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Microbiological corrosion of constructional materials in the fuel enviroment

Beza Waldemar

Abstract

The purpose of the study has been to examine the process of microbiological corrosion occurring in fuel tanks and transmission installations, determine the impact of the nickel layer on the reduction in the corrosion damages taking place on St3S construction steel - a material used in the fuel industry. The mechanically cleaned and degreased samples of St3S steel were covered with an anticorrosive coating from galvanic and chemical nickel. The samples protected with a layer of nickel were exposed in the corrosive environment that was a mixture of water and fuel taken from the propulsion fuel tanks. During the multi-day exposition of the samples in the water phase and near the limit of the water-fuel phases, the progress of corrosion damages was determined. The corrosive resistance tests of tested samples were performed using electrochemical methods (polarization and impedance method) and gravimetric method The electrochemical tests were performed using a computerized electrochemical tests set - ATLAS-98. The polarization tests were performed in the beginning (after 1 day of exposition in the corrosive environment) and after completion of the tests (after 60 days of exposition). The speed of corrosion of tested samples has been determined on the basis of cathodic and anodal polarization curves. The polarization curves have been made using the potential-dynamic method while polarizing the samples with the velocity of changes amounting to 10mV/min. The impedance characteristics of the tested samples have been made using a computer program IMP-98. The impedance tests were conducted at changing frequencies in the range from 0.001 to 100 kHz and the variable-current impulse amplitude of 10mV. The acquired data have been analyzed with respect to two substitute model systems. In the gravimetric tests, the speed of corrosion has been determined on the basis of depletion of masses of the examined samples during exposition in the corrosive environment. The speed of corrosion has been determined from the masses depletions in Vm (g/m2 day) and Vp (mm/year). The corrosion resistance of nickel coatings has been assessed on the basis of the test results. The acquired results demonstrate that nickel coatings fully protect the St3S steel against microorganisms present in fuel storage tanks and in the systems used for their transport. The speed of corrosion of steel covered with a nickel coating created chemically is within the range 0.001-0.005mm/year. (corrosive resistance group 2). The samples show high resistance corrosion resistance is shown by the steel covered with a layer of galvanic nickel. All test results achieved for the times above 14 days of exposition qualify the steel to the highest corrosive regardless of the place of their exposition in the corrosive environment. Even greater resistance group - 1
Diploma type
Engineer's / Bachelor of Science
Diploma type
Engineer's thesis
Author
Beza Waldemar Beza Waldemar,, Undefined Affiliation
Title in Polish
Korozja mikrobiologiczna tworzyw konstrukcyjnych w środowisku paliw
Supervisor
Marek Kamiński (FMSE) Marek Kamiński,, Faculty of Materials Science and Engineering (FMSE)
Certifying unit
Faculty of Materials Science and Engineering (FMSE)
Affiliation unit
Division of Surface Engineering (FMSE/DSE)
Study subject / specialization
, Inżynieria Materiałowa
Language
(pl) Polish
Status
Finished
Defense Date
26-01-2010
Issue date (year)
2009
Internal identifier
IM-D.001431
Reviewers
Krzysztof Rożniatowski (FMSE/DMD) Krzysztof Rożniatowski,, Division of Materials Design (FMSE/DMD)Faculty of Materials Science and Engineering (FMSE) Joanna Ryszkowska (FMSE/DSMP) Joanna Ryszkowska,, Division of Ceramic Materials and Polymers (FMSE/DSMP)Faculty of Materials Science and Engineering (FMSE)
Keywords in Polish
korozja
Abstract in Polish
urn:pw-repo:WUTbff0b7a5df064f0ea9589822937d7118