Sustainable Approaches to Surface Pretreatment of Additively Manufactured Aluminium Alloys
Status: Proposal
Date Announced: April, 2024
Project reference: PROP311400
This project aims to address the crucial need for environmentally responsible, corrosion-resistant treatments for additively manufactured (AM) aluminium alloys used in aerospace, defence, automotive, and other industrial applications. Chemical conversion coatings are widely used surface pre-treatments, but the restriction on use of hexavalent chromium (Cr VI) and replacement of phosphate coatings means suitable alternatives need to be found. This project primarily focuses on identifying REACH-compliant, Cr(VI)-free replacements, such as trivalent chromium (Cr III), rare earth element and silane based processes. There is also a need to understand how the performance of such pre-treatments may differ when applied to AM components, compared with cast or wrought versions.
Additionally, the project seeks to identify Cr(VI)-free paint systems comprising a chemical conversion coating (serving as a surface pre-treatment), primer, and top coat.The project aims to provide industrial guidance using service-relevant data on the corrosion performance of various pre-treatments in different environments; such as neutral salt spray and accelerated exposure testing (involving a combination of cyclic conditions based on salt solution, humidity and various temperatures). Furthermore, it will include an investigation into how microstructural variations in AM aluminium alloys and traditional cast and wrought alloys influence pretreatment performance, durability, and reliability.
This project also seeks to test the REACH compliant paint systems that are compatible with REACH compliant Cr(VI) free surface pretreatments in terms of corrosion resistance, surface appearance (blisters/cracks), roughness, adhesion, thermal resistance when applied to AM, cast and wrought aluminium alloys. By evaluating the corrosion performance, adhesive bonding chacteristics, and thermal cycling resistance, the project will generate insights into suitable Cr(VI)-free surface pretreatments and REACH compliant paint systems which will enable the development of guidelines for their selection for industrial applications.
If you are interested in finding out more, download the PDF Summary Outline using the following link.