Impact of Surface Profile on Thermal Spray Adhesion

The upcoming integration of Joint Strike Fighter, F-35B Variant—short take off/vertical landing (STOVL)—aboard amphibious ships within the US Navy has introduced an operational issue as it relates to flight deck nonskid coatings.   Based on scaled nozzle testing at projected F-35B operating parameters, qualified traditional (epoxy) nonskids, currently used in the Fleet, would not survive a full deployment.   The traditional products severely degrade after at most 15 to 20 stimulated vertical landings.  Therefore, the US Navy needs to identify alternative nonskid technology applicable for intended JSF operational scenarios and conditions.  Leveraging off program efforts initiated by the Office of Naval Research and Naval Sea Systems Command, thermal spray technology of the alternative nonskids evaluated appears to be the most viable resolution.  

Given the adhesion issues of thermal sprays previously encountered within the US Navy, an assessment of the role of surface profile on adhesion was executed using the leading candidate system for Joint Strike Fighter.  The objective was to maximize adhesion and to optimize the application process independent of the steel.  Therefore, an evaluation of both steel and aluminum oxide abrasive grits of various sizes was conducted on the three main deck steels employed—HY-80, HY-100, and HSLA-100.  Angularity, profile depth, and total effective surface area of each resulting surface profile were assessed, and then the relative impact of that profile on adhesion was determined.   The resultant of the analysis was that abrasive blasting with a 16/24 Aluminum Oxide grit package provided the optimum method for surface preparation.