Electrolytic Bath Research Articles

Physico-chemical studies of Cd1−xZnxS thin films produced by simple two-electrode electrodeposition system for solar cell application

Cd1−xZnxS thin films have been cathodically electrodeposited on glass/fluorine-doped tin oxide substrates using a low-cost two-electrode configuration with an electrolytic bath containing cadmium chloride, zinc chloride and sodium thiosulphate precursors. The deposition was carried out by varying zinc chloride concentration (0 M, 0.3 M, 0.6 M and 0.9 M) in the deposition electrolyte. The structural, compositional, phonon vibrational, morphological and optical properties of the resulting films have been characterized using glancing incidence X-ray diffraction, energy-dispersive X-ray (EDX) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM) and UV–Vis spectrophotometry respectively. The XRD result indicates the existence of hexagonal structure of Cd1−xZnxS with intensities of the diffraction peaks decreasing as more Zn is incorporated into the film as a result of decrease in deposition rate. EDX results show the presence of Cd, Zn and S in the deposited Cd1−xZnxS thin films. SEM images show uniform and densely packed surface morphology of the films with distinct shaped grains which gradually less distinct as more Zn is incorporated into the films. The optical measurements reveal a significant increase in energy band gap of the Cd1−xZnxS material as more zinc is incorporated into the films and a film thickness decreases with the energy band gap increasing from 2.40 eV for CdS to 2.62 eV for Cd1−xZnxS. These results show that Cd1−xZnxS material can be applied as a better window material for CdTe, CIG(S,Se) and CZTS-based solar cells than CdS.

Spatially Resolved Chemical Detection with a Nanoneedle-Probe-Supported Biological Nanopore.

In this article, we describe the quantitative characterization of a gold nanoneedle ion channel probe and demonstrate the utility of this probe for spatially resolved detection of a small molecule using ion channel activity. Our report builds on recent reports of Ide and co-workers, who reported the use of an etched gold wire modified with a poly(ethylene) glycol monolayer as a support for a lipid bilayer and subsequent single ion channel recordings. Although this nanoneedle electrode approach was reported previously, in our report, we investigate the effects of several operational parameters on the performance of the ion channel measurement and electrochemical phenomenon that occur in the nanoconfined space between the supported bilayer and the gold electrode. More specifically, we address the effects of length of the supporting monolayer and the composition of the electrolyte baths on channel current measurements and provide a quantitative description of what carries current at the working electrode (double-layer charging). In addition, we demonstrate the ability to control the direction of protein insertion (tip side vs bath side) with freely diffusing protein, which has not been previously reported, with the former method (tip side) enabling single-molecule detection of β-cyclodextrin (βCD) using a reconstituted α-hemolysin channel. Finally, anticipating future use of a nanoneedle-based biological nanopore probe in a scanned-probe microscopy, we demonstrate the ability to quantify and spatially resolve the concentration of βCD molecules in a microfluidic channel. We believe, in the long term, the described nanoneedle-based biological nanopore probe can be employed in, for example, scanning ion conductance microscopy using ion channels.

Development and relative comparison of polypyrrole-calcium phosphate composite coatings with differential concentration of chlorophyll functionalized polymer particle achieved through pulsed electro deposition

Polypyrrole-calcium orthophosphate-hydroxyapatite functional composite coating is synthesized over the metallic implant surfaces through pulsed electrochemical deposition. Polypyrrole particles are photo-functionalized with the help of chlorophyll during polymerization for their dispersion in the aqueous electrolyte bath. In-situ formation of calcium phosphate phases along with co-deposition of chlorophyll functionalized-polypyrrole particles lead to formation of a ceramic-polymer composite coating. Concentration of chlorophyll molecule in the solution greatly affects the polymerization reaction and subsequent incorporation of functionalized polymer in final coating. Thus, various types of composites structures are developed based on differential amount of polypyrrole presence through varying concentration of chlorophyll, for a detailed comparative study. The polymer chain length and formation bond energy significantly influence the in-situ formation mechanism along with crystal growth direction and rate of formation of various calcium phosphate phases. At low concentration, polymer reinforced hydroxyapatite flakes are formed. High concentration of chlorophyll lead to formation of both the individual polymer phase along with polymer reinforced calcium phosphate phase. While at very high concentration, a polymer layer is formed reinforced with nanocrystalline hydroxyapatite particles. Reinforced coating exhibits three fold higher electrochemical corrosion resistances as compared to bare hydroxyapatite coating. All the coating surfaces display superior osteoconduction capabilities through the formation of stoichiometric hydroxyapatite spherical particles within 7 to 14 days of contact. During osteoconduction, a unique nano porous honeycomb structure over the formed apatite surface enriched with sodium and magnesium ions are formed which would help to ensure higher protein absorption along with a better bonding of cells over the coating surface. Thus, this ceramic-polymer composite developed for the first time through chlorophyll functionalization, can act as one of the potential materials for improvement of both bio-functionalities and corrosion resistance of metallic implant surfaces.

