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Abstract The effective strength of butt joints under uniaxial tensile loading significantly depends on the adhesive thickness as well as on the elastic contrast of adhesive and adherend. For an assessment of their impact using sensitivity analysis, for joint design optimisation, or for an efficient evaluation of butt joint test data, a suitable modelling approach is desired. In the present work, the joint's failure is modelled assuming a spontaneous formation of finite cracks along the interface between adhesive and adherend. A coupled stress and energy approach is used requiring only two fundamental material parameters, that is, material strength and toughness. Presuming the length of initiating cracks to be small compared to the adhesive thickness, the method of matched asymptotic expansions in combination with a complex potential formalism is applied. This enables an efficient description of the stress distribution in the vicinity of the bi-material notch tip and the derivation of scaling laws for the energy dissipation during crack nucleation. The joint strength is calculated for a varying adhesive thickness and for different layups of the composite adherends. The theoretical predictions based on the asymptotic coupled stress and energy approach are validated against numerical cohesive zone data and experimental findings from literature. [ABSTRACT FROM AUTHOR]

A new general computational framework for the stress and effective strength analysis of ductile adhesive composite joints is proposed. Composite adherends are modelled using First Order Shear Deformation Theory accounting for bending-extension coupling and an asymptotic approach for the bondline within deformation theory of plasticity is employed. The governing one-dimensional boundary value problem is solved using an efficient finite-difference scheme in Matlab. Based on the proposed stress solution, different failure criteria motivated either by strength criteria or fracture mechanics are implemented and benchmarked against experimental data for an effective joint strength assessment. A comparison to numerical finite element analyses demonstrates the model's ability to render the adhesive stress field accurately. The impact of different stress-strain curve approximations and effective stress quantities within deformation theory of plasticity are studied and discussed. Finally, effective joint strength predictions are compared to experimental data from literature. The paper concludes with a discussion on distinct failure criteria for elastic-plastic adhesive joints and recommendations for reliable accurate joint strength predictions. [ABSTRACT FROM AUTHOR]

The onset of cracks at elliptical holes in finite-width laminated plates under uniaxial tension loading is investigated using a finite fracture mechanics approach. A coupled stress and energy criterion is applied in order to determine the effective strength of the notched plate and the size of instantaneously initiating cracks. A semi-analytical approach based on complex potential theory in combination with a two-scale asymptotic analysis is proposed leading to explicit relations for the stress field and energy quantities due to crack formation. This allows for an efficient finite fracture mechanics solution and a significant reduction of the numerical effort compared to a full-numerical treatment. The effect of higher-order terms in the asymptotic procedure and a technique leading to an improved convergence of the expansions are discussed in detail. A thorough comparison with numerical data is performed in order to analyse the validity range of the asymptotic solution. Furthermore, the failure load predictions are compared to experimental data from literature. [ABSTRACT FROM AUTHOR]

In the present work, brittle failure of finite-width composite plates containing a circular hole under uniaxial tension loading is investigated using a coupled stress and energy criterion within the framework of finite fracture mechanics. Depending on the material anisotropy, the onsets of symmetric and antisymmetric crack patterns are investigated considering mixed-mode fracture. In order to provide an efficient finite fracture mechanics analysis, a semi-analytical approach is proposed combining the method of complex potentials with a two-scale asymptotic solution procedure. Within the asymptotic framework, higher-order terms and the application of Padé approximation are implemented allowing for an extended applicability of asymptotic solutions. In addition, full-numerical analyses are performed and the accuracy of the asymptotic approach, in particular with regard to the finite-width, is thoroughly examined. The effects of hole size and fibre orientation on the plate’s effective strength are studied using the proposed finite fracture mechanics approach and theoretical strength predictions are compared to experimental results from literature. [ABSTRACT FROM AUTHOR]

Functionally graded adhesives yielding a varying adhesive Young's modulus along the overlap are increasingly considered in order to allow for a more uniform stress distribution and to reduce the occuring stress concentrations in the adhesive layer of adhesively bonded single lap joints. The present work provides a comparative study of the existing analytical models for planar functionally graded adhesive single lap joints. The respective modelling assumptions as well as the conditions of applicability of the different approaches are examined in detail. In addition, a novel approach and possible extensions of the presented approaches are outlined and discussed. A thorough comparative study comprising various single lap joint configurations and adhesive Young's modulus distributions along the overlap is performed in order to assist the engineer choosing the adequate model for a particular single lap joint design. For an assessment of the accuracy, the calculated adhesive stress fields are compared to numerical results obtained by Finite Element Analyses. In addition, the effects of the adhesive Young's modulus range on the peak adhesive stresses are studied and discussed. [ABSTRACT FROM AUTHOR]

