Chiang Mai Journal of Science

 Scratch testing on a cross-section of a plasma sprayed coating produces cone-shaped damage at the top of the coating. The cone area reflects the cohesion strength of the coating.  This work investigates the effect of the mounting resin on the projected cone area. Air plasma sprayed thermal barrier coatings (TBC) were prepared using four different mounting resins and methods namely cold mounting epoxy resin, cold mounting epoxy resin with added filler, hot mounting Bakelite, and hot mounting carbon conductive thermosetting. The cold mounting epoxy resin gave a well-defined cone area and a largest average projected cone area (lowest cohesion of the coating) values than other mounting resin. Additive component in the mounting resin increases the scratch resistance of the TBCs by altering the deformation mechanisms.