Master thesis, spring 2020.
The aim of this Master thesis project is to investigate the properties of anodic coatings on AM parts by varying the process parameters. Advanced characterization technique such as Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) can be used. Also further surface treatments will be investigated and evaluated regarding corrosion protection and surface finish.
Additive manufacturing (AM) is a technology where material is added layer upon layer to create a 3D part. This makes it the opposite of milling which is a subtractive process.
The use of AM aluminum for aircraft applications is in a development phase and no clear surface treatment process exists. The geometry is often complex and the surface roughness high, therefore conventional surface treatments do not provide sufficient quality, both regarding corrosion protection and surface finish. Contrary to e.g. titanium, which is common today, aluminum is sensitive to corrosion and in most applications some form of corrosion protection is needed.
The most common surface treatment of aluminium today is anodizing. The surface treatment is used both as a corrosion protection and as a pre-treatment before painting and adhesive bonding as its porous structure enables a very good adhesion. In order to improve the corrosion protection further the porous structure can be sealed, meaning that the pores are filled with chemical substances (mainly hexavalent chromium) and then closed by hot water treatment. One of the main topics in industry today is to reduce the use of environmentally harmful substances. Many chemical substances used in surface treatments and paints today contain hexavalent chromium which is carcinogenic and toxic and its use is regulated by the European Union. There is an urgent need for new products! But the requirements are high (especially for the aircraft industry) and the most important aspect when looking at new alternatives is the adhesion to the substrate and the corrosion protecting ability.
Contacts at SAAB:
Christian Ulrich (Materials engineer), e-mail: email@example.com
Last updated: 18 October 2019 • 15:36