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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Progress in Color, Colorants and Coatings
- نوع مقاله: Journal Article
- کلمات کلیدی: Wavelet Analysis,Electrochemical,Electrochemical noise,Nanocomposite Polyvinyl butyral,mpedance Spectroscopy
- چکیده:
- چکیده انگلیسی: In this work, polypyrrole/ZnO nanocomposite (PPy/ZnO NC) was produced through synthesis of polypyrrole polymer in the presence of ZnO nanoparticles. The corrosion behavior of polyvinyl butyral coatings without and with different weight percentages of nanocomposite on the surface of 7075 Al alloy was investigated in 3.5% NaCl solution at different immersion times using electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) techniques. The coating with 0.025% PPy/ZnO NC revealed the highest corrosion resistance. In order to analysis of EN data, wavelet transform was used to obtain the standard deviation of partial signal (SDPS) plots. The good agreement between the EIS and EN results indicates that the EN technique, as well as the EIS method, can be used successfully for the corrosion evaluation of coatings.
- انتشار مقاله: 11-10-1348
- نویسندگان: G.S. Sajadi,S.M.A. Hosseini,M.J. Bahrami,M. Shahidi
- مشاهده
- جایگاه : پژوهشی
- مجله: Progress in Color, Colorants and Coatings
- نوع مقاله: Journal Article
- کلمات کلیدی: Phosphoric acid,Polarization,Corrosion inhibitor,Electrochemical Impedance Spectroscopy (EIS),Scanning Electron Microscopy (SEM),Electrochemical noise resistance
- چکیده:
- چکیده انگلیسی: The inhibitive effect of apricot gum AG on mild steel in 0.5 M phosphoric acid solution was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy EIS, linear polarization resistance and electrochemical noise EN techniques. The inhibition efficiency increased with increasing AG concentration up to a certain value and decreased with increasing temperature. Polarization curves indicated that AG acts as a mixed type inhibitor. The EN data were analyzed by statistical and wavelet methods. The results obtained from analysis of EN data was in good agreement with those arising from the polarization and EIS measurements. The adsorption of the inhibitor on the alloy surface in 0.5 M H3PO4 followed the Langmuir isotherm. According to the calculated values of free energy and enthalpy adsorption it was revealed that the adsorption of inhibitor on the steel surface was a combination of physical and chemical adsorption. The morphologies of the uninhibited and inhibited mild steel surfaces in 0.5 M H3PO4 were analyzed by scanning electron microscope SEM. SEM images showed that the alloy surface damage is significantly decreased in presence of the inhibitor.
- انتشار مقاله: 11-10-1348
- نویسندگان: A. Mohammadi,S.M.A. Hosseini,M.J. Bahrami,M. Shahidi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Mining and Environment
- نوع مقاله: Journal Article
- کلمات کلیدی: Salt rock,Long-term creep,Uniaxial Creep Test,lever arm,rock testing standards
- چکیده:
- چکیده انگلیسی: Creep phenomenon in rock engineering plays a key role in development of underground spaces as they must be stable enough for a long period of time. Current research involved designing and manufacturing of a new creep testing machine. The equipment is capable to perform simultaneous light-duty creep tests on more than one cylindrical rock samples at a very low cost.
To evaluate the equipment’s performance, a series of creep test was performed on salt rock samples and their axial and lateral deformations were measured by dial gauges. Measurements were taken under constant temperature, humidity and sustained loads. The results revealed that the creep rate in lateral direction was far greater than in the axial direction. Another important conclusion was that both axial and lateral creep curves follow the same pattern with an idealized salt rock creep curve. Also, experiments indicated that the steady state creep rate increases with increasing initial stress state. Also, initial stress state showed a great influence on salt primary creep response.- انتشار مقاله: 30-10-1390
- نویسندگان: S.M.A Hosseini,F Sereshki,M Shariati,S.M.E Jalali,F Crotogino
- مشاهده