To typer av overflater, polyester-belagt stål og polyester belagt med et lag av silikananopartikler, ble undersøkt. Begge overflater ble eksponert for sollys, som ble funnet å forårsake vesentlige forandringer i kjemien og nanoskala topografien av overflaten.
Korrosjon på metalloverflater er utbredt i miljøet og er til stor bekymring i mange områder, inkludert militære, transport, luftfart, bygg og næringsmiddelindustrien, blant andre. Polyester og belegg som inneholder både polyester og silikananopartikler (SiO 2 NPS) har vært mye brukt for å beskytte stål grunnen mot korrosjon. I denne studien benyttet vi X-ray fotoelektron spektroskopi, dempes total refleksjon infrarød mikrospektroskopi, vann kontaktvinkelmålinger, optisk profilering og atomic force mikroskopi for å gi et innblikk i hvordan eksponering for sollys kan føre til endringer i mikro- og nanoskala integritet av beleggene. Ingen signifikant endring i overflatetopografi mikro ble påvist ved anvendelse av optisk profilometri ble imidlertid statistisk signifikante endringer i nanoskala overflaten påvises ved hjelp av atomkraftmikroskopi. Analyse av røntgenfotoelektronspektroskopi og svekket total refleksjon infrarød mikro-spektroskopi data viste at nedbrytningen av estergruppene hadde forekommet ved eksponering for ultrafiolett lys for å danne COO ·, -H 2 C ·, -O ·, -CO · radikaler. Under nedbrytningsprosessen, ble CO og CO 2 også produsert.
Environmental corrosion of metals in the environment is both prevalent and costly1-3. A recent study conducted by the Australasian Corrosion Association (ACA) reported that corrosion of metals resulted in a yearly cost of $982 million, which was directly associated with the degradation of assets and infrastructure through metallic corrosion within the water industry4. From an international perspective, the World Corrosion Organization estimated that metallic corrosion was responsible for a direct cost of $3.3 trillion, over 3% of the world’s GDP5. The process of galvanizing as a corrosion preventative method has been widely used to increase the lifespan of steel material6. In humid and subtropical climates, however, water tends to condense into small pockets or grooves within the surface of the galvanized steel, leading to the acceleration of corrosion rates through pit corrosion7,8. Thermosetting polymer coatings based on polyesters have been developed to coat the galvanized steel substrata increasing their ability to withstand humid weathering conditions for items such as satellite dishes, garden furniture, air-conditioning units or agricultural construction equipment9-11. Unfortunately polymer coatings on steel surfaces have been found to be considerably adversely affected by the presence of high levels of ultraviolet (uv) radiation12-14. Coatings comprised of silica nanoparticles (SiO2) spread over a polymer layer have been widely used with a view to increasing their corrosion-, wear-, tear- and degradation-resistance15,16. The tendency of the protective polymeric coatings to form pores and cracks can be reduced by incorporating nanoparticles (NPs), which contribute to the passive obstruction of corrosion initiation17,18. Also, the mechanical stability of the protective polymeric layer can be improved by NPs inclusion. However, these coatings act as passive physical barriers and, in comparison to the galvanization approach, cannot inhibit corrosion propagation actively.
An in-depth understanding of the effect that high-levels of ultraviolet light exposure under humid conditions upon these metal coatings is yet to be obtained. In this paper, a wide range of surface analytical techniques, including X-ray photoelectron spectroscopy (XPS), attenuated total reflection infrared micro-spectroscopy (ATR IR), contact angle goniometry, optical profiling and atomic force microscopy (AFM) will be employed to examine the changes in the surface of steel coatings prepared from polyester- and silica nanoparticle-coated polyester (silica nanoparticles/polyester) after exposure to sunlight. Furthermore, the aim of this work is to give a concise, practical overview of the overall characterization techniques to examine weathered samples.
Polyester belegg har blitt mye brukt for å beskytte stål substratet fra den korrosjon som ville inntreffe på en ubelagt overflate på grunn av opphopning av fuktighet og forurensninger. Anvendelsen av polyester belegg kan beskytte stålet mot korrosjon; men på lengre sikt effektiviteten til disse beleggene blir redusert hvis de blir utsatt for høye nivåer av ultrafiolett lys under fuktige betingelser som forekommer i tropiske klima. Silikananopartikler kan påføres på overflaten av polyester for å øke robusthe…
The authors have nothing to disclose.
Funding from the Australian Research Council Industrial Transformation Research Hubs Scheme (Project Number IH130100017) is gratefully acknowledged. Authors gratefully acknowledge the RMIT Microscopy and Microanalysis Facility (RMMF) for providing access to the characterisation instruments. This research was also undertaken on the Infrared Microscopectroscopy beamline at the Australian Synchrotron, Victoria, Australia.
polyester-coated steel silica nanoparticle-polyester coated steel substrata |
BlueScope Steel | Samples provided by company | |
Millipore PetriSlideTM | Fisher Scientific | PDMA04700 | Storing samples |
Thermo ScientificTM K-alpha X-ray Photoelectron Spectrometer |
Thermo Fisher Scientific, Inc. | IQLAADGAAFFACVMAHV | Acquire XPS spectra |
Avantage Data System | Thermo Fisher Scientific, Inc. | IQLAADGACKFAKRMAVI | Analyse XPS spectra |
A Bruker Hyperion 2000 microscope | Bruker Corporation | Synchrotron integrated instrument | |
Bruker Opus v. 7.2 | Bruker Corporation | ATR-IR analysis software | |
Contact angle goniometer, FTA1000c | First Ten Ångstroms Inc., VA, USA | Measuring the wettability of surfaces | |
FTA v. 2.0 | First Ten Ångstroms Inc., VA, USA | Anaylyzing water contact angle | |
Optical profiler, Wyko NT1100 | Bruker Corporation | Measure surface topography | |
Innova atomic force microscope | Bruker Corporation | Measure surface topography | |
Phosphorus doped silicon probes, MPP-31120-10 | Bruker Corporation | AFM probes | |
Gwyddion software | http://gwyddion.net/ | Software used to measure optical profiling and AFM data |