In recent years, functionally graded adhesives (FGAs) have been developed and successfully applied with the objective to reduce the stress concentrations occurring in bonded joints and to exploit their full lightweight design potential. The present work provides a computational framework based on a general predictive analytical model for FGA joints with composite adherends under mechanical and thermal loading embedded in an optimization procedure. In this way, an optimal homogenization of the adhesive stresses using FGAs is achieved. The proposed analysis approach follows the idea of general sandwich-type analyses and is thus applicable to various adhesive joint configurations as e.g. single lap joints, L-joints, T-joints, reinforcement patches and even balanced double lap joints. For the case of homogeneous adhesives, closed-form analytical solutions are presented and compared to existing solutions in literature. The predicted adhesive stress distributions of several FGA joint configurations are studied and compared to numerical results of finite element analyses where a good agreement is obtained. Moreover, a comprehensive study regarding the optimized functional grading for two particular joint configurations is performed and discussed. The corresponding grading functions are obtained solving an underlying optimization problem that minimizes a predefined objective function characterized by an equivalent stress quantity. [ABSTRACT FROM AUTHOR]

The present work provides a new model for the stress analysis of functionally graded adhesive lap joints with composite adherends. It is applicable to various joint configurations such as single lap joints, L-joints, T-joints, reinforcement patches, corner joints or balanced double lap joints. The modelling approach follows the concept of general sandwich-type analyses that consider only the overlap region of the joint with any combination of section forces and moments. To take into account shear deformations of the adherends, First Order Shear Deformation Theory is employed and bending-extension coupling of laminated adherends is covered. Several adhesive joint designs with various adhesive Young’s modulus variations are investigated and the obtained adhesive stress distributions are compared to results of detailed finite element analyses. In general, a very good agreement is observed. The present model accurately renders that the adhesive peak stresses can be significantly reduced by the functional grading of the adhesive. Further, the effects of different functional grading functions of the adhesive Young’s modulus on the adhesive stresses are studied and discussed. The paper concludes with design considerations for functionally graded adhesive joints. [ABSTRACT FROM AUTHOR]

Employing a functionally graded adhesive the efficiency of adhesively bonded lap joints can be improved significantly. However, up to now, analysis approaches for planar functionally graded adhesive joints are still not addressed well. With this work, an efficient model for the stress analysis of functionally graded adhesive single lap joints which considers peel as well as shear stresses in the adhesive is proposed. Two differential equations of the displacements are derived for the case of an axially loaded adhesive single lap joint. The differential equations are solved using a power series approach. The model incorporates the nonlinear geometric characteristics of a single lap joint under tensile loading and allows for the analysis of various adhesive Young׳s modulus variations. The obtained stress distributions are compared to results of detailed Finite Element analyses and show a good agreement for several single lap joint configurations. In addition, different adhesive Young׳s modulus distributions and their impact on the peel and shear stresses as well as the influence of the adhesive thickness are studied and discussed in detail. [ABSTRACT FROM AUTHOR]

This work deals with the analytical determination of section forces and moments in adhesively bonded single lap joints with composite laminate adherends including bending-extensional coupling. The analysis is also valid for unbalanced joints and the adhesive thickness is taken into account in the model. Several types of boundary conditions can be applied, e.g. simply supported ends, fixed ends, bonded doubler and single strap joints. Various configurations are studied and the results are compared to finite element analyses and other analytical approaches. Good agreement is achieved over a wide range of configurations. A closed form analytical solution is given for the section forces and moments at the overlap ends. [ABSTRACT FROM AUTHOR]

