Co-deposition Of Nanoparticles Research Articles

Pulse electrodeposition of a duplex-layer structured composite nickel-based coating with improved corrosion and abrasion resistance

In this study, a dual amorphous/crystalline nanocomposite coating of Ni–P/Ni–Mo–ZrO2 was designed and successfully deposited on pure copper substrates by pulse electrodeposition. The design of the Ni–P/Ni–Mo–ZrO2 dual coating takes advantage of the properties of the different structures and incorporates second phase reinforcing particles resulting in more comprehensive protective coatings. The surface morphology and microstructure were evaluated by SEM, EDS, WLI, XRD and TEM. The mechanical properties and electrochemical behaviors of the coating in a 3.5 wt% NaCl solution were investigated by wear tests, Tafel and EIS. The results show that the Ni–P/Ni–Mo and Ni–P/Ni–Mo–ZrO2 dual coatings are uniform, dense and crack-free, and the duplex interface is homogeneous. Compared with the Ni–Mo coating, the average friction coefficient and wear rate of the Ni–P/Ni–Mo duplex coating decreased to 0.18 and 5.433 × 10−4 mm3/N·m, respectively. The corrosion potential is positively shifted to −0.43 with a maximum impedance of 308 kΩ cm2. The mismatch of the interlayer defects causes a deviation in the corrosion path, resulting in a transformation from longitudinal pinhole corrosion into extended transverse corrosion, which effectively strengthens the capacity of the coating for corrosion resistance while maintaining the high hardness of its outer coating. Furthermore, the hardness of the dual Ni–P/Ni–Mo coating can be obviously reinforced by nanoparticles from 730 HV to 810 HV, the corrosion potential is shifted to −0.41 V, and the corrosion current density decrease to 7.7803 × 10−7 A/cm2. The improvement in the mechanical properties can be attributed to the ZrO2 nanoparticles, which could carry stress and transfer loads during the wear process. Meanwhile, the ZrO2 nanoparticles can reduce the nodule size by filling the binding boundary which is the main corrosion path, and reduce the number of surface defects, such as pinholes, which leads to a lower corrosion rate. In addition, the corrosion inhibition and nanoparticle codeposition mechanisms of the duplex coatings were further discussed.

Construction of Metal Hydrate-Based Amorphous Magnetic Nanosheets for Enhanced Protein Enrichment and Immobilization.

Inspired by the hierarchical fabrication technique, many self-assembly procedures have improved the construction of nanomaterials with unique physicochemical characteristics and multiple functions. The generation of multiple complexes is always accompanied by hierarchical structures and intriguing properties that are distinct from their individual segments. An interesting composite is amorphous magnetic Zn-Zr phosphate hydrated nanosheets (Zn-Zr APHNs), generated using templated synthesis and nanoparticle codeposition. The special porous structure of this construct, together with the abundance of metal ions and hydrate present, endows it with many interaction sites for proteins, provides high loading efficiency, and enhances bioactivity. Then, a series of proteins, including enzymes, was immobilized by the Zn-Zr APHNs by multiple interactions, high ionization, and larger surface of the nanosheets. In this study, novel methods for the enrichment of bioactive proteins while retaining the activity of protein payloads are presented. As a verification method, it is indicated that the Zn-Zr APHNs can deliver enzyme proteins (i.e., Cyt-c) to increase the catalytic activity with their biological function and structural integrity, resulting in a highly increased activity to free proteins.

Improvement of microstructure and properties of Ni–Al2O3 composite coating via jet electrodeposition

Ni–Al2O3 composite coatings were prepared with a modified Watt’s bath by using jet electrodeposition method. As the key process parameter, current density and the addition of Al2O3 nanoparticles in electrolyte were studied about the effect on the surface morphology and co-deposition of Al2O3 nanoparticles of composite coating. The mechanical and tribological properties of the composite coating were also tested. The results show that properly increasing the current density and Al2O3 addition can increase the co-deposition of nanoparticles in the coating and promote the formation of a dense and refined coating structure. Using the optimized process parameters of current density (300 A/dm2) and Al2O3 addition (30 g/L), the co-deposition of Al2O3 in the composite coating can reach a maximum of 13.1 at.%. The hardness of the coating reaches the peak at 623 HV. The wear rate of the composite coating is also greatly reduced with optimized parameters.

