Electrochemical Deposition Of Amorphous Carbon-based Films And Their Hydrophobic Corrosion Properties

The ocean covers about 71%of the Earth's surface and stores abundant resources.In recent years,with the strong demand for resources and the urgent development of the marine industry,the development of marine resources is attracting the attention of the state.The marine environment is highly corrosive,and various marine facilities,as well as ships and equipment,are seriously corroded in the marine environment,so the harsh environmental problems must be faced by marine development.Studies have shown that special wettability materials,especially superhydrophobic materials,have great potential in the development and utilization of marine resources based on their functional properties.The superhydrophobic material surface has excellent self-cleaning,barrier properties and low adhesion characteristics,and is of great significance in drag reduction,anti-corrosion and anti-biofouling.This work will carry out the design of micro/nano structure of carbon nanotubes?CNTs?-nanocrystalline amorphous carbon?a-C:H?films,and the aim is to construct the carbon nanotubes-nanocrystallite amorphous carbon-based composite films with excellent superhydrophobicity,self-cleaning and anti-corrosin.The closely relationship will be systematically analyzed between the composition,nanocrystallites,carbon nanotubes,micro/nano surface morphology and mechanical properties,wettability,self-cleaning ability and anti-corrosion for the carbon nanotubes-nanocrystalline amorphous carbon-based composite films.And the main conclusions are listed as follows:1.The amorphous carbon?a-C:H?films were prepared by using electrochemical deposition method with methanol as the carbon source and via adjusting different deposition voltages?800V¹600 V?.Based on the SEM,XPS,TEM,and Raman experimental research and vapor deposition theory,it was clarified that the growth mechanism of a-C:H films was the island model in the electrochemical deposition process.And the electrochemical deposition mechanism of a-C:H films was not the simple polarization-dissociation-electrochemical reaction process,but with the plasma process.The synergistic effect of the microstructure and surface morphology of the film determines the wetting properties of the a-C:H film.The water contact angle of the a-C:H film prepared at deposition voltage of 1200 V is about 101.20 deg,which is 33.30 deg higher than that of the pure silicon wafer surface;the corrosion current density is reduced from 2.81×10^-6 A·cm^-2 to 2.14×10^-6 A·cm^-2,decreased by 2 orders of magnitude,indicating that the corrosion resistance of the film has been greatly improved.2.The metal nickel particles are doped into the a-C:H film to form a novel low-dimensional carbon cluster nano/a-C:H composite films?Ni/a-C:H?.SEM and TEM tests show that the metal nano-Ni particles are embedded in the amorphous carbon-based film in the form of elemental nanocrystals.In virtue of the surface effect and small size effect of the Ni nanoparticles,the internal stress of the amorphous carbon film is effectively alleviated,and the micro-nano layered structure can be constructed on the surface of the a-C:H film,which imparts the novel superhydrophobic property and corrosion resistance of the a-C:H films.The water contact angle and sliding angle of the nanocrystalline/amorphous composite Ni/a-C:H film prepared at the nickel doping concentration of 0.08 mg/mL are 154.21 deg and 7.96 deg,respectively,exhibiting excellent superhydrophobic properties.In addition,the corrosion current density decreased by about 2 orders of magnitude compared with that of undoped film,which is 7.40×10^-10 A·cm^-2.3.The carbon nanotubes/nickel nanoparticles were co-doped into the amorphous carbon films,and the carbon nanotubes-nanocrystalline a-C:H composite films?CNTs/Ni/a-C:H?were successfully constructed.SEM and TEM tests showed that carbon nanotubes and metallic Ni nanoparticles are inlaid and grown in an amorphous carbon film.Because of the surface of the multi-walled carbon nanotubes contains a large number of surface groups such as carboxyl groups and their low surface energy properties,while maintaining the functional properties of the Ni/a-C:H films,the CNTs/Ni/a-C:H composite films exhibit outstanding superhydrophobic properties and superior corrosion resistance.Its water contact angle is as high as 158.89 deg and the sliding angle is 1.99 deg.At the same time,the corrosion current density is reduced to3.12×10^-10 A·cm^-2,and the low-frequency impedance modulus is as high as 6.84×10⁶?·cm².In addition,the superhydrophobic nanocomposite CNTs/Ni/a-C:H films not only shows good mechanical property,but also has excellent self-cleaning ability.It has greatly expanded the potential application of amorphous carbon-based film in the field of marine equipment and key components.