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Corrosion resistant Fe – Al / Al 2 O 3 duplex coating for pipeline steel X80 was prepared by a combined treatment of low-temperature aluminizing and micro-arc oxidation (MAO). Phase composition and microstructure of mono-layer Fe – Al coating and Fe – Al / Al 2 O 3 duplex coating were studied by X-ray diffraction (XRD), scanning electron microscope (SEM) with energy dispersive spectrometer (EDS). Corrosion resistance of the coated pipeline steel X80 in a simulated oil and gas well condition was also investigated. Mono-layer Fe – Al coating consists of Fe 2 Al 5 and FeAl , which is a suitable transitional layer for the preparation of ceramic coating by MAO on the surface of pipeline steel X80. Under the same corrosion condition at 373 K for 168 h with 1 MPa CO 2 and 0.1 MPa H 2 S , corrosion weight loss rate of pipeline steel X80 with Fe – Al / Al 2 O 3 duplex coating decreased to 23% of original pipeline steel X80, which improved by 10% than that of pipeline steel X80 with mono-layer Fe – Al coating. It cannot find obvious cracks and pits on the corrosion surface of pipeline steel X80 with Fe – Al / Al 2 O 3 duplex coating.

Multi-walled carbon nanotubes (MWCNTs) were irradiated by 1.2 keV Ar ion beams for 15–60 min at room temperature with current density of 60 µA/cm2. The morphology and microstructure are investigated by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that carbon nanofibers are achieved after 60 min ion irradiation and the formation of carbon nanofibers proceeds through four periods, carbon nanotubes—amorphous carbon nanowires—carbon nanoparticles along the tube axis—conical protrusions on the nanoparticles surface—carbon nanofibers from the conical protrusions.