Analysis of the phase disorder in electroplated nickel-boron coatings

Probable state of the phase disorder in electroplated nickel-boron coatings was analyzed. The electrical resistivity of the coatings and the microhardness and wear resistance of their surface was modeled. The calculated parameters of the nickel-boron coatings were analyzed in comparison with the corresponding experimental data.     

Electrochemical synthesis and properties of iron–titanium dioxide composite coatings

Deposition of Fe/TiO₂ composite coatings from a colloidal methanesulfonate electrolyte containing titanium dioxide hydrosol was studied. The TiO₂ content in the composite increases with increasing the dispersed phase content and decreasing the current density. Incorporation of TiO₂ particles into the iron matrix resilts in an increase in the microhardness of the deposit. The electroplated Fe/TiO₂ composite coating was used as a heterogeneous photocatalyst for the decomposition of an organic dye under the action of UV radiation.     

Electrodeposition of iron/titania composite coatings from methanesulfonate electrolyte

The possibility of deposition of Fe/TiO₂ composite electroplated coatings from methanesulfonate electrolyte was demonstrated. The kinetics of the codeposition of dispersed phase particles is described by the Guglielmi model. Incorporation of titania particles into the iron matrix leads to enhancement of the coating microhardness due to dispersion strengthening. The Fe/TiO₂ composite coatings exhibit catalytic activity in photochemical decomposition of Methyl Orange dye in aqueous solution.     

Composite electrochemical coatings with a carbon-containing dispersed phase or polytetrafluoroethylene

Composite electrochemical coatings based on nickel, zinc, and chromium were studied. The dispersed phase of these coatings is constituted by graphite, diamond, and polytetrafluoroethylene produced from wastes formed in manufacture of fluoroplastic and ultradispersed diamond produced from industrial waste. The conditions in which high-quality coatings with best characteristics, such as microhardness and corrosion resistance, were determined. The wear resistance was additionally found for the chromium-diamond coating.     

Production of composite electroplated nickel-fullerene C<Subscript>60</Subscript> coatings

Kinetic relationships of the deposition of composite electroplated coatings based on nickel with a disperse phase of C₆₀ fullerene were studied. The composition of the coatings was determined by secondary-ion mass spectrometry.     

Composite Copper-Based Coatings with Ultradispersed Phase

The electrolytic deposition of composite copper-based coatings with an ultradispersed phase(TiN or Al₂O₃) was studied. Conditions for obtaining coatings with the maximum microhardness were determined.     

Crystalline roughness as a morphological characteristic of the surface of electroplated silver coatings

Structure and morphology of electroplated silver coatings deposited from a borate-phosphate-carbonate electrolyte were studied in relation to the current density and temperature. Average values of the crystalline roughness were determined.     

Properties of nickel-cobalt-diamond composite coating deposited from a chloride electrolyte

Effect of electrolysis modes and electrolyte composition on physicomechanical properties of nickel-cobalt-diamond composite electroplated coatings deposited from a chloride electrolyte with introduction of an ultradispersed diamond suspension was studied and the possibility of replacement of wear-resistant chromium coatings with these composite coatings was demonstrated.     

Electrodeposited Ni and Ni-Co alloys using cysteine and conventional ultrasound waves

Ni-Co alloys were electroplated from sulphate electrolyte using addition agents including sodium gluconate,boric acid and cysteine on copper foil by the galvanostatic technique and ultrasound waves.The chemical composition,surface morphologies,crystalline structure and hardness of the Ni-Co alloys were studied using energy dispersive spectroscopy,scanning electron microscope,X-ray diffraction and Vickers testing method,respectively.The effect of current density and addition agents on the microstructure and morphology of Ni-Co alloys were examined.The appropriate concentration of additives and ultrasound waves were found to produce fine and smooth crystals leading to higher hardness of Ni-Co alloys.The microhardness of the Ni-Co alloys was varied between 4860–7530 HV.The surface morphology of coatings was changed from granular to fine due to using of gluconate,boric acid,cysteine and ultrasound waves.The mechanical properties of nanocrystalline Ni-Co alloys showed an increase of the hardness with the growing of Ni content in the alloy.The X-ray diffraction studies indicated that nanocrystalline structure was face-centred cubic for pure Ni and Ni-Co alloys with Co content in the range of 1–75 wt.%.A hexagonal closed-package structure was obtained for pure Co and Ni-Co alloys with the cobalt content with range of 75–99wt.%.     