In this work an efficient general Finite Fracture Mechanics model for crack initiation in adhesively bonded joints is presented which is applicable to various joint configurations with shear flexible laminate and metallic adherends. The mechanical behaviour of the adhesive joints is modeled by a general sandwich-type model for the analysis of bonded joints with composite adherends which gives solutions for the peel and shear stresses in the adhesive. The failure behaviour is described by a physically sound combined stress and energy criterion which requires only two basic failure parameters: the strength and the fracture toughness of the adhesive. The implicit equations are solved with a highly efficient iterative solution scheme. In a comprehensive study, experimental and numerical results of an elaborated Cohesive Zone Model (CZM) are used for comparison. It is shown that the predicted failure loads are in good to very good agreement with the experimentally determined results and the effects of the geometric parameters on the failure load are rendered correctly. [ABSTRACT FROM AUTHOR]

Efficient analyses of adhesive joints are very important for pre-dimensioning or optimization processes. In this work a new model for adhesive joints is presented that can be applied to various joint configurations, as e.g. single lap joints, T-joints, L-joints or reinforcement patches. This is done by means of a two-dimensional, plane-strain model of the overlap region of the adhesive joint that is loaded by arbitrary section forces and moments — a so called general sandwich-type model. To account for shear deformations of the adherends, First Order Shear Deformation Theory is used. Arbitrarily laminated adherends are considered including asymmetric laminates with bending-extension coupling. The model yields a shear and peel stress distribution in the thin adhesive layer that is constant over the thickness. The results are compared to Finite Element Analyses for several joint configurations and show good agreement. A closed-form analytical solution is given for the case of identical adherends without bending-extension coupling. The general solution can be obtained with very low numerical effort. To allow for a ready use of the present solution an efficient MATLAB implementation is provided as supplementary material to this paper. [ABSTRACT FROM AUTHOR]

Abstract: Diffusion of Bi+III, Sb+III and Te+IV cations in nitric acid, tartaric acid electrolytes were studied employing voltammetry and chronopotentiometry. From the Bard correction to the Sand equation, the diffusion coefficients of bismuth, antimony and tellurite ions were measured in the investigated solutions. The diffusivity of Sb+III was found to be systematically slower than other cations Bi+III and Te+IV. The results were discussed facing some compositions of electroplated Bi–Sb–Te films with the ones of the electrolyte solutions. [Copyright &y& Elsevier]

Abstract: Bismuth telluride nanowires were potentiostatically deposited from a water/DMSO 50%, v/v electrolyte within polycarbonate etched ion-track membranes covered by a platinum substrate. The presence of DMSO shifts the potentials to more negative values and slows down the cation diffusion. Cyclic voltammetries on recessed Pt nanoelectrodes using polycarbonate membranes highlight a complex electrochemical behavior through several cathodic and anodic peaks which are not observed onto platinum discs macroelectrodes. Analytical investigations enabled the determination of appropriate deposition conditions to finely tune the average composition of the nanowires. Calibrated TEM-EDX analyses evidence high aspect ratio nanowires, whose composition is strongly dependent on the deposition potential. In the same manner as for bismuth telluride film electroplating, bismuth enrichment occurs at more cathodic deposition potential whereas tellurium enrichment is observed at low cathodic potentials. Stoichiometric nanowires of 60nm diameter were obtained at −100mV vs Ag/AgCl from an electrolyte which contains [Bi3+]=1.5[HTeO2 +]=15mM. The composition is homogeneous along the nanowire except at both edges: the cap is rich in bismuth whereas the base is rich in tellurium. The composition at the nanowire base is adjusted by setting a short initial voltage step (U i =−300mV vs Ag/AgCl, t i =2s). In the case of stoichiometric compounds, the resulting nanostructures were found to be polycrystalline with a preferential orientation along the direction perpendicular to the planes (015). [Copyright &y& Elsevier]

Abstract: The molybdenum chalcogenides Mo6X8 (X=S, Se) offer the possibility of intercalation/de-intercalation processes by chemical or electrochemical way. Besides the different applications of so-called Chevrel phases, we have proposed an electrochemical transfer junction for selective recovery of metallic cations in the perspective of recycling of industrial liquid mineral wastes. Thus, the knowledge of the diffusion properties of cations in the Chevrel phases is essential. Here we report on the electrochemical determination of diffusion coefficients of Co2+, Ni2+, Fe2+, Cd2+, Zn2+, Mn2+ and Cu2+ for Mo6S8 and Mo6Se8 matrices. Experiments were realized on samples with compactness of 50% and 96–98%. They point out that the lower compactness is unfavorable to the mobility of the cobalt ions. From potential step chronoamperometry and electrochemical impedance spectroscopy, the diffusion coefficients were found around 10−9 cm2 s−1, even 10−6 cm2 s−1 for copper. These results confirm the high mobility of transition metal ions in studied phases and complete the data for Co, Fe or Mn–Mo6S8 system and Mn–Mo6Se8 system. For the sulfide phase, the following sequence for is observed Ni

