The bonded scarf joint is a common design for the repair of carbon fibre reinforced polymer (CFRP). Surface treatment is an essential factor for the performance of such joints. Infrared (IR) laser surface treatment is of particular interest, as it has the potential for a fast and automatable process. The effect of the IR laser surface treatment on the morphology was investigated by scanning electron microscopy in combination with ion beam milling. Change of surface chemical composition was assessed by X-ray photoelectron spectroscopy. Additionally, IR laser treated CFRP scarf joints were tested under tensile load. Surface analysis revealed a stripping of carbon fibres in combination with a roughening. On the other hand, a decrease of oxygen and nitrogen on the surface was detected. The increase of the bonding strength was attributed to the increase of the effective surface and mechanical interlocking due to the roughening of the CFRP surface.