METHOD FOR ASSESSING SURFACE QUALITY OF COPPER CATHODES

In order to stabilize spiral elongation number at the required level (in accordance with the requirements of the European standard EN 12893 not less than 400 mm) the assessment of its distribution on the cathode sheet was carried out. The experimentally obtained results, processed using methods of mathematical statistics, showed significant discrepancies between the values of spiral elongation in the central and other parts of the cathode (upper, lower, side), which indicates an uneven distribution of the spiral elongation number along the cathode sheet. It was found that in order to form a representative analytical sample under cathode copper production of the Polar Division of MMC «Norilsk Nickel», the testing of cathodes should be performed using methods that include all areas of the cathode sheet, for example, cutting of a vertical strip from each cathode which has got in a representative sample, including edges and hanging ears. To determine the dependence of the spiral elongation number on the surface quality of copper cathodes, developed a special technique, based on the detection of the most frequently encountered defects in the surface of the cathode sheet, which assigned a certain numerical value in accordance with the ranking results. The proposed scoring system for the quality of cathodes in appearance allowed us to establish for the first time that stabilization of the spiral elongation number at a level of at least 400 mm is possible if the defectiveness of the cathode surface does not exceed 17 points per one electrolysis bath. The method has found practical application for preliminary quantitative estimation of the most widespread superficial defects of copper cathodes in the conditions of current production.

Physicochemical characterization of PEG-modified PbO2 coatings electrodeposited from a methanesulfonate bath

This study explores the preparation and application of polyethylene glycol (PEG)-modified PbO2 electrodes. The PEG-modified PbO2 coatings were electrodeposited on a Ti/SnO2-Sb substrate from a methanesulfonate electrolytic bath containing different amounts of PEG. Structural and morphologic characterization was carried out for the deposited electrodes. The presence of PEG in the deposition bath represses the nucleation process and grain growth process in PbO2 deposition. Increasing PEG addition results in an increased [Formula: see text]-PbO2 content and decreased crystallite size. At a limited PEG addition [Formula: see text]4 g/L, a rough and pyramidal surface morphology is presented in the PbO2 coatings. A higher PEG addition at 6 g/L leads to a dense and smooth coating surface yet with less uniformity. Electrochemical characterization reveals a great electrocatalytic activity for the modified PbO2 electrodes when the PEG addition is [Formula: see text]4 g/L.

Optical and Morphological Studies of Electrodeposited CdS Thin Film Grown at Different Deposition Times from Acetate Precursor

Electrodeposited cadmium sulfide (ED-CdS) thin films were prepared on fluorine-doped tin oxide (FTO) substrate at six different deposition times in order to study the impact of deposition time on their properties for possible solar cell application. The deposition was carried out from an electrolytic bath containing cadmium acetate Cd(CH3COO)2 and sodium thiosulfate (Na2S2O3) using simple two electrode configuration. The deposition time was varied at 30, 40, 50, 60, 70 and 80 minutes. The corresponding optical, morphological, surface roughness, compositional and structural properties of the deposited films were characterized using UV-Vis spectroscopy, scanning electron microscopy (SEM), scanning probe microscopy (SPM), energy dispersive X-ray spectroscopy (EDS) and glancing incidence X-ray diffraction (GIXRD) respectively. The results show that, the estimated energy band gaps were in the range of 2.35 to 2.20 eV as deposition time increases, for as-deposited films and 2.38 to 2.30 eV for annealed films. SEM images show very compact and agglomerated spherical grains. From SPM measurements it is observed that, the surface roughness ranges from 2.51 nm to 2.73 nm for as-deposited samples and 1.76 nm to 2.15 nm for annealed ones. EDS shows that the films are cadmium-rich in both as-deposited and annealed conditions.

