scholarly journals The Electrochemical and Surface Studies of the Corrosion Behavior of Sputter-deposited W-Ni Alloys in 0.5 M NaCl Solution

1970 ◽  
Vol 23 ◽  
pp. 45-53
Author(s):  
S. P. Sah ◽  
Jagadish Bhattarai
Keyword(s):  
Corrosion Behavior ◽  
Nickel Content ◽  
Electrochemical Measurement ◽  
Open Circuit ◽  
Nacl Solution ◽  
Corrosion Rates ◽  
Ni Alloys ◽  
Confocal Scanning ◽  
Confocal Scanning Laser ◽  
Sputter Deposited

The corrosion behavior of the sputter-deposited amorphous or/and nanocrystalline W-Ni alloys is studied in neutral 0.5 M NaCl solution at 25ºC, open to air using immersion tests, electrochemical measurements and confocal scanning laser microscopic (CSLM) techniques. In general, the corrosion rates of the W-Ni alloys containing less than 20 at% nickel content are slightly lower than that of tungsten metal whereas the corrosion rates of the alloys containing 20 at% nickel or more increased with the addition of nickel in the alloys. The pitting corrosion is observed in the nickel-rich W-69Ni alloy from CSLM studies. The open circuit corrosion potentials of all the examined W-Ni alloys are shifted to noble direction with the addition of nickel content in the alloys.Keywords: W-Ni alloys, passivation, NaCl, electrochemical measurement, pitting.DOI: 10.3126/jncs.v23i0.2096J. Nepal Chem. Soc., Vol. 23, 2008/2009 Page : 45-53

scholarly journals The Corrosion Behavior of Sputter-deposited W-Ti Alloys in 0.5 M NaCl Solution

1970 ◽  
Vol 10 ◽  
pp. 109-113 ◽  
Author(s):  
Jagadeesh Bhattarai
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Open Circuit ◽  
Nacl Solution ◽  
Corrosion Resistant ◽  
Corrosion Rates ◽  
Ti Alloys ◽  
Confocal Scanning ◽  
Confocal Scanning Laser ◽  
Sputter Deposited

The corrosion behavior of the sputter-deposited amorphous or nanocrystalline W-Ti alloys was studied in neutral 0.5 MNaCl solution at 25°C, open to air by immersion tests, electrochemical measurements and confocal scanning laser microscopic(CSLM) techniques. Titanium metal acts synergistically with tungsten in enhancing the corrosion resistance of the sputter-deposited W-Ti alloys so as to show higher corrosion resistance than those of alloy-constituting elements (that is, tungsten and titanium) in neutral 0.5 M NaCl solution. In particular, the amorphous W-Ti alloys containing 30-53 at% titanium showed lowest corrosion rates (that is, about 1 × 10-3 mm.y-1). Open circuit potentials of all the examined W-Ti alloys were shifted to more noble direction than those of the open circuit potentials of alloyconstituting elements in 0.5 M NaCl solution.Key words: Sputter deposition; W-Ti alloys; Corrosion-resistant; CSLM; NaCl solution.DOI: 10.3126/njst.v10i0.2899Nepal Journal of Science and Technology Volume 10, 2009 December Page:109-113 

scholarly journals Electrochemical and Surface Studies on the Passivation Behavior of Sputter-deposited W-Ni Alloys in NaOH Solutions

1970 ◽  
Vol 22 ◽  
pp. 7-16
Author(s):  
J. Bhattarai ◽  
S. P. Sah ◽  
H. Jha
Keyword(s):  
Chemical Society ◽  
Open Circuit ◽  
Nickel Metal ◽  
Corrosion Rates ◽  
Ni Alloys ◽  
Naoh Solution ◽  
Confocal Scanning ◽  
Confocal Scanning Laser ◽  
Sputter Deposited ◽  
The Stability

