2009 | 50, No. 4

strane /pages/ 187-233



ZAŠTITA MATERIJALA 2009 50(4) 187-192

Scientific paper

UDC:620.197.3



[pdf] (283 KB)         



 
A. LEEMA ROSE1, FELICIA RAJAMMAL SELVA RANI1, A. PETER PASCAL REGIS2, SUSAI RAJENDRAN3, S. KANCHANA4, A. KRISHNAVENI5

1Department of Chemistry, Holy Cross College, Trichirappali-620002, India
2Department of Chemistry St. Joseph’s College, Trichirappali-620002, India
3Corrosion Research Center, Department of Physical Sciences, Servite College of Education for Women, Thogaimalai-621313, India
4Department of Chemistry, Jerusalem College of Engineering, Pallikaranai, Narayanapurum, Chennai-600100, India
5Department of Chemistry, Yadava College, Madurai, India

Corrosion inhibition by monosodium glutamate-Zn2+ system
Abstract: The inhibition efficiency of mono sodium glutamate (MSG)-Zn2+ system in controlling corrosion of carbon steel in an aqueous environment has been evaluated by mass- loss method. The synergistic effect is noticed between mono sodium glutamate and Zn2+. The formulation consisting of 100 ppm of mono sodium glutamate and 50 ppm of Zn2+ shows 86% inhibition efficiency(IE). At lower PH value IE decreases and in alkaline solution IE increases. Polarisation study reveals that MSG-Zn2+ system functions as a mixed inhibitor. AC impedance spectra reveal that a protective film is formed on the metal surface. FTIR spectra reveal that the protective film consists of Fe2+-MSG complex and Zn(OH)2.



ZAŠTITA MATERIJALA 2009 50(4) 193-196

Scientific paper

UDC:678.7:547.73



[pdf] (268 KB)         



G. M. El ENANY
Physical Sciences Department, Faculty of Engineering, Suez Canal University, Port Said, Egypt

Electrochemical synthesis of high charge capacity poly(3,4-ethylenedioxythiophene) using pulse polymerization technique

Abstract: Using pulse electrochemical polymerization technique we prepared high charge capacity polymer of 3,4-Ethylenedioxythiophene (PEDOT) on glassy carbon (GC) substrate. The effect of pulse time on the growth processes and charge capacity of (PEDOT) has been investigated. Pulse on time plays an important role in controlling chain size and chain defects whereas pulse off time contributes in polymer conjugation and orientation. Stable PEDOT films with good electrochemical reversibility, high doping degree and high charge capacity were obtained by applying ultra short on time current pulse for polymerization. The characterization using scanning electron microscopy confirmed that the obtained PEDOT deposits were firstly formed as a thin layer followed by rough, nodular growth which produces an open and porous structure. A charge capacity up to 114 F g-1 was obtained at time on of 10 ms.
Keywords:
pulse electrochemical polymerization, 3,4-ethylenedioxythiophene, charge capacity.



ZAŠTITA MATERIJALA 2009 50(4) 197-203

Scientific paper

UDC:620.193.4:669.721.5



[pdf] (2.022 KB)         



M. GOVINDARAJU1, M. JAYALAKSHMI1, K. PRASAD RAO2, UDAY CHAKKINGAL2, K. BALASUBRAMANIAN1

1Non-Ferrous Materials Technology Development Centre (NFTDC), Kanchanbagh Post, Hyderabad- 500058, India
2Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Chennai, 600036, India

Corrosion of friction welded areas of Mg-Mg, Mg-AZ91D Mg alloy and AZ91D-AZ91D Mg alloy in carbonate solutions

Abstract: Studies on the corrosion of welded areas of friction welded magnesium and its alloy AZ91D are done in view of their applications as structural materials in automotive and aerospace engineering. Friction welding of magnesium-magnesium, magnesium-AZ91D alloy and AZ91D alloy-AZ91D alloy is carried out at the welding speed of 600 RPM which produced a burn length of 2 mm. Corrosion of this welded area is studied using E-log I  polarization in 0.1 M ammonium carbonate solution. It is found that the welded areas are more corrosion resistant than their respective parent samples under similar experimental conditions. Scanning electron microscopic images confirm the grain refinement of welded zones. For better understanding, E-log polarization studies of pure magnesium and its alloy are also done.

Keywords: friction welding, magnesium, AZ91D alloy, E-log I polarization, welded zones, corrosion.



ZAŠTITA MATERIJALA 2009 50(4) 205-212

Scientific paper

UDC:620.197.6:663.245



[pdf] (236 KB)        



M. ABDALLAH, S.O. Al KARANEE, A.A. ABDEL FATTAH

Chem. Dept., Faculty of Science, Benha University, Benha, Egypt

Corrosion behavior of nickel and its alloys in HCl and its inhibition by natural rosemary oil

Abstract: The corrosion behavior of nickel, Inconel 600 and Inconel 690 was studied in different concentrations of HCl solution and its inhibition by natural rosemary oil using galvanostatic polarization techniques. It was found that, HCl accelerate the corrosion of nickel and its alloys. The corrosion rate decreases in the following order Inconel 690 > Inconel 600 > Ni. This was attributed to the presence of high Cr content in the chemical composition of Inconel 690. Natural Rosemery oil inhibit the corrosion of nickel and its two alloys in 0.1 M HCl. The inhibition efficiency increases with increasing the concentration of this oil which act as an inhibitor of the mixed type. The inhibitive effect of this oil was explain in view of adsorption on the metal surface. The adsorption process follows Langmuir adsorption isotherm. The addition of this oil to the
potentiodynamic anodic polarization curves of nickel and its two alloys in chloride solutions shift the pitting potential to more noble direction, indicating an increased resistance to pitting attack.

