Laser induced surface nano-structuring of Ti–6Al–4V for adhesive bonding

In this paper, the effect of pulsed laser irradiation (Nd:YVO4, 1064 nm) on the surface morphology and adhesion behaviour of Ti–6Al–4V was investigated. The surfaces were inspected by scanning electron microscopy (SEM), the chemical composition was obtained using X-ray photoelectron spectroscopy (XPS) and the adhesive properties were evaluated by means of wedge tests and floating roller peeling tests.The experiments revealed a homogeneous morphology consisting of a nano-structured oxide layer obtained within a particular set of laser parameters. The chemical investigation showed a considerable decrease of the contamination level on the surface compared to alkaline etching. The wedge test and floating roller peeling test showed that the nano-structured oxide layer formed after the laser process leads to a long-term stable adhesion behaviour. Using the laser pre-treatment the adhesion properties on titanium can be improved as compared to wet chemical pre-treatment processes like alkaline etching (Turco 5578) or anodising (NaTESi).