Effects of deposition parameters on the microstructure and properties of Jet-electrodeposited Ni-La2O3 composite coatings

By adding La2O3 nanoparticles in the electrolyte, Ni-La2O3 composite coatings were prepared with a modified Watt’s bath by using jet electrodeposition method. The effects of process parameters on the surface morphology, phase structure, and co-deposition of La2O3 nanoparticles of composite coating were studied. The mechanical and tribological properties of the composite coating were tested. The results show that appropriately increasing the jet velocity and increasing the cathode current density can help to increase the co-deposition of nanoparticles in the coating and promote the formation of a dense and refined coating structure. Using the optimized process parameters such as current density of 80 A/dm2 and jet velocity of 10 m/s, the co-deposition of La2O3 nanoparticles in the composite coating can reach a maximum of 3.6 wt%. The hardness and the tensile strength reach their peaks at 620 HV and 1180 MPa. The wear rate of the composite coating also greatly reduces with optimized parameters.

Structure and Phase Composition of Sputtered Films of Hafnium–Carbon Alloys

Ion-plasma sputtering and codeposition of ultrafine particles of hafnium and carbon were used to produce film coatings in the concentration ranges of 5.3–59.8 at % C. Structural investigations revealed the existence of Hf–C solid solutions in the concentration range of 5.3–11.5 at % C. In the concentration range of 21.5–59.8 at % C, the coatings consist of the hafnium-carbide phase; and at 16.2 at % C, both phases coexist. The lattice parameters of the phases present in the films and their variation depending on the carbon concentration have been determined. The dependence of the HfС lattice parameter in the range of 16.2–35.0 at % C on the nature of the substrate on which the coating is deposited has been established. The solid solutions of carbon in hafnium exhibit conductivity of metallic type; the resistance of the hafnium carbide almost does not change upon cooling from 300 to 11 K. The direct synthesis of hafnium carbide HfC by a codeposition of nanoparticles on the surface of products can be used as a technological method.

The Anticorrosive and Antifouling Properties of Ni-W-P-nSiO2 Composite Coating in A Simulated Oilfield Environment

Aiming at the problem of tubing corrosion and scaling in the oilfield environment, the corrosion and scaling behaviour of nickel-tungsten-phosphorus-silica (Ni-W-P-nSiO2) composite coatings prepared on L245 is investigated by immersion test, electrochemical measurement and static scaling test. The results indicated that the corrosion rate of Ni-W-P coating (0.1075 mm a−1) was higher than that of Ni-W-P-nSiO2 coating (0.0552 mm a−1), consistent with the results of corrosion current density (icorr). It was also found that the compact corrosion product film that forms on the Ni-W-P-nSiO2 coating consists of Ni3S2 and FeO. The average scaling rate and calcium loss rate value of the Ni-W-P-nSiO2 coating (2.43 × 10−6 g cm−2 h−1, 0.0344−2 cm−2) were both lower than those of the Ni-W-P coating (1.53 × 10−5 g cm−2 h−1, 0.0542 cm−2), which indicates that SiO2 nanoparticle co-deposition in Ni-W-P coating with the contact angle of 93.71° can improve its antifouling property.

Multifunctional HA/Cu nano-coatings on titanium using PPy coordination and doping via pulse electrochemical polymerization.

The incorporation of hydroxyapatite nanoparticles onto the surface of titanium is an effective method to improve its osteoinductive ability. However, there are still issues with the hydroxyapatite nanoparticle coatings fabricated using current methods, such as particle aggregation and unsatisfactory binding ability with the matrix, in addition to the difficulties in the multi-functionalization of antibacterial, anti-wear and bioinductive ability. In the present study, we propose a strategy to fabricate a refined hydroxyapatite nanoparticles/copper nanoparticles co-deposition titanium matrix by the mediation of pulse electrochemical polymerized pyrrole through its coordination and doping of cations and anions. During this process, PO43- in the electrolyte is doped into the corresponding anion structure in the polypyrrole chain and forms HA with Ca2+ and OH- because of electrostatic interaction. The bioactivity investigation indicates that the composite coatings are able to induce the formation of apatite in supersaturated calcium phosphate solution. Furthermore, the friction and wear tests show that the composite coatings improve the friction properties of the material to a certain extent. The composites also exhibit an antibacterial rate of 97% in the antibacterial test. Finally, in virtue of the dual regulation of polypyrrole by coordination and doping, we successfully fabricate multifunctional hydroxyapatite/copper nano-coatings on titanium surfaces.

