چكيده به لاتين
Erosion-corrosion is a complex phenomenon that includes interactions between the mechanical erosion from solid particles and the electrochemical process resulting from corrosion. The phenomenon is a challenging problem in oil and gas refineries, pipelines, pumps, automobile industry and air industry. In this study, the behavior of erosion-corrosion of API 5L X65 steel coated with chromium nitride has been investigated. Chromium nitride was coated in two steps; chromium plating and plasma nitriding. Hard chromium electroplating was carried out in standard solution (250 g.l-1 chromic acid and 2.5 g.l-1 sulfuric acid) at 60 °C and current density of 60 A.dm-2 for one hour. In the following, plasma nitriding was performed at 530 °C and 10 hours. The effects of various impact velocities (4, 5, 6, 7.5 m.s-1) and different impact angles (30◦, 45◦, 60◦, 90◦) on the erosion-corrosion behavior were studied by using the slurry containing of 3.5 wt.% NaCl, 3 wt.% SiO2. The degradation rate was determined through erosion corrosion, total corrosion and total erosion separately for X65 steel and coating. Total corrosion test was determined simultaneously with erosion corrosion test using potentiostat instrument. The phase and surface morphology of samples were characterized by X-ray diffractometry and scanning electron microscopy techinques. The results of erosion corrosion of X65 steel showed that the maximum damage at angle of 45◦ and the degradation slightly decreased with the increase of impact angle. However, the maximum degradation was observed at angle of 90◦. Furthermore, the amount of degradation has increased with increase of impact velocity for the coated and base samples.
