Nanostructured coatings for car and aerospace industries

Abstract

Alumiiniumsulamid on kerged ning suurepäraste mehaaniliste omadustega, mille tõttu kasutatakse neid laialdaselt komponentide valmistamiseks lennu- ja autotööstuses. Paraku on parimad alumiiniumsulamid tundlikud korrosiooni suhtes, mida saab takistada erinevate kaitsekatete abil. Põhiliseks väljakutseks on seejuures kaitse tagamine täppisdetailidele, mille mõõtmed ei tohi palju muutuda ja mis võivad olla keeruka kolmemõõtmelise kujuga ning sisaldada ka keermetega auke. Selle probleemiga tegeleti antud uurimustöös, kus uuriti nanokatete rakendamist alumiiniumsulamite korrosioonikindluse tõstmiseks. Erinevate keraamiliste kaitsekatete valmistamiseks kasutati uurimustöös aatomkihtsadestuse meetodit, millega kaeti erineva eeltöötlusega alumiiniumdetailide. Süstemaatiliste uuringute vältel töötati välja uudne meetod et valmistada nanostruktuurseid kaitsekatteid, mis tagasid alumiiniumdetailidele suurepärase kaitse korrosiooni eest. Samuti testiti kaitsekatet energeetilise atomaarse hapnikuga, millega simuleeriti 1 aasta pikkust kokkupuudet kosmose tingimustega madalal orbiidil. Uudne nanostruktuurne kate on praeguseks kantud üle 50-le alumiiniumdetailile satelliidil WISA Woodsat, kus tema eesmärk on tagada funktsionaalsus kriitilistele liikuvatele detailidele. Samuti uuritakse peagi uudse katte käitumist kosmoses materjalide testimise mooduli abil, mis on integreeritud satelliidile ESTCube-2.

Aluminum alloys are widely used for manufacturing components in aerospace and automobile industries. Aluminum alloys are favored in these applications as they have light weight and superior mechanical properties but are also easy to process. However, these alloys are vulnerable to corrosion, which can be mitigated by using various protective coatings. The primary challenge with aluminum alloys in practical applications is the protection of high precision substrates that may also have a sophisticated three-dimensional shape or contain threaded cavities. This problem was addressed in this study, where the use of nanometric protective coatings was investigated. For that purpose, atomic layer deposition technique was used to grow various ceramic materials onto the aluminum alloy substrates that had received different pre-treatments. During these systematic studies, a technique was developed for the preparation of a novel nanostructured coating which protected the aluminum alloy against corrosion in salt spray tests. The novel coating also suffered only negligible damage from energetic atomic oxygen, which was used to simulate 1 year of exposure to space in low Earth orbit. Finally, the novel nanostructured coating was successfully applied on over 50 aluminum parts of satellite WISA Woodsat and will also be tested soon in space on the materials testing module on ESTCube-2.