High-temperature corrosion of a nickel-based alloy in a molten chloride environment – The effect of thermal and chemical purifications

Corrosion Study of Ni-Based Alloy in Ternary Chloride Salt for Thermal Storage Application

“…Aluminum outward diffusion has shown a strong role even though its concentration is low (1.28 at %) and is explained by its small atomic radius. Moreover, MgAl 2 O 4 was also identified on the outermost layer, but no evidence was spotted of its growth over MgO grains, while it can be assumed that it forms in the same way as MgCr 2 O 4 , following reaction 15 [16]. A schematic representation of these spinels formation can be found on Fig.…”

“…Mortazavi et al showed that a simple thermal dehydration process is useful for elimination of most hydrates, and suggested that the addition of Mg particles could protect alloys surfaces by interacting with oxyanions but should be only used below its melting point (649ºC), for the cold leg of a CSP plant [16].…”

“…This surface appearance could be explained by spallation suffered by the samples along the experiment or the later washing step. Moreover, a bi-layer can be distinguished on S1 with a first formation of NiO, (Mg,Cr) 2 O 4[6,16,18], MgAl 2 O 4[7,11,16,19] and (Co,Cr) 2 O 4 spinels transitions within the second layer and then, Al 2 O 3 and formation on the outermost one. Indeed, NiO phase was not predicted by Thermocalc simulations but was confirmed in literature[9,20,21].…”

Behavior of Ni20Cr Alloy in Molten Nitrate Salts

“…However, in recent years, there has been a growing interest in the corrosion problems that occur in CSP plants due to the corrosive effect of HTFs on the materials with which it is in contact. Various studies have been reported in the literature to understand the behavior of materials that are in contact with an HTF [ 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. In general, HFTs have a low melting temperature, low viscosity, and low vapor pressure.…”

“…It has been observed that the content of both Ni and Cr improves the corrosion resistance; with a higher content of these elements, the corrosion resistance is increased [ 2 , 6 , 10 , 11 , 12 ]. Therefore, the various studies carried out to date have indicated that nickel-based alloys show excellent performance in various HFT fluids [ 4 , 5 , 7 ].…”