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 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 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

scholarly journals Passivation Behavior of Steel Rod and Wires of Nepal in Acidic and Alkaline Solutions

1970 ◽  
Vol 9 ◽  
pp. 157-162
Author(s):  
Jagadeesh Bhattarai
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Open Circuit Potential ◽  
Immersion Test ◽  
Open Circuit ◽  
Electrochemical Measurements ◽  
Alkaline Solutions ◽  
Alkaline Environments ◽  
Naoh Solution ◽  
Hcl Solution

The passivation behavior of steel rods and wires those are produced in Nepal was studied in 1 M HCl and 1 M NaOH solutions at 25°C, open to air using immersion tests and electrochemical measurements. The corrosion resistance of all the examined steel rods and wires in this work is found significantly higher in alkaline 1 M NaOH than in acidic 1 M HCl, mostly due to an ennoblement of the open circuit corrosion potentials of the steels at passive potential regions in 1 M NaOH solution at 25°C. The corrosion rate of all the examined steel rods and wires is about in the range of 1-5 x 101 mm/y in acidic 1 M HCl solution which is nearly three orders of magnitude lower corrosion resistance than in alkaline 1 M NaOH solution at 25°C. Therefore, these steel rods and wires seem to be very corrosion resistance materials in very alkaline environments like a reinforcing concrete. Key words: steels; corrosion rate; open circuit potential; immersion test; electrochemical measurements. DOI: 10.3126/njst.v9i0.3181 Nepal Journal of Science and Technology 9 (2008) 91-97

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 Passivation Behavior of Carbon Steel Rods of Nepal in Different Media

1970 ◽  
Vol 22 ◽  
pp. 34-40
Author(s):  
J. Bhattarai ◽  
A. Kafle ◽  
N. P. Bhattarai
Keyword(s):  
Corrosion Resistance ◽  
Carbon Steel ◽  
Corrosion Rate ◽  
Open Circuit ◽  
Electrochemical Measurements ◽  
High Corrosion Resistance ◽  
Iron Wire ◽  
High Corrosion ◽  
Naoh Solution ◽  
Hcl Solution

The passivation behavior of carbon steel rods of Nepal is studied in 1 M HCl, 0.5 M NaCl and 1 M NaOH solutions at 25°C, open to air using corrosion tests and electrochemical measurements. The corrosion rate of all the examined steel rods is significantly lower in 1 M NaOH solution (about 10-3 mm/y) than those in 0.5 M NaCl (about 10-2 mm/y) and 1 M HCl (about 101-102 mm/y) solutions. The corrosion rate of SR71 steel rod is remarkably lower (3.65 mm/y) than those of other four different steel rods (3-4 x 102 mm/y) of Nepal in 1 M HCl solution. The ennoblement of the open circuit potentials of all the examined steel rod specimens is clearly observed in 1 M NaOH solution than those in 0.5 M NaCl and 1 M HCl solutions. The open circuit potentials of the steel rods are in the passive potential regions of the iron wire in 1 M NaOH solution. Therefore, steel rods of different companies of Nepal showed significantly high corrosion resistance in 1 M NaOH solution at 25°C.DOI: 10.3126/jncs.v22i0.520Journal of Nepal Chemical SocietyVol. 22, 2007 pp.34-40

Effects of Solid Solution Treatment and Rolling Treatment on Electrochemical Properties of Al Anode Alloy

2013 ◽  
Vol 800 ◽  
pp. 492-495
Author(s):  
Deng Hui Li ◽  
Jiu Ba Wen ◽  
Jun Guang He
Keyword(s):  
Solid Solution ◽  
Corrosion Resistance ◽  
Electrochemical Properties ◽  
Hydrogen Evolution ◽  
Open Circuit Potential ◽  
Cast Alloy ◽  
Solution Treatment ◽  
Open Circuit ◽  
Electrochemical Measurements ◽  
Solid Solution Treatment

Effects of solid solution treatment and rolling treatment on microstructure and electrochemical properties of Al-Ga-Mg-Mn-Bi anode alloy were investigated by means of SEM and electrochemical measurements. The results show that after solid solution treatment the microstructure segregation of the as-cast alloy was reduced, the hydrogen evolution was restrained, the corrosion resistance was increased. The open circuit potential moves towards negative after solid solution treatment. Rolling treatment had little impact on the alloy. The effects of solid solution treatment were superior to rolling treatment.