Effects of Silica Nanoparticle Co-Deposition on Macrothrowing Power of Zinc-Nickel Alloy Plating from an Acid Sulfate Bath

Effects of Silica Nanoparticle Co-Deposition on Macrothrowing Power of Zinc-Nickel Alloy Plating from an Acid Sulfate Bath

(Research Award of the Electrodeposition Division) Mathematical Modeling in Electrodeposition Studies

Mathematical modeling has a long history in electrodeposition. The modeling may range from current distribution simulations for the design of electrochemical cells to molecular modeling for the design of next-generation additives. In other instances, modeling is used for data analysis, for troubleshooting, and for more efficient design of experiment. In some cases, models create value by providing a framework to communicate in interdisciplinary or industrial settings, as a means of protecting intellectual property or as means of explaining to the uninitiated the role of plating-bath constituents. While models of the impact of transport phenomena on current distribution, may be quite straightforward, models involving reaction mechanisms can be highly controversial. Because of the inherent complexity of electrodeposition processes, modeling efforts are often tightly coupled to experiments, and it is rare that a model can explain all or even most experimental observations. Crafting a model requires a deep understanding of which experimental observations are most relevant to the business or technological goals. We discuss some of our past experience in modeling electrodeposition systems. We briefly discuss work and practical uses of modeling additives in Cu electrodeposition, a process in which a tremendous understanding is available due to its commercial importance. We then discuss multi-scale modeling of electrochemical nucleation and its impact on current distributions on resistive substrates. As a final example, we discuss the role of relatively primitive modeling in understanding the co-deposition of nanoparticles and microparticles with nickel.

Fabrication and Characterization of Electrodeposited Ni–SiC–h/BN Composite Coatings

Ni–SiC–h/BN composite materials were prepared by electrodeposition technique with the dispersion of SiC (10 g/L) and h/BN nanosheets (10 g/L) in a nickel sulfamate electrolytic bath. Different ratio of sodium dodecyl sulfate (SDS) and cetyltrymethyl ammonium bromide (CTAB) surfactants were used to evaluate the effect of surfactants on the properties of the electrodeposited composite coatings. The coating samples were characterized by scanning electron microscopy, X-ray diffraction, Vickers microhardness test, scratch and tribology tests. The results revealed that the co-deposition of nanoparticles was significantly influenced by surfactants during electrodeposition process. Pyramidal or polyhedral nickel crystallites were observed at higher ratio of SDS/CTAB while smaller oval grains with refined surface morphologies were obtained at lower ratio of SDS/CTAB surfactants. In addition, wt% of particles co-deposition was increased, and Vickers microhardness, wear and coefficient of friction of the electrodeposited composite coatings were improved at increased CTAB and decreased SDS contents in the electrolyte during electrodeposition process.

硫酸酸性浴による亜鉛-ニッケル合金めっきの均一電着性に及ぼすシリカナノ粒子共析の影響

硫酸酸性浴による亜鉛-ニッケル合金めっきの均一電着性に及ぼすシリカナノ粒子共析の影響

Codeposition mechanism in Sn/Ag nanoparticle composite plating

Mechanism of the Ag nanoparticle codeposition in Sn/Ag–nanoparticle composite plating was studied using a rotating disk electrode. The bath chemistry of the Ag–nanoparticle/Sn2+–pyrophosphate colloidal solutions and the kinetics of the Sn matrix deposition were also discussed. The dialysis experiments of the plating baths showed that the composition of the Ag nanoparticles were stoichiometric, AgSn0.54+(NP), and that their structure was Ag core/Sn4+–pyrophosphate complex shell type. The current density–potential relationships of the Sn matrix deposition showed a two-step features. The first current plateau at around −1.4V vs. Ag/AgCl was related to the diffusion limited current of SnP2O72−. The Ag codeposition rate was controlled by Tafel kinetics and reached the diffusion limited values, showing that the codeposition rate of the AgSn0.54+(NP) is controlled by electrochemical reactions. The electrochemical kinetic parameters and the diffusion coefficient of the AgSn0.54+(NP) were estimated by fitting the experimental data to the Tafel equation taking into account the concentration of the electroactive species at the cathode. The diameter of the AgSn0.54+(NP) was calculated to be 4.2nm by substituting the diffusion coefficient estimated here into the Einstein–Stokes equation. The diameter was agreed with the results from the transmission electron microscope examination and the small angle X-ray scattering analysis.

