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

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

Corrosion Behavior of Electroless Deposited Fe-Zn Coating

2011 ◽  
Vol 117-119 ◽  
pp. 81-84
Author(s):  
Xi Ran Wang ◽  
Jing Wu ◽  
Xin Gang Hu
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Open Circuit Potential ◽  
Corrosion Current ◽  
Open Circuit ◽  
Nacl Solution ◽  
Positive Direction ◽  
Heat Treated ◽  
Heat Treated Temperature ◽  
Electronic Microscope

In this work, Fe-Zn coating on copper is obtained by electroless plating. The surface mor -phologies and composition of the coatings has been investigated using scanning electronic microscope (SEM) and energy dispersive spectroscopy(EDS). Corrosion behavior of Fe-Zn coating in3.5% NaCl solution is gaved a further insight. The impedance diagram indicates that corrosion resistance of coating is better. The open circuit potential of Fe-Zn coating is at about -1V. Self-corrosion potential of Fe-Zn coating in 3.5%NaCl solution shifts in the positive direction first and then shifts from -0.622V to -0.603V with increasing heat-treated temperature, while corresponding self-corrosion current decreases at first and then. increases Corrosion resistance of coating is the best when heat-treated temperature is 300°C.

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

The Corrosion Characteristics of AlSi1MgMn

2015 ◽  
Vol 818 ◽  
pp. 125-128
Author(s):  
Petra Lacková ◽  
Mária Mihaliková ◽  
Jana Cervová ◽  
Anna Lišková
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Exposure Time ◽  
Polarization Resistance ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Open Circuit ◽  
Atmospheric Conditions ◽  
X Ray ◽  
Industrial Atmosphere

The paper presents the evaluation of corrosion resistance of aluminium alloy AlSi1MgMn. This alloy is used above all in any atmospheric conditions. The corrosion resistance of the alloy was evaluated by determining the open circuit potential (OCP) in solution SARS (this solution simulates the industrial atmosphere) after the 10 months of exposure time. The surface of aluminum alloys were analyzed by using energy dispersive X-ray analysis after the exposure time. The basic of corrosion characteristics (corrosion potential Ecorr, corrosion rate icorr and polarization resistance Rp) were determined by potenciodynamic measurements according to Tafel’s and Stern’s methods.

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 

Effect of Phosphating Additives on Corrosion Resistance of Phosphate Coatings on AZ91D Magnesium Alloy

2011 ◽  
Vol 337 ◽  
pp. 112-115 ◽  
Author(s):  
Bi Lan Lin ◽  
Yu Ye Xu ◽  
En Cai Li
Keyword(s):  
Corrosion Resistance ◽  
Sodium Fluoride ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Zinc Nitrate ◽  
Open Circuit ◽  
Nacl Solution ◽  
Tafel Polarization ◽  
Phosphate Coatings ◽  
Corrosion Behaviors

AZ91D magnesium alloys were immersed in different phosphating solutions with zinc nitrate and sodium fluoride additives to enhance the corrosion resistance. The devolution law of the Open Circuit Potential (OCP) of AZ91D alloys during phosphating was measured. The corrosion behaviors of AZ91D alloys in 3.5%NaCl solution were investigated using OCP and Tafel polarization methods, and the effect of phosphating additives was discussed. The results show that the changes of the OCP of AZ91D alloys with phosphating time in different phosphating solutions are different; the anodic and cathodic corrosion processes of AZ91D alloys are conspicuously inhibited with phosphate coatings; zinc nitrate and sodium fluoride are benefit to form phosphate coatings with better corrosion resistance. The corrosion potential of AZ91D alloy phosphated in solutions with both zinc nitrate and sodium fluoride is most positive.

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 Structure and Corrosion Behavior of Sputter-Deposited W-Mo Alloys

1970 ◽  
Vol 21 ◽  
pp. 19-25 ◽  
Author(s):  
Jagadeesh Bhattarai
Keyword(s):  
Corrosion Resistance ◽  
Magnetron Sputtering ◽  
Corrosion Behavior ◽  
Solid Solutions ◽  
Chemical Society ◽  
High Corrosion Resistance ◽  
Corrosion Rates ◽  
High Corrosion ◽  
Sputter Deposited

Nanocrystalline, single bcc solid solutions of W-Mo alloys have been successfully prepared by D. C. magnetron sputtering in a wide composition. The corrosion behavior of the sputter-deposited W-Mo alloys was studied. The W-Mo alloys showed significantly high corrosion resistance in 12 M HCl at 30o C. Their corrosion rates are about one and half orders of magnitude lower than that of sputter-deposited tungsten and lower than that of the sputter-deposited molybdenum even after prolonged immersion.DOI: 10.3126/jncs.v21i0.217Journal of Nepal Chemical Society Vol.21 2006 pp.19-25

The Influence of Sn Addition on the Corrosion Behavior of Mg-5Al-1Zn Alloy

2009 ◽  
Vol 620-622 ◽  
pp. 153-156 ◽  
Author(s):  
Kyung Chul Park ◽  
Byung Ho Kim ◽  
Jong Jin Jeon ◽  
Yong Ho Park ◽  
Ik Min Park
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Volume Fraction ◽  
Secondary Phases ◽  
Nacl Solution ◽  
High Hydrogen ◽  
Hydrogen Overvoltage ◽  
Mg2sn Phase ◽  
Superior Corrosion Resistance

In the present work, the effect of Sn addition on the corrosion behavior of Mg–5Al–1Zn alloys was investigated. Microstructure, potentiodynamic polarization and immersion tests were carried out in 3.5% NaCl solution of pH 7.2 to estimate the corrosion behavior of AZ51 alloys with and without Sn addition. Mg17Al12 and Mg2Sn phases were mainly precipitated in inter-dendrite structures. With increasing the Sn content, the volume fraction of the Mg2Sn phase was increased and coarsening tendency was observed. The corrosion resistance was increased by Sn addition. Especially, the AZ51-5wt.%Sn alloy characterized the superior corrosion resistance among the four alloys. The Sn is known for a high hydrogen overvoltage and the secondary phases effectively formed the network structure, resulting in a drastically decreasing corrosion rate of AZ51 alloy.

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

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