Keywords: Rosemary oil, nickel, Inconel 600, Inconel 690, corrosion inhibitors, pitting corrosion.



ZAŠTITA MATERIJALA 2009 50(4) 213-221

Scientific paper

UDC:620.193.4.197.3:669.245



[pdf] (254 KB)        



S.K. BADR, M. ABDALLAH

Chemistry Department, Faculty of Science, Benha University, Benha, Egypt, drsamykh@yahoo.com & metwally552@hotmail.com

Preparation of new saturated polyamide compounds and its application as corrosion inhibitors for corrosion of carbon steel in hydrochloric acid solution

Abstract: New one series of saturated polyamide was prepared by polycondensation of methylenedisalyclic acid (MDSA) with adipic acid and several diamine such as ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine and pentaethylenehexamine. The structure of the prepared polyamide was detected by IR and 1H NMR spectra physical properties of these compounds were detected. These compounds were tested as a corrosion inhibitors for dissolution of carbon steel type (L-52) used in Egyptain petroleum pipe lines in 0.1M HCl solution using potentiodynamic polarization technique. The percentage inhibition efficiency increases with increasing the inhibitor concentration and number of amino group in the structure of polyamide. The inhibitive action of these compounds was explained in view of adsorption of these compounds on the surface of steel. The adsorption follows Langmuir adsorption process isotherm.



ZAŠTITA MATERIJALA 2009 50(4) 223-226

Scientific paper

UDC:620.167.3



[pdf] (116 KB)         



SUSAI RAJENDRAN1, P. SUMITHRA1, B. SHYAMALA DEVI2, J. JEYASUNDARI3

1Corrosion Research Centre, Post Graduate and Research Department of Chemistry, GTN Arts College, Dindigul – 624 005, India
2Department of Chemistry, Vivekananda Institute of Engineering and Technology for Women, Tirchengodu, Tamil Nadu, India
3Department of Chemistry, SVN College, Madurai, India

Corrosion inhibition by spirulina

Abstract: An environmental friendly green inhibitor namely an aqueous extract of spirulina has been used to prevent the corrosion of carbon steel in aqueous solution containing 60 ppm of Cl- ion. Inhibition efficiencies of various concentrations of a 0.5% aqueous solution of spirulina have been evaluated by weight loss method and electrochemical studies such as polarization study and AC impedance spectra. As the concentration of spirulina increases, inhibition efficiency (IE) increases. As the value of pH increases, the IE of spirulina increases. As the duration of immersion increases, IE decreases. 6ml of spirulina solution offers inhibition efficiency greater than 80%. At pH 11 6ml of spirulina solution offers 90% corrosion inhibition efficiency. Electrochemical studies confirm the formation of a protective film on the metal surface.

Keywords: corrosion and oxidation, metal and alloys, green inhibitor, spirulina, carbon steel.



ZAŠTITA MATERIJALA 2009 50(4) 227-233

Originalni naučni rad

UDC:669.14.018.7:621.791



[pdf] (279 KB)        



B. B. PEJOVIĆ, M. V. TOMIĆ, V. M. MIĆIĆ, M. G. PAVLOVIĆ

Tehnološki fakultet Zvornik, Republika Srpska, BiH

Specifičnosti zavarivanja čelika otpornih na koroziju

Izvod: U radu su date najbitnije specifičnosti zavarivanja čelika otpornih odnosno postojanih na koroziju. Poseban akcenat je stavljen na njihovu korozionu otpornost, mere za sprečavanje korozije kao i posebne uslove i zahteve pri njihovom zavarivanju. Sa stanovišta tehnologije zavarivanja od posebnog značaja su postupci i parametri za pravilno zavarivanje, sobzirom na njihov uticaj na deformaciono naponsku sliku zavarenog spoja. Pored osnovnih i specifičnosti koje se odnose na koroziono delovanje, date su i tehnološko-metalurške specifičnosti, na koje treba obratiti pažnju pri njhovoj primeni u različitim granama tehnike odnosno industrije, posebno sa stanovišta radne sposobnosti. Kroz prikazanu analizu karakterističnih specifičnosti, date su neke važne tehničko-tehnološke informacije, karakteristike, podaci kao i posebni uslovi koji mogu biti od značaja za inženjersku praksu, posebno za slučaj primene u procesnoj odnosno hemijskoj industriji.

Ključne reči: zavarivanje nerđajućih čelka, otpornost na koroziju, tehnološke i metalurške specifičnosti, klasifikacija otpornosti na koroziju, mere za sprečavanje korozije, tehnologija zavarivanja, greške zavarivanja, praktična primenljivost, eksploatacioni zahtevi, podaci za projektovanje..