Abstract Biofouling has been persisting as a worldwide problem due to the difficulties in finding efficient environment-friendly antifouling coatings for long-term applications. Developing novel coatings with desired antifouling properties has been one of the research goals for surface coating community. Recently hydrogel coating was proposed to serve as antifouling layer, for it offers the advantages of the ease of incorporating green biocides, and resisting attachment of microorganisms by its soft surface. Yet poor adhesion of the hydrogel on steel surfaces is a big concern. In this study, porous matrix aluminum coatings were fabricated by cored wire arc spray, and the sizes of the pores in the aluminum (Al) coatings were controlled by altering the size of the cored powder of sodium chloride. Silicone hydrogel was further deposited on the porous coating. The hydrogel penetrated into the open pores of the porous Al coatings, and the porous Al structure significantly enhanced the adhesion of the hydrogel. In addition, hydrogel coating exhibited very encouraging antifouling properties.

Abstract In subzero conditions, atmospheric ice naturally accretes on surfaces in outdoor environments. This accretion can compromise the operational performance of several industrial applications, such as wind turbines, power lines, aviation, and maritime transport. To effectively prevent icing problems, the development of durable icephobic coating solutions is strongly needed. Here, the durability of lubricated icephobic coatings was studied under repeated icing/deicing cycles. Lubricated coatings were produced in one-step by flame spraying with hybrid feedstock injection. The coating icephobicity was investigated by accreting ice from supercooled microdroplets using an icing wind tunnel. The ice adhesion strength was evaluated by a centrifugal ice adhesion tester. The icing performance was investigated over four icing/deicing cycles. Surface properties of coatings, such as morphology, topography, chemical composition and wettability, were analyzed before and after the cycles. The results showed an increase in ice adhesion over the cycles, while a stable icephobic behaviour was retained for one selected coating. Moreover, consecutive ice detachment caused a surface roughness increase. This promotes the formation of mechanical interlocking with ice, thus justifying the increased ice adhesion. Finally, the coating hydrophobicity mainly decreased as a consequence of the damaged surface topography. In summary, lubricated coatings retained a good icephobic level after the cycles, thus demonstrating their potential for icephobic applications.

Abstract The high velocity oxy-fuel (HVOF) combustion spray technique has been shown previously to be an excellent solution for depositing crystalline matrix nano-reinforced polymer coatings. Dense polymer coatings can be produced by controlling both the particle dwell time in the HVOF jet and through substrate thermal management. In composite materials, it is often desirable to incorporate the maximum amount of reinforcing material into the polymer matrix to achieve optimum mechanical properties. The experiments described here were performed to determine the maximum amount of different scales of silica particles that could be incorporated into a nylon 11 matrix and the time required to do so. Ashing results indicated a maximum amount of silica that can be incorporated. Also, the maximum level of silica incorporation occurs in a shorter time than previously believed. Microscopy, however, indicated that other physical changes continued to occur within the powders when ball milling was allowed to continue beyond this time.

Abstract The governments, in order to protect the environment, have increased the restrictions on products containing Volatile Organic Compounds. These products include the paints, which are usually used as protection of metallic structures. An alternative to these products are polymeric coatings obtained by thermal spray techniques. In this paper, the abrasion wear resistance and corrosion resistance of polyamide 11 and polyamide 11 + aluminum oxide coatings, flamesprayed, are compared. The electrochemical investigations are carried out to analyze the corrosion resistance in a marine environment. The structural examinations of such layers are carried out by means of optical and scanning electron microscopy. Paper includes a German-language abstract.

Abstract The high velocity oxy-fuel (HVOF) combustion spray technique has been shown previously to be an excellent solution for depositing crystalline matrix nano-reinforced polymer coatings [1]. Dense polymer coatings can be produced by HVOF combustion spraying by controlling particle dwell time in the jet and through substrate thermal management. Use of an amorphous matrix material, polycarbonate, will enable the role of matrix crystallinity on the structure and properties of thermally sprayed polymer composite coatings to be separated from effects resulting from the reinforcing phase. An amorphous, commercial polycarbonate resin with a broad particle size distribution of irregular particle morphology has been successfully deposited. Results from optical microscopy, X-ray diffraction, scratch and density measurements are presented. The influence of variations in process parameters such as spray distance, nozzle length, chiller temperature, fuel: oxygen ratio, and total gas flow rate on coating microstructure are presented.

Abstract This paper aims to fabricate wear resistant composite coatings on light metal substrates which also exhibit low friction coefficients. It demonstrates that combined ceramic polymer coating systems are a powerful concept for industrial applications where high wear resistance, creep resistance and compressive strength as well as low friction coefficients are required. The results show that, under the specific experimental conditions used, the titanium dioxide layer in connection with the applied lubricant lacquer showed better performance than the mixed aluminum oxide/titanium dioxide layers. Paper includes a German-language abstract.

Abstract Electrostatic fluidized bed spraying is a coating process that is often used for coating plastic. A novel flame spray technology with a controlled atmosphere was developed by Air Liquide in order to realize coatings with thermoplastics as well as composite coatings such as plastic/ceramic or plastic/metal. This technology expands the scope of the applications of plastic coatings especially for all types of shapes and materials as well as for on-site coating. Two types of powder, namely Rilsan and Gotalene were used in this study. The tests were carried out by HTI, which is Air Liquide's partner in the development of such applications. After introducing the principle of this process, this paper presents and discusses the coating process and the properties of such coatings. Then the advantages and limitations of the process are highlighted. Paper includes a German-language abstract.