Corrosion behavior of Cu–SiO2 nanocomposite coatings obtained by electrodeposition in the presence of cetyl trimethyl ammonium bromide

Copper silica composite coatings are an attractive alternative to chromium and nickel coatings in order to avoid environmental problems and for application in electrical devices. However, co-deposition of SiO2 particles with metals occurs to a rather limited extent, generally under 1%, due to the hydrophilicity of SiO2, which makes the incorporation of particles in a metallic matrix difficult. To overcome this drawback, the influence of cetyl trimethyl ammonium bromide (CTAB) on the deposition and corrosion behavior of Cu–SiO2 coatings on steel has been studied. It was established that CTAB plays a beneficial role in SiO2 suspension stabilization, promotes the co-deposition of nanoparticles in the copper matrix and improves the deposit morphology and structure. Consequently, a higher corrosion resistance of Cu–SiO2 deposits obtained in the presence of CTAB was noticed. The most important effect was observed in the case when CTAB was used in concentration of 10−3 M in the electroplating bath.

Homogeneous functional Ni–P/ceramic nanocomposite coatings via stable dispersions in electroless nickel electrolytes

Stable nanoparticle dispersions in concentrated electrolytes are prerequisite for a variety of advanced nanocomposites prepared by deposition techniques. In this work we investigate the synthesis of electroless Ni–P/functional ceramic coatings from concentrated electrolytes containing functional nanoparticles such as TiO 2, α-Fe 2O 3, ITO, and CeO 2. Stable nanoparticle dispersions in both low and high phosphorus electrolytes are achieved at plating temperatures (80–90 °C) by a generalized scheme employing comb-polyelectrolyte and antifreeze additives. Dispersion stability at room temperature is achieved in both low and high phosphorus EN media using anionic comb-polyelectrolyte surfactants with polyether side chain of 1100 g/mol. The optimal surfactant concentration is determined by zeta-potential and thermo-gravimetric analysis. Without additives the dispersions flocculate and sediment between 65 and 80 °C. Such phenomenon is believed to be associated with a critical flocculation temperature (CFT). The CFT is also weekly dependent on the particle type and the high ionic strength media. Addition of antifreeze additives such as propylene glycol and urea to the dispersions restores stability and increase the CFT for all particles. We estimate an average increase of the CFT by 1.5–2 °C per 1% additive for all particles and electrolytes. While the particle stabilization scheme is generalized in this work, the composite EN plating proved highly dependent on particle type. Baths containing ITO nanoparticles showed no plating reactions and those containing α-Fe 2O 3 no nanoparticle co-deposition. In contrast, homogeneous Ni–P/TiO 2 and Ni–P/CeO 2 nanocomposites with up to 22 vol.% nanoparticles are produced. The possible application of the stabilization principles developed here for other functional nanocomposite systems is discussed.

Study of the influence of sonication during the electrod­eposition of nickel matrix nanocomposite coatings on the protective properties