The passivation behavior of the sputter-deposited amorphous or/and nanocrystalline W-Ni alloys is studied in different concentrations of NaOH solutions at 25°C, open to air using corrosion tests, electrochemical measurements and confocal scanning laser microscopic (CSLM) techniques. The corrosion rates of the W-Ni alloys containing about 60-80 at% nickel are nearly two orders of magnitude lower than that of tungsten and even lower than that of nickel metal in 1 M NaOH solution at 25°C. The pitting corrosion is observed in the tungsten-rich W-9Ni alloy from CSLM studies. The open circuit potentials of all the examined W-Ni alloys are located between those of tungsten and nickel metals in 0.01, 0.1 and 1 M NaOH solutions. The stability of the passive films formed on the sputter-deposited W-Ni alloys increased with decreasing the concentrations of NaOH solutions. DOI: 10.3126/jncs.v22i0.517Journal of Nepal Chemical Society Vol. 22, 2007 pp. 7-16

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

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

scholarly journals The Passivation Behavior of Sputter-Deposited W-Ti Alloys in 1 M NaOH Solution

1970 ◽  
Vol 22 ◽  
pp. 17-25
Author(s):  
A. Sharmah ◽  
H. Jha ◽  
J. Bhattarai
Keyword(s):  
Chemical Society ◽  
Titanium Content ◽  
Open Circuit ◽  
Titanium Metal ◽  
Corrosion Rates ◽  
Ti Alloys ◽  
Naoh Solution ◽  
Confocal Scanning ◽  
Confocal Scanning Laser ◽  
Sputter Deposited

The passivation behavior of the sputter-deposited amorphous or nanocrystalline W-Ti alloys is studied in alkaline 1 M NaOH solution at 25oC, open to air using corrosion tests, electrochemical measurements and confocal scanning laser microscopic (CSLM) techniques. The corrosion rates of the W-Ti alloys decreased with increasing titanium content and the corrosion rates of the alloys containing 53 at % (atomic percentage) or more titanium as well as the sputter-deposited titanium metal are nearly two orders of magnitude lower than that of the sputter-deposited tungsten in 1 M NaOH solution. The pitting corrosion is clearly observed in the W-Ti alloys containing 30-53 at % titanium from CSLM studies. The open circuit potentials of all the examined W-Ti alloys are located between those of tungsten and titanium metals. DOI: 10.3126/jncs.v22i0.518Journal of Nepal Chemical Society Vol. 22, 2007 pp.17-25

scholarly journals Effects of Alloying Elements on the Corrosion Behavior of Sputter–deposited Zr–(12–21)Cr–W Alloys in 0.5 M NaCl Solution

1970 ◽  
Vol 25 ◽  
pp. 75-82
Author(s):  
Basu Ram Aryal ◽  
Jagadeesh Bhattarai
Keyword(s):  
Corrosion Test ◽  
Open Circuit Potential ◽  
Chemical Society ◽  
Open Circuit ◽  
Sputter Deposition ◽  
Nacl Solution ◽  
Corrosion Rates ◽  
Sputter Deposited ◽  
Stable Passivity ◽  
Zirconium Metal

The synergistic effect of the simultaneous additions of tungsten and zirconium in thesputter-deposited amorphous or nanocrystalline Zr-(12-21)Cr-W alloys is studied in 0.5 MNaCl solution open to air at 25°C using corrosion tests and open circuit potentialmeasurements. Corrosion rates of the sputter-deposited Zr-(12-21)Cr-W alloys containing10-80 at % tungsten (that is, 0.95-1.85 x 10-2 mm.y-1) are more than one order of magnitudelower than that of the sputter-deposited tungsten and even lower than those of zirconium aswell as chromium in 0.5 M NaCl solution. The addition of 8-73 at % zirconium content inthe sputter-deposited binary W-(12-21)Cr alloys seems to be more effective to improve thecorrosion-resistant properties of the sputter-deposited ternary Zr-Cr-W alloys containing12-21 at % chromium in 0.5 M NaCl solution. The sputter-deposited Zr-(17-21)Cr-W alloyscontaining an adequate amounts of zirconium metal showed the more stable passivity andshowed higher corrosion resistance than those of alloy-constituting elements in 0.5 M NaClsolution open to air at 25°C.Keywords: Zr-(12-21)Cr-W alloys, sputter deposition, corrosion test, open circuit potential,0.5 M NaCl.DOI:  10.3126/jncs.v25i0.3305Journal of Nepal Chemical Society Volume 25, 2010 pp 75-82

scholarly journals The Confocal Scanning Laser Microscopic Study of the Pitting Corrosion on Sputter-Deposited W-Ti Alloys in 1 M NaOH Solution

