Abstract:The influence of the stirring conditions in the electrolyte on the structure and properties of Ni/Al 2 O 3 nanocomposite coatings was studied. The coatings were produced by electrochemical reduction on a copper substrate in a Watts bath modified by nickel grain inhibitor, cationic surfactant and low concentrated nanometric alumina. The process has been carried out with different types of agitation (mechanical, ultrasonic stirring and with a copper rotating disc electrode). The structures of the produced coatin… Show more
“…Meanwhile, the microhardness of the Ni–Al 2 O 3 and Ni–TiO 2 coatings resulted in significant improvement due to the strengthening effect of incorporated hard nano particles [34,35]. The better ability of Al 2 O 3 particles to adhere with Ni matrix coating makes it achieve a higher hardness of the composite coating [36]. Figure 5 Microhardness results of Ni- and Ni-based composite coatings.…”
The tribological behaviour of Ni-based composite coatings on Al6061 substrate with secondary phase hard oxide particles like ZrO 2 , TiO 2 , and Al 2 O 3 at different elevated temperature conditions was compared. The composite coatings with different reinforcement of nano particles were characterized by scanning electron microscopy and X-ray diffraction technique. The higher microhardness value is reported for the Ni coating with TiO 2 particles and Al 2 O 3 particles. At higher temperature limits of 120°C and 140°C Ni-ZrO 2 coatings have found better specific wear rate. The Ni-Al 2 O 3 -TiO 2 -ZrO 2 composite coating fails to achieve better properties due to higher agglomeration of the particles and dendrite growth. The Ni-Al 2 O 3 coating showed steady wear behaviour at different temperature limits. The coefficient of friction values is found nearly similar for all the type coatings at 40°C and 120°C.
“…Meanwhile, the microhardness of the Ni–Al 2 O 3 and Ni–TiO 2 coatings resulted in significant improvement due to the strengthening effect of incorporated hard nano particles [34,35]. The better ability of Al 2 O 3 particles to adhere with Ni matrix coating makes it achieve a higher hardness of the composite coating [36]. Figure 5 Microhardness results of Ni- and Ni-based composite coatings.…”
The tribological behaviour of Ni-based composite coatings on Al6061 substrate with secondary phase hard oxide particles like ZrO 2 , TiO 2 , and Al 2 O 3 at different elevated temperature conditions was compared. The composite coatings with different reinforcement of nano particles were characterized by scanning electron microscopy and X-ray diffraction technique. The higher microhardness value is reported for the Ni coating with TiO 2 particles and Al 2 O 3 particles. At higher temperature limits of 120°C and 140°C Ni-ZrO 2 coatings have found better specific wear rate. The Ni-Al 2 O 3 -TiO 2 -ZrO 2 composite coating fails to achieve better properties due to higher agglomeration of the particles and dendrite growth. The Ni-Al 2 O 3 coating showed steady wear behaviour at different temperature limits. The coefficient of friction values is found nearly similar for all the type coatings at 40°C and 120°C.
“…From the materials engineering standpoint, the surface of materials has a crucial role since the most hazards usually initiate from the surface defects [1][2][3]. Nanocomposites coatings show brilliant physical, mechanical and chemical properties in different situations, thus they are proposed to be applied on the surface layer of different materials as an effective way to boost their wear and corrosion resistance [4][5][6][7][8][9]. Among diverse deposition processes to produce nanocomposites coatings, electrodeposition is a contemporary one because of its feasibility and unique economical characteristics [1,10].…”
One of the important techniques for developing coatings with proper electrochemical and mechanical properties is electrodeposition method. The goal of the current work is to optimise contents of SiC particles in the bath to achieve Ni-B/SiC composite coatings with high corrosion resistance and wear properties. Pulse plating method was used to prepare Ni-B/SiC composite deposits of Watts bath including trimethylamine borane (TMAB) and SiC nanopowder addition. The effects of SiC concentration in the bath, which is the principal factor, on the main properties of the coatings were studied. Field Emission Scanning Electron Microscopy (FE-SEM), Energy-dispersive Spectroscopy (EDS) and X-ray diffraction (XRD) were used to analyse the characterisations of the coatings. In order to evaluate the corrosion behaviour of the coatings, the open circuit potential (OCP), electrochemical impedance (EIS) and potentiodynamic polarisation (Tafel) tests were applied in 3.5% NaCl solution. Moreover, the pin-on-disc procedure was designed to assess the wear behaviour of coatings. Increasing the SiC nanoparticles up to 12 g l −1 in the bath leads to produce a coating including 11 wt-% SiC particles which have a positive effect on the coating microstructure. Corrosion resistance improves by raising 4-12 g l −1 SiC incorporation in the coatings; so that corrosion resistance of the Ni-B/SiC12 g l −1 coating reaches to nearly 62 kΩ. The presence of SiC phase in the coating can result in decrease electrochemical active regions; therefore, this phenomenon can promote corrosion resistance of the composite coatings. Ni-B/SiC 12 g l −1 composite coating illustrates the best wear resistance in comparison with the others after which it shows the lowest weight losses (0.98 mg cm −2 ) and the friction coefficient of 0.57 due to the formation of the packed structures with less porosity and high content of SiC particles in the deposit.
“…The particles such as SiC, ZrC, TiO 2 , SiC, CeO 2 , Al 2 O 3 , Si 3 N 4 , WS 2 , CrAlY, WC, B, B 4 C, ZrO 2 , zircon, pumice, carbon nanotubes (CNTs), diamond, etc. have been electrodeposited [5][6][7][8][9][10][11][12][13][14]. With growing concerns about environment, there is a need to evolve new strategies in the reclamation of industrial waste.…”
In the exploration for newer and inexpensive distributed phases that can be used in electrodeposited Ni-composite coatings, cenosphere particles which are one of the constituents of fly ash, the waste product of thermal power plants has been explored as a potential candidate material. An attempt was made to prepare electrodeposited Nicenosphere composite coating. The as-received cenosphere particles could be codeposited only after reducing the particle size by ball milling. The loading of cenosphere particles in the Ni-sulphamate bath was varied (25, 75 and 100 g L −1) and a maximum microhardness of 430 HK at 50 gF load was obtained for the coating deposited from 100 g L −1 cenosphere containing bath. The Ni-cenosphere composite coating with higher microhardness exhibited lower wear rate. Thus cenosphere, a waste product from thermal power plants is a potential candidate for a greener surface engineering strategy for improving the wear resistance of electrodeposited Ni composite coating.
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