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

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

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Study of Corrosion Inhibition Mechanism of Sputter-Deposited W-42Cr-5Ni and Cr-10Zr-10w Alloys by Sodium Nitrite as Green Inhibitor in 0.5 M NaCl and 1 M NaOH Solutions

International Journal of Applied Sciences and Biotechnology ◽

10.3126/ijasbt.v2i4.11531 ◽

2014 ◽

Vol 2 (4) ◽

pp. 537-543

Author(s):

Dhruba Babu Subedi ◽

Durga Bhakta Pokharel ◽

Jagadeesh Bhattarai

Keyword(s):

Corrosion Resistance ◽

Corrosion Inhibitor ◽

Corrosion Inhibition ◽

Sodium Nitrite ◽

Physical Adsorption ◽

Inhibition Mechanism ◽

Green Inhibitor ◽

Green Corrosion Inhibitor ◽

Corrosion Resistance Property ◽

Sputter Deposited

The effect of different concentrations of sodium nitrite as a green corrosion inhibitor on the corrosion inhibition mechanism of the sputterdeposited ternary W-42Cr-5Ni and Cr-10Zr-10W alloys was studied in 0.5 M NaCl and 1 M NaOH solutions open to air at 25ºC using corrosion tests. The use of the sodium nitrite enhanced the corrosion resistance properties of both the alloys in 0.5 M NaCl and 1 M NaOH solutions. It is found that the sodium nitrite is strongly adsorbed on the surface of the sputter-deposited these two alloys by physical adsorption, not by the chemisorption. As a result the corrosion resistance property of the alloys was found to be significantly increased with increasing the concentration of the green corrosion inhibitor of sodium nitrite. The corrosion rates of the sputter-deposited W-42Cr-5Ni and Cr-10Zr-10W alloys were decreased with increasing the concentrations of sodium nitrite of 2400 ppm. DOI: http://dx.doi.org/10.3126/ijasbt.v2i4.11531Int J Appl Sci Biotechnol, Vol. 2(4): 537-543

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The Corrosion Behavior of Sputter?deposited W?xTa Alloys in 0.5 M NaCl Solution

Nepal Journal of Science and Technology ◽

10.3126/njst.v14i1.8929 ◽

2013 ◽

Vol 14 (1) ◽

pp. 103-108

Author(s):

Jagadeesh Bhattarai ◽

Susil Baral

Keyword(s):

Corrosion Resistance ◽

Corrosion Rate ◽

Corrosion Behavior ◽

Open Circuit Potential ◽

Corrosion Potential ◽

Open Circuit ◽

Nacl Solution ◽

High Corrosion Resistance ◽

Positive Direction ◽

Sputter Deposited

The corrosion behavior of the sputter–deposited amorphous and nanocrystalline W–xTa (x = 8–77) alloys was studied in 0.5 M NaCl solution open to air at 25°C using corrosion tests and electrochemical measurements. Tungsten and tantalum metals act synergistically in enhancing the corrosion resistance of the sputter–deposited W–xTa alloys and hence additions of 23 at. % of tantalum or more to the sputter–deposited W–xTa alloys were found to be effective to achieve significantly high corrosion resistance properties of the alloys than those of alloy– constituting elements. In particular, the corrosion rate of the W–60Ta alloy showed the lowest corrosion rate (that is, 2.0×10-3). The open circuit potential of the alloys shifted noble (positive) direction with immersion time. Addition of tantalum metal in W–xTa alloys is effective for ennoblement of the open circuit corrosion potential of the tungsten metal in 0.5 M NaCl solution open to air at 25°C. Nepal Journal of Science and Technology Vol. 14, No. 1 (2013) 103-108 DOI: http://dx.doi.org/10.3126/njst.v14i1.8929

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Electrochemical Impedance Spectroscopy (EIS) Study of Nano-Composite Polyurea Coating under the Wet-Dry Cyclic Conditions

Materials Science Forum ◽

10.4028/www.scientific.net/msf.789.495 ◽

2014 ◽

Vol 789 ◽

pp. 495-500

Author(s):

Bing Ying Wang ◽

Qing Hao Shi ◽

Wen Long Zhang

Keyword(s):

Corrosion Resistance ◽

Electrochemical Impedance Spectroscopy ◽

Impedance Spectroscopy ◽

Composite Coating ◽

Electrochemical Impedance ◽

Protective Action ◽

Experimental Result ◽

Resistance Property ◽

Corrosion Resistance Property ◽

Mass Fractions

The polyurea was modified by adding different amounts of nanometer ZnO. The corrosion behavior of polyurea/primer composite coating system in wet-dry cyclic environment of 3.5% NaCl solution was studied by using the Electrochemical Impedance Spectroscopy (EIS) measurement and adhesion test technology. The experimental result showed that, different mass fractions of nanometer ZnO had different influences on the corrosion resistance property of coating. When the mass fraction of nanometer ZnO was 5%, the composite coating had the largest protective action. The corrosion resistance property of nanometer ZnO can be improved by increasing the density of polyurea coating, however, the corrosion resistance property of polyurea coating will be weakened in case of exceeding the critical adding amount.

