INFLUENCE OF SURFACE-TREATMENT ON THE DURABILITY OF STAINLESS-STEEL SHEETS BONDED WITH EPOXY

Fifteen different surface treatments were used to bond AISI 304 stainless steel. The objectives of the programme were to select treatments able to produce durable adhesive bonds and to contribute to the understanding of interface bonding phenomena and of phenomena responsible for debonding while ageing. Peel and sheer tests were carried out to assess the behaviour of the bonded joints at the initial state and after ageing. The test results indicate that only two treatments, sulphuric chromic acid anodization and nitric acid anodization, exhibit a high performance level after exposure to a moist environment. The chemical and physical properties of surfaces were determined. The surface morphology was observed with a scanning electron microscope, and chemical composition was studied by X-ray photoelectron spectroscopy and secondary ion mass spectrometry. A correlation between bond durability, surface morphology, and oxide film composition was established.