Corrosion Behaviour of Amorphous and Nanocrystalline Ti60Ni40 in Aqueous HNO3 Solution

2009 ◽  
Vol 67 ◽  
pp. 173-178 ◽  
Author(s):  
Shubhra Mathur ◽  
Rishi Vyas ◽  
S.N. Dolia ◽  
Kanu Sachdev ◽  
S.K. Sharma

Potentiodynamic polarization studies were carried out on amorphous, nanocrystalline and crystalline states of the alloy Ti60Ni40 in 0.1 M HNO3, 0.5 M HNO3 and 1 M HNO3 aqueous solutions at room temperature. It was observed that the amorphous state exhibited higher corrosion current density than that by the nanocrystalline state. These results are corroborated by the weight loss studies performed on the different structural states of Ti60Ni40 alloy in 0.1 M HNO3, 0.5 M HNO3 and 1 M HNO3 aqueous media. Thus the nanocrystalline state is least prone to corrosion than the amorphous and the crystalline states.

2009 ◽  
Vol 67 ◽  
pp. 179-184 ◽  
Author(s):  
Shubhra Mathur ◽  
Rishi Vyas ◽  
S.N. Dolia ◽  
Kanu Sachdev ◽  
S.K. Sharma

Corrosion studies were carried out using potentiodynamic polarization method on amorphous, nanocrystalline and crystalline states of the alloy Ti60Ni40 in 0.5 M H2SO4 and 0.5 M HNO3 aqueous media at room temperature. The nanocrystalline state of Ti60Ni40 was obtained by removing about 10 μm from the air side surface (crystalline state) by polishing. The presence of nanocrystalline phase was confirmed by X-ray diffraction (XRD). It was found from polarization results that the corrosion current density was higher in the amorphous state than in the nanocrystalline state in both 0.5 M H2SO4 and 0.5 M HNO3 aqueous media. These results are corroborated by the weight loss studies which were carried out in both of these media. Results are discussed in the paper in the light of data reported in the literature on similar type of alloys.


CORROSION ◽  
1976 ◽  
Vol 32 (7) ◽  
pp. 263-266 ◽  
Author(s):  
E. A. LIZLOVS

Abstract The effect of the molybdate ion (MoO4=) concentration on the corrosion inhibition of 1010 steel was investigated in aerated chloride/sulfate-containing solutions. The chloride content was 304 ppm Cl−, and the sulfate was 352 ppm SO4=. Weight loss measurements and electrochemical methods were employed for the investigation. The pH was controlled at 8.7. Weight loss measurements indicated that about 165 ppm of molybdate reduced the corrosion rate below 10 mg·dm−2/day at room temperature. At 160 F (71 C), about 50 ppm of molybdate reduced the corrosion rate to 4 to 5 mg·dm−2/day. The potentiodynamic polarization studies and the examination of corrosion potential and immersion time relationship disclosed that the molybdate ion acts as a passivating agent in the presence of oxygen. Passivity was also obtained under potentiodynamic polarization conditions in a nitrogenated solution. No passivation was obtained in the absence of the molybdate ion. For spontaneous passivation, both molybdate and oxygen (oxidizing agent) were needed. Corrosion rates in a passive state according to the polarization curve should be nil.


2015 ◽  
Vol 227 ◽  
pp. 63-66
Author(s):  
Ileana Manciulea ◽  
Cristina Bogatu ◽  
Cristina Cazan ◽  
Lucia Dumitrescu ◽  
Anca Duta

The paper presents the results obtained when using two ketonic Mannich bases (BM1 and BM2) as corrosion inhibitors in saline (standard sea water-3.5% NaCl) for different types of steel, with various alloying elements. The corrosion experiments were performed by potentiodynamic polarization studies. Based on the polarization curves, the corrosion current density and rate were calculated. The inhibitors efficiencies were evalued and the protection mechanisms were discussed.


2011 ◽  
Vol 239-242 ◽  
pp. 1582-1585
Author(s):  
Ya Ni Zhang ◽  
Mao Sheng Zheng ◽  
Jie Wu Zhu

The potentiodynamic polarization and cyclic voltommogroms studies were carried out on the copper with micro-addition of Cr and Zr in solutions of 0.5M NaCl, 0.5M NaOH and 0.5M HCl at room temperature. The corrosion resistance of pure copper is deteriorated with addition of the alloying elements Cr and Zr. Significant reducing in the corrosion resistance is observed when Cr and Zr are added simultaneously. Moreover, the lowest corrosion current density is obtained in the NaCl solution followed by the NaOH solution and HCl solution. Compared with the different effect on the passive layer in the NaCl solution, the micro-addition of Cr and Zr leads to the increasing of the corrosion resistance for the passive layer in 0.5M NaOH solution and 0.5M HCl solution.


