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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 126 (1995), S. 369-376 
    ISSN: 1434-4475
    Keywords: Acid corrosion ; Inhibition ; Iron ; Oxygen and nitrogen containing compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die von Chinin, Ephedrin, Brucin, Chinchonin, Codein und Harmalin ausgeübte Korrosionshemmung bei der Auflösung von Eisen in 2M Schwefelsäure wurde mittels elektrochemischer Methoden untersucht. Polarisationskurven zeigen, daß die erwähnten Verbindungen als Inhibitoren gemischten Typs fungieren, d. h. sowohl die kathodische als auch die anodische Kurve wurde beeinflußt. Der beobachtete Effekt folgt derTemkinschen Adsorptionsisotherme. Die Auswirkung von Strukturänderungen auf die Effizienz der Hemmung und einige thermodynamische Funktionen werden diskutiert. Die Korrosionstrate von Eisen steigt sowohl in Gegenwart als auch in Abwesenheit der Inhibitoren im Bereich von 30–50°C mit steigender Temperatur.
    Notes: Summary Corrosion inhibition by quinine, ephedrine, brucine, cinchonine, codeine, and harmaline with respect to the dissolution of iron in 2M sulphuric acid was measured using electrochemical methods. Polarization curves indicated that these compounds act as mixed-type inhibitors,i.e. both the cathodic and anodic curves are affected. The observed effect follows theTemkin adsorption isotherm. The effect of the different structural features of these compounds on their inhibition efficiency has been studied. Results indicate that the rate of corrosion of iron increases with increasing temperature over the range 30–50 °C both in the absence and in the presence of inhibitors. Some thermodynamic functions were also computed and are discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 118 (1987), S. 709-716 
    ISSN: 1434-4475
    Keywords: Corrosion ; Inhibitor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wurden fünf Derivate von Phenylthiosemicarbazid hergestellt und als Inhibitoren für die Korrosion von Aluminium in 2M NaOH eingesetzt. Die Substanzen ergaben 98.5 bis 75% Schutz für Aluminium in NaOH. Dabei war 1-(Methoxybenzoyl)-4-phenyl-3-thiosemicarbazid der effizienteste Inhibitor. Thermometrische und Gewichtsverlustmethoden zeigten, daß die Inhibition prinzipiell von der Adsorption dieser Verbindungen auf der Metalloberfläche gesteuert wird, wobei die Adsorbierbarkeit der Inhibitoren von der Basizität der teilnehmenden Sauerstoff- und Schwefelfunktionen abhängt.
    Notes: Abstract Five derivatives of phenylthiosemicarbazide have been prepared and treated as inhibitors for the corrosion of aluminium in 2M sodium hydroxide. All the five substances afford 98.5 to 75% protection to aluminium in sodium hydroxide. 1(-Methoxybenzoyl)-4-phenyl-3-thiosemicarbazide being the most efficient inhibitor. Thermometric and weight loss methods indicate that the inhibition is principally governed by the adsorption of these compounds on the surface of the aluminium metal and the adsorbability of inhibitors is dependent on the basicity of the oxygen and sulphur sites involved.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 117 (1986), S. 159-165 
    ISSN: 1434-4475
    Keywords: Corrosion ; Thiophene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wurde die Korrosion von Eisen in 2M HNO3 mittels Messungen der elektrochemischen Polarisation und des Gewichtsverlustes untersucht. Dabei wurde der Einfluß einiger Thiophenderivate überprüft. Die Ergebnisse zeigen, daß die Inhibitoren, die den kathodischen und den anodischen Prozeß beeinflussen, an der Metalloberfläche in molekularer Form adsorbiert werden. Dabei wird der Reaktionsmechanismus der Reaktion zwischen Eisen und Salpetersäure nicht geändert, es wird jedoch die Geschwindigkeit herabgesetzt. Dieser Effekt ist mit den Dipolmomenten korrelierbar. Die Gewichtsverlustmessungen ergaben übereinstimmende Resultate.
    Notes: Abstract Corrosion of iron in 2MHNO3 has been studied by the electrochemical polarization and weight loss measurements. The effect of some thiophene derivatives has been investigated. The results show that the inhibitors under consideration, influencing both the cathodic and anodic process, are adsorbed on the metal surface in molecular form. They do not change the mechanism of the reaction between iron and nitric acid, but decrease its rate. This effect is controlled by the values of their dipole moments. The weight loss technique also gave the same order of inhibition efficiency of the tested inhibitors.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 39 (1988), S. 23-26 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Substituierte Phenole als Inhibitoren der Korrosion von Kupfer in SalpetersäureDie Auflösung von Kupfer in Salpetersäure in Gegenwart von Resorcin, o- und p-Aminophenolen, Brenzkatechin, o-Kresol und Salicylaldehyd als Korrosionsinhibitor wurde gravimetrisch und mittels galvanostatischer Polarisation untersucht. Beide Methoden ergaben für die genannten Verbindungen übereinstimmende Ergebnisse. Aufgrund der Polarisationsdaten ist zu vermuten, daß diese Inhibitoren unter Einwirkung eines äußeren Stroms die Kathode bevorzugt polarisieren. Die Wirkung dieser Inhibitoren dürfte auf Adsorption entsprechend einer Langmuir-Isotherme beruhen. Die Wirkung besteht darin, daß die entstehende salpetrige Säure zersetzt und ihr Einfluß auf die kathodische Reaktion ausgeschaltet wird.
