Study the effect of sodium nitrite as a green corrosion inhibitor for the sputter-deposited tungsten-based ternary alloys in 0.5 M NaCl solution

Abstract

Effects of sodium nitrite on the corrosion resistance and mechanism of the sputter-deposited W-80Cr-10Zr and W-42Cr-5Ni alloys were studied using corrosion tests and open circuit potential (OCP) measurements in 0.5 M NaCl solution, open to air at 25ºC. The corrosion resistance property of the W-80Cr-10Zr and W-42Cr-5Ni alloys was enhanced by the use of environmental friendly corrosion inhibitor of sodium nitrite. Higher corrosion resistance property and passivation behavior was observed for the W-42Cr-5Ni alloy than that for the W-80Cr-10Zr alloy based on the corrosion rate and OCP measurements. Adsorption process obeyed Langmuir adsorption isotherm to explain the corrosion inhibition mechanism of the alloys by sodium nitrite solution. The standard free energy change of adsorption of sodium nitrite on the W-80Cr-10Zr and W-42Cr-5Ni alloys was found to be -23.70 KJ/mole and -23.38 KJ/mole, respectively which suggested that sodium nitrite is strongly adsorbed on the surfaces of the alloy surfaces by physical adsorption, not by the chemisorption. As a result the corrosion resistance property of the alloys was significantly increased with increasing the sodium nitrite concentration. From the OCP measurement, it is concluded that sodium nitrite acts as an anodic corrosion inhibitor, because the OCPs of the alloys in presences of the corrosion inhibitors were shifted to more positive direction with increasing the concentration of sodium nitrite in 0.5 M NaCl solution open to air at 25ºC.DOI: http://dx.doi.org/10.3126/bibechana.v12i0.11670BIBECHANA 12 (2015) 1-12

An overview on the non-destructive in-depth surface analysis of corrosion-resistant films: A case study of W-xCr deposits in 12 M HCl solution

“…Three sputter-deposited W-xCr alloys were characterized as nano-crystalline structure having an apparent grain size between 8 and 15 nm [31] from XRD patterns using Scherrer formula as describes elsewhere [54,80]. Before the immersion tests and AR-XPS analyses, the alloy specimens were mechanically polished with a SiC paper having the grit number 1500 in cyclohexane, degreased by acetone, and dried by blowing dry air to remove the oxide film formed on the surface of the alloys as described elsewhere [81][82][83]. The average corrosion rate was estimated using weight loss methods as described elsewhere [84,85].…”

Appraisal of Different Inorganic Inhibitors Action on the Corrosion Control Mechanism of Mild Steel in HNO3 Solution

“…Past researches had reported that some organic [20][21][22][23][24][25] and inorganic [26][27][28][29][30] compounds were used as eco-friendly corrosion inhibitors because they form complexes with metal ions on metal/alloy surface. Investigations of corrosion-inhibiting ability of inorganic radicals or ions, e.g., nitrites, molybdates, tungstates, polyphosphates are now being increasingly used as eco-friendly inhibitor due to their zero-toxic nature [10,[31][32][33][34][35][36]. It was reported that calcium nitrate acted as retarder against chloride-induced concrete structures like well-known corrosion inhibitor of calcium nitrite [37] because it is also cheaper, less harmful and more available [38].…”

A comparative study of the anticorrosive response ofTinospora cordifoliastem extract for Al and Cu in biodiesel-based fuels

“…Thus, adsorption of these phytoconstituents on the surfaces of the corroded Al and Cu enhances to fabrication of highly stable and less reactive layers, which blocks anodic/cathodic or both sides, and hence prevents significantly the corrosion rates of the metals in the presence of the inhibitors [63]. The degree of such corrosion-preventing layer is mostly in proportionate to the inhibitor concentrations, and it affects the physicochemical characteristics as described above in the adsorption models [64].…”