisation measurements. Other properties such as microhardness and surface electrical conductivity were also investigated. Compositionally modulated zinc-nickel and ziJlc-nickel-manganese were successfully deposited from single baths with nickel contents ranging from 5-20% Ni and manganese contents varying from 0-12% Mn. Current efficiency measurements showed the efficiency to be low especially for the zinc-nickel-manganese coatings, which exhibited a distinct morphology when electroplated from the citrate bath. Corrosion testing indicated that both coatings had a lower corrosion resistance than cadmium especially in accelerated tests, with a reduction in corrosion resistance being seen as the nickel content was increased; due to a decrease in density of the electroplate. This, and increasing through-thickness porosity promoted ennoblement of zinc-nickel and zinc-nickel-manganese leading to the coatings becoming nonsacri ficial to the substrate in accelerated tests. Zinc-nickel-manganese showed less white rust than zinc-nickel and exhibited lligher micro-hardness than zinc, cadmium and zinc-nickel. Electrical measurements indicated that both coatings were sufficiently conductive to meet the surface conductivity requirements for use on electrical connector shells.

Neste estudo, a sorção e recuperação de íons metálicos de resíduos sólidos industriais provenientes de uma indústria de galvanoplastia situada no Rio de Janeiro (Brasil) foram investigadas através da utilização de duas resinas comerciais de troca iônica: Lewatit VPOC 1800 (fortemente ácida, tipo gel) e Lewatit VPOC 1960 (fortemente básica, tipo gel), produzidas pela Lanxess-Bayer Chemicals. As características físico-quimicas das resinas e do lodo galvânico foram determinadas. Os estudos de sorção das resinas foram conduzidos em batelada e em coluna. Baseado nesses estudos, os parâmetros de sorção e das curvas de ruptura foram determinados. Os estudos de equilíbrio e cinética de sorção também foram realizados. O resíduo de galvanoplastia era composto pelos metais: Cu2+, Fe3+, Al3+, Ni2+ e Cr3+. A capacidade de sorção qe das resinas Lewatit VPOC 1800 variou entre 0,1-1,9 mg g-1 para Cu2+, 0,01-0,6 mg g-1 para Fe3+ e 0,2-0,4 mg g-1 para Al3+. Enquanto que para a resina Lewatit VPOC 1960, os valores de qe variou entre 0,01-0,4 mg g-1 para Cu2+ e 0,01 0,2 mg g-1 para Fe3+ dependendo da concentração do metal e do tempo de contato. A capacidade de sorção para a resina Lewatit VPOC 1960 foi restrita para íons Cu2+ e Fe3+ os quais formam complexos aniônicos com íons Cl-. O modelo de Freundlich foi o mais adequado para descrever o equilíbrio de troca iônica de ambas as resinas. Já em relação ao mecanismo de sorção, o modelo pseudo-segunda ordem tipo 1 foi o mais aplicável. O ponto de ruptura das resinas Lewatit VPOC 1800 e Lewatit VPOC 1960 em relação aos íons Cu2+ocorreu quando passou através da coluna, 1860 cm3 e 2220 cm3 de solução de resíduo sólido respectivamente (20 g de resina, 100 mg L-1 de íons Cu2+, vazão de 60 cm3 min-1). Os íons metálicos Cu2+, Fe3+, Al3+, foram dessorvidos em alta proporção da resina Lewatit VPOC 1800 passando pela coluna solução aquosa de H2SO4 2,4 mol L-1. Já os metais Cu2+ e Fe3+ foram eluídos da resina Lewatit VPOC 1960 com solução aquosa de HCl 2,0 mol L-1. A recuperação seletiva de Cu2+ não foi alcançada porque Cu2+ e Fe3+ precipitam na mesma faixa de pH / In the present study, the sorption and recovery of metal ions from industrial solid residues proceeding from galvanoplasty industry (Rio de Janeiro, Brazil) was investigated by using two commercial ion exchange resins Lewatit VPOC 1800 (strong acid, gel type) and Lewatit VPOC 1960 (strong basic, gel type) produced by Lanxess - Bayer Chemicals. The physical-chemical characteristics of the resins and galvanic sludge were determined. The studies of sorption of the resins were conduced under batch and column conditions. Based on these studies the sorption parameters and the breakthrough curves for both resins were determined. Studies of equilibrium and kinetic of the sorption were also performed. The electroplating residue were composed of the metals Cu2+, Fe3+, Al3+, Ni2+ and Cr3+. The sorption capacity qe of the resin Lewatit VPOC1800 varied between 0.1-1.9 mg g-1 to Cu2+, 0.01-0.6 mg g-1 to Fe3+ and 0.2-0.4 mg g-1 to Al3+. While for the resin Lewatit VPOC1960 the values of qe varied between 0.01-0.4 mg g-1 to Cu2+ and 0.01-0.2 mg g-1 to Fe3+ depending of the metal concentration and contact time. The sorption capacity for Lewatit VPOC1960 was restricted to ions Cu2+ and Fe3+ that to form anionic complexes with chloride. The Freudlich model was more adequate to describe the ion exchange equilibrium for both resins and the sorption mechanism was compliant to the kinetic model of pseudo second order type 1. The breakpoint to Cu2+ occurred after passing 1860 cm3 and 2220 cm3 of residue solution through the resins Lewatit VPOC1800 and Lewatit VPOC1960, respectively (20 g of the resin, 100 ppm of Cu2+, flow rate of 60 cm3 min-1). The metals Cu2+, Fe3+ and Al3+ were desorbed on high proportion of the Lewatit VPOC1800 through passing a aqueous solution H2SO4 2.4 mol L-1. Already the metals Cu2+ and Fe3+ were eluted to Lewatit VPOC1960 with HCl aqueous solution 2.0 mol L-1. The selective recuperation of the Cu2+ was not reach because the Cu2+ and Fe3+ precipitated on similar pH

