Abstract:
The study examined the elemental composition and morphology of selected stainless steels and an aluminium alloy, and determine the tribocorrosion characteristics of the selected steels and an aluminium alloy. This was with view to determining their suitability as materials of construction for renewable energy system. Ttribocorrosion behaviour of 316 austenitic stainless steel, 2205 duplex stainless steel and 6063 aluminium alloy were investigated in simulated acid rain (different concentrations of sulphuric acid, nitric acid) and 3.5 weight percent sodium chloride environment. The corrosion behaviour was studied by potentiodynamic method and the tribocorrosion behaviour were studied in sand slury pot using Tafel polarization and tribo-electrochemistry technique. The surface morphology of the alloys were examined by optical microscopy. The tribocorrosion and electrochemical results showed that 316 austenitic steel showed higher corrosion rate in both chloride environment and sulphuric environment for all concentrations than 2205 duplex stainless steel and Aluminium alloys. Aluminium 6063 has the least corrosion rate in chloride environment while 2205 duplex stainless steel was the least in suphuric acid environment. Aluminium 6063 alloy had the most positive corrosion potential in nitric acid environment for all concentrations while 316 austenitic stainless steel had the most negative potential. Electrochemical potential increased with increase in concentration of the simulated environment and tribocorrosion analysis revealed the dynamics of rapid dissolution of possible passive films which are formed by the tested materials. The overall results of tribocorrosion and electrochemistry obtained by Tafel polarization and linear polarization with weight loss of 316Austenitic stainless steel, 2205 Duplex stainless steel and Al 6063 in 0.001M, 0.01M, 0.1M of Sulphuric acid, Nitric acid and 3.5% wt Sodium Chloride solution in millimeter per year were in agreement with the passivity breakdown envisaged.
