The wear resistance of electrodeposited (ED) Ni-B and Ni-B-Si 3N4 composite coatings is compared. The effect of incorporation of Si3N4 particles in the ED Ni-B matrix on the surface morphology, structural characteristics and microhardness has been evaluated to correlate the wear resistance. The wear mechanism of ED Ni-B and Ni-B-Si3N4 composite coatings appears to be similar; both involve intensive plastic deformation of the coating due to the ploughing action of the hard counter disc. However, the extent of wear damage is relatively small for ED Ni-B-Si3N4 composite coatings. © 2008 Springer Science+Business Media, LLC.

Suresh Krishnamoorthy Seshadri

Coatings

corrosion

Hard coatings

Nickel

Polymer matrix composites

Silicon

tribology

Wear resistance

INTENSIVE PLASTIC DEFORMATIONS

PLOUGHING ACTIONS

Structural characteristics

WEAR DAMAGES

Wear mechanisms

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

Journal of Materials Science

Deposition of electroless (EL) Ni-B-Si 3N 4 composite coating and its characteristic properties are addressed.Hydrogen evolution limits the level of incorporation of Si 3N 4 particles in the EL Ni-B matrix to 2 wt%. Incorporation Si 3N 4 particles increased the surface roughness of the matrix but did not influence its structure. The microhardness of EL Ni-B-Si 3N 4 composite coating in its as-plated condition is 632 ± 17 HV0. 1. Heat treatment at 350 and 450°C for 1 h increased its hardness. Adhesive wear is the predominant wear mechanism of EL Ni-B-Si 3N 4 composite coating. Its corrosion protective ability did not differ much with its plain counterpart. © 2012 Copyright Taylor and Francis Group, LLC.

Synthesis and Reactivity in Inorganic, Metal-Organic and Nano-Metal Chemistry

Electroless Ni-B-Si 3N 4 composite coating: Deposition and evaluation of its characteristic properties

Surface degradation processes such as wear, oxidation, corrosion and fatigue cause failure of many engineering components under varied circumstances. Among the various surface engineering processes, phosphate conversion coatings and, electro- and electroless plating processes have received widespread acceptance following their less complex processing sequence and cost-effectiveness. The present review addresses the recent developments in the areas of phosphate conversion coatings, electro deposition and electroless deposition. © 2011, by Walter de Gruyter GmbH & Co. All rights reserved.

Fulltext

Corrosion Reviews

Recent advances in surface treatment and electrodeposition

The preparation of Ni-B-Si3N4 composite coatings by electrodeposition technique and evaluation of their characteristic properties are addressed in this paper. The Ni-B-Si3N4 composite coatings were electrodeposited using a dimethylamine borane (DMAB)-modified Watt's nickel bath containing Si3N4 particles dispersed in it. The effect of chemical composition, structural and morphological characteristics, and hardness of electrodeposited (ED) Ni-B-Si3N4 composite coatings were evaluated and compared with that of ED Ni-B coatings. The study reveals that Si3N4 particles can be successfully codeposited in the ED Ni-B matrix. The maximum level of incorporation of Si3N4 particles, about 8 wt.%, is obtained at a bath loading of 50 g/l and at 1 A/dm2. The incorporation of Si3N4 particles decreases the metallic lustre, increases the surface roughness and alters the chemical composition of the ED Ni-B matrix. The average surface roughness of the ED Ni-B-Si3N4 composite coatings is 1.17 μm. The coating contains 89.6 wt.% Ni, 2.4 wt.% B and 8 wt.% Si3N4. The surface morphology of the coating reveals uniform distribution of Si3N4 particles in the ED Ni-B matrix. Incorporation of Si3N4 particles in the ED Ni-B matrix causes a change in crystal orientation. Heat treatment (400 °C for 1 h) increases the crystallinity and enables the formation of Ni3B phase. The Ni (1 1 1) texture is retained even after heat treatment at 400 °C for 1 h. The grain size of the coating is 6-8 nm in as-plated condition and it increases to 12-14 nm after heat treatment at 400 °C for 1 h. The microhardness of as-plated ED Ni-B-Si3N4 composite coating is 640 HV0.1 and it increases to 955 HV0.1 when the coating is heat treated at 400 °C for 1 h. © 2007 Elsevier B.V. All rights reserved.