The oxidation process of the Pb-0.08 wt.% Ca-1.2 wt.% Sn alloy was investigated by in situ spectroscopic ellipsometry measurements, combined with electrochemical measurements. The evolutions of the electrochemical and optical parameters show a mechanism of the film growth in two parts. In the first 10 min, the ellipsometric spectra exhibit large variations, whereas the measured current is approximately 0.3 mA cm−2. During this complex step, the surface topography is continuously changing. This stage corresponds to the growth of lead sulfate crystals, which is then oxidized in a thin and flat PbO2 layer, as confirmed by ex situ X-ray diffraction and scanning electron microscopy analysis. The second part is identified by a rapid and important decrease of the current, down to a low and steady value of approximately 0.01 mA cm−2. At once, the optical spectra vary slightly. A duplex layer model has been used to interpret spectroscopic ellipsometric measurements. The upper layer is likely composed of β-PbO2 as suggested by ex situ X-ray diffraction analysis. This model indicates a total thickness of the film approximately 480 nm at the end of the polarization (24 h). [Copyright &y& Elsevier]

Porous alumina films have been synthesised by anodisation of high purity aluminium in 0.4 M phosphoric acid at constant current density. The dissolution process of those coatings in 2 M phosphoric acid has been investigated by in situ spectroscopic ellipsometry (SE) combined with electrochemical measurements. A sharp drop of the open current potential is observed due to film removal. The dissolution time depends on total barrier layer thickness. Those results are confirmed by SE measurements. A three layer optical model has been used to interpret SE spectra. During the dissolution process, the porous top layer has a quasi-constant thickness, whereas porosity increases significantly. The dissolution proceeds within the pores. Only the thickness of pure alumina barrier layer (upper part) decreases during the dissolution process whereas the interface barrier layer (lower part) does not change. [Copyright &y& Elsevier]

The present work introduces an efficient general sandwich-type model that allows for stress analyses of arbitrarily shaped adhesive lap joints with composite adherends with an elastic-perfectly plastic adhesive layer obeying the von Mises yield criterion. For the analysis of the nonlinear adhesive layer the plastic zone approach is applied. The model is applicable to various joint configurations, as e.g. single-lap joints, T-joints, L-joints, reinforcement patches or balanced double-lap joints. It considers only the overlap region of the joint with any combination of section forces and moments and is therefore denoted as sandwich-type model. First Order Shear Deformation Theory is employed to account for shear deformations of the composite adherends. Bending extension coupling is covered. The adhesive layer is assumed to be very thin compared to the thickness of the adherends and the shear and peel stress distributions are assumed as constant through the bondline thickness. To allow for a comparison of several different structural situations a two-dimensional Finite Element model of the overlap region is used. The stress distributions predicted by the present model are in good agreement with the results of detailed Finite Element analyses. [ABSTRACT FROM AUTHOR]

Plates notched with open-holes that are subject to combined tensile and in-plane bending loading are studied in this analysis of crack onset. A finite fracture mechanics approach is employed to study the onset of asymmetric crack patterns in the notched structure. The stress field and the energy release rates required to solve the coupled stress and energy criterion are obtained from linear elastic finite element analyses. Closed-form expressions for the dependence of the solution on governing parameters as e.g. the structural size, the Young’s modulus or the ratio of bending to normal loading are given significantly reducing the computational effort required for the failure model. A comparison to experimental results and to numerical analyses using a cohesive zone model highlights the model’s ability to render brittle failure of the notched structure and to provide reliable failure load estimates. The results reveal that a certain threshold of the hole diameter exists, below which the hole does not affect the failure load. The threshold and the corresponding bearable loads are discussed using explicit solutions. [ABSTRACT FROM AUTHOR]