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Effects of tungsten, chromium and zirconium on the corrosion behavior of ternary amorphous W–Cr–Zr alloys in 1 M NaOh solution

Scientific World ◽

10.3126/sw.v9i9.5516 ◽

1970 ◽

Vol 9 (9) ◽

pp. 39-43

Author(s):

Basu Ram Aryal ◽

Jagadeesh Bhattarai

Keyword(s):

Corrosion Resistance ◽

Corrosion Rate ◽

Open Circuit Potential ◽

Open Circuit ◽

Corrosion Rates ◽

Corrosion Resistance Property ◽

Naoh Solution ◽

Order Of Magnitude ◽

Sputter Deposited ◽

Zr Alloys

Simultaneous additions of tungsten, chromium and zirconium in the chromium- and zirconium-enriched sputter-deposited binary W-xCr and W-yZr are effective to improve the corrosion resistance property of the ternary amorphous W- xCr-yZr alloys after immersion for 240 h in 1 M NaOH solution open to air at 25°C. The corrosion rates of all the examined sputter-deposited (10-57)W-(18-42)Cr-(25-73)Zr alloys is higher than those of alloy-constituting elements (that is, tungsten, chromium and zirconium) in aggressive 1 M NaOH solution open to air at 25°C. The corrosion rates of all the examined sputter−deposited W–xCr–yZr alloys containing 10-57 at% tungsten, 18-42 at% chromium and 25-73 at% zirconium were in the range of 1.5-2.5 × 10−3 mm/y or lower which are more than two orders of magnitude lower than that of sputter-deposited tungsten and even about one order of magnitude lower than those of the sputter-deposited zirconium in 1 M NaOH solution. Keywords: Ternary W–Cr–Zr alloys; Amorphous; Corrosion rate; Open circuit potential; 1 M NaOH. DOI: http://dx.doi.org/10.3126/sw.v9i9.5516 SW 2011; 9(9): 39-43

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The Corrosion Behavior of Sputter-Deposited Nanocrystalline W-Cr Alloys in Nacl and NaohaSolutions

Journal of Nepal Chemical Society ◽

10.3126/jncs.v25i0.3300 ◽

1970 ◽

Vol 25 ◽

pp. 53-61

Author(s):

Minu Basnet ◽

Jagadeesh Bhattarai

Keyword(s):

Corrosion Resistance ◽

Corrosion Rate ◽

Corrosion Behavior ◽

Chromium Content ◽

Open Circuit ◽

Nacl Solution ◽

Corrosion Rates ◽

Naoh Solution ◽

Order Of Magnitude ◽

Sputter Deposited

The corrosion behavior of the sputter-deposited nanocrystalline W-Cr alloys wasstudied in 0.5 M NaCl and alkaline 1 M NaOH solutions at 25°C, open to air usingimmersion tests and electrochemical measurements. Chromium metal acts synergisticallywith tungsten in enhancing the corrosion resistance of the sputter-deposited W-Cr alloys soas to show higher corrosion resistance than those of alloy-constituting elements in both 0.5M NaCl and 1 M NaOH solutions. In particular, the nanocrystalline W-Cr alloys containing25-91 at% chromium showed about one order of magnitude lower corrosion rates (that is,about 1-2 × 10-3 mm.y-1) than those of tungsten and chromium metals even for prolongedimmersion in 0.5 M NaCl solution at 25°C. On the other hand, the corrosion rate of thesputter-deposited W-Cr alloys containing 25-75 at % chromium was decreased significantlywith increasing chromium content and showed lowest corrosion rates (that is, 1.5-2.0 × 10-3 mm.y-1) after immersed for prolonged immersion in 1 M NaOH solution. The corrosion ratesof these nanocrystalline W-(25-75)Cr alloys are nearly two orders of magnitude lower thanthat of tungsten and more than one order of magnitude lower corrosion rate than that ofsputter-deposited chromium metal in 1 M NaOH solution. The corrosion-resistant of all theexamined sputter-deposited W-Cr alloys in 0.5 M NaCl solution is higher than in alkaline 1M NaOH solution at 25°C. Open circuit potentials of all the examined W-Cr alloys areshifted to more noble direction with increasing the chromium content in the alloys afterimmersion for 72 h in both 0.5 M NaCl and 1 M NaOH solutions at 25°C, open to air.Keywords: Sputter deposition, nanocrystalline W-Cr alloys, corrosion test, electrochemicalmeasurement, NaCl and NaOH solutions.DOI: 10.3126/jncs.v25i0.3300Journal of Nepal Chemical Society Volume 25, 2010 pp 53-61

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