Plasma-sprayed, molten molybdenum particles (~40 µm diameter) were photographed during impact (with velocity ~110 m/s) on Inconel surfaces that were preheated or maintained at room temperature or 400oC. A droplet approaching the surface was sensed using a photodetector and after a known delay, a fast CCD camera was triggered to capture images of the spreading splat from the substrate front surface. A rapid two-color pyrometer was used to collect the thermal radiation from the impacting particles to follow the evolution of their temperature and size after impact. Molten molybdenum particles impacting on surfaces at room temperature disintegrated and splashed, after achieving a maximum diameter larger than 400 µm. Impact on preheated and heated Inconel produced splats with maximum diameters between 200 µm and 300 µm and with less splashing. The cooling rate of splats on the preheated Inconel was larger than that of splats on non-heated Inconel, suggesting that the splat-substrate contact was improved.

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