The interest in the electrocodeposition has been revived due the development of new nanotechnology methods for the production of nano-particles. The codeposition of nanoparticles might enhance the mechanical properties of composite deposits without penalizing the corrosion resistance and avoid the formation of an abrasive third body during the wear process. On the other hand, the volume fraction of codeposited nano-particles is generally low and usually inversely proportional to their size. Many efforts have been done in order to improve the codeposition rate of nanoparticles. Most of the research on nickel composites is focused on the electrodeposition process or on the mechanical and wear properties rather than on the corrosion resistance. In this work, the protective properties of nickel matrix nanocomposite coatings have been studied by means of potentiodynamic curves and electrochemical impedance spectroscopy. Two different nanopowders, i.e., silicon carbide and alumina, were added to a Watts type galvanic bath in order to deposit the nanocomposites coatings on steel substrate. Ultrasonic vibrations have been considered as new process parameter to improve the dispersion of the powder into both the plating bath and metal matrix coating and to substitute pitting control agents for the production of defect-free coatings. Unique, functional properties of composite coatings are derived not only from the presence of the particles dispersed in the bulk of the metallic matrix but also on the matrix microstructural changes induced by the interaction between particles and electrocrystallization process. It has been demonstrated that the codeposition of the silicon carbide particles induces an important microstructural refinement. On the contrary, the aluminum oxide powder is strongly agglomerated and only under ultrasonic vibrations can be dispersed. Ultrasounds have a positive effect not only in hindering the porosity but also in dispersing the ceramic powder and increasing the codeposition rate leading thus to the production of protective and very refined coatings. Moreover, the better dispersed powder induces an improvement also in the corrosion protection leading to the formation of a more stable and resistant passive nickel oxide.

Pulse Electrodeposition and Characterization of Ni-Si3N4Composite Coatings

<TEX>$Ni-Si_3N_4$</TEX> nano-composite coatings were prepared by pulse current (PC) electrodeposition and direct current (DC) electrodeposition techniques. The micro-structure of the coatings was characterized by scanning electron microscopy (SEM), vickers microhardness, X-Ray Diffraction (XRD) and wear-friction tests. The results showed that the micro-structure and wear performance of the coatings were affected by the electrodeposition techniques. Pulse current electrodeposited <TEX>$Ni-Si_3N_4$</TEX> composite coatings exhibited higher microhardness, smooth surface, and better wear resistance properties as compared to coatings prepared under DC condition. The <TEX>$Ni-Si_3N_4$</TEX> composite coatings prepared at 50 Hz pulse frequency with 10% duty cycles has shown higher codeposition of nano-particles. Consequently, increased microhardness and less plastic deformations occurred in coatings during sliding wear test. The XRD patterns revealed that the increased pulse frequencies changed the preferred (100) nickel crystallite orientations into mixed (111) and (100) orientations.

Particle Balance and Fuel Retention in Tore Supra

Fuel retention in carbon plasma-facing components (PFCs) is such a major concern for next-step operation that it could prevent the use of this material in the D-T phase of ITER. Because of its complete set of actively cooled PFCs, Tore Supra offers a unique opportunity to study this phenomenon in conditions where the plasma exposure time is much longer than the thermal equilibration time of the PFCs. In addition to the main characteristics of permanent retention measured during long-discharge operation, this paper discusses the different mechanisms possibly at work in the continuous increase of the in-vessel inventory and describes the morphology and physical properties of the deposits found at several locations in the vacuum chamber. The main results are (1) that D retention mainly depends on the lower hybrid power coupled to the plasma and, to a lesser extent, on the edge temperature and fueling method, (2) that permanent D retention is mainly due to codeposition, and (3) that the hydrogenated carbon deposits present at the surface of the different PFCs are strongly disorganized graphite carbons when they are exposed to high heat fluxes, whose formation occurs through a heterogeneous growth involving both codeposition of nanoparticles and basic structural unit vapor condensates.

Study of tribological characteristics and wear mechanism of nano-particle strengthened nickel-based composite coatings under abrasive contaminant lubrication

In desert areas, abrasive particles entering the machines cause serious wear of the sliding components. To improve the wear resistance of the machine parts, the Al 2O 3, TiO 2, Si 3N 4, diamond nano-particle strengthened nickel-based brush plating composite coatings were prepared by co-deposition of nano-particles with Ni metal–matrix. The effects of different types of nano-particle and nano-particle contents, in the solution, on the tribological properties of the composite coatings under abrasive lubrication conditions were tested on a commercial ball-on-disk friction and wear test machine. The scanning electron microscopy (SEM) was used to reveal the wear mechanisms. The results show that all of the composite coatings have finer microstructures and higher micro-hardness compared with the pure nickel coating, but only n-diamond/Ni and n-Al 2O 3/Ni composite coatings show improved tribological properties. Among them, the n-Al 2O 3/Ni composite coating has the highest cost performance. And the optimum Al 2O 3 nano-particle content in the solution is 20 g/L. The main wear mechanisms of the composite coating are plastic deformation, micro-cutting, and scuffing.