Fish-scale pattern key to long-lasting aluminum industrial equipment

Aluminum alloy 6061 is commonly used in industrial equipment because it is easily welded and shaped for a variety of applications. However, it is soft and corrosion-prone, causing abrasive chips that can damage hardware.

To solve this, Li and Liu looked to nature. They combined fish-scale shaped laser ablation and plasma electrolytic oxidation (PEO) technology to design a wear resistant 6061 aluminum alloy.

“In my daily life, I found that fish scales have a higher hydrophobic capability, and the grooves on the surface of fish scales have an obvious drag reduction effect,” said author Changhong Liu.

To prepare the fish scale texture, the authors used an ultra-short pulse laser to etch the designated pattern onto the metal.

“The scale shape should not be too complicated, because it would cause too many ablative particles on the metal surface and is not conducive to the industrial application in large quantities,” said Liu. “The scale size should be within the processable range so that the metal surface has the best wear resistance and hydrophobicity.”

After etching, the authors applied PEO, which generates an oxide layer to smooth and harden the alloy’s surface. Wear resistance tests included sliding steel balls across the surface and submerging the treated alloy into a corrosive solution.

Compared to a laser-produced rectangular etch pattern and a non-etched surface, both coated with PEO, the scales produced better wear, corrosion resistance, and hydrophobicity than other treatments. Fish scales better facilitate liquid flow and capture abrasive chips.

This work demonstrates the power of bionic studies in synthetic and industrial applications.

Source: “Preparation of the wear and corrosion resistant coating using a composite process of laser surface texturing technology and plasma electrolytic oxidation,” by Shengchun Li and Changhong Liu, AIP Advances (2023). The article can be accessed at https://doi.org/10.1063/5.0136460 .