Ablation Experiments of High-Temperature Materials (Inconel, C–C and SiC) Using a High-Velocity Oxygen-Fuel Torch

Ablation experiments of three different material specimens for high-temperature aerospace applications, namely Inconel, C–C and SiC were carried out using a high-velocity oxygen-fuel system. Originally designed for spray coating, the HVOF can be used as an easy-to-operate and inexpensive alternative to plasma wind tunnels. The HVOF flow characterization was performed intrusively using a water-cooled Gardon gauge for stagnation point heat fluxes and wedge probes for supersonic Mach numbers. The specimen surface temperatures were measured using a two-colour pyrometer and an IR camera. The SiC specimen showed the maximum surface temperature around 2200 K. The stagnation point heat fluxes were measured at 80 mm, 100 mm, 120 mm, 140 mm, 160 mm and 180 mm away from the HVOF torch nozzle exit as 10.935 MW/m², 8.026 MW/m², 5.111 MW/m², 3.263 MW/m², 1.935 MW/m², and 1.600 MW/m², respectively. Using an HVOF system, this is the first study to report heat flux values measured experimentally at specimen test locations. A constant supersonic Mach number of 1.38 was obtained up to 80 mm of the flow. Three-dimensional mappings were performed to study the specimen surface feature changes before and after the tests. SEM and EDS were performed. The SiC specimen showed excellent ablation resistance, even though it was tested at a higher heat flux condition compared to other two material specimens.