The surface of the AISI 420 martensitic stainless steel was subjected to High Current Pulsed Electron Beam (HCPEB) treatment. The microstructure in the melted layer consisted of a three phase mixture: (i) fine δ-Fe grains formed via epitaxial growth from the substrate, (ii) larger γ–grains nucleated from the top surface of the melt and (iii) some needles-like variants issued from the solid state martenitic transformation. Despite this complex multi-phase microstructure, the corrosion performance, tested in a sulfuric acid solution, was significantly enhanced by the HCPEB treatment. The increase in corrosion potential and delayed pitting are essentially attributed to an increase in Cr content, rising from 13.3 wt. % in the bulk to about 14 wt. % at the surface, together with a very limited amount of surface craters. This low density of craters did not give rise to significant deep hardening in the sub-surface but the top surface melted layer hardness was increased by more than 50% because of the triggering of the martensitic transformation. [ABSTRACT FROM AUTHOR]

It is demonstrated that significant surface modifications can be generated by low-energy, high-current pulsed electron beam treatments in the “heating mode” (which does not melt the surface). The extremely fast thermomechanical cycles generate grain refinement and texture modification at the surface of a Fe–40at.% Al alloy. Together with the formation of vacancies, this accounts for a significant increase in the surface microhardness. Nevertheless, because of the absence of craters with the heating mode, the corrosion resistance was unchanged. [Copyright &y& Elsevier]

Abstract: We synthesized polycrystalline Bi2+ x Te3− x (−0.2< x <0.2) thin films by electrodeposition in acidic medium. Since Bi2Te3-like structure may be uniaxially anisotropic due to its rhombohedral crystallographic system, we investigated their optical behavior using ex and in situ Mueller matrix spectroscopic ellipsometry in the wavelength range of 470 to 830 nm (1.5–2.6 eV). We found that room-temperature electroplated polycrystalline appears optically isotropic and that no depolarization effect occurs from the first steps of growth until several micrometers thick films. Additional ex situ measurements permit to obtain their optical constants from far-ultraviolet to near-infrared (190–2100 nm). [Copyright &y& Elsevier]

Abstract: This work reports the feasibility of thermoelectric thin films synthesis via a new aqueous chemical deposition process. Bismuth telluride thin films have been prepared using this method. A bath containing the dissolved precursors in acidic solution was used. The reaction generated between the bismuth and the tellurite ions on an electrodeposited Ni° on stainless steel substrate gave Bi2Te3 thin films. The reaction took place at ambient temperatures with stirring with different ratios of [BiIII]/[TeIV] ions. The tellurite ion concentration was fixed to 5.10−3 mol/l in HNO3 1 mol/l. The films formed were bright and adhesive to the substrate. It was shown that the composition of the deposited film is influenced by the composition of the chemical bath. The products characterized by X-ray diffraction were polycrystalline; the morphology of the film examined by scanning electron microscopy showed a compact structure. The thickness of the film determined by observation of the section by electronic microscopy was about 4 μm thickness. [Copyright &y& Elsevier]

The ice giant planets, Uranus and Neptune, are fundamentally different from the gas giant and terrestrial planets. Though ice giants represent the most common size of exoplanet and possess characteristics that challenge our understanding of the way our solar system formed and evolved, they remain the only class of planetary object without a dedicated spacecraft mission. The inclusion of a Uranus orbiter as the third highest priority Flagship mission in the NASA Planetary Science Decadal Survey "Vision and Voyages for Planetary Science in the Decade 2013–2022" indicates a high level of support for exploration of the ice giants by the planetary science community. However, given the substantial costs associated with a flagship mission, it is critical to explore lower cost options if we intend to visit Uranus within an ideal launch window of 2029–2034 when a Jupiter gravity assist becomes available. In this paper, we describe the Quest to Uranus to Explore Solar System Theories (QUEST), a New Frontiers class Uranus orbiter mission concept study performed at the 30th Annual NASA/JPL Planetary Science Summer Seminar. The proposed QUEST platform is a spin-stabilized spacecraft designed to undergo highly elliptical, polar orbits around Uranus during a notional one-year primary science mission. The proposed major science goals of the mission are (1) to use Uranus as a natural laboratory to better understand the dynamos that drive magnetospheres in the solar system and beyond and (2) to identify the energy transport mechanisms in Uranus' magnetic, atmospheric, and interior environments in contrast with the other giant planets. With substantial mass, power, and cost margins, this mission concept demonstrates a compelling, feasible option for a New Frontiers Uranus orbiter mission. • QUEST is a Uranus orbiter mission concept based extensively on the Juno mission. • The mission would address the top two objectives for a Uranus flagship mission in the NASA Decadal Survey. • The mission would investigate Uranus' unique magnetic field, atmosphere and interior environments. [ABSTRACT FROM AUTHOR]