Journal of Alloys and Compounds

Electrodeposited Ni-B-Si3N4 composite coating: Preparation and evaluation of its characteristic properties

The formation of electrodeposited Ni-B alloy coatings using a dimethylamine borane (DMAB) modified Watt's nickel bath and evaluation of their structural characteristics, hardness and wear resistance are discussed. The boron content in the electrodeposited Ni-B alloy coating is determined by the ratio of rate of reduction of nickel and rate of decomposition of DMAB. The boron content of the electrodeposited Ni-B coating decreases as the current density increased from 0.4 to 4 A dm-2. XRD diffraction pattern of electrodeposited Ni-B coatings in their as-plated condition exhibits the presence of Ni (1 1 1), (2 0 0) and (2 2 0) reflections with (1 1 1) texture. Heat treatment at 400 °C for 1 h has resulted in the formation of nickel boride phases, which results in an increase in hardness and wear resistance. The mechanism of wear in electrodeposited Ni-B coatings is intensive plastic deformation of the coating due to the ploughing action of the hard counter disk. © 2005 Elsevier B.V. All rights reserved.

Materials Chemistry and Physics

Electrodeposited Ni-B coatings: Formation and evaluation of hardness and wear resistance

The present work aims to study the hardness and wear resistance of electroless Ni-B coatings. An alkaline bath having nickel chloride as the source of nickel and borohydride as the reducing agent was used to prepare the electroless Ni-B coatings. The structure, microhardness and wear resistance of electroless Ni-B coatings, both in as-plated and heat-treated conditions, were evaluated using X-ray diffraction (XRD), Leitz microhardness tester and a pin-on-disc wear test apparatus. XRD patterns reveal that electroless Ni-B coatings are amorphous in as-plated condition and undergo phase transformation to crystalline nickel and nickel borides upon heat-treatment. The microhardness of the electroless Ni-B coatings increases with increase in heat-treatment temperature and exhibit two maxima in the hardness vs. heat-treatment temperature curve. The specific wear rate increases with increase in applied load from 20 to 40 N and at all applied loads, the specific wear rate and coefficient of friction are less for heat-treated electroless Ni-B deposits compared to that obtained for as-plated ones. The wear process of electroless Ni-B coatings is governed by an adhesive wear mechanism. © 2004 Elsevier B.V. All rights reserved.

Surface and Coatings Technology

Electroless Ni-B coatings: Preparation and evaluation of hardness and wear resistance

The present work aims to study the formation of electroless Ni-B deposits and evaluation of their characteristic properties. An alkaline bath having nickel chloride as the source of nickel and borohydride as the reducing agent was used to prepare the electroless Ni-B deposits. The influence of variation in bath constituents as well as operating conditions on the plating rate, and, the nickel and boron content, of the resultant Ni-B deposits were studied. Selected deposits were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), evolved gas analysis (EGA), vibrating sample magnetometer (VSM) and transmission electron microscope (TEM), respectively, for assessing the phase content, phase transformation behaviour, liberation of hydrogen during crystallization, saturation magnetic moment and micro-structural features. The corrosion resistance of Ni-B deposits, in 3.5% sodium chloride solution, both in as-plated and heat-treated (450°C/1 h) conditions, was also evaluated by potentiostatic polarization and electrochemical impedance studies. XRD patterns reveal that Ni-B deposits of the present study are amorphous in as-plated condition and undergo phase transformation to crystalline nickel and nickel borides upon heat-treatment. DSC traces exhibit two exothermic peaks at 306 and 427°C, corresponding to the phase transformation of amorphous Ni-B to crystalline nickel and Ni 3B phases and the transformation of a higher phase compound to Ni3B and Ni2B, respectively. TEM microstructures and EGA strongly support the occurrence of phase transitions at 306 and 427°C. Electroless Ni-B deposits demonstrate a moderate corrosion resistance in 3.5% sodium chloride solution. The extent of corrosion resistance offered by electroless Ni-B deposits is relatively less compared to electroless Ni-9 wt.% P deposit. © 2003 Elsevier B.V. All rights reserved.

Formation and characterization of borohydride reduced electroless nickel deposits

This review outlines the development of electroless Ni-P composite coatings. It highlights the method of formation, mechanism of particle incorporation, factors influencing particle incorporation, effect of particle incorporation on the structure, hardness, friction, wear and abrasion resistance, corrosion resistance, high temperature oxidation resistance of electroless Ni-P composite coatings as well as their applications. The improvement in surface properties offered by such composite coatings will have a significant impact on numerous industrial applications and in the future they will secure a more prominent place in the surface engineering of metals and alloys.

Journal	Journal of Materials Science
ISSN	00222461
Open Access	No