Electroless Ni coatings for the improvement of wear resistance of bearings for lightweight rotary gear pumps

Veronesi, Paolo; Sola, Ramona; Poli, Giorgio

doi:10.1504/ijsurfse.2008.020493

Cited by 8 publications

(5 citation statements)

References 16 publications

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“…It is important to note that roughness values are higher than those usually reported for Ni-P based films deposited on metal substrates [20,41]. This is due to the chemical activation treatment underwent by NBR before electroless deposition [15].…”

Section: Roughness and Wettabilitymentioning

confidence: 86%

“…The release of internal stress in electroless Ni-P coatings is known to be associated with increased fatigue strength, reduction in cracks and fissures [38,39] and higher ductility [40] and, as a consequence, higher peeling resistance. Poor Ni-P-PTFE coatings adhesion has also been attributed to hardness mismatch between the metallic substrate and the soft PTFE particles [17,41].…”

Section: Crystalline Structure and Adhesionmentioning

confidence: 99%

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Characterization and Tribological Behavior of Electroless-Deposited Ni-P-PTFE Films on NBR Substrates for Dynamic Contact Applications

et al. 2022

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The use of rubber in dynamic contacts often results in severe degradation and wear of the rubber surface, which is why dynamic rubber seal contacts are usually oil lubricated to ensure their functionality. However, the increasing demand for more convenient and environmentally friendly sealing solutions has prompted the development of dry low-friction rubber coatings. In this work, and for the first time, Ni-P and polytetrafluoroethylene (PTFE) particles were co-deposited by electroless plating on Nitrile Butadiene Rubber (NBR), as a low-cost solution to improve the NBR tribological behavior. A cationic surfactant, cetyltrimethylammonium bromide (CTAB), was added to the plating bath to ensure a homogeneous and efficient incorporation of PTFE into the Ni-P. The optimized PTFE incorporation reached 6.8%, and the composite coating adhesion to NBR was 20% higher than that of nickel-phosphorous (Ni-P) films. The tribological properties of the coatings evaluated by pin-on-disk tests showed a marginal decrease in the coefficient of friction (CoF) (10%, 1 N load), compared to that of Ni-P. However, the tested PTFE-based coatings displayed significantly smoother surfaces with less debris and cracks, clearly demonstrating the benefits of the PTFE in terms of wear resistance for loads up to 5 N.

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Section: Roughness and Wettabilitymentioning

confidence: 86%

Section: Crystalline Structure and Adhesionmentioning

confidence: 99%

Characterization and Tribological Behavior of Electroless-Deposited Ni-P-PTFE Films on NBR Substrates for Dynamic Contact Applications

et al. 2022

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“…In addition, there have been some improvements in the design of gears from materials with smoother surface finish. 17 When graphite surfaces with very small amounts of surfaceadsorbed liquids slide against metal surfaces, the amount of metal debris loss from the surfaces (wear) was shown to be reduced drastically. 18 Moreover, it was shown that colloidal graphite deposits on metal surfaces have superior tribological performance compared to conventional colloidal solid lubricants such as MoS 2 .…”

Section: Resultsmentioning

confidence: 99%

“…In general, good film-forming hydraulic fluids can partially alleviate the resulting problems such as local adhesion, wear, and scuffing. In addition, there have been some improvements in the design of gears from materials with smoother surface finish …”

Section: Resultsmentioning

confidence: 99%

Effect of Graphite and Carbon Nanofiber Additives on the Performance Efficiency of a Gear Pump Driven Hydraulic Circuit Using Ethanol

Martorana¹,

Bayer²,

Steele³

et al. 2010

Ind. Eng. Chem. Res.

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We show that fine graphite flake and carbon nanofiber dispersed ethanol solutions can potentially replace conventional hydraulic fluids in gear pump-driven hydraulic circuits operating below 1 MPa gauge pressure. Low-viscosity hydraulic fluids are generally detrimental to pump life. However, both graphite and carbon nanofiber dispersions in ethanol within a concentration range of 195-1500 ppm can sustain hydraulic circuits with increases in pump efficiency and without modifying the viscosity of ethanol. Pump inlet pressure, volumetric flow rate, and electric power consumption data were recorded over a range of pump discharge pressures. Pump power consumption at a given differential pump pressure was found to remain approximately constant for all suspensions. However, increases in both volumetric flow rate and overall pump efficiency were observed when pure ethanol was replaced by the nanostructured carbon/ethanol solutions. The presence of the additives can partially or collectively improve a number of lubrication mechanisms which exist in a gear pump such as boundary, hydrodynamic, hydrostatic, elastohydrodynamic, and mixed-film lubrication. Additionally, we observed that the additives deposited permanently on gear and enclosure surfaces creating low shear strength films which can help reduce friction. Qualitative examination of environmental scanning electron microscope images of colloidal graphite and carbon nanofiber additive morphology before and after extended run periods indicated that graphite retained significant resilience, whereas carbon nanofibers appear to have undergone some scission.

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“…UHMWPE, an advanced engineering plastic used in making sea water hydraulic drive is found to produce the lowest friction coefficient when sliding against electroless Ni-P coating under sea water lubrication (Wang, Yan & Xue, 2009). Composite coatings of electroless Ni-P-PTFE were considered for improving the performances of aluminium alloys in the bearings regions of lightweight external gear pumps (Veronesi, Sola & Poli, 2008).…”

Section: Selection Of Proper Substrate Coating and Optimization Strategymentioning

confidence: 99%

Optimization Studies on Electroless Nickel Coatings

Kundu

Sahoo

Das

2014

International Journal of Manufacturing, Materials, and Mechanical Engineering

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Electroless nickel coating is a novel method of coating which can be developed in various combinations of alloys and composites each having its unique set of characteristics. Electroless nickel coatings are mainly used for wear and corrosion resistant properties. However, additional characteristics like smoothness of deposit, low friction, descent plating rate, electrical and magnetic properties also make them suitable for a host of applications. The properties of electroless nickel coatings depend mainly on the electroless solution ingredients as well as deposition conditions. Important deposition parameters include bath temperature, concentration of nickel source, concentration of reducing agent, pH of the solution, concentration of surfactants, and so on. Moreover, heat treatment is found to modify the microstructure of the coating and influence certain properties viz. hardness, wear resistance, corrosion resistance, etc. A large number of works have been published by the researchers on the evaluation of electroless nickel coating performance on the basis of hardness, roughness, corrosion resistance, friction and wear resistance for various types of coatings and substrates. Several approaches are proposed in the literatures to solve the problems related with optimization of these parameters. It is felt that a review of the various approaches developed would help to compare their main features and their relative advantages or limitations which will enable to choose the most suitable approach for a particular application and also throw light on aspects that needs further attention. In this regard, the present paper presents a review on the developments done on the optimization of electroless nickel coatings to increase its efficiency.

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Electroless Ni coatings for the improvement of wear resistance of bearings for lightweight rotary gear pumps

Cited by 8 publications

References 16 publications

Characterization and Tribological Behavior of Electroless-Deposited Ni-P-PTFE Films on NBR Substrates for Dynamic Contact Applications

Characterization and Tribological Behavior of Electroless-Deposited Ni-P-PTFE Films on NBR Substrates for Dynamic Contact Applications

Effect of Graphite and Carbon Nanofiber Additives on the Performance Efficiency of a Gear Pump Driven Hydraulic Circuit Using Ethanol

Optimization Studies on Electroless Nickel Coatings

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