    Notes: The dissolution of copper in nitric acid solution in the presence of resorcinol, o, p-aminophenols, catechol, o-cresol and salicylaldehyde as corrosion inhibitors has been studied by galvanostatic polarization and weight loss methods. For these compounds the two methods gave consistent results.Polarization data suggest that in the case of these inhibitors the cathode is preferentially polarized under the influence of an external current. The inhibitors appear to function through general adsorption following the Langmuir adsorption isotherm. The inhibiting effect of tested compounds is due to the destruction of the HNO2 formed and its interference with the cathodic reaction.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 46 (1995), S. 468-472 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Inhibition der Kupferkorrosion in 1M Salpetersäure mit BenzoylbenzaldehydhydrazinderivatenDie Wirkung von Benzoylbenzaldehydhydrazinderivaten auf die Inhibierung der Kupferkorrosion in IM Salpetersäure-Lösungen bei 303 K wurde mit Hilfe potentiodynamischer und Massenverlustmessungen untersucht. Bei Zugabe der verwendeten Substanzen ergab sich eine deutliche Abnahme der Korrosionsgeschwindigkeit des Kupfers. Die Korrosionsgeschwindigkeit hängt dabei von der Beschaffenheit und der Konzentration des Inhibitors ab. Die Neigung der Tafelgeraden ist unabhängig von der Konzentration des Inhibitors annähernd konstant. Die ermittelten Korrosionsdaten deuten an, daß die Inhibierung der Kupferkorrosion auf die Oberflächenadsorption der Inhibitormoleküle zurückgeführt werden kann, die der Langmuir-Adsorptions-Isotherme folgen. Die Ergebnisse der potentiodynamischen Messungen lassen darauf schließen, daß alle untersuchten Substanzen im wesentlichen kathodisch wirken.
    Notes: The effect of substituted benzoyl benzaldehyde hydrazone derivatives on the inhibition of copper corrosion in IM nitric acid solution at 303 K was investigated by potentiodynamic and weight-loss measurements. A significant decrease in the corrosion rate of copper was observed in the presence of the investigated compounds. The corrosion rate was found to depend on the nature and the concentration of the inhibitors. The Tafel slope is approximately constant independent of the concentration of the inhibitor. The observed corrosion data indicate that the inhibition of copper corrosion is due to surface adsorption of inhibitor molecules which follow the Langmuir adsorption isotherm. The results of potentiodynamic measurements indicate that all investigated compounds act mainly cathodically.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 118 (1987), S. 45-58 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Electrodeposition of tellurium from metal salt solutions in the presence of phthalic acid and inorganic substances at controlled pH has been investigated. The current density ranged from 0.28 to 11.34 mA cm−2. The percentage cathodic current efficiency was relatively low and increased with increasing concentration of tellurion ions in the bath. The purity of the deposited metal was better than 99%. X-ray diffraction analysis shows that the deposit belongs to the hexagonal structure.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 26 (1995), S. 488-492 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The electrodeposition of palladium from electrolytes containing palladium chloride along with potassium-dihydrogen phosphate, sodium fluoride or oxalic acid was studied under a variety of condition. The conditions used were: 1.0 M palladium chloride, 0.15 M potassium dihydrogen phosphate, pH 1.5 at 298 K and current density 0.85 mA cm-2/ The current efficiency was calculated and the crystal structure confirmed by X-ray analysis. Spectrophotomteric and chemical analysis reveals that the purity of the metal is better than 99%. Palladium electrode can function satisfactorily as indicator electrode for hydrogen ions in acid-base titrations. Titration of acids with sodium hydroxide and of salts of weak acids with hydrochloric acid showed that palladium can indicate very accurately the end point. The end point coincide to great extent with the visual values with an error not more than ± 2%.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 26 (1995), S. 342-346 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The dissolution of aluminium in hydrochloric acid and sodium hydroxide solutions in the presence of semicarbazide, thiosemicarbazide and sym.diphenylcarbazide as corrosion inhibitors has been studied using thermometric, weight-loss and polarization methods. The three methods gave consistent results. The higher inhibition efficiency of these compounds in acidic than in alkaline madia may be due to the less negative potential of aluminium in hydrochloric acid solution, favouring adsorption of the additive. The adsorption of these compounds were found to obey Frumkin adsorption isotherm.Cathodic polarization measurements showed that these compounds are cathodic inhibitors and their adsorption in the double layer does not change the mechanism of the hydrogen evolution reaction. The results are analysed in terms of both molecular and cationic adsorption.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 28 (1997), S. 439-443 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The inhibition action of 1-benzylidene-4-phenylthiosemicarbazone derivatives on the corrosion behaviour of iron in 1M H2SO4 was investigated using potentiostatic and potentiodynamic techniques. Results showed that these derivatives act as mixed-type inhibitors, but the cathode is more preferentially polarized. All the inhibitors follow the Frumkin adsorption. The results of the potentiodynamic indicate that the adsorption process depends on both adsorption potential (Eads) and adsorption time (tads). THe results obtained were analysed and discussed on the basis of competitive adsorption.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 26 (1995), S. 357-361 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The effect of some hydrazone oxime derivatives on the corrosion of iron in 2M HCl have been studied by polarization and weight-loss techniques. It was found that the compounds under consideration are adsorbed on the iron surface according toe the Temkin isotherm. The Tafel slope is approximately constant independent of the concentration of the inhibitor. The results of polarization indicate that all compounds tested were of a mixed type, but the cathodic is more preferenially polarized.The inhibition efficiency was found to follow the order:I〉III〉IV〉VI〉II.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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