In this investigation, the behavior of overlapping HVOF-sprayed WC-Co splats is analyzed. Samples are sprayed and documented in several steps with a low density of splats. This method enables to distinguish between several splats in areas where overlapping clusters of splats occur. The splats are sorted according to their chronological order of impact. With this information, cross sections are made of these clusters to study the porous structure, developing in the center and at the boundaries of the splats. An ion-polishing method was employed to avoid the corruption of small pores and structures by mechanical force. It turns out that pores in HVOF coatings are initiated by the overlapping regions at the edges of the splats. Splats impacting directly onto each other show very dense microstructures at the interface in the center region of the impact.

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