Compatibility of SiC–and MAX phase-based ceramics with a KNO3-NaNO3 molten solar salt

K. Van Loo, T. Lapauw, N. Ozalp, E. Ström, K. Lambrinou, J. Vleugels

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2 Citations (Scopus)

Abstract

In this work, several ceramic materials were exposed together with two reference structural materials (i.e., 316 L stainless steel and Inconel 600) to a molten solar salt (40 wt% KNO 3 and 60 wt% NaNO 3 ) for 1000 h at 600 °C to investigate their compatibility with the molten salt medium, thus assessing their potential use in concentrated solar power (CSP) applications. The exposed ceramics included different SiC grades (solid state-sintered, liquid phase-sintered, and silicon-infiltrated) and MAX phase-based materials (Maxthal ® 211 & 312 (nominally, Ti 2 AlC & Ti 3 SiC 2 , respectively), Cr 2 AlC, Nb 4 AlC 3 , (Nb,Zr) 4 AlC 3 , and a cermet comprising 40 vol% Fe and 60 vol% (Nb,Zr) 4 AlC 3 ). All SiC grades were chemically stable in the molten salt, whereas all Nb-containing MAX phase ceramics were severely oxidized. Comparing the two Maxthal ® grades showed that the 312 was chemically more stable than the 211, and both grades formed a Na-based oxide scale. Interestingly, Cr 2 AlC showed practically no interaction with the molten salt during the performed exposure, forming a stable, sub-micrometre-thick Cr 7 C 3 scale. Hence, it may be considered as promising structural/coating material candidate for the targeted CSP application.

Original languageEnglish
Pages (from-to)228-240
Number of pages13
JournalSolar Energy Materials and Solar Cells
Volume195
Early online date16 Mar 2019
DOIs
Publication statusPublished - 15 Jun 2019
Externally publishedYes

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