Ion Beam Assisted Deposition of Thin Carbonaceous Films: II . Adhesion Characteristics in Aqueous and Cathodically Delaminating Conditions

Abstract

The adhesion characteristics of thin (ca. 160Å) carbonaceous films produced by ion beam assisted deposition (IBAD) on steel were tested by the tape peel test under dry, wet, and cathodically delaminating conditions. It has been proposed that the degree of bonding established in IBAD films is dependent on the amount of energy transferred in recoil processes at the interface. To test this, ion beams of various gases (H, He, Ne, , ) were accelerated (30 keV) and directed into a monomeric target gas (1,3 butadiene) held in front of the steel substrate. For purposes of comparison, adhesion tests were also performed on a series of conventional marine coatings (epoxy‐polyamide, polyurethane, vinyl). The work of adhesion of each film/substrate combination was calculated and compared to the adhesion data. The adhesion of ion assisted coatings under all conditions tested was found to be many orders of magnitude greater than conventional coatings and did not correlate with surface energy or work of adhesion calculations. The adhesion performance of conventional coatings, on the other hand, did correlate with surface energy data. Although the adhesion of the ion assisted coatings is attributed to an atomically mixed interface created by recoil processes, electronic damage due to “stitching” phenomenon may also contribute to enhanced film bonding when irradiated by lighter ion species.