To investigate the role of Cr and Cu in steels in different solutions, four kinds of low carbon steel with different Cr and Cu concentrations were prepared to investigate the effect of alloying elements on their corrosion behavior. Solutions of 3.5 wt.% NaCl, diluted hydrochloric acid and diluted sulphuric acid (pH=1.4-1.5) were used.
7267 2016 CP
Many researchers have reported the positive or negative effects of Cr and Cu addition on the corrosion behavior of steels. It is generally considered that Cr and Cu play different roles when the steels exposed to the different solution. The aim of this work is to investigate the role of Cr and Cu in steels in different solutions. In this study, four kinds of low carbon steel with different Cr and Cu concentrations were prepared in the laboratory, in order to investigate the effect of alloying elements on their corrosion behavior, solutions of 3.5 wt.% NaCl, diluted hydrochloric acid and diluted sulphuric acid (pH=1.4-1.5) were used, respectively. Electrochemical measurement and immersion test were performed at room temperature to characterize the corrosion behavior and evaluate the corrosion rate. Experimental results indicated that the corrosion resistance increased as a result of both Cr and Cu addition in 3.5 wt.% NaCl solution, while the corrosion resistance decreased as a result of Cr or Cu addition in acidic solution. In acidic solution, electrochemical impedance spectroscopy (EIS) revealed a capacitive semicircle in the high frequency range and an inductive loop in the low frequency range, the alloy elements of Cr and Cu exhibited a synergistic effect, leading to an increase in the corrosion rate of steel.
Key words: downloadable, low alloy steel, copper, chromium, acid solution, corrosion product