Ni-W/SiC nanocomposite coatings were systematically deposited at varying pulse parameters and subsequently characterized using SEM, XRD, TEM for surface morphology, composition and SiC particle/Ni-W matrix interface phase boundary. In addition, mechanical properties of nanocomposite were also evaluated using nanoindentation. Uniform distribution of submicron SiC particles in nanocrystalline Ni-W alloy coatings was obtained using pulsed electrodeposition. The results indicated increase in SiC content of nanocrystalline Ni-W matrix with increase in pulse frequency and decrease in duty cycle. The incorporation of SiC was attributed to pulse current effect at cathode-solution interface leading to changes in pulsating diffusion layer thickness. A simplified mechanism of composite electrodeposition is proposed. The hardness and modulus of nanocomposite varied with SiC content. The variation in mechanical properties was rationalized based on rule of mixture and inverse Hall-Petch effect. © 2016 Elsevier Ltd

Sundararajan G

Department of Metallurgical and Materials Engineering

Composite materials

Electrodeposition

Electrodes

Hardness

Inverse problems

Matrix algebra

Mechanical properties

Metallic matrix composites

Nanocomposites

Nanocrystalline alloys

Nanocrystals

Nickel

Plating

Silicon carbide

Tungsten

tungsten carbide

TUNGSTEN PLATING

COMPOSITE ELECTRODEPOSITION

DIFFUSION LAYER THICKNESS

INVERSE HALL-PETCH EFFECTS

METAL MATRICES

Nano-composite coating

NICKEL-TUNGSTEN

PULSED ELECTRODEPOSITION

Uniform distribution

Composite coatings

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Materials and Design

The aim of the present study is to understand the sliding wear response of pulse electrodeposited nanocrystalline nickel (Ni) – tungsten (W) alloy coatings in both as-deposited and heat-treated conditions. Ni-W alloy coatings with a wide range of W content (0% to 25 at%) were deposited using pulse electrodeposition and subsequently annealed at 700 °C up to 1 h. The tribological behaviour of Ni and Ni-W coatings (both as-deposited and heat-treated) was studied using a unidirectional pin-on-disc configuration at two different normal loads 3 kg and 5 kg respectively. All tests were performed in atmospheric air, at room temperature and at a constant sliding speed of 0.67 m s−1 using WC-Co disc as countersurface. Wear test results indicated that Ni-W alloy coatings exhibit greater wear resistance when compared to pure Ni coatings at both the loads. The wear mechanism in pure Ni coatings was attributed to severe abrasive wear along with brittle fracture whereas Ni-W alloy coatings exhibited mild ductile wear characterized by micro-ploughing. In the case of as-deposited Ni-W alloy coatings, the addition of W up to 17 at% increased the wear resistance due to improvement in hardness, however, further increase in W content resulted in amorphization and reduced the hardness with corresponding decrement in wear resistance. Heat treatment of coatings resulted in grain growth, crystallization of amorphous phase and precipitation of nanoprecipitates (beyond 12 at% W). Presence of nanoprecipitates and crystallization of amorphous phase resulted in significant improvement in wear resistance of the heat-treated coatings compared to their as-deposited counterparts. Addition of W to Ni did not vary the coefficient of friction (CoF) significantly and was found to be independent of W content, load and hardness of the coatings. The effect of load and hardness of the coatings on wear rate did not follow the wear relationship proposed by Archard. © 2018 Elsevier B.V.

Wear

Sliding wear of as-deposited and heat-treated nanocrystalline nickel-tungsten alloy coatings

Ni-14&nbsp;at.% W/SiC nanocomposite coatings containing 0-6&nbsp;vol.% of submicron size (0.35&nbsp;μm) SiC particles were obtained using pulsed electrodeposition technique on mild steel substrate. The coatings were subsequently characterized for uniformity of SiC distribution, grain size and mechanical properties (hardness and elastic modulus) using SEM, XRD and nanoindentation techniques, respectively. It was observed that the SiC particulates were uniformly distributed within the coating. The coating matrix (Ni-W) also exhibited nanograin size. Tribological behavior of&nbsp;Ni-14&nbsp;W/SiC nanocomposite was analyzed under dry sliding wear test conditions using pin on disk method. The interrelationship between SiC content, interparticle spacing, mechanical properties and wear behavior was analyzed. The results suggest that whereas hardness and modulus of nanocomposite coatings varied with SiC content as per Rule of Mixtures, wear mechanism can be best explained on the basis of Inverse Rule of Mixtures. © 2018, ASM International.

