Surface free energies of electroless Ni–P based composite coatings (original) (raw)
Related papers
Electroless Ni-P composite coatings
Journal of Applied Electrochemistry, 2003
This review outlines the development of electroless NiP 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 NiP 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.
Applied Surface Science, 2011
The effects of the addition of three types of surfactants (cationic, anionic, non-ionic) at different concentrations in the plating bath on the deposition rate, PTFE content and surface morphology of electroless Ni-P/PTFE composite coatings were investigated. It was demonstrated that the cationic and non-ionic surfactants created a uniform distribution of PTFE particles in the coatings. The effects of the surfactant type and concentration on the corrosion properties of Ni-P/PTFE coatings were also studied. The corrosion resistance was increased by the incorporation of PTFE particles into the NiP matrix. The level of improvement depended largely on the type and concentration of the applied surfactants.
Progress in Natural Science: Materials International, 2012
In current research, in order to enhance the incorporation of nano-sized TiC particles into electroless NiP (EN) coating, different types of surfactant (cationic, anionic, and polymeric) were added to the plating bath. The effects of addition of the surfactants on surface morphology, deposition rate, TiC and P contents of the prepared coatings were investigated. The surface morphology was evaluated by scanning electron microscopy (SEM). It was demonstrated that in the presence of the anionic, polymeric and somehow cationic surfactants, TiC nano-particles were embedded in the matrix which influenced the surface morphology. The effect of surfactant types on the corrosion properties of Ni-P/TiC coated steel was also studied. Corrosion behavior of the coated steel was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) which affected by the incorporation of TiC particles into the NiP matrix. The level of corrosion resistance improvement depended largely on the phosphorous and TiC concentration of the applied coating.
International Journal of Modern Physics: Conference Series, 2012
Electroless composite coatings have been vastly used in various industries during last decades due to their good properties, such as corrosion and wear resistance, hardness and uniform thickness. In this paper, co-deposition of TiO 2 nano-particles with Nickel-Phosphorus electroless coatings on API-5L-X65 steel substrates was investigated. Surface morphology and composition of coatings were studied via SEM and EDX, respectively. XRD analyses showed that these coatings had amorphous structure with TiO 2 crystalline particles. TiO 2 nano-particles increased microhardness of coatings. Corrosion resistance of these coatings was tested using linear polarization in 0.5M sulfuric acid electrolyte. Results showed that NiP - TiO 2 electroless composite coatings increased corrosion resistance of substrates.
Structure and phase transformation behaviour of electroless Ni–P composite coatings
Materials Research Bulletin, 2006
This paper addresses the structural characteristics and phase transformation behaviour of plain electroless Ni–P coating and electroless Ni–P–Si3N4, Ni–P–CeO2 and Ni–P–TiO2 composite coatings. The X-ray diffraction patterns of electroless Ni–P–Si3N4, Ni–P–CeO2 and Ni–P–TiO2 composite coatings are very similar to that of plain electroless Ni–P coating, both in as plated and heat-treated conditions. Selected area electron diffraction (SAED) patterns obtained on the Ni–P matrix of Ni–P–Si3N4, Ni–P–CeO2 and Ni–P–TiO2 composite coatings exhibit diffuse ring patterns resembling the one obtained for plain electroless Ni–P coating. Phase transformation behaviour studied by differential scanning calorimetry (DSC) indicates that the variation in crystallization temperature and the energy evolved during crystallization of plain electroless Ni–P coating and electroless Ni–P–Si3N4, Ni–P–CeO2 and Ni–P–TiO2 composite coatings is not significant. The study concludes that incorporation of Si3N4, CeO2 and TiO2 particles in the Ni–P matrix does not have any influence on the structure and phase transformation behaviour of electroless Ni–P coatings.
Electroless NiP micro- and nano-composite coatings
Surface & Coatings Technology, 2006
Electroless NiP composite coatings were obtained by incorporating two kinds of particles, SiC and Si 3 N 4 , to analyze the influence of the type of particle both on the codeposition process and on the coating properties. Particles with sizes ranging from 30 nm to 2 μm were selected to study the influence of this parameter on the amount of embedded particles. All composite coatings were characterized by composition, morphology, structure, roughness and some tribological properties. Results indicated that, while there was almost no difference between carbide and nitride incorporation for micron-sized particles, this variable was very important with the nano-sized ones. Moreover, it was observed that the growth mechanism of the metallic matrix was much more modified by the nano-particles than by the micron-sized ones.
Materials Research
NiP -(Cu) composite coatings were applied on a St37 steel in an acidic bath of hypophosphite composite. The effect of the concentration of the Cu particles and pH of the solutionon the amount of Ni and P of the coatings, their morphology, and hardness of the coatings were explored. Some of the coated samples were also heat treated at 400ºC for 1 hour. The phases formed, the microstructure and the amount of the alloying elements of the coatings were analyzed by X-Ray powder diffraction (XRD), Scanning Electron Microscope (SEM) equiped with Energy Dispersive Spectroscopy (EDS). Results show that although adding Cu particles reduced the hardness of NiP coating (from 482.4 to 351.2 VH in 1 gr/lit Cu), within NiP -Cu composite coatings the hardness of NiP -Cu composite coating increased from 351.2 to 380.7 VH by increasing the Cu particles from 1 to 7 gr/lit. The structure of the coating was crystalline during the heat treatment making the coating harder. With increasing the pH of the solution from 4.5 to 7 and then to 9, the weight percent of P and the particle of Cu were reduced.
Progress in Natural Science: Materials International, 2012
NiP electroless coating was applied on low carbon steel with the incorporation of different amounts of nano Al 2 O 3 powder (ranging from 3 g/l to 30 g/l) in electroless bath. Corrosion properties and microstructures of the coating were studied. The dispersion stability of alumina colloidal particles stabilized by polymeric (non-ionic) surfactants in an electroless bath was also investigated. The surface morphology and the relevant structure were evaluated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Corrosion behavior of the coated steel was evaluated by electrochemical impedance spectroscopy (EIS) and polarization techniques. The results showed that increasing alumina concentration not only changed the surface morphology, but also promoted the corrosion resistance. Addition of surfactants has an indirect effect on the amount of the incorporated particles. Meanwhile, in the presence of surfactant, corrosion resistance of NiP coating containing even a small quantity of alumina was improved since a stabilized bath was obtained.
Development of electroless Ni–P/nano-WC composite coatings and investigation on its properties
Surface and Coatings Technology, 2015
In this study, a NiP -WC nanocomposite coating was prepared by electroless deposition methods, modifying the typical NiP coating through the addition of WC nano-particles. The morphology, structure, microhardness and corrosion resistance of the NiP -WC coating and conventional NiP coating were analyzed by using the optical stereoscopic microscopy (OSM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), anodic polarization curve and electrochemical impedance spectroscopy (EIS). It was observed that WC nano-particles and NiP deposited homogeneously on the NiP matrix, electroless deposited composite coatings exhibit an amorphous structure of the nickel matrix in which crystalline tungsten carbide is incorporated. The microhardness of the coating increased due to the existence of the nano-particles, and it will be improved after heat treatment. According to the results of corrosion testing in the 3.5 wt.% sodium chloride solution, the electroless NiP -WC coatings showed significantly improved corrosion resistance due to its special structure, compared to a conventional NiP electroless coating, even after 40 days immersion, it also exhibited good corrosion resistance ability.