Properties of Alumina Coating Formed by Microarc Oxidation Technique on 6061 Aluminum Alloy
| Autor: | Murat Makaraci, Aytekin Polat, Ali Ata, Metin Usta, Zakir Tas |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Materials science
Metallurgy Alloy Metals and Alloys chemistry.chemical_element Mullite engineering.material Condensed Matter Physics Electronic Optical and Magnetic Materials chemistry Coating Mechanics of Materials Aluminium Phase (matter) engineering Surface roughness Composite material Current density Deposition (law) |
| Zdroj: | Practical Metallography. 45:594-609 |
| ISSN: | 2195-8599 0032-678X |
| DOI: | 10.3139/147.100406 |
| Popis: | In this study, thick and hard alumina coatings were produced on 6061-T6 Al alloy substrates for different oxidation times and current densities by using of microarc oxidation (MAO) technique in an alkali-silicate electrolytic solution. The influence of oxidation time and current density on the kinetics, phase composition, hardness, surface roughness and structure of the coating were investigated. It is found that the kinetics of coating mainly depends on applied current density and oxidation time. The XRD results revealed that the coatings are composed of mainly α-Al2O3, γ-Al2O3 and mullite phase. The relative ratio of harder and denser α-Al2O3 phase increases with increasing current density and oxidation time. For the same coating time, the position of maximum hardness of coatings moves away from the substrate-coating interface to the coating surface with increasing current density. The surface roughness of coating is a function of coating thickness and increases with increasing deposition time and current density. The surface micro hardness of Al 6061-T6 alloy substrate was increased up to 2200 HV hardness after the coating. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|