High temperature oxidation and erosion of candidate materials for particle receivers of concentrated solar power tower systems

The centrifugal particle receiver is a novel concept proposed for concentrated solar power plants (CSP) to increase their operating temperature and efficiency. In this concept solar radiation is directly absorbed by a layer of ceramic particles held at the inner surface of a rotating cylindrical receiver by the centrifugal force. During operation, the hot ceramic particles (up to 1000 degrees C) move slowly along the receiver wall as well as other system components (e.g. tubes), which leads to their degradation through high-temperature oxidation and erosion. In the present study, a series of high temperature erosion-oxidation exposures was undertaken to experimentally evaluate performance of selected candidate metallic materials for centrifugal particle receivers. The exposures were conducted in a laboratory test facility consisting of a resistance heated furnace filled with ceramic particles, in which the specimen holder was rotated. Typical high temperature materials, such as martensitic, ferritic and austenitic stainless steels, Ni-base and Co-base alloys were investigated. The specimens were discontinuously exposed at 400-750 degrees C for up to 500 h and further characterized by scanning electron microscopy (SEM) and energy/wavelength dispersive x-ray spectroscopy (EDX/WDX).