Growth of a Pure and Single Phase Iron Sulfide (Pyrite) Thin Film by Electrochemical Deposition for Photovoltaic Applications

Single phase iron pyrite (FeS2) films have been successfully deposited on ITO-coated glass substrates using a 3-electrode electrochemical system with graphite as the counter electrode and Ag/AgCl as the reference electrode. In this single-step electrodeposition, the FeS precursor thin film was directly electrodeposited on the conductive substrate from the electrolytic bath solution which contained FeSO4.7H2O as an iron source, and Na2S2O3.5H2O as a sulfur source. The deposition was carried out potentiostatically at a constant potential of -0.9 V vs. Ag/AgCl at room temperature. The growth of the iron pyrite phase was achieved by annealing the as-deposited at 500°C for an hour in an ambient of sulfur to form the pyrite phase. For sulfurization, two different techniques, one using the Kipp’s apparatus and a second, which involved heating elemental sulfur at 200°C, were used for the production of the sulfur gas. X-ray diffraction analyses of the sulfurized films showed that both sulfurization techniques appeared to form the pyrite phase, however, the second method yielded films with maximum crystalline order and stoichiometry with no discernable impurity peaks. Optical absorption measurements revealed the existence of a direct transition with an estimated band gap of 1.75 eV. SEM micrograph showed a compact morphology with a rough surface made up of crystallites of irregular shapes and sizes with well-defined edges, covering the entire substrate. EDAX analysis of the film was consistent with the formation of FeS2 pyrite thin films.

Electrodeposition of Single Phase SnS Thin Films: Effect of Electrolytic Bath Temperature on the Final Film Properties

In this article, the electrodeposition of single-phase tin monosulfide (SnS) films at different electrolytic bath temperatures is studied. The electrodeposition was carried out potentiostaticaly onto transparent conductive substrates (fluorine-doped tin oxide, and indium tin oxide on a glass substrate) from an acidic solution of SnSO4 and Na2S2O3 as tin and sulfur precursors, respectively. The films were characterized through different techniques: field-emission scanning electron microscopy, energy dispersive X-ray analyses, X-ray diffraction measurements, profilometry, Raman spectra, UV-vis measurements, electrochemical impedance spectroscopy and linear sweep photovoltammetry. The films obtained were stoichiometric and no other phases different from SnS were evidenced. A change in the morphology from cubic-like to sheet-like was observed with an increase of bath temperature, which was reflected in the texture coefficient obtained from X-ray diffraction analyses. The bandgap of the films was obtained using a direct absorption edge in the Tauc plots. A decreasing bandgap with electrodeposition temperature was observed, which is attributed to an improvement in the crystallinity of the films. Mott-Schottky plots and linear sweep photovoltammetry measurements confirmed that the films are p-type semiconductors. An increase in the photocurrent of the photoelectrodes was observed with the electrolytic bath temperature, which is attributed to the change of SnS morphology with the electrodeposition temperature.

Microstructure-electrochemical property correlation in electrodeposited CuFeNiCoCr high-entropy alloy-graphene oxide composite coatings

ABSTRACTThis study investigates the microstructure-electrochemical property correlation in high-entropy alloy-graphene oxide (HEA-GO) composite coatings. HEA coating containing Cu, Fe, Cr, Co, and Ni was electrodeposited over mild steel. Graphene oxide (GO) content in the coating was varied by changing the amount of GO in the electrolyte bath during the electrodeposition. Corrosion behaviour of the coatings was examined through potentiodynamic polarisation and electrochemical impedance spectroscopy methods. It was observed that with an increase in the GO amount, the corrosion resistance of HEA-GO composite coatings progressively increased. Microstructural charaterisation, using the transmission electron microscopy technique, revealed that the addition of GO enhanced the amount of Cr in the coatings and also produced a layered microstructure with Cu and Cr-rich layer covering the coating surface. Both these factors along with the impermeability of GO facilitated enhancement in the corrosion resistance. Major application areas that require protective coatings over mild steel are oil and gas pipe lines, structural components exposed to marine environments, automobiles, industrial cleaning, etc.

