PREPARATION OF STAINLESS-STEEL ADHERENDS FOR ADHESIVE BONDING

Adhesively bonded stainless steel aircraft components often fail prema turely at the adhesive/adherend interface. This failure results from e xposure of the adhesively bonded joint to various mechanical and therm al stresses, as well as the exposure to hostile environments. Currentl y, there is not a single, reliable preparation for adhesive bonding th at is universally employed for all classes of stainless steel. This st udy was conducted to evaluate several existing stainless steel prebond ing processes, to determine the significant process factors contributi ng to the adhesive/stainless steel interfacial performance, and to dev elop a single reliable prebond preparation for stainless steels. Sever al surface pretreatments were evaluated with various classes of stainl ess steel. Wedge crack extension test results of moisture conditioned test specimens show that a newly developed pretreatment process yields the most stable passivation surface for various classes of stainless steel.