Wear Behavior Of Composite Coatings Research Articles

Optimization of Coating Parameters on Dry Sliding Wear Behaviour of Ni-Al2O3 Composite Coatings using Taguchi Method

Recent advancements in the field of coating have shown that the Ni-Al2O3 electrodeposited coatings are of excellent wear-resistant, corrosion-resistant. In this study, Ni-Al2O3 composite coating is produced by electrodeposition process by using standard watts bath due to the advantage over other coating techniques. Al2O3 nanoparticles are co-deposited on AA6061 with Nickel. There are many parameters that influence the coating characteristics, however, in this study temperature, current density and percentage of nanoparticle loading are considered as significant parameters. Optimization of the coating parameters is examined by using the Taguchi method. The coating morphology and microstructure are studied using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). The dry sliding wear behaviour of composite coatings is tested on a pin-on-disc wear test rig.

Effect of Ni additions on microstructure, interfacial diffusion behavior and properties of Fe-based/B4C composite coating by vacuum cladding

In order to improve the hardenability and toughness of Fe-based/B 4 C composite coatings, which were bonded on ASTM 1045 steel by vacuum cladding, nNi ( n = 0, 1, 3, 5, weight %) were added into the coatings. The influences of Ni additions on the microstructures, interfacial diffusion behavior, impact toughness and three-body abrasive wear behavior of composite coatings were investigated systematically. The results indicated that coatings were completely fused with steel substrate without micro-defects. When the amount of Ni was increased, the activity of the C atom on the coating side was enhanced, the decarburization zone near the interface disappeared, and the metallurgical bonding state of interface was strengthened. Furthermore, the increment of Ni improved the hardenability of coating and promoted the transformation from pearlite to martensite in the matrix structure of the coating. The impact toughness of the coating samples also increased with the increment of Ni additions, and reached the maximum of 4.8 J/cm 2 at 5Ni sample. The three-body abrasive wear test implied that when 3 wt% Ni was added to the coating, the mass loss was 0.14 g, which was much lower than that of other samples and exhibited the best wear resistance. The wear mechanism of coatings changed from partial plastic cutting and fatigue spalling to single fatigue spalling. • Ni addition strengthens the metallurgical bonding state of the coating interface. • The increase of Ni addition improves the hardenability of the coating matrix. • Ni addition improves the impact toughness and wear resistance of the coating.

On enhancing wear resistance of titanium alloys by laser cladded WC-Co composite coatings

WC-Co composites comparable to titanium in thermal expansion coefficient can be used as wear-resistant coatings, extending the applications of titanium alloys. This study aims to investigate the effect of laser power on the quality of composite coatings on the Ti-6Al-4 V substrate, and to study the phase constituents comprehensively, microstructural evolution, microhardness, and wear behavior of composite coatings. The experimental results show that there is a good metallurgical bonding between the WC-Co composite coatings with high densification and the substrate. Furthermore, a considerably high microhardness up to 1536 HV0.5, and a wear rate of 1.5 g/h were achieved owing to the synergistic effect of excellent metallurgical bonding and fine microstructures of the composite coating under laser power of 2000 W. Based on the experimental results, the process-structure-properties relationship of laser cladded WC-Co composite was established. It is expected to be applied to improve the wear resistance of petroleum titanium alloys in deep and ultra-deep wells.

Effects of graphene oxide addition on wear behaviour of composite coatings fabricated by plasma electrolytic oxidation (PEO) on AZ91 magnesium alloy

Graphene oxide (GO) integrated composite coatings were deposited on AZ91 magnesium alloys by the PEO (Plasma Electrolytic Oxidation) and the treatment which has a post-PEO hydrothermal process. For the first group samples, PEO was performed in the silicate/phosphate-based electrolyte including 5–10 µm in size the GO particles synthesized using the Tour Method. For the second group samples, after PEO treatment, the post-PEO hydrothermal process was carried out in the oven in the GO-distilled water mixture containing GO produced with the same protocol. The effects of GO on wear behavior, structural and morphological features of composite coatings were examined with a pin-on-disc tribometer, X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy, respectively. The results showed that the addition of GO improved significantly the adhesion to the substrate material of composite coatings, increased the coating thickness and hardness. Post-PEO hydrothermal process resulted in the formation of partial a thin solid lubricant GO film on the surface of composite coatings and thus exhibited the best wear and friction resistance.