Magnesium Incorporation in n-CdTe to Produce Wide Bandgap p-Type CdTe:Mg Window Layers

In order to develop wide bandgap p-type window materials to use in graded bandgap devices, the effects of magnesium (Mg) in n-CdTe layers were explored. In this work, magnesium-incorporated cadmium telluride (CdTe:Mg) layers were electroplated using two-electrode method. The layers were deposited on glass/FTO (flourine doped tin oxide) substrates, using an aqueous solution containing Cd2+, Mg2+ and tellurium dioxide (TeO2) as the precursors. X-ray diffraction (XRD) studies indicate the reduction of crystallinity as the Mg concentration is increased in parts per million (ppm) level. Material becomes a completely amorphous layer at high Mg concentrations in the electrolytic bath. Photoelectrochemical (PEC) measurements show the gradual reduction of n-CdTe turning into p-CdTe layers when Mg concentration is increased in the electrolyte. Optical absorption measurements show the expansion of energy bandgap from CdTe bandgap (~1.48 eV) up to ~2.85 eV. The other characterisation results (energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL)) are also explored and presented together with above experimental results.

3D nickel foams with controlled morphologies for hydrogen evolution reaction in highly alkaline media

Water electrolysis is the cleanest method for hydrogen production, and can be 100% green when renewable energy is used as electricity source. When the hydrogen evolution reaction (HER) is carried out in alkaline media, nickel (Ni) is a low cost catalyst and an interesting alternative to platinum. Still, its performance has to be enhanced to meet the high efficiency of the nobler metals, an objective that requires further tailoring of the surface area and morphology of Ni-based electrode materials. Unlike commercially available porous Ni, these features can be easily controlled via electrodeposition, a one-step process, taking advantage of the dynamic hydrogen bubble template (DHBT). Generally, changes in surface porosity and morphology have been mainly achieved by altering the main parameters, such as the current density or the deposition time. However, very scarce work has been done on the role of supporting electrolyte (i.e., its concentration and composition) in tailoring the foam features and consequently their catalytic activity. Hence, this approach paves the way to optimum design of metallic foam structures that can be obtained only with modifications in the electrolytic bath. In this work, 3D Ni foams are obtained from different composition baths by galvanostatic electrodeposition in the hydrogen evolution regime on stainless steel current collectors. Their porosity and morphology are analysed by optical microscopy and SEM. The electrochemical performance is evaluated by cyclic voltammetry, while catalytic activity towards HER and materials’ stability in 8 M KOH are tested using polarisation curves and chronoamperometry measurements, respectively. The recorded high currents and extended stability of the Ni foams with dendritic morphology demonstrate its outstanding performance, making it an attractive cathode material for HER in highly alkaline media.

An Ex-ante LCA Study of Rare Earth Extraction from NdFeB Magnet Scrap Using Molten Salt Electrolysis

A new recycling process for the extraction of rare earths from neodymium–iron–boron (NdFeB) magnet scrap is being developed, based on the direct extraction of rare earths from end-of-life magnet material in a molten fluoride electrolysis bath. Rare earths are required in their metallic form for the production of new NdFeB magnets, and the suggested process achieves this through a single step. The process is being developed on a laboratory scale and has been proven to work in principle. It is expected to be environmentally beneficial when compared to longer processing routes. Conducting life cycle assessment at R&D stage can provide valuable information to help steer process development into an environmentally favorable direction. We conducted a life cycle assessment study to provide a quantitative estimate of the impacts associated with the process being developed and to compare the prospective impacts against those of the current state-of-the-art technology. The comparison of this recycling route with primary production shows that the recycling process has the potential for much lower process-specific impacts when compared against the current rare earth primary production route. The study also highlights that perfluorocarbon emissions, which occur during primary rare earth production, warrant further investigation.

Corrosion properties of mild steel surface modified by bright Zn-Co alloy electrodeposit from acetate electrolytic bath

The zinc-cobalt (Zn-Co) alloy coatings were electrodeposited on mild steel using acetate electrolytic bath at various current densities. The corrosion behaviour of the Zn-Co alloys was determined in a 3.5% sodium chloride solution. Highest corrosion protection efficiency with corrosion rate of 7.33 mpy was obtained at Current density 4.0 A.dm−2. The effect of current density with temperature, throwing power, corrosion behaviour and surface morphology of the deposits were discussed. The surface texture and hardness of the deposit were investigated by scanning electron microscopy (SEM) and Vickers hardness tester. The surface morphology of an alloy deposit depends mostly on the presence of cobalt in the alloy deposit. The XRD pattern has shown the η-phase orientation of (110) plane and the peak intensity were hugely increased with Co content in the deposit.

