Influence of laser treatment on the adhesion force of metallized carbon fiber reinforced polymer (CFRP) composite

Carbon fiber reinforced polymer (CFRP) is an engineering composite material with excellent performance. After metallization, the CFRP composite exhibits unique properties such as electromagnetic shielding and high electrical conductivity. In this study, we utilized laser treatment process to enhance the adhesion strength of the copper layer electrolessed on CFRP composite. The surface microstructure of CFRP and the copper layer was determined using an optical microscope, and the adhesion force of the copper layer on CFRP composite was measured through 3M tape and pull-out tests. The results indicate that with an increase in the number of laser treatment cycles, the trenches depth on the surface of CFRP composite also increases, leading to high surface roughness and thus enhancing the adhesion strength between the copper layer and the composite. The adhesion state of the copper layer on laser-treated CFRP composite can be qualitatively classified as grade 5B. Additionally, both mechanical cutting and laser treatment can improve the adhesion strength of the samples. The samples treated by mechanical cutting and the laser scan with ±45° exhibit the highest adhesion strength of 5.48 MPa. This is 415 % higher than that of the untreated sample, with a minimum damage area after pull-out testing, approximately 10 %. Compared to the sandblasting pretreatment process, the adhesion strength of the sample by laser treatment increased by 119 %.