Cavitation erosion of NiAl-bronze layers generated by friction surfacing

Friction surfacing is a solid-state process, which allows deposition welding at temperatures below the melting range. For this investigation coating layers of NiAl-bronze were deposited by friction surfacing on self-mating substrates, followed by microstructural characterisation. Further, cavitation tests were performed in order to investigate wear resistance. Cavitation erosion mechanisms were analysed by means of optical and electron microscopy. All coatings show incubation periods about twice as long as those of the substrate material, while their average rate of material loss is about one half of that of the substrate. The differences in cavitation erosion resistance are due to more ductile behaviour of the coatings, as well as corrosion increasing the wear of the as-cast material.

► Friction surfacing leads to homogeneous and fine-grained microstructure.
► Cavitation erosion on as-cast material starts and propagates at phase boundaries.
► Grain boundary attack points to corrosion influence on wear in as-cast material.
► Coatings produced by friction surfacing show less wear due to ductility and less corrosion.