Crystallization behavior of calcium-magnesium-alumina-silicate coupled with NaCl/Na2SO4

Promoting molten calcium-magnesium-alumina-silicate (CMAS) crystallization can highly reduce the melt penetration into thermal barrier coatings (TBCs), which alleviates its corrosion to TBCs. In marine environments, many salts are coupled with CMAS. In this study, we investigated the crystallization behavior of CMAS + NaCl/NaSO4, 4 , and pointed out its influence on the corrosion behavior of TBCs. At 1200 degrees C, CMAS + NaCl was crystalized into CaMgSi2O6, 2 O 6 , CaSiO3 3 and CaAl2Si2O8, 2 Si 2 O 8 , while the crystallization products of CMAS + NaSO4 4 depended on NaSO4 4 content, i.e., 4 wt.% and 10 wt.% NaSO4 4 addition leading to CaAl2Si2O8 2 Si 2 O 8 and Ca2Al(AlSiO7) 2 Al(AlSiO 7 ) phases, respectively, in addition to CaMgSi2O6 2 O 6 and CaSiO3. 3 . At 1100 degrees C, CMAS + NaSO4 4 crystalized, while CMAS + NaCl had no crystallization. At lower temperatures, both NaCl and NaSO4 4 additions could suppress CMAS crystallization. It reveals that CMAS coupled with molten salt is hard to crystallize, which is detrimental to corrosion protection. (c) 2023 The Author(s). Published by Elsevier B.V. on behalf of Institute of Metal Research, Chinese Academy of Sciences. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )