By: Ege Gülçiçek, Ege Anıl Diler, and Onur Ertugrul
As Published In: International Journal of Adhesion & Adhesives
In high-stakes industries like automotive and aerospace, joining lightweight materials securely is a critical challenge. While adhesive bonding offers significant advantages over traditional methods like welding or riveting, its success hinges on one crucial factor: perfect surface preparation.
A groundbreaking new study by researchers Ege Gülçiçek, Ege Anıl Diler, and Onur Ertugrul, published in the prestigious International Journal of Adhesion & Adhesives, provides a definitive look into optimizing the bonding performance of thin Al6061-T4 aluminum sheets—a material essential for modern lightweight vehicle construction.
The Focus of the Study: The Right Treatment and the Right Adhesive
The research meticulously investigated how bonding performance is affected by two key variables:
Surface Treatments: Aluminum surfaces were tested under four conditions: untreated, mechanically ground, treated with atmospheric plasma, and a synergistic combination of grinding followed by plasma (GrPl).Adhesive Types: Three different industrial adhesives were used: a cyanoacrylate, a Bisphenol A (BPA)-based epoxy, and a Bisphenol A/F (BPA/F)-based epoxy.
The advanced atmospheric plasma surface treatment in the study was performed using a PTP 22-01 model DBD air plasma system from Pacem Technology.
The Results: A Clear Performance Leader
The findings demonstrate the profound impact of advanced surface preparation, with plasma technology emerging as the clear winner.
Superior Wettability: Effective bonding requires the adhesive to properly "wet" or spread across the surface. The study found that plasma treatment dramatically decreased the surface's contact angle. While an untreated surface had a contact angle of 71.8°, the combined Grinding + Plasma (GrPl) process lowered it to an exceptional 25.9°. This confirms a far more receptive surface for bonding.Record-Breaking Strength Gains: The ultimate measure of performance is strength. The lap-shear tests revealed remarkable improvements:
Grinding alone improved shear strength by up to 72% compared to untreated samples.Plasma treatment alone was even more effective, increasing strength by an impressive 149%.
The synergistic combination of Grinding + Plasma (GrPl) delivered the best results, achieving a massive 174% enhancement in shear strength.
Resilience at High Temperatures: When tests were conducted at an elevated temperature of 60°C, all joints showed some performance decrease as expected. However, the joints treated with plasma maintained the highest shear strength, proving the durability and reliability of the treatment under more demanding thermal conditions.
The Science Behind the Success: Why Plasma is so Effective
The incredible performance boost from plasma technology is based on creating an ideal surface for adhesion at both a mechanical and chemical level. While grinding creates a rougher profile for mechanical interlocking, Pacem’s plasma technology elevates the surface in two ways:
Surface Cleaning and Activation: The plasma process meticulously cleans the surface of micro-contaminants. More importantly, it activates the surface by forming polar chemical groups, such as hydroxyls. These active groups form powerful chemical bonds with the adhesive, creating a much stronger interface.Synergy with Mechanical Prep: When an already ground surface is treated with plasma, the result is a perfect combination of a high-surface-area profile for mechanical interlocking and a chemically activated surface ready for superior chemical bonding.
This comprehensive research, conducted as part of an EU Horizon/M-ERA.NET project funded by The Scientific and Technological Research Council of Türkiye (TÜBİTAK), scientifically validates that the synergistic use of mechanical preparation and advanced atmospheric plasma treatment is the optimal path to achieving superior bonding strength. The findings are critical for the future of manufacturing in the automotive, aerospace, and battery housing industries, proving that Pacem Technology’s plasma solutions can make materials lighter, stronger, and more reliable.