Ultra-high temperature ceramics (UHTCs) are the ideal material for extreme conditions thanks to very high melting points, high refractoriness and good thermo-mechanical properties at high temperatures. This paper reports, for the first time to the best of our knowledge, on the microstructural and optical characterization of several tantalum diboride (TaB2) samples with density values from 67% to full density. Pristine samples have been investigated at room temperature by means of SEM, XRD and spectral hemispherical reflectance measurements. Thermal emittance in the temperature range 1050-1800 K has been measured. Structural, compositional and optical properties after high temperature exposure have been characterized as well and property changes have been explained. The obtained results favorably compare TaB2 over conventional solar absorbers for novel solar plants operating at higher temperatures. (C) 2014 Elsevier B.V. All rights reserved.
Tantalum diboride-based ceramics for bulk solar absorbers
Sciti Diletta;Silvestroni Laura;Mercatelli Luca;Meucci Marco;Sani Elisa
2014
Abstract
Ultra-high temperature ceramics (UHTCs) are the ideal material for extreme conditions thanks to very high melting points, high refractoriness and good thermo-mechanical properties at high temperatures. This paper reports, for the first time to the best of our knowledge, on the microstructural and optical characterization of several tantalum diboride (TaB2) samples with density values from 67% to full density. Pristine samples have been investigated at room temperature by means of SEM, XRD and spectral hemispherical reflectance measurements. Thermal emittance in the temperature range 1050-1800 K has been measured. Structural, compositional and optical properties after high temperature exposure have been characterized as well and property changes have been explained. The obtained results favorably compare TaB2 over conventional solar absorbers for novel solar plants operating at higher temperatures. (C) 2014 Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.