1970 ◽  
Vol 26 (1) ◽  
pp. 17-26
Author(s):  
Jagadeesh Bhattarai
Keyword(s):  
Passive Film ◽  
Pitting Corrosion ◽  
Corrosion Potential ◽  
Open Circuit ◽  
Scanning Laser ◽  
Ti Alloys ◽  
Naoh Solution ◽  
Confocal Scanning ◽  
Confocal Scanning Laser ◽  
Sputter Deposited

The pitting corrosion of the passive films formed on the surface of sputter-deposited W-30Ti and W-53Ti alloys after immersion for 24 hours in alkaline 1 M NaOH soution at 25°C was studied by using the surface sensitive technique of the confocal scanning laser microscopic (CSLM) technique including corrosion tests and electrochemical measurements. The higher corrosion rate of the W-30Ti alloy (i.e., about 3x 10-2 mm/y) than those of the W-53Ti and W-90Ti alloys (i.e., about 4-5 x 10-3 mm/y) was mostly due to the deep type of pitting corrosion observed on the surface of the passive film formed on the W-30Ti alloy in 1 M NaOH solution. The shallow type of pits was developed on the surface of the passive film formed on the W-53Ti alloy, whereas no pitting corrosion on the titanium-rich W-90Ti alloy.Keywords: Pitting corrosion; Open circuit corrosion potential; Corrosion test; CSLM studyTribhuvan University Journal Vol. XXVI, No. 1, 2009 Page: 17-26

scholarly journals Roles of alloying elements on the corrosion behavior of sputter-deposited amorphous W-Cr-Zr alloys in 0.5m NaCl solution

1970 ◽  
Vol 9 (9) ◽  
pp. 34-38
Author(s):  
Jagadeesh Bhattarai
Keyword(s):  
Open Circuit Potential ◽  
Synergistic Effects ◽  
Open Circuit ◽  
Sputter Deposition ◽  
Nacl Solution ◽  
Dc Magnetron Sputtering ◽  
Corrosion Rates ◽  
Order Of Magnitude ◽  
Sputter Deposited ◽  
Zr Alloys

Ternary amorphous W–xCr–yZr alloys containing 9--38 at % tungsten, 15--42 at % chromium and 39--73 at % zirconium were successfully prepared by direct current (DC) magnetron sputtering technique. The corrosion rates of all the examined sputter-deposited W–xCr–yZr alloys were in the range of 1 × 10−3 mm/y or lower which are nearly one order of magnitude lower than those of the sputter-deposited tungsten, chromium and zirconium metals after immersion for 240 h in 0.5 M NaCl solution open to air at 25°C. In particular, the simultaneous additions of tungsten, chromium and zirconium to the amorphous ternary W–xCr–yZr alloys in the chromium- and zirconium-enriched W--91Cr and W--88Zr alloys, respectively, showed a synergistic effects for showing the higher corrosion resistance than those of binary WCr and W--Zr alloys in neutral NaCl solution. Keywords: W–Cr–Zr alloys; Sputter deposition; Corrosion test; Open circuit potential; 0.5 M NaCl DOI: http://dx.doi.org/10.3126/sw.v9i9.5515SW 2011; 9(9): 34-38

scholarly journals The Influence of the Chemical Composition on the Corrosion Performances of Some Al-Fe-Si, Al-Mg-Si and Al-Mg-Mn Type of Alloys

2014 ◽  
Vol 20 (4) ◽  
pp. 217-234 ◽  
Author(s):  
Kemal Delijić ◽  
Boštjan Markoli ◽  
Iztok Naglič
Keyword(s):  
Chemical Composition ◽  
Corrosion Behavior ◽  
Total Content ◽  
Open Circuit ◽  
Chloride Ions ◽  
Nacl Solution ◽  
Aqueous Corrosion ◽  
Corrosion Rates ◽  
Alloy Chemistry ◽  
Aa5182 Alloy

