Cathodic arc evaporation is a well-established physical vapor deposition technique which is characterized by a high degree of ionization and high deposition rate. So far, this technique has been mainly used for the de...Cathodic arc evaporation is a well-established physical vapor deposition technique which is characterized by a high degree of ionization and high deposition rate. So far, this technique has been mainly used for the deposition of tribological coatings. In this study, anti-corrosive and electrical conductive carbon-based coatings with a metallic interlayer were prepared on stainless steel substrates as surface modification for metallic bipolar plates. Hereby, the influence of the deposition temperature during the deposition of the carbon top layer was investigated. Raman spectroscopy revealed differences in the microstructure at 200°C compared to 300°C and 100°C. Measurements of the interfacial contact resistance showed that the deposited coatings significantly improve the electrical conductivity. There are only minor differences between the different carbon top layers. The corrosion resistance of the coatings was studied via potentiodynamic polarization at room temperature and 80°C. Experiments showed that the coating with a carbon top layer deposited at 200°C, considerably reduces the current density and thus corrosion of the substrate is suppressed.展开更多
In the present paper, coating systems consisting of a metallic corrosion barrier and a conductive graphitic carbon layer were deposited by a DC vacuum arc process. The coatings were developed in a batch process for ap...In the present paper, coating systems consisting of a metallic corrosion barrier and a conductive graphitic carbon layer were deposited by a DC vacuum arc process. The coatings were developed in a batch process for application in the polymer electrolyte membrane fuel cell (PEMFC), and transferred to a continuous coil process to facilitate industrial mass production. The coating samples in the coil process had to achieve comparable results to the samples produced in the batch process, to meet the requirements of the environment prevailing in the fuel cell.The transfer to roll-to-roll processes is a crucial factor for commercial upscaling of PEMFC production. The experimental results showed that the electrical conductivity and corrosion resistance of the samples in the coil process were significantly improved compared to the uncoated base material and showed comparable performance to batch coated samples. X-ray photoelectron spectroscopy (XPS) was performed to determine the depth profile and the surface composition. Additional measurements were recorded for the contact resistances using the four-wire sensing method as well as corrosion resistance using potentiodynamic methods.展开更多
文摘Cathodic arc evaporation is a well-established physical vapor deposition technique which is characterized by a high degree of ionization and high deposition rate. So far, this technique has been mainly used for the deposition of tribological coatings. In this study, anti-corrosive and electrical conductive carbon-based coatings with a metallic interlayer were prepared on stainless steel substrates as surface modification for metallic bipolar plates. Hereby, the influence of the deposition temperature during the deposition of the carbon top layer was investigated. Raman spectroscopy revealed differences in the microstructure at 200°C compared to 300°C and 100°C. Measurements of the interfacial contact resistance showed that the deposited coatings significantly improve the electrical conductivity. There are only minor differences between the different carbon top layers. The corrosion resistance of the coatings was studied via potentiodynamic polarization at room temperature and 80°C. Experiments showed that the coating with a carbon top layer deposited at 200°C, considerably reduces the current density and thus corrosion of the substrate is suppressed.
文摘In the present paper, coating systems consisting of a metallic corrosion barrier and a conductive graphitic carbon layer were deposited by a DC vacuum arc process. The coatings were developed in a batch process for application in the polymer electrolyte membrane fuel cell (PEMFC), and transferred to a continuous coil process to facilitate industrial mass production. The coating samples in the coil process had to achieve comparable results to the samples produced in the batch process, to meet the requirements of the environment prevailing in the fuel cell.The transfer to roll-to-roll processes is a crucial factor for commercial upscaling of PEMFC production. The experimental results showed that the electrical conductivity and corrosion resistance of the samples in the coil process were significantly improved compared to the uncoated base material and showed comparable performance to batch coated samples. X-ray photoelectron spectroscopy (XPS) was performed to determine the depth profile and the surface composition. Additional measurements were recorded for the contact resistances using the four-wire sensing method as well as corrosion resistance using potentiodynamic methods.
