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To enhance the tribological performance of Si 3 N 4 /TiC ceramics, MoS 2 /PTFE composite coatings were deposited on the ceramic substrate through spraying method. The micrographs and basic properties of the MoS 2 /PTFE coated samples were investigated. Dry sliding friction experiments against WC/Co ball were performed with the coated ceramics and traditional ones. These results showed that the composite coatings could significantly reduce the friction coefficient of ceramics, and protect the substrate from adhesion wear. The primary tribological mechanisms of the coated ceramics were abrasive wear, coating spalling and delamination, and the tribological property was transited from slight wear to serious wear with the increase of load because of the lower surface hardness and shear strength. The possible mechanisms for the effects of MoS 2 /PTFE composite coatings on the friction performance of ceramics were discussed. [ABSTRACT FROM AUTHOR]

PTFE coatings were deposited on the Si 3 N 4 /TiC ceramic substrate by using spray technology. The surface and cross-section micrographs, adhesive force of coatings with substrate, surface roughness and micro-hardness of the coated ceramics were examined. The friction and wear behaviors of ceramic samples with and without coatings were investigated through carrying out dry sliding friction tests against WC/Co ball. The test results indicated that the coated ceramics exhibited rougher surface and lower micro-hardness, and the PTFE coatings can significantly reduce the surface friction and adhesive wear of ceramics. The friction performance of PTFE-coated sample was affected by applied load due to the lower surface hardness and shear strength of coatings, and the main wear failure mechanisms were abrasion wear, coating delamination and flaking. It can be considered that deposition of PTFE coatings is a promising approach to improve the friction and wear behavior of ceramic substrate. [ABSTRACT FROM AUTHOR]

The electric double layer (EDL) has been found to play a critical role in not only electric double-layer capacitors (EDLCs) but also batteries and electrocatalysts. Although the influence of EDLs on the electrochemical behaviors of electrolytes has been extensively investigated, its influence on the electrode itself, particularly the energy storage mechanism, remains unclear. Herein, using popular α-Fe 2 O 3 , we look into the interaction between electrode and EDL and find the energy storage mechanism of an electrode can be tuned by modulating EDL. The EDL, which is mainly influenced by the inner Helmholtz plane (IHP) through the specific adsorption of ions onto the surface of Fe 2 O 3 , determines which ions are present at the interface and how they react with the electrode. Ultimately, the composition and properties of the EDL determine the energy storage mechanism of an Fe 2 O 3 electrode, including conversion reaction, ions insertion, surface redox reaction and pseudocapacitance. Our results not only provide a new understanding on the nature of the EDL but also demonstrate that the EDL should be promoted as a functional "component" which can be designed for achieving the optimum synergy of an electrode-electrolyte interface. [Display omitted] [ABSTRACT FROM AUTHOR]