scholarly journals The Corrosion Behavior of Sputter-deposited W-Cr-(4-15)Ni Alloys in NaOH Solutions

1970 ◽  
Vol 24 ◽  
pp. 3-11
Author(s):  
Pom Lal Kharel ◽  
Jagadish Bhattarai
Keyword(s):  
Corrosion Resistance ◽  
Open Circuit Potential ◽  
Chromium Content ◽  
Chemical Society ◽  
Open Circuit ◽  
Ni Alloys ◽  
Ni Alloy ◽  
Naoh Solution ◽  
Order Of Magnitude ◽  
Sputter Deposited

The synergistic effect of chromium addition in the sputter-deposited amorphous or nanocrystalline W-Cr-(4-15)Ni alloys is studied in alkaline NaOH solutions at 25°C, open to air using immersion tests and electrochemical measurements. In 1 M NaOH solution, the addition of chromium to W-Cr-(4-15)Ni alloys containing 42-75 at % chromium increased the corrosion resistance and shifted the open circuit potential more noble so as to show higher corrosion resistance than those of alloy-constituting elements (that is, tungsten, chromium and nickel). The corrosion rates (that is, about 2-5 x 10-3 mm.y-1) of all the examined W-Cr-(4-15)Ni alloys are about two orders of magnitude lower than that of tungsten and nearly one order of magnitude lower than that of chromium metal. The open circuit potential of the W-Cr-(4-15)Ni alloys is generally increased with increasing chromium content in different concentrations of NaOH solutions. The passivity of the WCr-(4-15)Ni alloys is increased with decreasing the concentration of NaOH solutions at 25°C. Keywords: Corrosion resistance; Sputter deposition;  W-Cr-Ni alloy;  NaOH solution; Open Circuit  potential. DOI: 10.3126/jncs.v24i0.2380Journal of Nepal Chemical Society, Vol. 24, 2009 Page: 3-11

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

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

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 Roles of Alloying Elements on the Corrosion Behavior of Amorphous W–Zr–(15–33)Cr Alloys in 1 M NaOH Solution

1970 ◽  
Vol 25 ◽  
pp. 93-100
Author(s):  
Raju Ram Kumal ◽  
Jagadeesh Bhattarai
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Open Circuit Potential ◽  
Chromium Content ◽  
Chemical Society ◽  
Immersion Test ◽  
Open Circuit ◽  
Corrosion Rates ◽  
Naoh Solution ◽  
Zirconium Metal

Roles of alloy-constituting elements on the corrosion behavior of the sputter-depositedamorphous W-Zr-(15-33)Cr alloys was studied in 1 M NaOH solution open to air at 25°Cusing corrosion tests and open circuit potential measurements. Zirconium and chromiummetals act synergistically with tungsten in enhancing the corrosion resistance of the sputterdepositedamorphous W-Zr-Cr alloys containing 15-33 at % chromium content so as toshow higher corrosion resistance than those of alloy-constituting elements in 1 M NaOHsolution. The corrosion rates of the amorphous W-Zr-(15-33)Cr alloys containing 9-33 at %tungsten are in the ranges of 2.0-5.0×10-3 mm.y-1 after immersion for 240 h in 1 M NaOHsolution which is about two orders of magnitude lower corrosion rates lower than that oftungsten and even slightly lower than that of the zirconium metal. The simultaneousadditions of zirconium and chromium metals in W-Zr-(15-33)Cr alloys are effective forennoblement of the open circuit potential of the tungsten metal.Keywords: W-Zr-Cr alloys, corrosion resistance, immersion test, open circuit potential, 1 MNaOH.DOI:  10.3126/jncs.v25i0.3312Journal of Nepal Chemical Society Volume 25, 2010 pp 93-100

scholarly journals The Effects of Chromium and Nickel on the Passivation Behaviour of Sputter-Deposited W-Cr-Ni Alloys in 12 M HCl Solution

1970 ◽  
Vol 7 (7) ◽  
pp. 24-28
Author(s):  
Jagadesh Bhattarai
Keyword(s):  
Corrosion Resistance ◽  
Open Circuit Potential ◽  
Hydrogen Reduction ◽  
Open Circuit ◽  
Electrochemical Measurements ◽  
Corrosion Resistant ◽  
Ni Alloys ◽  
Scientific World ◽  
Sputter Deposited ◽  
Hcl Solution

The passivity of sputter-deposited ternary W-Cr-Ni alloys is investigated by immersion tests and electrochemical measurements in 12 M HCl solution at 30°C, open to air. Particular attention is paid to the effects of alloying elements to the corrosion behavior. All the examined amorphous or/and nanocrystalline W-Cr-Ni alloys are passivated spontaneously even in an aggressive environment of 12 M HCl, and hence these alloys showed higher corrosion resistance than those of alloyconstituting elements. The chromium addition suppresses the anodic dissolution current because of the formation of tetravalent chromium oxyhydroxide having a relatively high activity for both cathodic oxygen and hydrogen reduction with a consequent ennoblement of the open circuit potential. The ennoblement of the open circuit potential leads to the formation of the passive chromium oxyhydroxide film. It is, therefore, considered that the addition of chromium improves synergistically the corrosion resistance and passivating abilities of the sputter-deposited binary W-Ni alloys in 12 M HCl solution. Keywords: Sputter-deposition; Ternary W-Cr-Ni alloys; Corrosion-resistant; Electrochemical measurements. DOI: 10.3126/sw.v7i7.3819 Scientific World Vol.7(7) 2009 pp.24-28

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 Passivation Behavior of Sputter-deposited W-Zr Alloys in NaCl and NaOH Solutions

