|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|5365287||1388328||2007||6 صفحه PDF||سفارش دهید||دانلود رایگان|
The formation of chromium carbide-based hard-coatings on steels using a 90Â°-bend filtered cathodic vacuum arc (FCVA) has extensive industrial applications; such coatings are free of macroparticles and exhibit excellent characteristics. In this investigation, a working pressure of C2H2/Ar was adopted to synthesize amorphous chromium carbide film (a-C:Cr) and crystalline chromium carbide film (cryst-Cr3C2) from a Cr target (99.95%) at 500Â Â°C under a substrate voltage of â50Â V. The corrosion behavior of a-C:Cr coated on steel (a-C:Cr/steel) and cryst-Cr3C2 coated on steel (cryst-Cr3C2/steel) were compared in terms of open-circuit potentials (OCP) and polarization resistance (Rp) in an aerated 3.5Â wt% NaCl aqueous solution, as determined by electrochemical impedance spectroscopy (EIS). The XRD results indicated that the transformation of a-C:Cr to cryst-Cr3C2 is distinct as the working pressure declines from 1.2Â ÃÂ 10â2 to 2.9Â ÃÂ 10â3Â Torr. The OCP of a-C:Cr/steel and cryst-Cr3C2/steel resemble each other and both assembly are nobler than uncoated steel. The Rp of the coatings exceeds that of the uncoated steel. The SEM observation and the EIS results demonstrate that the cryst-Cr3C2/steel more effectively isolates the defects than dose a-C:Cr/steel.
Journal: Applied Surface Science - Volume 253, Issue 11, 30 March 2007, Pages 5011-5016