Laser cladding of Inconel 625-based composite coatings reinforced by porous chromium carbide particles

Inconel 625/Cr3C2 composite coatings were produced via a laser cladding process using Cr3C2 reinforcing particles presenting an open porosity of about 60%. A laser cladding system used consisted of a direct diode laser with a rectangular beam spot and the top-hat beam profile, and an off-axis powder injection nozzle. The microstructural characteristics of the coatings was investigated with the use of scanning electron microscopy and X-ray diffraction. A complete infiltration of the porous structure of Cr3C2 reinforcing particles and low degree of their dissolution have been achieved in a very narrow range of processing parameters. Crack-free composite coatings having a uniform distribution of the Cr3C2 particles and their fraction up to 36vol% were produced. Comparative erosion tests between the Inconel 625/Cr3C2 composite coatings and the metallic Inconel 625 coatings were performed following the ASTM G 76 standard test method. It was found that the composite coatings have a significantly higher erosion resistance to that of metallic coatings for both 30° and 90° impingement angles. Additionally, the erosion performances of composite coatings were similar for both the normal and oblique impact conditions. The erosive wear behaviour of composite coatings is discussed and related to the unique microstructure of these coatings.

Wear behaviors of Fe-based amorphous composite coatings reinforced by Al2O3 particles in air and in NaCl solution

Abstract In this paper, the influence of the addition of Al2O3 particles on the microstructure and wear properties of Fe-based amorphous coatings prepared by high velocity oxygen fuel (HVOF) has been studied. The wear behaviors of the composite coatings were evaluated against Si3N4 in a pin-on-disk mode in air and in 3.5 wt.% NaCl solution. It was found that the Al2O3 particles were homogenously distributed in the amorphous matrix and the composite coatings exhibited improved wear resistance and reduced coefficient of friction (COF) in both air and wet conditions as compared to the monolithic amorphous coating. The composite coating reinforced with 20 wt.% Al2O3 particles exhibit the best wear performance, which, for example, has extremely low COF (

Wear characteristics of electroless NiP/bio-composite coatings on En8 steel

The availability of sea shell waste is increasing day-by-day in the coastal areas of the world, where proper utilization of these sea shells can have a significant impact on the environment in terms of biocompatibility and reducing raw material cost. This paper, as a preliminary work, reveals the advantages of using sea shell particles (SSPs) as reinforcement on the tribological performance of the NiP coating on En8 steel substrate. Pure NiP and NiP with various amounts (0.5g/l, 1.0g/l, 1.5g/l, 2.0g/l, 2.5g/l, 3.0g/l, 3.5g/l, 4.0g/l and 4.5g/l) of SSP dispersed composite coatings are prepared using the electroless coating process. The structural characterization of sea shell particles, NiP and various composite coatings is done using an XRD analyzer. Sea shell particles exhibit both amorphous and crystalline structures. The phase structure of NiP is similar to that of the SSP incorporated NiP coating with some metastable peaks. Morphology and elemental study of the coatings is done using SEM with EDAX analyzer. Friction and wear behavior of composite coatings is investigated using a pin-on-disc apparatus. A better wear property with high frictional force is seen for 3.0g/l composite coatings when compared to the pure NiP coating and uncoated En8 substrate.

Wear performance of bonded composite coatings under dry sliding

In this study, epoxy bonded composite coatings were prepared by spraying process. The influence of Fe3O4 nano-particles and Ni–Zn–Cu ferrite particles as additives on the wear behavior of composite coatings was investigated. The wear behaviors of composite coatings were evaluated with a block-on-ring tribo-tester under dry sliding condition. The worn morphology of the composite coatings on the surface of counterpart steel ring was observed using scanning electron microscope (SEM). It was found that the wear resistance of the composite coatings was significantly improved when incorporated with Fe3O4 nano-particles, while less affected with Ni–Zn–Cu ferrite particles. The extreme pressure anti-wear characteristic of the composite coatings filled with magnetic nano-particle could be improved drastically, and the wear process of the composite coatings was predominantly caused by adhesive wear.

Tribological characteristics of electroless Ni–P–MoS2 composite coatings at elevated temperatures

Ni–P–MoS2 composite coatings were deposited on AISI-1045 steel plate by electroless plating followed by a heat treatment at 300°C for 2h. The high-temperature tribological characteristics of the composite coatings were evaluated under dry sliding conditions in a tribometer with ball-on-disk configuration. The effect of the co-deposition of MoS2 on the friction and wear behaviors of composite coatings at elevated temperature was investigated. Scanning electron microscopy was used to determine the morphology of the worn surface of composite coating. The chemical states of some typical elements on the worn surfaces were determined by X-ray photoelectron spectroscope. The results indicate that friction coefficient of the composite coatings decreases with the increase of test temperature up to 500°C, and the best tribological properties of Ni–P–MoS2 composite coatings are achieved at 400°C. The worn surface of Ni–P–MoS2 composite coatings are characterized by mild scuffing and deformation. The improvement of tribological properties of the composite coatings was attributed to the formation of the lubricious oxide film composed of oxides of Ni and Mo at high temperatures. With the test temperature increasing to 600°C, the tribological properties of the composite coating begin to deteriorate due to softening of the coating.