1970 ◽  
Vol 25 ◽  
pp. 37-45
Author(s):  
Prakash Shrestha ◽  
Jagadeesh Bhattarai
Keyword(s):  
Chemical Society ◽  
Open Circuit ◽  
Corrosion Resistant ◽  
Corrosion Rates ◽  
Naoh Solution ◽  
Order Of Magnitude ◽  
Sputter Deposited ◽  
Lower Corrosion Rate ◽  
Zirconium Metal ◽  
Zr Alloys

The passivation behavior of the sputter-deposited amorphous or/and nanocrystallineW-Zr alloys is studied in 0.5 M NaCl and 1 M NaOH solutions at 25°C, open to air usingcorrosion tests and electrochemical measurements. Zirconium metal acts synergisticallywith tungsten in enhancing the corrosion resistance of the sputter-deposited W-Zr alloys soas to show lower corrosion rates than those of alloy-constituting elements (that is, tungstenand zirconium) in 0.5 M NaCl solution. In particular, corrosion rates of the binary W-Zralloys containing 23-76 at % zirconium are more than one order of magnitude lower thanthat of tungsten (that is, about 0.8-1.1 × 10-3 mm.y-1) and even lower than that of the sputterdepositedzirconium. On the other hand, the corrosion rates of the W-Zr alloys containing54-76 at% zirconium are nearly two orders of magnitude lower than that of tungsten andeven about one order of magnitude lower corrosion rate than that of sputter-depositedzirconium metal in alkaline 1 M NaOH solution. These results clearly revealed that thesimultaneous additions of both tungsten and zirconium metals to the sputter-depositedamorphous or nanocrystalline W-Zr alloys are effective in enhancing the corrosionresistance of the alloys in both 0.5 M NaCl and alkaline 1 M NaOH solutions at 25°C, opento air. The corrosion-resistant of all the examined binary W-Zr alloys in 0.5 M NaClsolution is higher than in 1 M NaOH solution at 25°C. In general, the open circuit potentialsof all the examined W-Zr alloys are shifted to more noble direction with increasing the alloyzirconium content in both 0.5 M NaCl and 1 M NaOH solutions.Keywords: Sputter-deposited W-Zr alloys, amorphous, corrosion test, electrochemicalmeasurement, NaCl and NaOH solutions.DOI:  10.3126/jncs.v25i0.3283Journal of Nepal Chemical Society Volume 25, 2010 pp 37-45

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 Effect of Sodium Tungstate as a Green Corrosion Inhibitor on the Passivation Behavior of Mild Steel Sheet in Aggressive Media

2016 ◽  
Vol 4 (2) ◽  
pp. 183-190 ◽  
Author(s):  
Deepak V.K. ◽  
Jagadeesh Bhattarai
Keyword(s):  
Corrosion Resistance ◽  
Mild Steel ◽  
Steel Sheet ◽  
Open Circuit Potential ◽  
Inhibition Efficiency ◽  
Sodium Tungstate ◽  
Open Circuit ◽  
Green Corrosion Inhibitor ◽  
Naoh Solution ◽  
Corrosion Inhibition Efficiency

The effect of sodium tungstate on the passivation behavior of grille sheet made by mild steel was studied using corrosion tests and electrochemical measurements in 1 M HCl, 0.5 M NaCl and 1 M NaOH solutions, open to air at 25 °C. The grille sheet showed the highest corrosion resistance properties in 1 M NaOH solution as compared with 1 M HCl and 0.5 M NaCl solutions. The corrosion resistance properties of the steel sheet was decreased with increasing the concentration of sodium tungstate up to 800 ppm and its corrosion inhibition efficiency was increased with increasing the concentration. The open circuit potential of the mild steel sheet was more negative value in 0.5 M NaCl than that in 1 M HCl, whereas more positive potential value was observed in 1 M NaOH than in 0.5 M NaCl solution. It was found that the mild steel sheet used in the study was found to be more passive in 1 M NaOH than in 1 M HCl and 0.5 M NaCl solutions. Hence, a more stable anodic passive film was formed on the surface of the steel sheet in 1 M NaOH than those in 1 M HCl and 0.5 M NaCl solutions from electrochemical measurements.Int J Appl Sci Biotechnol, Vol 4(2): 183-190  

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 Electrochemical Behavior of Carbon Steel Wires of Nepal in Different Environments

1970 ◽  
Vol 24 ◽  
pp. 31-38
Author(s):  
Jagadish Bhattarai
Keyword(s):  
Corrosion Resistance ◽  
Carbon Steel ◽  
Electrochemical Behavior ◽  
Steel Wire ◽  
Chemical Society ◽  
Open Circuit ◽  
Polarization Measurement ◽  
Steel Wires ◽  
Alkaline Environments ◽  
Naoh Solution

The electrochemical behavior of carbon steel wires of Nepal is studied in 1 M HCl, 0.5 M NaCl and 1 M NaOH solutions at 25°C, open to air using immersion tests and electrochemical measurements. The corrosion rates of the carbon steel wires were found to be about 20-50 mm/y in acidic 1 M HCl and 0.1-0.2 mm/y in neutral 0.5 M NaCl. The corrosion rate of all the examined steel wires in alkaline 1 M NaOH solution (that is, 7 - 18 x 10-3 mm/y) was found nearly three orders of magnitude lower corrosion resistance than in 1 M HCl solution at 25°C, mostly due to an ennoblement of the open circuit potentials of the steel wires at passive potential regions (that is, -200 to 250 mV vs SCE) in 1 M NaOH solution. The steel wires seem to be very corrosion resistance materials in very alkaline environments like cement-based materials. Keywords: Carbon steel wire; Corrosion tests; Polarization measurement; HCl;  NaCl and NaOH solutionsDOI: 10.3126/jncs.v24i0.2388Journal of Nepal Chemical Society Vol. 24, 2009 Page: 31-38   

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