Neste estudo, a sorção e recuperação de íons metálicos de resíduos sólidos industriais provenientes de uma indústria de galvanoplastia situada no Rio de Janeiro (Brasil) foram investigadas através da utilização de duas resinas comerciais de troca iônica: Lewatit VPOC 1800 (fortemente ácida, tipo gel) e Lewatit VPOC 1960 (fortemente básica, tipo gel), produzidas pela Lanxess-Bayer Chemicals. As características físico-quimicas das resinas e do lodo galvânico foram determinadas. Os estudos de sorção das resinas foram conduzidos em batelada e em coluna. Baseado nesses estudos, os parâmetros de sorção e das curvas de ruptura foram determinados. Os estudos de equilíbrio e cinética de sorção também foram realizados. O resíduo de galvanoplastia era composto pelos metais: Cu2+, Fe3+, Al3+, Ni2+ e Cr3+. A capacidade de sorção qe das resinas Lewatit VPOC 1800 variou entre 0,1-1,9 mg g-1 para Cu2+, 0,01-0,6 mg g-1 para Fe3+ e 0,2-0,4 mg g-1 para Al3+. Enquanto que para a resina Lewatit VPOC 1960, os valores de qe variou entre 0,01-0,4 mg g-1 para Cu2+ e 0,01 0,2 mg g-1 para Fe3+ dependendo da concentração do metal e do tempo de contato. A capacidade de sorção para a resina Lewatit VPOC 1960 foi restrita para íons Cu2+ e Fe3+ os quais formam complexos aniônicos com íons Cl-. O modelo de Freundlich foi o mais adequado para descrever o equilíbrio de troca iônica de ambas as resinas. Já em relação ao mecanismo de sorção, o modelo pseudo-segunda ordem tipo 1 foi o mais aplicável. O ponto de ruptura das resinas Lewatit VPOC 1800 e Lewatit VPOC 1960 em relação aos íons Cu2+ocorreu quando passou através da coluna, 1860 cm3 e 2220 cm3 de solução de resíduo sólido respectivamente (20 g de resina, 100 mg L-1 de íons Cu2+, vazão de 60 cm3 min-1). Os íons metálicos Cu2+, Fe3+, Al3+, foram dessorvidos em alta proporção da resina Lewatit VPOC 1800 passando pela coluna solução aquosa de H2SO4 2,4 mol L-1. Já os metais Cu2+ e Fe3+ foram eluídos da resina Lewatit VPOC 1960 com solução aquosa de HCl 2,0 mol L-1. A recuperação seletiva de Cu2+ não foi alcançada porque Cu2+ e Fe3+ precipitam na mesma faixa de pH / In the present study, the sorption and recovery of metal ions from industrial solid residues proceeding from galvanoplasty industry (Rio de Janeiro, Brazil) was investigated by using two commercial ion exchange resins Lewatit VPOC 1800 (strong acid, gel type) and Lewatit VPOC 1960 (strong basic, gel type) produced by Lanxess - Bayer Chemicals. The physical-chemical characteristics of the resins and galvanic sludge were determined. The studies of sorption of the resins were conduced under batch and column conditions. Based on these studies the sorption parameters and the breakthrough curves for both resins were determined. Studies of equilibrium and kinetic of the sorption were also performed. The electroplating residue were composed of the metals Cu2+, Fe3+, Al3+, Ni2+ and Cr3+. The sorption capacity qe of the resin Lewatit VPOC1800 varied between 0.1-1.9 mg g-1 to Cu2+, 0.01-0.6 mg g-1 to Fe3+ and 0.2-0.4 mg g-1 to Al3+. While for the resin Lewatit VPOC1960 the values of qe varied between 0.01-0.4 mg g-1 to Cu2+ and 0.01-0.2 mg g-1 to Fe3+ depending of the metal concentration and contact time. The sorption capacity for Lewatit VPOC1960 was restricted to ions Cu2+ and Fe3+ that to form anionic complexes with chloride. The Freudlich model was more adequate to describe the ion exchange equilibrium for both resins and the sorption mechanism was compliant to the kinetic model of pseudo second order type 1. The breakpoint to Cu2+ occurred after passing 1860 cm3 and 2220 cm3 of residue solution through the resins Lewatit VPOC1800 and Lewatit VPOC1960, respectively (20 g of the resin, 100 ppm of Cu2+, flow rate of 60 cm3 min-1). The metals Cu2+, Fe3+ and Al3+ were desorbed on high proportion of the Lewatit VPOC1800 through passing a aqueous solution H2SO4 2.4 mol L-1. Already the metals Cu2+ and Fe3+ were eluted to Lewatit VPOC1960 with HCl aqueous solution 2.0 mol L-1. The selective recuperation of the Cu2+ was not reach because the Cu2+ and Fe3+ precipitated on similar pH

