magistrsko delo
Alain Kerhe (Author), Regina Fuchs-Godec (Mentor), Urban Bren (Co-mentor), Martin Rozman (Co-mentor)

Abstract

Nezaščitene železne in jeklene površine so dovzetne za zračno vlago in kisik. Na njih se zaradi termodinamske nestabilnosti tvori šibka pasivna plast oksida, ki se lušči in poškoduje kovinske konstrukcijske materiale. V magistrskem delu smo nerjavno jeklo AISI 304 prevlekli s postopkom sol-gel ter izdelano protikorozijsko zaščito na osnovi TiO2, ki naj bi preprečevala tvorbo korozijskih produktov in inhibirala proces korozije. Nanesli smo po več plasti tankoslojne zaščite, med nanašanjem posameznih plasti pa smo jih za stabilizacijo sušili v sušilniku ali avtoklavu: tri plasti pri 500 °C, pet plasti pri 200 °C in 500 °C ter deset plasti pri 200 °C. Plasti smo toplotno obdelali, da bi iz njih odstranili organske komponente, ostali so samo kompleksni oksidi Ti4+. To je vodilo do večje homogenosti in adhezivnosti, manjše poroznosti in boljšega prekrivanja med plastmi. Preizkušali smo različne sestave plasti ter določali njeno stabilnost, obstojnost, medplastno prekrivanje in inhibicijsko zaščito prevlek v agresivnih medijih, predvsem v HCl pri različnih koncentracijah: 2-%, 8,5-% in 17-%. Za analizo plasti smo uporabljali elektrokemijsko impedančno spektroskopijo (EIS) in potenciodinamsko polarizacijsko spektroskopijo (PP). Eksperimentalne točke, pridobljene z metodo EIS, smo predstavili z Nyquistovimi in Bodejevimi diagrami, hkrati pa si z interpretacijo konstruiranih karakterističnih nadomestnih vezij pridobili vpogled v impedančne parametre ter na njihovi podlagi ugotovili pozitivne zaviralne (inhibicijske) lastnosti proti korozijskim procesom pri več nanosih plasti. Najboljšo protikorozijsko zaščito je kovini dajalo pet plasti, sušenih na 200 °C, najslabšo protikorozijsko zaščito pa je imel premazni sistem z vsebnostjo naravnega voska P123 in s tremi plastmi, sušenimi na 500 °C.

Keywords

protikorozijska zaščita;nerjavno jeklo;postopek sol-gel;inhibicijska hitrost;elektrokemijska impedančna spektroskopija;potenciodinamska polarizacijska spektroskopija;magistrske naloge;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher: [A. Kerhe]
UDC: 620.193:544.023.2(043.2)
COBISS: 56662275 Link will open in a new window
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Downloads: 52
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Other data

Secondary language: English
Secondary title: Fabrication of thin layers tio 2 layers as a corrosion barrier on metallic surfaces
Secondary abstract: Unprotected iron and steel aread are susceptible to air moisture and oxygen. Because of the termodinamical unstability a weak layer of oxides is formed, which peels down and destroys construction materials. In this master's degree work we covered stainlees steel AISI 304 with an anticorrosion coating based on TiO2 using the salt-gel procedure, which should inhibit the proces of corrosion and prevent the formation of the corrosion products. Thin layer coating was applied in several layers, with every layer burnt in the dryer or autoclave: 3 layers of coating burnt by 200 °C, 5 layers of coating burnt by 200 and 500 °C and 10 layers of coating burnt by 200 and 500 °C. Layers of coating are burned, because we must remove any organic compounds out of the coating, so that only Ti4+ oxide remains. That leads to bigger homogeneity and adhesivity, less porosivity and to a better overlap between each of the coating layers. The performance of Ti4+ coatings in 2-%, 8,5-% and 17-% HCl was measured and studied by electrochemical methods such as electrochemical impedance spectroscopy (EIS) and potentiodynamic polarisation (PP). All of the results show that Ti4+ coating exhibit an effective resistance and positive corrosion inhibition characteristics by several layers of coating, the best anticorrosion properties were displayed by the metal coaded with 5 layers and burnt at 200 °C, meanwhile the weakest coating was with three layers burnt by 500 °C including P123 wax content. The experimental data were presented with Nyquist and Bode diagrams, simultaneously characteristic equivalent circuit models were constructed, which provided the impedance parameters for the intrepretation of our coating system.
Secondary keywords: surface protective coatings;stainless steel;salt-gel coatings;corrosion inhibition;electrochemical impedance spectroscopy;potentiodynamic polarisation spectroscopy;
Type (COBISS): Master's thesis/paper
Thesis comment: Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages: XV, 89 f.
ID: 12508367