Improvement of Ni-CFRP interfacial properties using compound coupling agent treatment

When nickel and carbon fiber-reinforced plastics (CFRP) are combined, poor surface wettability of nickel makes it difficult to obtain ideal interfacial properties, which limits its extensive application in the aerospace field. In this paper, the surface of the nickel plate was modified by sandblasting, coupling agent treatment, and compound coupling agent treatment, the results showed that the bonding strength of CFRP/Ni joints was increased by 19.6 %, 30.2 %, and 49.7 %, respectively, compared with the untreated joint. From the aspects of microstructure, surface wetting, and chemical bonding, the mechanism of strengthening nickel and CFRP bonding with the above surface modification methods were researched. Sandblasting treatment could form irregular pits on the surface of the nickel plate. These irregular pits effectively improved the surface roughness of nickel plate, but had little effect on the surface wettability. Coupling agent treatment has little effect on the surface roughness of the nickel plate, but greatly improvement on wettability with grafting the coupling agent molecule. Compound coupling agent treatment introduces -OH and -NH2 groups through plasma treatment to improve the grafting rate of coupling agent molecules on the surface of the nickel plate, achieving the purpose of strengthening the bonding of CFRP/Ni. This research is expected to provide research ideas for the connection of Ni and CFRP and other heterogeneous materials.