Characterization of a zinc-nickel alloy coating obtained from an electrolytic bath produced with spent batteries as raw materials

Alkaline and Ni-MH spent batteries contain heavy metals such as zinc and nickel that may affect the environment. Such materials can be used for the manufacturing of Zn-Ni anticorrosive coatings, which have better behavior against corrosion than the traditional galvanized steel. In this work, spent alkaline and Ni-MH batteries were disassembled, to extract the metals of interest. The electrode powders extracted from these batteries were leached, by separate, in ammonia plus citric acid solutions. Once the pregnant solutions were chemically analyzed to determine the concentration of zinc and nickel, an alkaline electrolytic bath was prepared with a mass proportion of 2:1 Zn-Ni. A potentiostatic deposition over low carbon steel was made using this bath. Then, the morphology and composition of the obtained coating was analyzed by scanning electron microscopy (SEM-EDS) and finally the electrochemical stability of the coating in 3.5 wt % of NaCl solution was evaluated by the following techniques: open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV). SEM results show a homogeneous, compact and adherent coating on steel and the electrochemical tests indicated that the properties of the galvanized coating were improved by the addition of 8.92 wt % of nickel.

Electrodialytic remediation of fluorine contaminated soil using 2-electrolysis compartment

ABSTRACTFluorine pollutants, emitted from numerous anthropogenic actions, can enter the surrounding environment and lead to soil pollution by fluorine. The aim of this study is to evaluate the remediation possibility and efficiency of fluorine contaminated soil by EDR (electrodialytic remediation) with the 2-electrolysis compartment, compared to EDR with 3-electrolysis compartment. Four runs of EDR experiments were carried out using the 3-compartment (run A, run C) and 2-compartment electrolysis bath (run B, run D). Important electrodialytic parameters such as electric current, electroosmotic flow, the removal efficiency and energy consumption were investigated. The results showed that the removal efficiency of fluorine in run A, B, C and D was 61.6%, 80.5%, 49.1% and 58.8%, respectively. And 2-electrolysis compartment positively affected the fluorine removal because of higher electric current and soil pH, which led to more desorption of F ions from the contaminated soil and more electro-migration of F ions into the electrolyte, but 2-electrolysis compartment consumed more energy (run A: 0.13 kwh kg−1, run B: 0.24 kwh kg−1, run C: 0.08 kwh kg−1 and run D: 0.12 kwh kg−1). After EDR, fluorine of contaminated soil was mainly bound to stable and low toxic RESF (the residual fraction of fluorine).

Application of Evolutionary Rietveld Method Based XRD Phase Analysis and a Self-Configuring Genetic Algorithm to the Inspection of Electrolyte Composition in Aluminum Electrolysis Baths

The technological inspection of the electrolyte composition in aluminum production is performed using calibration X-ray quantitative phase analysis (QPA). For this purpose, the use of QPA by the Rietveld method, which does not require the creation of multiphase reference samples and is able to take into account the actual structure of the phases in the samples, could be promising. However, its limitations are in its low automation and in the problem of setting the correct initial values of profile and structural parameters. A possible solution to this problem is the application of the genetic algorithm we proposed earlier for finding suitable initial parameter values individually for each sample. However, the genetic algorithm also needs tuning. A self-configuring genetic algorithm that does not require tuning and provides a fully automatic analysis of the electrolyte composition by the Rietveld method was proposed, and successful testing results were presented.

A highly selective and sensitive colorimetric chemosensor based on polyurethane foam impregnated with 3-methyl-2, 6-dimercapto-1,4-thiopyrone for on-site preconcentration and determination of palladium(II)

ABSTRACTA new sorbent and chemosensor for highly selective and sensitive on-site preconcentration and colorimetric determination of Pd(II) was developed based on its reaction with 3-methyl-2,6-dimercapto-1,4-thiopyrone (MDT) immobilised onto polyurethane foam (PUF). Complexation of Pd(II) with MDT sorbed on PUF tablets leads to a contrast change in the sorbent colour from pale yellow to reddish-brown. The developed chemosensor is highly selective with respect to the transition and platinum group metals. It has a maximum sorption capacity of 17 µmol g−1 for Pd(II). Reaction is possible in a strongly acidic medium (up to10 M HCl), and the properties of the chemosensor do not change during storage for a long time. The colorimetric response of the chemosensor was measured using red–green–blue (RGB) colour model. The dependence of the luminosity of the G channel on the Pd(II) concentration was linear in the concentration range from 0.3 to 64 µg L−1 with a detection limit of 0.1 µg L−1 (R2 = 0.997). The colour scale for visual detection of Pd(II) was constructed in the concentration range of 0.02–0.64 mg L‒1 for the sorption from 20 mL of an aqueous sample. The accuracy of the developed methods was assessed by the analysis of a certified reference material (platinum–palladium alloy) and by comparison with the results of gravimetric or graphite furnace atomic absorption spectrometry (GFAAS) determination of Pd. The developed method was successfully applied to determine Pd in samples of mine water and road dust, in the electrolyte bath and in the sewage sludge of a palladium electroplating bath.