Abstract Polyphenylene-sulphide (PPS) and polyphenyletheretherketone (PEEK) have high heat and corrosion-resistant performance. Thermal sprayed coatings of PPS and PEEK have been produced by the HVAF spray system. The molecular structures of these coatings have been analyzed by Fourier Transform Infrared Spectrophotometer (FT-IR) and Differential Scanning Calorimeter (DSC). The microstructures of cross-section and surfaces of these coatings have been observed. The formation mechanism of these coatings has been estimated as follows; (1) PPS and PEEK powders are melted and oxidized during thermal spraying. However, the amount of coating oxidation is very small, so that high anti-corrosion performance of sprayed coatings is obtained. (2) These coatings have some pores including the incomplete melting particles. However, it is estimated that these pores are closed-pores.

Abstract Fiber-reinforced polymer composites are an important class of structural materials, offering high strength-to-weight ratios and high rigidities. For many applications, however, their wear resistance is less than desirable. Wear-resistant thermal spray coatings have the potential to improve the surface properties of fiber-reinforced polymer composites, although some require the application of a bond coat to achieve sufficient adhesion. The present study was conducted to find acceptable bond coat materials and compare their performance. Materials such as polyamides, polyimides, polyether-ether-ketone, or simply aluminum or nickel were found to be suitable bond coats for many composite substrates.

Abstract The last decade has seen a rapid increase in the use of Thermally Sprayed Coatings for Oil and Gas production applications. In particular, since 1982 the Offshore Oil and Gas Industry has considered Thermally Sprayed Aluminum (TSA) for protection of steel structures in the splash zone and other areas in the marine environment. Experience to date has indicated that when TSA is properly applied with a specific sealer system a service life in excess of 30 years with zero maintenance is possible. This produces a corresponding reduction in life cycle costs. Other coating systems such as nickel-based alloys, ceramics and thermoplastics are also finding useful applications. This paper discusses recent advances in thermal spraying technology and current and future applications in the Oil and Gas Industry. This is illustrated with reference to several projects and details on life cycle costs. In particular, thermal spraying of pressure vessels, risers, pipelines and structural components are detailed.

Abstract The mechanical properties of EMAA copolymer are dependent upon the thermal spray processing parameters. The parameters determine coating temperatures which, in turn, affects the microstructure. If the deposition temperature is too low, (104 °C for PFl 13 and 160 °C for PFl 11) coatings have low strengths and low energy to break values. Increased coating temperatures allow the particles to fully coalesce resulting in maximized strength and elongation to break. However, at 271 °C, PFl 11 had visible porosity which decreased both strength and elastic modulus. Pigment acts as reinforcement in the sense that the modulus increased but the elongation to break decreased, thus reducing the energy to break. Water quenching reduces the elastic modulus and yield strength, but increases the elongation to break for both EMAA formulations. The mechanical properties of post consumer commingled plastic and PCCP / EMMA blends improved if the recycled plastic was pre-processed by melt-compounding. Melt compounding increased the strength and toughness by improving the compatibility among the various polymer constituents. The addition of PCCP increases the modulus and yield strength of ethylene methaciylic acid copolymer.

Abstract Plasma spray deposition of epoxies under normal conditions produces coatings with low wear resistance. The research shows that the difficulty in achieving satisfactory properties is a result of the rapid heat flow from the coating to the substrate, which suppresses the crosslinking reaction. The results indicate that the use of substrate preheating or ceramic undercoats enhances the wear resistance by promoting the curing reaction during spraying.

Abstract A heat transfer analysis has been undertaken to predict the influence of process parameters on the decomposition of in-flight particles and deposited layers during thermal spraying of polymer coatings. The theoretical analysis shows that polymers are unique in developing large temperature gradients, which accelerates the degradation of the surface of the particles and the coating layers. However, the analysis indicates that the degradation can be limited by the control of the plasma gas composition, the spraying distance and the torch traverse speed. The theoretical analysis has been confirmed by weight loss measurements, wear tests and microstructural observations of plasma sprayed PMMA coatings. The work shows the existence of a critical traverse speed below which satisfactory coatings cannot be produced.

Abstract Polymeric coatings are now widely used for their corrosion resistance, low friction coefficient against many materials, decorative properties but also, when doped with ceramic particles, their protection against slipping and their good erosion resistance. Compared to traditional means of deposition, flame spraying in controlled atmosphere extends the scope of their applications either for shapes that can be coated or for site deposition. The materials chosen for spraying were Rislan, Gotalene and Tefzel. In this paper are presented the flame spraying technique which was used and the parameters controlling particles melting as well as, the substrates on which coatings were achieved (metals, woods, concretes, ceramics...) and their preparation. A few applications are then described with for example coatings reinforced by ceramic particles against slipping in wet or greasy area.

Abstract Experimental studies of the subsonic combustion process have been conducted in order to determine the quality and economics of polyester, epoxy, urethane, and hybrid polyester-epoxy coatings. Thermally sprayed polymer coatings are of interest to several industries for anti-corrosion applications, including the infrastructural, chemical, automotive, and aircraft industries. Classical experiments were conducted, from which a substantial range of thermal processing conditions and their effect on the resultant coating were obtained. The coatings were characterized and evaluated by a number of techniques, including Knoop microhardness tests, optical metallography, image analysis, and bond strength. Characterization of the coatings yielded thickness, bond strength, hardness, and porosity.

Abstract Thermal sprayed coatings of polypenylene-sulphide (PPS) and polyphenyletherether-ketone (PEEK) have been produced by HVAF spray system. The properties of these coatings have been investigated by corrosion test and FT-IR analysis. The main results of this study are summarized as follows; (1) In case of PPS coatings, PPS powder is oxidized during thermal spraying. However, PPS coatings have a good corrosion resistance. However, PEEK coatings have high porosity so that corrosion of the substrate occurs. (2) In case of PEEK coatings, the molecular structure of PEEK powder is not changed during thermal spraying.