Properties of composite nickel-cobalt-aluminum oxide coating deposited from chloride electrolyte

Effect of the cathodic current density, pH value, electrolyte temperature, and concentration of aluminum oxide introduced into the electrolyte on the wear, microhardness, and internal stresses in nickel-cobalt-aluminum oxide composite electrolytic coatings was studied. It is shown that the coatings under consideration can be used instead of chromium coatings.     

Reinforcement of metal-ceramic coatings in the course of their partial fusion

Factors and mechanisms responsible for the appearance of layered structures of variable cross section in protective coatings based on self-fluxing alloys were studied. A number of structural fragments of composite coatings based on safe-fluxing PG-10K-01 and PG-SR3 alloys (initial formulations and those reinforced with oxide ceramic particles), formed by sputtering in a plasma flux and then partially fused in a furnace, by a gas-oxygen flame, and with laser and electron beams, were revealed and studied. The relationships of the element distribution across the coating layer as a whole and in separate phases were determined. The effect exerted on the chemical composition and microhardness of coatings by the size, structure, and arrangement of inclusions in the coating cross section was demonstrated.     

Physicomechanical properties of nickel coating deposited from sulfate nickel plating electrolyte using preliminary underpotential deposition

A study of nickel coatings electroplated from electrolytes of the compositions (M) NiSO₄ 0.5, NiCl₂ 0.3, and H₃BO₃ 0.404 (electrolyte 1) and NiSO₄ 0.5, NiCl₂ 0.3, and H₃BO₃ 0.404 with the addition of 2 mg L^–1 RADO (electrolyte 2) in the constant-current mode after preliminary potentiostatic treatment (underpotential deposition) of the support revealed the formation of Fe–Ni alloy in the initial moment of formation of the nickel coating. Pretreatment of the steel surface in the underpotential deposition mode allows preparation of uniform finely crystalline nickel coatings with enhanced levels of the wear resistance, microhardness, and corrosion resistance.     

The effect of co-electrodeposited ZrO<Subscript>2</Subscript> particles on the microstructure and corrosion resistance of Ni coatings

Pure Ni and Ni–ZrO₂ composite coatings were electroplated using a Watt’s bath containing different amounts of ZrO₂ to be co-deposited. Surface morphology and microstructure of the samples and particle distribution in the coatings were studied using optical microscope, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The results showed that the electroplated sample in the bath containing 90 g l⁻¹ ZrO₂ has the maximum particle content and the best particle distribution. Evaluation of microstructure and corrosion behavior demonstrated that with increasing ZrO₂ content in the coating, the corrosion potential shifted toward noble and positive values. This is probably due to diminishing of the metallic surface area exposed to the solution. Higher ZrO₂ contents in the coating results in lower corrosion current densities probably due to the changing of the microstructure from coarse-grained columnar to fine-grained granular structure. The results revealed that the electroplated sample in the bath containing 90 g l⁻¹ ZrO₂ has the best corrosion resistance.     

Effect of Y2O3 on microstructural characteristics and wear resistance of cobalt‐based composite coatings produced on TA15 titanium alloy surface by laser cladding

The effects of Y₂O₃ on the microstructure, phase composition of the coatings, microhardness and wear resistance of cobalt‐based composite coatings prepared by laser cladding were investigated. The TA15 titanium alloy was selected as substrate which the cobalt‐based composite powder with different content of Y₂O₃ was cladded on. The microstructure of the coatings was observed by scanning electron microscope (SEM) and metallurgical microscope. The phase structure of the coatings was determined by X‐ray diffraction (XRD), and the microhardness and wear resistance of the coatings were measured by hardness tester and wear testing machine. The results show that the rare earth oxide Y₂O₃ can refine and purify the microstructure of the coatings, reduce the porosities and cracks and improve compactness of the coatings. Moreover the addition of Y₂O₃ improves the microhardness of the coatings and reduces the friction coefficient, thus improving the wear property of the coatings. And the wear resistance of the coating with Y₂O₃ has improved about 50 times; the highest value of microhardness in the coating is HV1181.1. And 0.8 wt% content of Y₂O₃ in the coating is the best choice for improving the microhardness and wear resistance of the coating. It is feasible to improve the microstructure and tribological properties of laser cladding coatings by adding of Y₂O₃. Copyright © 2014 John Wiley & Sons, Ltd.     

