Additional data and experimental setups, for a comparative study of alloys in contact to eutectic melts for thermal storage

Abstract

Three different eutectic salt mixtures have been brought into contact with three different high temperature alloys to assess corrosion damages for next-generation CSPs. This article contains additional material to support findings and assessments reported on our main article in the Solar Energy Journal [ https://doi.org/10.1016/j.solener.2021.06.069 ]. Five sections, A-E, provide data to ensure reproducibility and confidence in our claims in the main article. A newly designed experimental setup for high temperature exposures is described as well as impurities within used chemicals. Material thickness measurements document alloy consumption by eutectic salts. Reaction enthalpies are listed illustrating individual metal species in contact with salt species at relevant temperatures. Thermodynamic single point equilibrium calculations have extended environmentally induced Laves phase precipitation found for alloy Kanthal APMT in contact with molten chlorides.

Superior Protection by Α-Al2o3/Α-Lialo2 Double Oxide Scales Against Alkali Carbonate Corrosion

“…Tested metal coupons with initial measurements of 15 × 15 × 2 mm were ground and polished until 1 µm mirror-finished surfaces were obtained. Later, coupons were cleaned and dried using acetone and ethanol before being immersed in a salt mixture; see details of the corrosion testing procedure described in our former publication [35].…”

“…The Li 2 CO 3 (99.0%), Na 2 CO (99.9%), and K 2 CO 3 (99.8%) salts were purchased from VWR chemicals, EMSURE anhydrous, and ThermoFisher Scientific, respectively. The salt mixture preparation procedure and impurities concentrations in each salt were summarised in [35].…”

“…We assigned one sample for cross-section analysis, while the second was dedicated to surface analysis. Exposures were conducted for 500 h and 1000 h at 800 • C. Every 336 h, the experiment was paused and cooled to room temperature to refill the crucibles with salt; see [35]. Due to the necessity of rinsing the coupons with water after exposure completion for mass change measurements, each sample could only be measured once.…”

“…A metal coupon was rinsed with water according to the standard methods [36] and dedicated to mass change measurements, surface morphology investigation and X-ray diffraction (XRD) analysis. Samples were rinsed with distilled water at room temperature to remove the salt remnants; see the detailed rinsing procedure [35]. It is noteworthy to remind the reader that even though the rinsing procedure followed standard methods, water-soluble corrosion products could be lost [35,36].…”

“…Samples were rinsed with distilled water at room temperature to remove the salt remnants; see the detailed rinsing procedure [35]. It is noteworthy to remind the reader that even though the rinsing procedure followed standard methods, water-soluble corrosion products could be lost [35,36]. Therefore, mass change values need to be treated carefully.…”