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In order to meet the requirements of high corrosion resistance, wear resistance, and self-lubrication of composite coatings for marine applications, epoxy matrix composite coatings containing PTFE and TiO2 nanoparticles were prepared on the steel substrate. With silane coupling agent KH570 (CH2=C(CH3)COOC3H6Si(OCH3)3), titanium dioxide nanoparticles were modified, and organic functional groups were grafted on their surface to improve their dispersion and interface compatibility in the epoxy matrix. Then, the section morphology, tribological, and anticorrosion properties of prepared coatings, including pure epoxy, epoxy–PTFE, and the composite coating with unmodified and modified TiO2, respectively, were fully characterized by scanning electron microscopy, friction–abrasion testing machine, and an electrochemical workstation. The analytical results show that the modified TiO2 nanoparticles are able to improve the epoxy–PTFE composite coating’s mechanical properties of epoxy–PTFE composite coating including section toughness, hardness, and binding force. With the synergistic action of the friction reduction of PTFE and dispersion enhancement of TiO2 nanoparticles, the dry friction coefficient decreases by more than 73%. Simultaneously, modified titanium dioxide will not have much influence on the water contact angles of the coating. A larger water contact angle and uniform and compact microstructure make the composite coating incorporated modified TiO2 nanoparticles show excellent anti-corrosion ability, which has the minimum corrosion current density of 1.688 × 10−7 A·cm−2.

Abstract:In this paper, interfacial stress analysis for a brittle coating/ductile substrate system, which is involved in a sliding contact with a rigid ball, is presented. By combining interface mechanics theory and the image point method, stress and displacement responses within a coated material for normal load, tangential load, and thermal load are obtained; further, the Green's functions are established. The effects of coating thickness, friction coefficient, and a coating's thermoelastic properties on the interfacial shear stress, τ xz , and transverse stress, σ xx , distributions are discussed in detail. A phenomenon, where interfacial shear stress tends to be relieved by frictional heating, is found in the case of a coating material's thermal expansion coefficient being less than a substrate material's thermal expansion coefficient. Additionally, numerical results show that distribution of interfacial stress can be altered and, therefore, interfacial damage can be modified by adjusting a coating's structural parameters and thermoelastic properties.

The different folding and storage forms of an inflatable boarding platform will have a direct impact on the deployment effect of the marine emergency evacuation system. This paper proposes different folding and storage methods for an inflatable boarding platform in a marine emergency evacuation system. According to the difference between the fold line and the fold direction, the numerical models of a boarding platform with partial fold, "Z" type fold and inner spiral fold are established. The platform models with three folding modes are simulated by numerical simulation. According to the numerical results of the inflation process, the displacement changes of the inflatable membrane and the surface characteristics of the model are compared and analyzed, and the synchronization of the deployment process of the upper and lower airbags in three folding forms is studied. The deployment characteristics of different folding inflatable boarding platforms in different stages are analyzed. The numerical results are of great reference value to the folding and releasing process of an inflatable boarding platform and its practical design as well as its application in the evacuation system.

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