Studies on Corrosion of Annealed and Aged 18 Ni 250 Grade Maraging Steel in Sulphuric Acid Medium

Abstract

The corrosion behavior of aged and annealed sample of 18 Ni 250 grade maraging steel was investigated in varied conditions of concentration and temperature of sulphuric acid medium, using electrochemical techniques like Tafel polarization and electrochemical impedance spectroscopy (EIS). The results obtained from both the techniques are in good agreement. These results have shown increase in corrosion rate of aged specimen with increase in concentration and temperature of sulphuric acid. With increase in concentration of sulphuric acid from 0.025 M to 0.25 M the corrosion rate of annealed sample was found to increase, but there after in 0.5 M, 0.75 M and 1 M, the rate of corrosion decreases, indicating passivation of alloy surface at higher concentration of sulphuric acid. The corrosion rate of aged specimen was found to be higher than that of the annealed specimen. Similar observations are revealed by SEM images. The thermodynamic parameters like activation energy, enthalpy of activation and entropy of activation were calculated.

Corrosion resistance performance of newly developed cobalt-free maraging steel over conventional maraging steel in acidic media

“…[16] Maraging steels were found to be less susceptible to hydrogen embrittlement than common high-strength steels owing to significantly low diffusion of hydrogen in them. [17] Poornima et al [4] have studied the corrosion behavior of 18 Ni 250 grade maraging steel in a phosphoric acid medium and reported that the corrosion rate of the annealed sample is less than that of the aged sample. Similar observations also have been reported for the corrosion of 18 Ni 250 grade maraging steel in suphuric acid medium.…”

“…Similar observations also have been reported for the corrosion of 18 Ni 250 grade maraging steel in suphuric acid medium. [18] In this work, the corrosion behaviour of two grades of cobalt-free as well as conventional maraging steel welded pipe steel in 1 M H 2 SO 4 solutions was investigated using linear polarisation and electrochemical impedance spectroscopy(EIS) techniques.…”

“…[1][2][3][4] Maraging refers to the ageing of martensite, a martensite that is easily obtained at normal cooling rates due to the high nickel content. [5] The alloy is a low carbon steel that classically contains about 18 wt% Ni, substantial amounts of Co and Mo, together with small additions of Ti.…”

Potentiodynamic Studies of Aluminium 2024 Alloy in Different Concentration of Hydrochloric Acid Medium at Laboratory Temperature

“…Finely polished Al 2024 alloy specimens with 1.0 cm 2 surface area were exposed to corrosion medium of different concentrations of hydrochloric acid (1 N, 0.75 N, 0.5 N and 0.25 N) separately at a laboratory temperature [19,20] . The potentiodynamic current-potential curves were recorded by polarizing the specimen to -250 mV cathodically and +250 mV anodically with respect to open circuit potential (OCP) at a scan rate of 0.01 V/s (Figures 1-5).…”

The Inhibition Effect of Potassium Iodide on the Corrosion of Pure Iron in Sulphuric Acid

“…and on the nature of the inhibitor [10]. Sulfuric acid is one of the most aggressive acids for iron and its alloys and is often used during cleaning, pickling, descaling, acidizing, and so forth [11,12]. The inhibitor molecules get bonded to the metal surface by chemisorption, physisorption, or complexation with the polar groups acting as the reactive centers in the molecules [13].…”