This　study　investigates　the　use　of　high-frequency　eddy　current　testing　(ECT)　to　assess　the　structural　integrity　of　aluminide　coatings　on　MAR-M247　nickel　superalloy　under　simulated　fatigue　conditions.　Aluminide　coatings,　deposited　via　chemical　vapor　deposition　at　thicknesses　of　20　mu　m　and　40　mu　m,　were　tested　using　custom-designed　probes　optimized　for　defect　detection.　Results　demonstrate　that　substrate　grain　structure　and　coating　thickness　significantly　influence　coating　durability,　with　fine-grain　substrates　exhibiting　the　least　resistance　changes　and　greatest　fatigue　tolerance.　Eddy　current　signal　variations　correlated　with　microstructural　changes,　enabling　detection　of　damage　otherwise　invisible　to　traditional　methods.　These　findings　establish　ECT　as　a　precise,　nondestructive　approach　for　monitoring　aluminide　coatings　in　critical　applications.