Passivation Behavior of Steel Rod and Wires of Nepal in Acidic and Alkaline Solutions

Abstract

The passivation behavior of steel rods and wires those are produced in Nepal was studied in 1 M HCl and 1 M NaOH solutions at 25°C, open to air using immersion tests and electrochemical measurements. The corrosion resistance of all the examined steel rods and wires in this work is found significantly higher in alkaline 1 M NaOH than in acidic 1 M HCl, mostly due to an ennoblement of the open circuit corrosion potentials of the steels at passive potential regions in 1 M NaOH solution at 25°C. The corrosion rate of all the examined steel rods and wires is about in the range of 1-5 x 10¹ mm/y in acidic 1 M HCl solution which is nearly three orders of magnitude lower corrosion resistance than in alkaline 1 M NaOH solution at 25°C. Therefore, these steel rods and wires seem to be very corrosion resistance materials in very alkaline environments like a reinforcing concrete.

Key words: steels; corrosion rate; open circuit potential; immersion test; electrochemical measurements.

DOI: 10.3126/njst.v9i0.3181

Nepal Journal of Science and Technology 9 (2008) 91-97