Curiosity landed on plains to the north of Mount Sharp in August 2012. By June 2016 the rover had traversed 12.9 km to the southwest, encountering extensive strata that were deposited in a fluvial-deltaic-lacustrine system. Initial drives across sharp sandstone outcrops initiated an unacceptably high rate of punctures and cracks in the thin aluminum wheel skin structures. Initial damage was found to be related to the drive control mode of the six wheel drive actuators and the kinematics of the rocker-bogie suspension. Wheels leading a suspension pivot were forced onto sharp, immobile surfaces by the other wheels as they maintained their commanded angular velocities. Wheel damage mechanisms such as geometry-induced stress concentration cracking and low-cycle fatigue were then exacerbated. A geomorphic map was generated to assist in planning traverses that would minimize further wheel damage. A steady increase in punctures and cracks between landing and June 2016 was due in part because of drives across the sharp sandstone outcrops that could not be avoided. Wheel lifetime estimates show that with careful path planning the wheels will be operational for an additional ten kilometers or more, allowing the rover to reach key strata exposed on the slopes of Mount Sharp. [ABSTRACT FROM AUTHOR]

Aminated tannin submitted to hydrothermal treatment led to nitrogen-doped gels in the absence of any cross-linker. Such gels were subcritically dried, freeze-dried or supercritically dried to obtain organic xerogels, cryogels and aerogels, respectively, having nitrogen contents between 3.0 and 3.7 wt.%. After pyrolysis at 900 °C, the materials presented nitrogen contents ranging from 1.9 to 3.0 wt.%, and surface areas as high as 860, 754 and 585 m 2 g −1 for carbon aerogels, cryogels and xerogels, respectively. All of them displayed micropores associated with different mesopore volumes, depending on both the drying method and initial dilution of the precursor. When tested as supercapacitor electrodes, these carbon gels presented outstanding specific and normalised capacitances, up to 387.6 F g −1 and 69.5 μF cm −2 , respectively, at a scan rate of 2 mV s −1 in 4 mol L −1 H 2 SO 4 aqueous solution. These performances are higher than those obtained with high apparent surface area-activated carbons, as the measured capacitances are indeed among the highest ever reported. The influence of nitrogen- and oxygen-based moieties was investigated, and optimal N and O contents of 2–3 and 17–18 wt.%, respectively, were observed. [ABSTRACT FROM AUTHOR]

Six porous carbon materials, produced by hydrothermal treatment of flavonoid tannin and subsequent carbonization at 1173 K, were tested as electrodes of supercapacitors. Four of these carbons were doped with nitrogen by putting tannin in contact with ammonia before or during the hydrothermal treatment. The pyrolyzed hydrothermal carbons had moderate surface areas, within the range 442–684 m 2 g −1 , and nitrogen contents ranging from 0.7 to 8.0 wt.%. Specific capacitances as high as 320 F g −1 and normalized capacitances as high as 58 μF cm −2 were measured at 2 mV s −1 . These performances are comparable with those obtained with high surface area-activated carbons, whereas, normalized capacitances values are among the highest ever reported. Mesostructuration, within the range 3–13 nm, of these materials appears to be a good strategy to improve their electrochemical performances at higher scan rates. We confirmed the beneficial role of oxygen up to 18 wt.%, while an optimum in nitrogen content exists from 3 to 6 wt.%. [ABSTRACT FROM AUTHOR]

Abstract: Composition modulated Bi2Te3 thin films have been deposited onto stainless-steel substrates using a potentiostatic or a galvanostatic process. The deposition potentials and current densities for different bath compositions and concentrations have been estimated from voltamperometric curves. Solutions with two Bi/Te ratios were studied. Only Bi3+ and HTeO2 + solutions in the volumetric proportion of 1:1 with equimolar solution concentrations of 0.01, 0.015 or 0.02M allow one to obtain films with an excess or a deficiency of Bi in relation to stoichiometric Bi2Te3 (Bi=40at%, Te=60at%) by changing the deposition potential or the current density. The structure and the morphology of films have been studied as a function of the electrolyte concentration and the deposition conditions. [Copyright &y& Elsevier]