2009 ◽  
Vol 79-82 ◽  
pp. 1963-1966
Author(s):  
Cristina Bogatu ◽  
Ileana Manciulea ◽  
Anca Duta

The paper presents the results obtained when using Mannich bases (and derivatives) as corrosion inhibitors in saline environment, for different types of steels, with various alloying elements. The Mannich basis (ketonic combinations with naphtenic and nitrogen containing rings) were synthesized as such (polar) and as chlorhydrates (ionic) and used in corrosion experiments, in concentrations varying from 0….1300 ppm. The corrosion experiments were performed by potentiodynamic polarization studies. Based on the polarization curves, the corrosion current density and rate were calculated. The inhibitor efficiency was evaluated and based on these values the protection mechanisms was discussed.


2000 ◽  
Vol 65 (1) ◽  
pp. 73-81
Author(s):  
P. Zivkovic ◽  
J. Pjescic ◽  
S. Mentus

The alloy composed of Al(95.53%), Zn(2.85%), Sn(0.515%), Ga(0.1%) and Sr(0.009%), with the weight percents in the parentheses, was prepared by melting, using Al(99.84%), a product of the Aluminium Plant-Podgorica, as the base material. The corrosion behaviour of this alloy was tested in relation to the behaviour of the base metals, by both open curcuit potential and polarization resistance methods, in aqueous solutions of both NaCl and Na2SO4, the concentration of which varied within the range 0.00051 - 0.51 mol dm -3. Over the whole salt concentration ranges, the corrosion parameters indicate that the corrosion rate of the alloy is significantly higher than the rate of the base material. For instance, for the concentration range 0.00051 - 0.51 mol dm -3 , the stationary open circuit potentials, related to SCE, in NaCl solutions were - 1.200 to - 1.460 V for the alloy and - 0.693 to - 0.920 V for Al, while in Na2SO4 solutions, the stationary open circuit potentials were - 1.190 to - 1.465V for the alloy and - 0.780 to - 0.860V for Al. At the same time, the corrosion current density in NaCl solutions varied within 11-89 mA cm -2 for the alloy and 0.35 - 0.80 for Al, while in Na2SO4 solutions it amounted to 5.7.52 mA cm -2 for the alloy and 0.28 - 0.88 mA cm -2 for Al.


2012 ◽  
Vol 58 (2) ◽  
Author(s):  
W. B. Wan Nik ◽  
S. Syahrullail ◽  
R. Rosliza ◽  
M. M. Rahman ◽  
M. F. R. Zulkifli

The aim of this study is to determine the corrosion effect of palm oil methyl ester (POME) on aluminium alloy 5083 (AA5083). The static immersion test was carried out at 60°C for 68 days according to ASTM G–31–72. The corrosion analysis was done by using weight loss method and electrochemical test. The result from weight loss method shows the decreasing in weight loss of AA5083 which signifies the ability of POME to reduce corrosion rate. The electrochemical test shows the decreasing in polarization resistance,Rp, while the corrosion current densities, Icorr, increase. The corrosion rate reduces from 2.250mpy to 0.1946mpy. The low concentration of fatty acid C18:2 and high anti oxidant element contributes to the reduction of corrosion rate of AA5083 in POME.


Author(s):  
A. H. EL-ASKALANY ◽  
S. I. MOSTAFA ◽  
A. M. EID

The inhibitive action of Saponinic extract of both Zygophylium album and Zygophylium Egyptian leaves which could serve as eco-friendly materials was investigated on the corrosion of N80 carbon steel in 1 M HCl solution. The techniques employed for the study were weight loss measurements. potentiodynamic polarization, electrochemical frequency modulation (EFM), and electrochemical impedance spectroscopy (EIS). The results obtained show that these extracts could serve as an effective inhibitor for N80 carbon steel. The percentage inhibition increases with increasing concentration of the inhibitor at 25 °C The percentage inhibitor efficiency above 90% was obtained at a concentration of 700 ppm for both extracts. The corrosion rates of steel and inhibitive efficiencies obtained from impedance and polarization measurements were in good agreement with those obtained from weight loss measurements. Potentiodynamic polarization studies clearly reveal that both extracts act as mixed-type inhibitors The study shows that the inhibition efficiency decreased with the temperature rise of the medium. Heat of adsorption and thermodynamic parameters and indicated that the adsorption process is mainly controlled by the physical adsorption process.


2012 ◽  
Vol 326-328 ◽  
pp. 620-625 ◽  
Author(s):  
Joanna Michalska

Hydrogen entering into steel affects its electrochemical properties and may enhance the susceptibility to environmental degradation. The present work has been aimed at further clarifying the effect of hydrogenation on the corrosion behaviour and passivity of highly-alloyed stainless steels. The results were discussed by taking into account hydrogen charged samples and without hydrogen. The corrosion resistance to pitting was qualified with the cyclic polarization curves. The conclusion is that hydrogen may deteriorated the passive film stability and corrosion resistance to pitting of highly-alloyed stainless steel. Furthermore, the presence of hydrogen in passive films increases corrosion current density, decreasing the potential of the film breakdown and repassivation potential. It was also found that the degree of susceptibility to hydrogen-enhanced pitting corrosion was dependent on the type of steel.


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