Porous and dense hafnium and zirconium ultra-high temperature ceramics for solar receivers

The present work reports on the comparative characterization of optical properties of hafnium and zirconium-based ultra-refractory ceramics at room and high temperature, in view of their possible use in novel solar receivers for thermal solar plants operating at higher temperatures. We show how porosity and surface finishing affect both the spectral reflectance and the high-temperature emittance. Moreover, structural and chemical changes occurring at high temperatures are assessed. © 2013 Elsevier B.V. All rights reserved.