Paper presents the results on the corrosion behavior of some Al-Fe-Si, Al-Mg-Si and Al-Mg-Mn alloys in their final commercially usable tempered state. Durability of alloys was quantified and compared in the sense of corrosion rates in aqueous solutions while also having in mind the role of alloy chemistry. Open circuit corrosion potential (OCP) measurements, linear polarization and potentiodynamic anodic/cathodic polarization was employed in order to determine the corrosion behavior of samples in the mixture of chloride ions containing aqueous corrosion ambient. We found out that AlFe0.83Si0.18(AA8079), AlMg0.63Si0.72 (AA6005) and AlMg4Mn (AA5182) alloy exhibited the highest rates of passivation in 0.51 mol NaCl solution. The group of Al-Fe-Si alloys exhibited the greatest sensitivity to the changes in chemical composition under potentiodynamic polarization. Artificially aged Al-Mg-Si extruded profiles and fully annealed (after cold rolling) Al-Mg-Mn sheets exhibit very similar levels of equilibrium potentials E(I=0) in 0.51 mol NaCl solution. In the case of Al-Fe-Si alloys, we found that Fe/Si ratio also plays an important role, next to the total content of Fe and Si. Alloys with high Fe/Si ratios showed almost 30 % lower polarization resistance compared to the alloys with balanced Fe/Si, even in the case of the equal total content of alloying elements. The AlMg0.7Si1.2Mn0.8 alloy aged after quenching in the sprayed water and AlMg4Zn1.3Mn0.4 annealed sheet exhibit very similar levels of corrosion rates in 0.51 mol NaCl solution.

scholarly journals The effect of tantalum addition on the corrosion behavior of W-xTa alloys in 1 M NaOH solution

BIBECHANA ◽  
2013 ◽  
Vol 10 ◽  
pp. 1-8
Author(s):  
Susil Baral ◽  
Jagadeesh Bhattarai
Keyword(s):  
Corrosion Behavior ◽  
Corrosion Potential ◽  
Open Circuit ◽  
Corrosion Resistant ◽  
Corrosion Rates ◽  
Nanocrystalline And Amorphous ◽  
Naoh Solution ◽  
Tungsten Metal ◽  
Sputter Deposited

The role of tantalum addition on the corrosion behavior of the sputter-deposited nanocrystalline and amorphous W-xTa (x=8-77) alloys was studied in 1 M NaOH solution open to air at 25°C using corrosion tests and electrochemical measurements. Tungsten and tantalum metals act synergistically in enhancing the corrosion resistant properties of the W-xTa alloys and hence addition of 23 at% or more tantalum to the alloys were found to be effective to lower the corrosion rate of the alloys than those of alloy-constituting tungsten and tantalum elements. The corrosion rates of the W-xTa alloys containing 23-77 at% tantalum are nearly two orders of magnitude lower than that of tungsten and even slightly lower than that of tantalum in 1 M NaOH. Addition of tantalum metal in W-xTa alloys is effective for ennoblement of the open circuit corrosion potential of the tungsten metal in 1 M NaOH solution 25°C.DOI: http://dx.doi.org/10.3126/bibechana.v10i0.8363 BIBECHANA 10 (2014) 1-8

scholarly journals The passivation behavior of sputter-deposited W-xMo alloys on 0.5M NaCl solution

2012 ◽  
Vol 10 (10) ◽  
pp. 29-32
Author(s):  
Jagadeesh Bhattarai
Keyword(s):  
Open Circuit Potential ◽  
Open Circuit ◽  
Molybdenum Content ◽  
Electrochemical Measurements ◽  
Nacl Solution ◽  
Corrosion Rates ◽  
Passive Transition ◽  
Scientific World ◽  
Tungsten Metal ◽  
Sputter Deposited

The passivation behavior of the sputter-deposited W-xMo alloys was studied in 0.5 M NaCl solution open to air at 25°C using immersion tests and electrochemical measurements. Corrosion rates of the W-xMo alloys containing less than 50 at% molybdenum content are in the range of 1.7-2.0 x10-2 mm/y and are slightly lower than that of tungsten metal whereas the corrosion rates of the alloys containing more than 50 at% molybdenum increased with the addition of molybdenum in the alloys. The W-83Mo alloy showed active-passive transition and transpassive dissolution. The open circuit potential of all the examined W-xMo alloys is shifted to noble direction with the addition of molybdenum content in the alloys. Scientific World, Vol. 10, No. 10, July 2012 p29-32 DOI: http://dx.doi.org/10.3126/sw.v10i10.6858

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