Laser surface structuring of Ti6Al4V substrates for adhesion enhancement in Ti6Al4V-PEEK joints.

PEEK is a promising polymer possessing high mechanical strength and biocompatibility and therefore it can be associated to titanium for biomedical applications. This study aimed at producing Ti6Al4V-PEEK joints with enhanced adhesion through laser-structuring Ti6Al4V treatments. Ti6Al4V cylindrical substrates were prepared by two types of surface treatments: alumina blasting and laser structuring. The holes number and size in laser-structured surfaces was varied. PEEK was then hot pressed against the metallic substrate to completely filling the surface cavities. The adhesion of the PEEK/Ti6Al4V joint was assessed by a shear bond strength test. Fracture surfaces and interfaces were investigated by SEM/EDS. Significant differences were found in the shear bond strength between alumina blasted and laser-structured samples. Bond strength improvement (exceeding 300%) was registered for the laser-structured specimens relative to grit-blasted ones. The laser-structuring technique showed to be very promising in the production of specifically designed surfaces for high strength and mechanically stable Ti6Al4V/PEEK joints.