چكيده به لاتين
High entropy alloys with the general composition of AlxCoCrFeNi (x: up to 3 molar ratio) have been widely studied and researched by researchers in recent years due to their interesting set of physical, mechanical and corrosion properties. Aluminum plays a significant role in the hardness and corrosion resistance properties of these alloys. The high atomic radius of aluminum causes the composition of the alloy to change from FCC to BCC by increasing the percentage of this element, thereby increasing the hardness properties of the alloy. On the other hand, the formation of an unstable layer of porous aluminum oxide reduces the pitting corrosion resistance of the alloy. Therefore, to maintain the corrosion properties, it is appropriate to keep the percentage of aluminum as low as possible. At the same time, adding ceramic reinforcing particles can compensate for the decrease in the hardness of the alloy. In line with this goal, the composite of Al0.3CoCrFeNi alloy system with silicon carbide particles by mechanical alloying method has been studied by Asia Planetary in the upcoming research. Also, due to the possibility of in-situ layering during grinding, this method was used to create Al0.3CoCrFeNi-SiC composite coatings. First, in order to determine the appropriate time for the formation of the alloy and the coating, the alloying of the mixture of the constituent metal powders was done in 5, 10, 15, 20, 25 and 30 hours with a constant speed and ratio of pellets to powder, and In the next step, by adding 5, 10, and 15 percent by weight of silicon carbide to the mixture of metal powders, a composite coating was created on the steel substrate under optimal grinding conditions. XRD analysis was used for phase identification and analysis, and light microscope and SEM images were used for microstructural investigations of the coating cross-section and elemental distribution. Vickers hardness tests, polarization and electrochemical impedance spectroscopy were also used to measure the hardness and corrosion properties of the coating. The results of XRD analysis showed 20 hours as the optimal time for alloy formation. The hardness of the alloy coating was 590 Vickers and the hardness of the composite coatings containing 5, 10 and 15% by weight of SiC in the charge were 624, 647 and 684, respectively. The data of potentiodynamic polarization analysis for the alloy sample showed the corrosion potential of -0.681 V and the corrosion current density of 56.66 μA/cm2, while the corrosion potential for the composite samples was -0.708, -0.703 and 769, respectively. -0.V and corrosion current density were obtained as 48.46, 4.53 and 11.77 microamps/cm2, respectively. The results of electrochemical impedance spectroscopy analysis for the optimal sample containing 10% by weight of silicon carbide showed that the load transfer resistance of this sample was 260 microfarads, CPE was equal to 8.4-E19 microfarads/cm2 and n was 0.78.