Solar energy is increasingly being considered a promising solution to reduce the emissions of CO2 and green house gas. The performance of solar collectors largely depends on the ability to absorb incoming solar radiation with minimal thermal radiation losses. To weigh the potential absorbed energy to thermal losses, the performance criterion (PC) can be used, calculated as PC =α−xε, where α is absorptance, ε is emittance and x is a scaling factor < 1. It has been shown by G. Vargas et al. that Co-Cr alloys excibit great potential (α = 0.98 and ε = 0.03) for use in solar concentrators. The main goal of this project is to quantify the impact of key factors (controlled input variables) on an electroplating process of Co-Cr alloys, using the design of experiment (DOE) methodology. It is part of an ongoing collaboration between Absolicon and the physics department at Umeå university. Six factors were investigated using a fractional factorial (FrF) design. Data was collected through a series of experiments where stainless steel substrates were electroplated with Co-Cr alloys. The resulting samples were analyzed in terms of α and ε as well as the quality of deposition (QD). Using the experimental results, three models were made in a DOE-software called MODDE. Models are used to correlate the factors with each response, i.e. α, ε and QD. Ideally the predictive power of the models (Q2) should be as high as possible, and at least > 0.5. The analysis of variance (ANOVA) test was used to determine the significance of the models. Based on the models, the ’Optimizer’ tool in MODDE was used to predict two set of optimum factor settings, producing two samples, S1 and S2. S1 and S2 were evaluated in terms of α, ε and QD as well as chemical composition and structural properties of the coatings. The predictive power of the models was 0.49 for α, 0.38 for ε and 0.53 for QD. The predictive power of the models were therefore limited. ANOVA-test showed that the models for α and QD were statistically significant. For all three responses the significant effects were mostly two factor interactions. All three models showed significant lack of fit (model error) as a result of high reproducibility. S1 had the best PCAbsolicon (performance criterion for Absolicons solar collectors) of all samples with 0.858. S2 was not as good, even though it was predicted to have a higher value of PCAbsolicon by MODDE. EDS, XPS and SEM measurements of samples S1 and S2 showed that the two samples were very similar in terms of chemical composition. The main difference was that the coating of S1 was more porous, and also thicker than S2, 0.81 μm compared to 0.26 μm. Even though the models showed some predictive capabilities, the impact of the factors could not be fully determined. That is due to the nature of the FrF-design, which cannot accurately determine two-factor interactions.