Layered Nickel-Cobalt Oxide Coatings on Stainless Steel as an Electrocatalyst for Oxygen Evolution Reaction

In this work, we have obtained spinel-type nickel-cobalt oxide nanostructures on low-cost and easy-handling AISI304-type stainless steel substrate via simple potentiostatic electrodeposition. Nickel and cobalt hydroxide layers were formed by varying the deposition potential at the same time intervals (− 1.15 V for Ni(OH)2 and − 0.85 V for Co(OH)2). An electrolyte bath containing 0.05 M Ni(NO3)2, 0.05 M Co(NO3)2, and 0.1 M KNO3 was used for the electrodeposition. Structural analysis confirmed the formation of a spinel NiCo2O4 after thermal treatment. The influence of annealing temperature in the range of 473–1073 K on the films activity in OER has been investigated using 0.1 M NaOH. Nickel-cobalt oxide coatings demonstrated OER activity close to the benchmark IrO2 with the onset potential value of + 1.6 (vs. RHE), overpotential of 530 mV at 10 mA cm−2, and Tafel slope of 49 mV dec−1. Meanwhile, the electrocatalytic activity of separate Co3O4 and NiO is far smaller.

ALTERNATIVE VERSION ON THE NATURE OF THE ANODE EFFECT IN ELECTROLYSIS OF CRYOLITE-ALUMINOUS MELTS

The paper gives prove the new hypothesis concerning the causes of the anode effect, which is manifested in the electrolytic production of aluminum. The nature of the anode effect is contradictory. The first version of the causes of its origin is based on the notions of the determining influence of the surface tension change on the boundary of the melt with a graphite electrode. The second version explains the increase in the operating voltage and sparking on the electrolyzer by the formation of the low conductive layer of the non-fluoride compounds with low wettability on the electrode surface. The new hypothesis is based on the taking into account the composition change of the electrolyte anode layer and the formation of cryolite-aluminous melt layer on the surface of the electrode. For its substantiation, the estimating calculations taking into account the density of the anode current in electrolysis and the dynamics of voltage increase on the electrolysis bath in the period between two anode effects have been carried out in the paper. Based on the provisions of the theory of mass transfer in near-electrode layers at the direct current flow, as well as Maxwell relations, describing the electrical conductivity of heterogeneous systems, the possibility of a heterogeneous phase formation at the electrode surface with electrical conductivity which is at least two orders lower than that of the initial cryolite-aluminous melt has been shown. The considered version does not contradict the phenomenon of the gaseous shirt formation around the anode, because the determining factor of this is not the wettability of electrode in the melt, but the consistency of the near-electrode layer of the electrolyte. Unlike other versions, it also explains the progressive voltage growth on the electrolysis just before the anode effect.

The influence of Mo addition on the microstructure and its thermal stability for electrodeposited Ni films

An investigation was conducted to study the effect of molybdenum (Mo) alloying on the grain size and lattice defect structure in nanocrystalline nickel (Ni) films processed by electrodeposition. Moreover, the influence of saccharin addition to the electrolyte bath on the microstructure of Ni-Mo layers with low and high Mo contents was studied. It was found that the higher Mo content resulted in a larger dislocation density and twin fault probability as well as a smaller grain size. The addition of saccharin to the bath resulted in a further increase in the density of both dislocations and twin faults. It was also revealed that Mo alloying improved the thermal stability of the nanostructure in Ni films while saccharin addition yielded a reduction of stability. The reasons for these opposite behaviors were discussed in detail. In addition, the defect structure and its stability in Ni-Mo layers were compared with that for fine-grained bulk samples with the same composition but processed by severe plastic deformation.