The effect of surface treatment on the adhesion of epoxy to stainless steel (oral presntation)

Mechanical properties of steel-epoxy composites crucially depend on the interphase properties; as those have a significant influence on the adhesion strength1. In this work, the effect of different surface treatments on the adhesion of epoxy to stainless steel plate (SS 304 BA) was studied. The surface treatments of the stainless steel plate were done by using a silane based coupling agent2. The stainless steel surface was first cleaned ultrasonically in acetone bath. Afterwards, atmospheric plasma and wet chemical dipping process were used to modify the stainless steel surface. Characterization of the stainless steel surface chemistry and surface energy was determined by tensiometry measurements. The adhesion strength was measured by pull off testing (dolly testing3). The dolly testing was modified for the thin plates to avoid the effect of bending and geometrical limitation of the dolly testing set up. Dolly samples were prepared by using an epoxy-amine based resin (EPIKOTE 828 LVEL + 1,2 diamino cyclohexane) by following the developed curing cycle (based on DSC measurements). Both treatments, atmospheric plasma and wet chemical dipping process shows an improvement of the adhesion strength of the stainless steel-epoxy system.

Reference:
1. W. Possart (2002). " Modern state of models for fundamental adhesion - a review extended abstract" Adhesion and Interface 3(1): 43
2. K. Won-Seock, L. Jung-ju ( 2007). "Adhesion strength and fatigue life improvement of co-cured composite/metal lap joints by silane-based interphase formation" Journal of Adhesion Science and Technology 21(2): 125
3. L. L. Zhai, G. P. L., Y. W. Wang (2007). "Effect of nano-Al2O3 on adhesion strength of epoxy adhesive and steel." International Journal of Adhesion & Adhesives 28: 6.