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 Angle resolver X-ray photoelectron spectroscopic analysis of the passive film of the corrosion-resistant W-32Zr alloy in 12 M HCl solution

2015 ◽  
Vol 49 (2) ◽  
pp. 103-110
Author(s):  
Jagadeesh Bhattarai
Keyword(s):  
Corrosion Resistance ◽  
Synergistic Effects ◽  
High Corrosion Resistance ◽  
Corrosion Resistant ◽  
X Ray ◽  
High Corrosion ◽  
Average Corrosion Rate ◽  
Sputter Deposited ◽  
Zirconium Metal ◽  
Hcl Solution

The sputter-deposited amorphous W-32Zr alloy was passivated spontaneously and showed a fairly high corrosion resistance in 12 M HCl solution in open air at 30°C. The average corrosion rate of the W-32Zr alloy (i.e., 5.2 × 10-3 mm/y) was found to be lower than those of alloy-constituting tungsten and zirconium elements. Such synergistic effects of simultaneous addition of tungsten and zirconium in the W–32Zr alloy was investigated by corrosion tests, electrochemical measurements and angle resolved X-ray photoelectron spectroscopic (ARXPS) analyses. High corrosion resistance of the binary W–32Zr alloy is mostly due to the formation of homogeneous passive oxyhydroxide film consisting of Wox and Zr4+ cations with a small concentration gradient in–depth from ARXPS analysis. Consequently, zirconium metal acts synergistically with tungsten in enhancing the anodic passivity as well as the corrosion resistance properties of the sputter–deposited W–32Zr alloy in 12 M HCl solution open to air at 30°C. DOI: http://dx.doi.org/10.3329/bjsir.v49i2.22004 Bangladesh J. Sci. Ind. Res. 49(2), 103-110, 2014

scholarly journals Corrosion and Electrochemical Properties of Nanocrystalline W-Mo Alloys in NaOH Solutions

1970 ◽  
Vol 11 ◽  
pp. 147-152
Author(s):  
Arun Khadka ◽  
Jagadeesh Bhattarai
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Properties ◽  
Open Circuit Potential ◽  
Science And Technology ◽  
Open Circuit ◽  
Sputter Deposition ◽  
Corrosion Tests ◽  
Corrosion Rates ◽  
Sputter Deposited ◽  
The Stability

The corrosion and electrochemical properties of sputter-deposited nanocrystalline binary W-Mo alloys were studied after immersion for 2429 h in different concentrations of NaOH solutions open to air at 25°C using corrosion tests and open circuit potential measurements. Molybdenum acts synergistically with tungsten in enhancing the corrosion resistance of the sputter-deposited binary W-Mo alloys so as to show higher corrosion resistance than those of alloy-constituting elements (i.e. tungsten and molybdenum) after immersion for 24 h in NaOH solutions. Open circuit potentials of all the examined sputter-deposited W-Mo alloys are shifted to the more positive (noble) direction with increasing molybdenum content in the alloys. The stability of the spontaneously passivated films formed on the binary W-Mo alloys is decreased with increasing concentrations of NaOH solutions. In spite of these facts, the corrosion rates of all the examined W-Mo alloys are almost independent of concentrations of NaOH solutions after immersion for 24 h at 25°C.Key words: nanocrystalline W-Mo alloys; sputter deposition; corrosion resistance; open circuit potential; NaOH solutions DOI: 10.3126/njst.v11i0.4137Nepal Journal of Science and Technology 11 (2010) 147-152

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

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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