Ilya Ostrovsky^1,2, Rubén Del Olmo Martínez² , Reynier Inocente Revilla Castillo² , Iris De Graeve² , Birgit Fassbender¹ , Andrea Monti³

1) Chemetall GmbH, Frankfurt/Germany
2) Vrije Universiteit Brussel, Research group of Sustainable Materials Engineering, Brussels/Belgium
3) Chemetall Italia, Giussano

BASF – Chemetall Surface Technologies continues to pioneer advancements in aluminum finishing, with a strong focus on sustainability, energy efficiency, and high-performance surface engineering. This presentation introduces a new generation of technologies designed to meet the evolving demands of the architectural and industrial aluminum markets, with particular emphasis on Anodizing and Conversion Coating technologies.

At first, we’ll discuss the last innovative temperature-tolerant sulfuric acid anodizing for aluminum extrusions.

Anodizing is a finishing process for aluminium that provides high resistance to corrosion as well as effective paint pretreatment. During anodizing, the electrolyte heats up, reducing electrical resistance and potentially causing overheating and burning of the aluminium substrate. To prevent this, continuous cooling of the electrolyte is employed, which uses electrical power and increases costs.

The state-of-the-art method to lower cooling expenses involves adding weak organic acids to sulfuric acid. The mixed electrolytes maintain similar electrical resistance at elevated temperatures compared to cooled sulfuric acid electrolyte, thus preventing burning.

This study evaluates a new method to increase temperature tolerance during Sulfuric Acid Anodizing without using weak acids. The microstructure of the anodic coating on AA6060/6063 alloy in the modified SAA process was analysed using Scanning Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy (SEM-EDX). Corrosion protection was evaluated through neutral salt spray tests and electrochemical methods.

In parallel, a nickel-free cold sealing system has been developed to meet the increasing demand for environmentally responsible solutions. This sealing technology demonstrates exceptional resistance to high-alkaline environments, making it ideal for applications exposed to aggressive cleaning cycles or harsh service conditions. Operating at low temperatures, it also contributes to energy savings with full compatibility with all coloring processes.

The presentation will also highlight an innovative acid etching process engineered through advanced electrochemical techniques. This formulation ensures effective Aluminum oxide and alloying element removal while protecting stainless steel plant components, extending equipment life and minimizing maintenance. The etch chemistry allows strong saving coming from reduced wastewater treatment
loads. Additionally, a new thin-film “plus” conversion coating will be introduced as a breakthrough in corrosion protection, particularly for recycled aluminum alloys. This technology forms a highly adherent, uniform layer that enhances paint adhesion and durability, even on
substrates with variable metallurgical composition. Electrochemical Impedance Spectroscopy (EIS), Open Circuit Potential (OCP) and Accelerated Cyclic Electrochemical Technique (ACET) have guided the development of this system, ensuring robust performance with the boost of cutting-edge electrochemical predictive systems.

Together, these technologies represent a holistic approach to aluminum surface treatment—combining electrochemical insight, sustainable chemistry, and process efficiency. By integrating advanced analytical tools and predictive modeling, BASF – Chemetall delivers solutions that not only meet but exceed the most ambitious targets in climate protection, eco-efficiency, and operational excellence.