Korozijska zaščita aluminijeve zlitine s konverzijsko in hibridno sol-gel prevleko

Bračič, Veronika (author), Požgan, Franc (mentor)

Korozija aluminija in njegovih zlitin v kloridnem mediju predstavlja velik~problem modernega sveta. V sklopu diplomske naloge sem se osredotočila na študijo korozijske zaščite aluminijeve zlitine s standardno oznako AlSi7Mg0.3, ki se pogosto uporablja v transportni industriji. Zlitina je korozijsko slabo odporna, zato je potrebno površino dodatno zaščititi. V preteklosti so se kot korozijska zaščita pogosto uporabljale kromatne konverzijske prevleke, toda njihova uporaba je danes zaradi negativnega vpliva na okolje in zdravje ljudi omejena. V zadnjih desetletjih se veliko pozornosti posveča razvoju različnih vrst okolju sprejemljivih protikorozijskih prevlek. Med učinkovitejše sodijo cirkonijeve konverzijske in hibridne sol-gel prevleke. Konverzijske prevleke izkazujejo aktivno zaščito, medtem ko hibridne sol-gel prevleke, sintetizirane iz različnih prekurzorjev, nudijo dobro zaporno zaščito. Diplomsko delo sestoji iz pregleda literature, v katerem so predstavljeni osnovni pojmi korozije, opis aluminija in njegovih zlitin, opisane pa so tudi konverzijske in hibridne sol-gel prevleke. Cilj diplomskega dela je torej ovrednotiti lastnosti posameznih prevlek in kombinacije obeh prevlek (aktivne in zaporne zaščite). V eksperimentalnem delu je v ospredje postavljena predvsem priprava vzorcev, tvorba konverzijske prevleke, sinteza hibridnega sol-gela ter karakterizacija površine, adhezije in korozijskih lastnosti pripravljenih prevlek. Rezultati potrjujejo, da razvite prevleke učinkovito ščitijo površino zlitine v kloridnem mediju, kar je pomemben korak v iskanju alternativih korozijskih zaščit.

• Language: Slovenian
• Keywords: aluminijeve zlitine, korozija, konverzijske cirkonijeve prevleke, hibridne sol-gel prevleke
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2021
• PID: 20.500.12556/RUL-132806
• COBISS.SI-ID: 89641219
• Publication date in RUL: 03.11.2021

Secondary language

• Language: English
• Title: Corrosion protection of aluminium alloy using conversion and hybrid sol-gel coatings

Abstract

Corrosion of aluminium and its alloys in chloride media is a major problem of the modern world. As a part of my thesis, I focused on the study of the corrosion protection of aluminium alloy AlSi7Mg0.3, which is widely used in the transport industry. The alloy has poor corrosion resistance, therefore the surface needs additional protection. Chromate conversion coatings have been used frequently in the past, but their use is now limited due to their negative impact on the environ\-ment and human health. In recent decades, a lot of attention is being paid to the development of various types of environmentally friendly coatings. Zirconium conversion and hybrid sol-gel coatings are among the most effective ones. Conversion coatings offer active protection, while hybrid sol-gel coatings, synthesized from various precursors, offer good barrier protection. The Bachelor's thesis is comprised of a literature review, in which the basic concepts of corrosion, aluminium and its alloys are presented, as well as conversion and hybrid sol-gel coatings. The aim of this thesis is therefore to evaluate the properties of individual coatings and combination of both coatings (active and barrier protection). In the experimental part, the focus is on the preparation of samples, formation of the conversion coating, synthesis of the hybrid sol-gel and characterization of the surface, adhesion and corrosion properties of the prepared coatings. The results confirm that the developed coatings effectively protect the surface of the alloy in chloride medium, which is an important step towards finding a replacement for chromate coatings and improving the corrosion protection of this alloy.

• Keywords: aluminium alloys, corrosion, conversion zirconium coatings, hybrid sol-gel coatings