Effect of surface treatment on the interfacial adhesion performance of aluminum foil/CFRP laminates for cryogenic propellant tanks

Abstract

In this study, an aluminum foil with a thickness of 0.08mm was inserted between plies of carbon fiber reinforced polymer (CFRP) composites to manufacture Al foil/CFRP laminates. Two kinds of surface treatments, including corrosion method with NaOH or H2SO4/CrO3 solution and addition of flexible layer composed of polyether triamine, were carried out successively on the surface of Al foil to improve the interfacial adhesion strength between Al foil and CFRP under cryogenic cycles. The results showed that, both corrosion methods could improve the interfacial adhesion strength between Al foil and CFRP obviously. The flexible layer applied was verified to be bonded to the surface of Al foil via OAl…N and AlOH…N. The interfacial adhesion performance of Al foil/CFRP laminates after cryogenic cycles improved significantly attributable to the surface treatments applied, which indicated that the flexible layer could adjust the thermal expansion coefficient mismatch between Al foil and CFRP as expected. Furthermore, the Al foil/CFRP laminates exhibit excellent gas barrier property, which is about 15 times higher than that of CFRP laminates. Consequently, the Al foil/CFRP laminates have great potential as cryogenic propellant tank material for aerospace craft.