Investigation of Corrosion and Structural Properties of the Coating Created by Active Screen Plasma Nitriding on Al۱۰۵۰

In this research, the effect of time and temperature of active screen plasma nitriding (ASPN is a novel method of coating) treatment on the surface properties of aluminum alloy ۱۰۵۰ was investigated. Al۱۰۵۰ samples were subjected to ASPN treatment in an atmosphere of %۲۰H۲-%۸۰N۲ at temperatures of ۴۵۰oC and ۵۰۰oC for ۵ and ۱۰ hours. The obtained phases and microstructure were studied by Grazing Incidence X-ray Diffraction (GIXRD) and Field Emission-Scanning Electron Microscope (FE-SEM) equipped with EDS analyzer. The corrosion resistance of treated and untreated samples was investigated by polarization and electrochemical impedance spectroscopy (EIS) measurements. The results showed that the formed layer on the surface of specimens consists of Fe۲-۳N and AlN phases. Microscopic evaluations revealed that the ASPN treatment for ۵ hours at ۴۵۰oC resulted in the formation of nitride grains with an average diameter of ~۸۵nm, while the average size of nitride grains after ۱۰ hours treatment at ۵۰۰oC was about ۲۳۳ nm. In addition, as the time and temperature of ASPN treatment increased, the thickness of nitride layer increased from ۱.۴±۰.۴ to ۵.۸±۰.۹ micrometer. The best corrosion resistance, were measured in the sample of plasma nitrided at ۵۰۰oC and ۱۰h. The corrosion mechanism of the nitride coating was localized pitting corrosion.

کلیدواژه ها:

Active screen plasma nitriding ، Al۱۰۵۰ ، Iron nitride ، Aluminium nitride ، Corrosion ، نیتروژن دهی پلاسمایی با توری فعال ، آلومینیم ۱۰۵۰ ، نیترید آهن ، نیترید آلومینیم ، خوردگی.