The project investigated the influence of coating processes and bake‑temperatures on the development of filiform corrosion in hot‑melt and phosphatized aluminium alloys, specifically AA6016 and AA6111. Experimental work comprised a series of controlled CASS tests on both unpolished and polished sheets, with coating sequences that included hot‑melt application, a thin film, and a model paint. The bake‑temperature was varied between 60 °C and 180 °C, and the corrosion width along longitudinal and transverse scratches was measured in millimetres. Results showed that for polished sheets the corrosion width increased dramatically when the bake‑temperature was raised from 60 °C to 180 °C, with a factor of five to twenty times greater corrosion observed. In contrast, unpolished sheets exhibited only minor changes, indicating that surface preparation plays a critical role in mitigating temperature‑induced corrosion. The study also compared phosphatized versus thin‑film coatings, revealing that phosphatization provided a more robust barrier under high‑temperature conditions, reducing the average corrosion width by up to 70 % compared with the thin‑film approach. These quantitative findings provide clear guidelines for selecting coating sequences and bake‑temperatures in industrial applications where aluminium components are exposed to elevated temperatures.

Beyond the laboratory, the project established a comprehensive transfer strategy to bring the scientific insights into practice. During the project period, the research team presented the results at international conferences in Lyon (ISE 2023) and Stockholm (ASST 2023), engaging both academic and industrial audiences. The findings were also disseminated through the project’s own web pages and incorporated into the IKS webinar series “Filiform corrosion on coated light metals.” In 2024, the team will deliver two tailored action recommendations—one for façade construction and one for the automotive sector—to small and medium‑sized enterprises (SMEs) and industry associations such as the German Society for Building Materials (GSB), the German Association for Corrosion Research (GfKORR), and Aluminium Deutschland. These recommendations include specific coating sequences, bake‑temperature limits, and inspection protocols designed to reduce corrosion risk in real‑world settings.

The collaboration framework involved multiple stakeholders. The core research was conducted by two German research institutions, which coordinated the experimental work, data analysis, and preparation of technical reports. Industry partners supplied test specimens and provided feedback on the practical relevance of the recommendations. The German Federal Ministry of Education and Research funded the initiative under the IGF project 21673 BG, ensuring alignment with national innovation priorities. The GfKORR e.V. played a pivotal role in facilitating knowledge exchange between academia and industry, organising workshops and supporting the dissemination of the final reports. The project’s timeline extended from the initial experimental phase in 2022 through to the planned transfer activities in 2024, with key milestones such as the completion of the façade and automotive recommendations scheduled for March 2024.

In addition to the technical deliverables, the project has laid out a series of educational and professional development activities. The results will be incorporated into the curriculum of the “Corrosion and Corrosion Protection” lecture at RWTH Aachen starting in the winter semester of 2024/25, ensuring that the next generation of materials scientists is familiar with the latest corrosion‑control strategies. Professional training courses, including the IKS “DIN‑certified coating inspector” and the “KOR‑certificate after ZTV‑ING,” will be updated to reflect the new findings, with annual and semi‑annual sessions beginning in March 2024 and September 2024, respectively. International publication plans include a paper in the journal Materials and Corrosion by June 2024, further extending the reach of the project’s outcomes. Overall, the transfer concept has proven realistic, with early industry engagement and a clear pathway for integrating the research results into manufacturing processes and professional practice.