Journal of Materials Engineering and Performance

Tribological Behavior of Pulsed Electrodeposited Ni-W/SiC Nanocomposites

The present study deals with the electrodeposition and structural characterization of as-deposited and heat treated nickel-tungsten (Ni-W) alloy coatings. The coatings were deposited using pulse reverse electrodeposition (PRED) and pulse electrodeposition (PED) from a Ni-W plating bath. Wide range of alloy compositions have been obtained with tungsten (W) percentage in the alloy ranging from 0% to 25&nbsp;at% by altering pulse parameters. The coatings were subsequently heat treated at a temperature of 700&nbsp;°C for 1&nbsp;h and were characterized in terms of phases present, grain size, hardness and elastic modulus. It was observed that the coatings were crystalline up to 12&nbsp;at% W and beyond which the coatings were found to be a mixture of amorphous and crystalline phases. Heat treatment resulted in crystallization of amorphous phase and precipitation of secondary phases. Substantial grain growth had occurred after heat treatment and as a result, the hardness of heat treated coatings was found to be less than that of their as-deposited counterparts up to 17&nbsp;at% W. Beyond 17&nbsp;at% W hardness of heat treated Ni-W was found to be higher due to dispersion hardening. © 2017 Elsevier B.V.

Surface and Coatings Technology

Influence of heat treatment on microstructure and mechanical properties of pulse electrodeposited Ni-W alloy coatings

Nickel and Ni–Al composites with varying Al nanoparticle content were produced by pulsed electrodeposition using an organic additive-free sulfamate bath. The as-deposited Ni–Al composites exhibited increased compressive residual stresses with increasing Al nanoparticles. Detailed microstructural investigation revealed that Al codeposition led to significant refinement of the columnar morphology and grain structure of Ni matrix along with a texture change from strong 〈001〉 to 〈011〉 fiber texture parallel to the growth direction. The as-deposited Ni with bimodal grain structure displayed good tensile strength and ductility. The microhardness and tensile strength of the Ni deposits were increased initially with Al content and then decreased at higher particle content. Particle induced grain refinement and texture changes could be related to change in the growth of upcoming Ni nuclei on to the surface of well-dispersed Al nanoparticles. Significant grain refinement and lesser internal stresses along with good particle distribution and relatively harder ⟨011⟩ fiber texture at lower particles concentration collectively contributed to the observed higher strengths in Ni–Al composites as compared to Ni deposits. There was substantial change in fracture morphology from spherical dimples to flat regions with increasing Al content due to agglomeration of nanoparticles at higher particle loading. © 2017 Elsevier Inc.

Materials Characterization

Microstructure, texture and tensile behavior of pulsed electrodeposited Ni–Al composites produced using organic additive-free sulfamate bath loaded with Al nanoparticles

The main purpose of the present work is to study the influence of current density, deposition mode and the presence of saccharin as an additive on the microstructure, sulfur content, grain size and microhardness of nanocrystalline Ni coatings. Towards this purpose, nanocrystalline nickel (Ni) coatings were deposited at various current densities in Watt's bath using direct, pulse and pulse reverse current (PRC) electrodeposition and subsequently characterized for sulfur content, grain size and hardness. It was observed that, the current density has no influence on the grain size/hardness of nanocrystalline Ni coatings in direct and pulsed current electrodeposition mode. However, the grain size increased from ~ 20 to ~ 200 nm with decrease in current density in PRC mode of deposition. In addition a substantial change in microstructure and texture of PRC Ni coatings was also evident. The experimental results have been rationalized based on the adsorption-desorption type of mechanism during electrodeposition. © 2016 Elsevier B.V..

Influence of mode of electrodeposition, current density and saccharin on the microstructure and hardness of electrodeposited nanocrystalline nickel coatings

Journal of Electroanalytical Chemistry

Effect of hydrodynamic conditions of electrodeposition process on microstructure and functional properties of Ni-W/ZrO2 nanocomposites

Applied Surface Science

Microstructural, phase evolution and corrosion properties of silicon carbide reinforced pulse electrodeposited nickel–tungsten composite coatings

Journal of The Electrochemical Society

Pulse Current Electrodeposition and Properties of Ni-W-GO Composite Coatings

Sliding wear behavior of electrodeposited Ni–W alloy and hard chrome coatings

Pulsed electrodeposition and mechanical properties of Ni-W/SiC nano-composite coatings

Journal	Data powered by TypesetMaterials and Design
Publisher	Data powered by TypesetElsevier Ltd
ISSN	02641275
Open Access	No