Friction and wear behavior of nanosilica-filled epoxy resin composite coatings

Hydrophilic silica nanoparticles (abridged as nano-SiO2) surface-capped with epoxide were dispersed in the solution of epoxy resin (abridged as EP) in tetrahydrofuran under magnetic stirring. Resultant suspension of nano-SiO2 in EP was then coated onto the surface of glass slides and dried at 80°C in a vacuum oven for 2h, generating epoxy resin-nanosilica composite coatings (coded as EP/nano-SiO2). EP coating without nano-SiO2 was also prepared as a reference in the same manner. A water contact angle meter and a surface profiler were separately performed to measure the water contact angles and surface roughness of as-prepared EP/nano-SiO2 composite coatings. The friction and wear behavior of as-prepared EP/nano-SiO2 composite coatings sliding against steel in a ball-on-plate contact configuration under unlubricated condition was evaluated. Particularly, the effect of coating composition on the friction and wear behavior of the composite coatings was highlighted in relation to their microstructure and worn surface morphology examined by means of scanning electron microscopy. Results indicate that EP/nano-SiO2 composite coatings have a higher surface roughness and water contact angle than EP coating. The EP-SiO2 coatings doped with a proper amount of hydrophilic SiO2 nanoparticles show lower friction coefficient than EP coating. However, the introduction of surface-capped nanosilica as the filler results in inconsistent change in the friction coefficient and wear rate of the filled EP-matrix composites; and it needs further study to achieve well balanced friction-reducing and antiwear abilities of the composite coatings for tribological applications.

Influence of pulse frequency on the microstructure and wear resistance of electrodeposited Ni–Al 2O 3 composite coatings

Nickel matrix composite coatings reinforced with sub-microsized Al 2O 3 particles were produced by pulse electrodeposition and the effect of pulse frequency on the microstructure, hardness and wear resistance of Ni–Al 2O 3 composite coatings were investigated. The results showed that the pulse frequency significantly influenced the preferred orientation of Ni–Al 2O 3 composite coatings; the texture of the coatings progressively changed from a strong (111) preferred orientation to a random orientation when pulse frequency increased. The hardness of composite coatings decreased slightly with the increase of volumetric content of alumina particles. The wear behaviors of composite coatings under dry sliding wear and oil-lubricated wear conditions were different significantly. The wear resistance of Ni–Al 2O 3 coatings decreased with the increase of incorporated alumina particles under dry sliding wear condition, which was largely influenced by the microstructure of Ni matrix due to the presence of adhesive wear. However, the wear resistance of composite coatings increased with the increase of volumetric content of the reinforcements under oil-lubricated wear condition, which mainly depends on the volumetric content of incorporated alumina particles because the adhesive wear can be avoided under oil-lubricated wear condition.

Friction and wear behavior of electroless Ni-based CNT composite coatings

Ni-based carbon nanotube (CNT) composite coatings with different volume fraction (from 5 to 12 vol.%) of CNTs were deposited on medium carbon steel substrates by electroless plating. The friction and wear behavior of the composite coatings were investigated using a pin-on-disk wear tester under unlubricated condition. Friction and wear tests were conducted at a sliding speed of 0.0623 m s −1 and at an applied load of 20 N. The experimental results indicated that the friction coefficient of the composite coatings decreased with increasing the volume fraction of CNTs due to self-lubrication and unique topological structure of CNTs. Within the range of volume fraction of CNTs from 0 to 11.2%, the wear rate of the composite coatings showed a steadily decreasing trend with increasing volume fraction of CNTs. Because of the conglomeration of CNTs in the matrix, however, the wear rate of the composite coatings increased with further increasing the volume fraction of CNTs.

Preparation and properties of hard-material layers for metal machining and jewelry

Cemented carbide parts coated with several-micron-thick layers of hard material are now used in large quantities in machining, particularly for turning and milling. Applications for jewelry purposes are assuming increasing importance. Following a brief survey of wear mechanisms in machining, the wear behavior of homogeneous coatings of TiC, TiN, and Al2O3 is discussed. Some conclusions concerning the wear-reducing effect of these coatings are derived. It is found that a complex interrelationship of several factors, such as diffusion barriers, reduction of friction, thermal conductivity, and others, play an important part. Effects of hardness and chemical behavior of hard-material coatings, especially of TiC and TiN layers on the wear decrease, are mentioned. The wear behavior of composite coatings consisting of TiC and Ti-carbonitrides of varying composition is then considered. By incorporation of these hard materials into multiple, inhomogeneous layers, significant improvements over homogeneous single-layer coatings are achieved. In addition to great hardness, the application of hard material layers for jewelry demands corrosion resistance, an attractive color, and good polishing characteristics. Examples for the corrosion resistance of TiC and TiN and the colors of Ti-carbonitrides are presented. The polishing characteristics of hard-material layers greatly depend on surface roughness. It is shown how roughness and surface structure of TiN layers produced by the CVD method vary in dependence of the deposition temperature but at equal deposition rate. Some important requirements for coatings applied to tools and jewelry articles and possible methods for their production are mentioned.