The new nickel/layered silicate nanocomposites were electrodeposited from different pHs to study the influence on the metal ions/layered silicate plating solution and on the properties of the deposited films. Nickel/layered silicate nanocomposites were fabricated from citrate bath atacidic pHs (1.6−3.0), from Watts’ type solution (pH ~4-5), and from citrate bath at basic pH (~9). Additionally, the new nickel/molybdenum/layered silicate nanocomposites were electrodeposited from citrate bath at pH 9.5. The silicate, montmorillonite (MMT), was exfoliated by stirring in aqueous solution over 24 hours. The plating solutions were analyzed for zeta potential, particle size, viscosity, and conductivity to investigate the effects of the composition at various pHs. The preferred crystalline orientation and the crystalline size of nickel, nickel/layered silicate, nickel/molybdenum, and nickel/molybdenum/layered silicate films were examined by X-ray diffraction. The microstructure of the coatings and the surface roughness was investigated by scanning electron microscopy and atomic force microscopy. Nickel/molybdenum/layered silicate nanocomposites containing low content of layered silicate (1.0 g/L) had increase 32 % hardness and 22 % Young’s modulus values over the pure nickel/molybdenum alloy films. The potentiodynamic polarization and electrochemical impedance measurements showed that the nickel/molybdenum/layered silicate nanocomposite layers have higher corrosion resistance in 3.5% NaCl compared to the pure alloy films. The corrosion current density of the nickel/molybdenum/layered silicate nanocomposite composed of 0.5 g/L MMT is 0.63 µA·cm-2 as compare to a nickel/molybdenum alloy which is 2.00 µA·cm-2.

No description available.

This paper reports the evaluation results of the mechanical structures of MEMS (micro electro mechanical systems) sensor implemented in the integrated MEMS inertial sensor for a wide sensing range from below 0.1 G to 20 G (1 G = 9.8 m/s^2). To investigate the mechanical tolerance, a maximum target acceleration of 20G was applied to the sub-1G sensor which had the heaviest proof mass of all that sensors had. The structure stability of Ti/Au multi-layered structures was also examined by using Ti/Au micro cantilevers. The results showed that the stoppers effectively functioned to prevent the proof mass and the springs from self-destruction, and that the stability of Ti/Au structures increased with an increase in width. Those results suggest that the proposed stopper and spring structures could be promising to realize MEMS sensors.

Zn-Mo coatings are very promising environment friendly anticorrosive coatings as replacement materials for cadmium and chromium (VI) based conversion layers. Electrodeposition has become a favorable technique in fabricating coatings due to its low cost, ease of use, and overall experimental control of coating quality. Very little research so far has been done for the electrodeposition of Zn-Mo coatings under alkaline conditions. In this work, Zn and Zn-Mo coatings were electrochemically deposited on stainless steel from an aqueous alkaline citrate solution. An organic compound, vanillin, was added to the electrolyte as a leveling agent for improving interlayer adherence and corrosion resistance of Zn-Mo coatings. Ni-Mo alloys have been known to possess high tensile strength and excellent corrosion protection of steels, and MoTe2 layers have a potential for the application in anticorrosive coatings due to their hydrophobic properties. In this study, MoTe2-Ni-Mo coatings were deposited on stainless steel using both sputtering and electrodeposition methods. These coatings with high corrosion resistance and other desirable properties are in demand in the oil and gas industry since they can protect and thus extend the lifetime of the underlying materials when exposed to aggressive environments. The Zn-Mo and MoTe2-Ni-Mo coatings were evaluated for chemical composition and corrosion behavior using different types of instrumental and electrochemical techniques. The addition of vanillin to the electrolyte did not change the crystalline structure or composition of the Zn-Mo coating, however, the corrosion resistance of the coating was significantly improved by the leveling effect of vanillin during the electrodeposition. The corrosion resistance of the Ni-Mo coating was also enhanced by applying the hydrophobic MoTe2 monolayer on the top surface.