Rethinking aluminum alkaline etching: Bonderite C‑AK 24600 boosts efficiency and sustainability

The first step in aluminum pretreatment is typically alkaline etching. This creates a rough surface to ensure adhesion and performance of the subsequent conversion coating. Traditionally, users achieve the highest etching performance at a higher temperature – and consume a lot of energy. This is where Henkel's new product Bonderite C-AK 24600 comes in: It allows the application temperature to be reduced by up to 7 °C, depending on the system configuration, while still achieving the required etching rate. Conversely, the user can increase the etching rate at the same temperature.

Compared to standard products, the new etchant provides a 30% higher etching rate at 43 °C and a 17 % higher etching rate at 50 °C in fresh baths. In older baths, the performance increase is 45 % at 43 °C and 27 % at 50 °C. This improved efficiency significantly reduces energy consumption and the CO₂ footprint. Based on a 7 °C temperature reduction in the alkaline etching stage, this results in a saving of more than 0.5 tons of CO₂ in natural gas per cubic meter of bath.  

Application examples illustrate the benefits: In one case, the required etching rate of 1.5 g/m² could be achieved at a temperature 5 °C lower, resulting in immediate energy savings. In another case, the product enabled a higher etching rate of 2 g/m² without increasing the operating temperature.

“Bonderite C-AK 24600 shows how innovation in the chemical industry can help reduce environmental impact and increase efficiency in the production chain,” says Cristina Acedo, Senior Product Development Manager at Henkel. “We are enabling our customers to achieve their sustainability goals, such as energy savings, or in other words, to achieve more with less. This was not possible with previously available products because they required a higher temperature to achieve the desired performance.”