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The suitable current density for copper electrodeposition was determined by measuring the cathodic polarization curve of copper electrodeposition. A gradient nanostructured (GNS) copper coating with a total thickness of 40 μm was then obtained by electrodeposition at different current densities for different time. The tribological behavior of GNS copper coating under dry sliding condition at room temperature was studied by cyclic friction and wear test. The results showed that the GNS copper coating underwent two different frictional wear stages. At the first steady-state stage, the sub-surface of GNS copper coating was stable, ensuring the formation of an integral Cu2O film. The main wear mechanism at this stage was oxidative wear with a friction factor about 0.20 and a wear rate of 2.53 x 10-6 mm³/(N·m). At the second steady-state stage, the sub-surface structure became rough with some cracks, the Cu2O film was broken and peeled off, and the wear mechanism transferred to fatigue wear with higher friction factor and wear rate. [ABSTRACT FROM AUTHOR]

Rubber tires, as an important part of automobiles, are produced by molding operation under molten temperature and high pressure. However, mold fouling during the vulcanization process is a rock-ribbed problem that not only leads to the loss in productivity and degradation of product quality but also results in severe accidents and enormous economic losses. In this work, a promising Co-Mo/CeO2 composite coating was electroplated and investigated to solve the mold fouling problem. The effect of CeO2 content on the surface morphology, microstructure, hardness, tribological and electrochemical behavior is systematically studied. With an addition of 10 g/L CeO2, the Co-Mo/CeO2 composite coating not only possesses the highest microhardness, the best wear and corrosion resistance but also features hydrophobicity and remarkable mold antifouling performance. This study offers a new strategy for producing composite coatings with excellent performance to reduce mold fouling in practical tire industry applications. Co-Mo/CeO2 composite coatings with excellent corrosion and wear resistance as well as low surface energy were simply electrodeposited and applicated for antifouling in tire mold for the first time. [ABSTRACT FROM AUTHOR]

The dispersity of incorporated particles is critical for the creation of composite coatings with enhanced performance. Here, we propose a mechanical agitation and ultrasound-assisted pulse electroplating technique for producing exfoliated MoS2 reinforced cobalt-based composite coatings with improved tribological and electrochemical properties. The dispersity of exfoliated MoS2 and its corresponding effect on the microstructure, microhardness, tribological and electrochemical behaviors of the resultant composite coatings are systematically investigated. The results reveal that the outstanding dispersity of exfoliated MoS2 in electrolyte is beneficial to its even distribution and incorporation in the composite coating, endowing the resultant composite coatings with a smooth surface, compact structure, high hardness, remarkable antiwear and friction reduction performance as well as superior corrosion resistance. This study offers a strategy for producing high-performance composite coatings with promising practical applications. [ABSTRACT FROM AUTHOR]

A novel colloidal solution containing low concentration carbon nanotubes (CNTs) is proposed as the plating solution of electrodeposition to prepare CNTs/copper (CNTs/Cu) composite coatings. The CNTs/Cu composite coatings are characterized by X-ray diffraction and scanning electron microscope. Their tribological behaviors are evaluated in dry conditions over a range of applied loads and CNTs content in plating solution. Negatively charged CNTs stably coexist with [Cu II EDTA] 2− complexes due to the electrostatic repulsion between them, which facilitates the homogenous electrodeposition of individual CNTs in the Cu matrix and reduction of CNTs content required in the plating solution. The CNTs concentration in plating solution significantly affects the surface morphology and compactness of the deposits. CNTs/copper composite coatings obtained from the plating solution with moderate CNTs concentration, e.g. 0.12 g L −1 , show obviously lower and steadier friction coefficient and higher wear resistance than pure copper coatings. [ABSTRACT FROM AUTHOR]