Rapid evaluation of the particle-erosion resistance of Al ₂ O ₃ ceramics, composites, and coatings using a resonant acoustic mixer

The solid particle technology usage in concentrated solar power plants as direct heat absorption and storage medium necessitate well selection of the materials for the components such as transport and sluice systems, which are in direct contact with moving and falling hot particles up to 1500 ˚C. Beyond mechanical properties, chemical inertness and high-temperature stability, abrasion/erosion resistance are one of the key properties, for which, there is no easy-applicable and rapid test method exist enabling controlled lab-scale parametric studies. A novel particle impact test was established using a resonance acoustic mixer, in which ceramic particles are strongly accelerated and collide with the ceramic surface within a closed vessel. After determination of the most representative parameters such as ceramic ball size, vessel diameter, and retainment/removal of debris, selected experiments were conducted on three candidate materials aimed to be used as high-temperature transport/port systems; dense C 799 Al ₂ O ₃ , porous water-plasma sprayed Plascera-type Al ₂ O ₃ and WHIPOX-type Al ₂ O ₃ /Al ₂ O ₃ ceramic matrix composites with porous matrix; with and without porous protective Al ₂ O ₃ coating. The distinct mass loss behaviour of candidate materials highlighted the viability of the test method and the relevance of microstructures of porous Al ₂ O ₃ materials on abrasion resistance.