Adhesion to Sintered Substrates

Abstract Although the consensus is that various forms of specific adhesion are prevalent in most adhesive systems, the importance of mechanical adhesion should not be overlooked. Cylindrical substrates of stainless steel, both the dense metal and in sintered form, have been bonded with a polyurethane “adhesive” and subjected to torsional shear loading. Overall strain and load at failure are considerably higher with porous substrates and the effective energy of adhesion is typically an order of magnitude greater. Mechanical interlocking of the polymer in interstices of the metallic substrate prevents catastrophic failure after the interface has failed. The behaviour has been modelled by taking the “glueline” to be a “composite” structure consisting both of bulk polymer and connecting fibrils.