Assessing the effects of shear, compression, and peel on the cathodic degradation of elastomer-to-metal adhesive bonds

Tests to evaluate the effect of peel stress on the delamination mode of bond degradation were also performed. To this end, a large number of custom, self-loading specimens called the strip blister specimen, were tested in cathodic environments according to a test matrix that included five levels of cathodic current density and four temperatures in two electrolytes. The rate of bond delamination was found to be sensitive to cathodic voltage, temperature, as well as the electrolyte. Blending the control primer with γ-aminopropyltriethoxysilane was found to significantly retard the rate of bond delamination. Similarly, passivation of the mild steel substrates by a zinc-phosphate coating treatment was found to considerably slow delamination.