Enhanced bonding strength of AZ31B/carbon-fiber-reinforced plastic laminates by anodization treatment in a saturated Na2SiO3 solution
Dehao Kong, Wangrui Ren, Lin Qi, Yu Zhang, Houwen Chen
Abstract
Surface treatment of the metal substrate plays a critical role in improving the bonding performance of fiber metal laminates. In this work, we use a saturated Na 2 SiO 3 solution to fabricate an anodized film on an AZ31B substrate by an anodizing process and achieve enhanced bonding strength between the AZ31B substrate and carbon-fiber-reinforced plastic (CFRP) composites. The results indicate that the primary breakdown voltage of anodization is reduced to approximately 35 V in the saturated Na 2 SiO 3 solution. The film presents a porous/linear texture composite structure after anodizing for 2 min, and the porous structure is composed of micro- and nano-pores. The bonding strength of the AZ31B substrate anodized for 2 min/CFRP laminate reaches 15.96 MPa, which is 106% higher than that of the uncoated sample. The enhanced bonding strength is mostly attributed to the mechanical interlocking effect caused by the micro- and nano-pore composite structure. With anodizing time prolonged to 30 min, the surface roughness of the substrate obviously increases, but larger pores and gaps form in the film, resulting in a lower film strength and thus a lower bonding strength.