Nanostrukturirani premazi za zaštitu od korozije na osnovi TiO2

doctoral thesis

• Title (english): TiO2 based nanostructured coatings for corrosion protection
• Author: Antonio Ivanković
• Mentor: Sanja Martinez (mentor)
• Committee member: Helena Otmačić Ćurković (predsjednik povjerenstva)
• Committee member: Marijana Kraljić Roković (član povjerenstva)
• Committee member: Frankica Kapor (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2016-12-14, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Basic Technical Sciences; Materials
• Universal decimal classification (UDC): 66 - Chemical technology. Chemical and related industries ; 620 - Materials testing. Power stations. Economics of energy

Abstract

U ovom radu ispitana je mogućnost dobivanja nanostrukturiranih vodenih disperzija na bazi TiO2 koje se mogu nanijeti na nehrđajući čelik sa svrhom zaštite od korozije. Ispitivane formulacije osim s nanočesticama, priređene su s različitim spojevima kao dodacima, kako bi se poboljšala stabilnost vodenih disperzija i spriječila tendencija prema stvaranju aglomerata i agregata te kako bi se spriječilo taloženje nanočestica. Također, formulacije su priređene pri različitim pH vrijednostima, jer pH predstavlja važan činilac pripreme stabilnih vodenih disperzija nanočestica TiO2. TiO2 disperzije nanesene su na podlogu od nehrđajućeg čelika AISI 304 i osušene na zraku. Morfologija i struktura prevlaka su analizirane korištenjem FTIR, XRD i SEM / EDX metoda. Elektrokemijska mjerenja anodne polarizacije i elektrokemijske impedancijske spektroskopije, provedena su bez osvjetljenja i pod UV svjetlošću u otopini 3,5% NaCl. Nanošenjem disperzija na površinu nehrđajućeg čelika i sušenjem na zraku, formira se TiO2 nanostrukturirana prevlaka koja predstavlja zaštitni sloj na površini. Elektrokemijska mjerenja pokazuju da su opća i lokalizirana korozija potisnute jer se struja u pasivnom području smanjuje, potencijal jamičaste korozije postaje plemenitiji i pasivno područje se proširuje. UV osvjetljenje pomiče potencijal otvorenog kruga nehrđajućeg čelika prema negativnijim vrijednostima u pasivnom području, dalje od potencijala inicijacije jamičaste korozije kao rezultat fotogenerirane struje katodne zaštite. Različite formulacije premaza pokazale su različite stupnjeve stabilnosti disperzije i različite zaštitne djelotvornosti nakon aplikacije na nehrđajući čelik. Najbolji rezultat pokazale su pH2 S i pH2 S UV formulacije. S djelotvornosšću od 84.9% i 85.3%, dok s obzirom na širinu pasivne zone najbolji rezultat pokazuju pH2 K i pH2+D K UV formulacije s pomakom potencijala od 684 mV i 457 mV.

Abstract (english)

In this paper, the possibility of obtaining nanostructured water-based dispersion of TiO2 in order to protect against corrosion was investigated. The tested formulations were prepared with different compounds and additives in order to prevent the tendency toward precipitation of the nanoparticles in the aqueous medium due to attractive forces between the nanoparticles in aqueous solution. Addition of various compounds should improve the stability of the water dispersion and prevent the tendency towards the formation of agglomerates and aggregates of nanoparticles TiO2. Likewise, formulations were prepared at different pH values in order to determine the optimum conditions for the preparation of stable aqueous dispersions of nanoparticles of TiO2. The goal is to get water-dilutable coating that does not contain organic solvents, and is not harmful to human health and the environment. TiO2 dispersions were deposited on AISI 304 stainless steel and air dried.
The morphology and structure of the coatings were analysed using FTIR, XRD and SEM / EDX. Electrochemical measurements were done without illumination and under UV illumination, in 3,5% NaCl. TiO2 nanostructured coatings on stainless steel act by forming a protective layer on the metal surface. Both, general and localized corrosion are suppressed, as the current in the passive range decreases, the corrosion and the pitting potential become more noble and the passive range broadens. The UV illumination pushes the open circuit potential of stainless steel to more negative values within the passive range, away from the pitting potential as a result of photogenerated cathodic protection current effect. The different coating formulations showed different degrees of dispersion stability and protective efficacy of different applications upon the stainless steel. The best result showed pH2 S and pH2 S UV formulations. The efficiency of 84.9% and 85.3%, while with respect to the width of the passive zone best result show pH2 K and pH2+D K UV formulation with a shift of potential of 684 mV and 457 mV.

• Keywords: fotogenerirana katodna zaštita; korozija; nehrđajući čelik; TiO2 premaz
• Keywords (english): photogenerated cathodic protection; corrosion; stainless steel; TiO2 coating
• Language: croatian
• URN:NBN: urn:nbn:hr:149:826787
• Promotion: 2016
• Study programme: Title: Engineering Chemistry - Doctoral Course; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija (doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija)
• Type of resource: Text
• Extent: 170 str. ; 30 cm
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2023-12-11 09:05:21