In this study, different surface pretreatments were applied to clean and activate titanium alloy surfaces. The samples were subjected to grit blasting treatments using two different pressures and afterwards, a UV/Ozone treatment was applied at different times to study the wettability and surface oxidation of the titanium samples. Scanning electron microscopy and laser confocal microscopy showed the surface morphology and the increased roughness with grit blasting pressure. X-ray Photoelectron Spectroscopy revealed that titanium was increasingly oxidized with increasing UV/Ozone treatment time, which leads to a reduced contact angle and a better adhesive performance in a butt tension test proving the effectivity of this surface treatment for titanium. Furthermore, the addition of sol-gel AC-120 and corrosion inhibition primer BR 6747 showed to be an additional improvement in the initial adhesion and after different degrees of aging by exposure to salt-spray, making the surface treatment techniques used in this research, a promising environmental friendly alternative to improve adhesive bonding performance. ... Read more

Surface morphology of adherends is an important factor to take into consideration when studying and improving the performance of an adhesive bonded joint. In this study, the adhesion performance three different surface morphologies of Selective Laser Melted (SLM) Ti6Al4V was studied. The three surface morphologies were created by manufacturing the adherends with different build directions (0, 45 and 90°). Scanning electron microscopy and laser confocal microscopy were used to assess the obtained morphology and roughness of the printed surface areas to be bonded. Those surfaces were subjected to 40 min of UV/Ozone treatment to remove organic contamination traces on the surface which lead to a reduced apparent contact angle and improved adhesive strength. The samples printed at 45°, which showed the highest surface roughness, presented the best adhesive performance during the tensile tests. The addition of sol-gel AC-120 and corrosion inhibition water-based primer BR 6747-1 showed an effective improvement in aging behaviour after 6 weeks of salt spray exposure. ... Read more