Influence of the Composition of Dilute Nickel-Plating Electrolytes on the Physicomechanical Properties of Electroplated Coatings

The influence of the composition of dilute nickel-plating electrolyte containing luster-forming additives on the leveling, plasticity, and internal stresses of coatings being electroplated was studied. The possibility of combining nickel sulfate, sodium chloride, and boric acid as the main composition of a dilute nickel-plating electrolyte was analyzed.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 4, 2005, pp. 572–574.Original Russian Text Copyright © 2005 by Binkauskene.     

Use of diamond stock in chromium plating

Cathodic deposition of a chromium coating from the standard electrolyte in the presence of a diamond stock was analyzed. The microhardness and wear resistance of chromium diamond coatings and the effect of the diamond stock on the electrical conductivity and throwing power of the electrolyte were studied.     

Possibility of raising the deposition rate of nickel coatings from a chloride electrolyte

Conditions under which nickel coatings can be deposited from a chloride electrolyte at a high rate were studied. The mechanism of this process was suggested and experimentally confirmed. The mass-transfer rate of nickel-containing particles was determined by chronopotentiometry, with temperature raised from 20 to 50°C. The dependence of pH_s on the current density was determined. Physicochemical parameters of the coatings (microhardness, internal stresses, porosity, luster, and adhesion) were measured.     

Dependence of physicomechanical properties of a nickel-cobalt-aluminum oxide composite electrolytic coating on the dispersity of the alloying component

Effect of the dispersity of aluminum oxide on the microhardness, wear, internal stresses, and porosity of nickel-cobalt-aluminum oxide composite electrolytic coatings deposited from a chloride electrolyte and the dependence of the content of aluminum oxide in the coating on the agitation rate and working duration of the electrolyte were studied.     

In vitro corrosion resistance and cytocompatibility of minerals substituted apatite/biopolymers duplex coatings on anodized Ti for orthopedic implant applications

In this work, strategies for the formation of duplex coatings with enhanced bioactivity, mechanical properties and corrosion resistance have been focused. TiO₂ arrays were fabricated on Ti alloy were carried out in a single step using suitable electrolyte by anodization method. Here, we have synthesized a novel bioactive material, minerals incorporated Hydroxyapatite (La/Tb-HAP)-chitosan-casein duplex coatings on anodized Ti via electrodeposition method. The fabricated novel composite coatings were characterized by FT-IR, XRD, FESEM and EDAX analyses. Also, the mechanical properties of duplex coatings were scrutinized by Dermitron thickness and microhardness tester. The corrosion resistance of the as-developed duplex coatings was studied by electrochemical techniques using Ringers solution as the electrolyte. In addition, the antibacterial activity, cell viability, live and dead staining were executed to substantiate the biocompatibility of TNT/CS-CA@M-HAP duplex coatings. From the overall summary of this work, it is proved that the resultant CS-CA@M-HAP coatings on TNT exhibit excellent bioactivity and improved corrosion resistance over pure Ti and serve as a potential candidate for orthopedic applications.     

Characterization of Two-Component Metal Coatings (Al/Sn) with SIMS

 Vacuum deposited films of immiscible metal–metal systems can be applied as tribological coatings for plain bearings in high performance diesel engines. These industrially manufactured coatings show higher lifetimes than conventional electroplated coatings. For our investigations we used aluminum-tin coatings of 1 μm thickness on a glass substrate produced by sequential deposition from two separate targets under working gas pressure of 0.4 Pa. The tough Al matrix takes high mechanical loads and the soft inclusions of Sn act as solid lubricant. While Sn is deposited it migrates on the Al surface and grows as islands. We characterized the conformation and the distribution of the Sn islands on the surface and to the interstitial area between the islands with 3-D secondary ion mass spectroscopy (SIMS). The existence of a Sn layer between the islands (“wetting layer”) has been detected by SIMS and verified by measurements with Auger electron spectroscopy (AES).