Utjecaj temperature na efikasnost antikorozivne zaštite konstrukcijskog čelika primjenom ekološkog inhibitora

master's thesis

• Title (english): Influence of temperature on efficiency of anticorrosion protection of structural steel using ecological inhibitor
• Author: Tanja Stefanovski
• Mentor: Anita Begić Hadžipašić (mentor)
• Committee member: Natalija Dolić (predsjednik povjerenstva)
• Committee member: Anita Begić Hadžipašić (član povjerenstva)
• Committee member: Stjepan Kožuh (član povjerenstva)
• Granter: University of Zagreb; Faculty of Metallurgy; Sisak
• Defense date and country: 2015-09-30, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Metallurgy; Process Metallurgy

Abstract

Primjena inhibitora u kontroli korozije metala i slitina, koje su u kontaktu s agresivnim medijem, danas je opće prihvaćena praksa. Velik broj organskih spojeva je proučavan u svrhu ispitivanja njihove učinkovitosti inhibicije korozije. Istraživanja su pokazala da organski spojevi, naročito oni s kisikom, dušikom i sumporom, imaju veliku učinkovitost u procesu zaštite metala od korozije. Međutim, mnogi ovi spojevi su skupi, ali i vrlo toksični za ljude i okoliš. Stoga, današnja istraživanja su najviše usmjerena prema proučavanjima ekološki prihvatljivih inhibitora poput tanina, prirodnih polimera i ekstrakata biljaka. U ovom radu je proučavan utjecaj temperature na efikasnost antikorozijske zaštite konstrukcijskog čelika u kiselom mediju primjenom Aloe vere kao ekološkog inhibitora. Metodom potenciodinamičke polarizacije je ustanovljeno da se povećanjem koncentracije Aloe vere u kiselom mediju do 10% smanjuje brzina korozije i povećava djelotvornost inhibitora. Međutim, djelotvornost Aloe vere kao inhibitora opada s porastom temperature. Analiza elektrokemijske impedancijske spektroskopije je pokazala da s porastom koncentracije Aloe vere do 10% raste otpor prijenosu naboja, što znači da raste i zaštitni sloj, koji omogućava povećanje korozijske otpornosti. Metalografskim ispitivanjima mikrostrukture površine konstrukcijskog čelika nakon korozije u kiselom mediju s različitim koncentracijama Aloe vere uočene su bijele nakupine željeznih oksikarbida adsorbiranih na površini metala, koje potječu od organskih spojeva Aloe vere, a djeluju kao centri antikorozijske zaštite.

Abstract (english)

The use of inhibitors to control corrosion of metals and alloys, which are in contact with aggressive media, it is now generally accepted practice. A large number of organic compounds have been studied in order to test the effectiveness of their corrosion inhibition. Studies have shown that organic compounds, especially those with oxygen, nitrogen and sulfur, have a high efficiency in the process of protecting metals against corrosion. However, many of these compounds are expensive, but also very toxic to humans and the environment. Therefore, the current investigations are mostly directed towards studies of environmentally friendly inhibitors such as tannins, natural polymers and plant extracts. In this work the effect of temperature on the efficiency of corrosion protection of structural steel in acid medium by adding Aloe vera as ecological inhibitor. By the method of potentiodynamic polarization it was found that increasing the concentration of Aloe vera to 10% in the acidic medium reduces the corrosion rate and increases the inhibitor effectiveness. However, the effectiveness of Aloe vera as an inhibitor decreases with increasing the temperature. Analysis of electrochemical impedance spectroscopy revealed that with increasing concentration of Aloe vera to 10% increases charge transfer resistance, which means that the protective layer increases, which enables an increase of corrosion resistance. Metallographic investigations of structural steel microstructure after corrosion in acidic medium with different concentrations of Aloe vera have revealed white clusters of iron oxicarbides adsorbed on the metal surface, which originate from organic compounds of Aloe vera, and act as centers of corrosion protection.

• Keywords: korozijska otpornost; konstrukcijski čelik; Aloe vera; zeleni inhibitor; mikrostruktura
• Keywords (english): corrosion resistance; structural steel; Aloe vera; green inhibitor; microstructure
• Language: croatian
• URN:NBN: urn:nbn:hr:115:137233
• Study programme: Title: Graduate study program Metallurgy; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka metalurgije (magistar/magistra inženjer/inženjerka metalurgije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2015-10-15 09:58:16