TY  - JOUR
AU  - Wang, Yaping
AU  - Pillai, Rishi
AU  - Yazhenskikh, Elena
AU  - Frommherz, Martin
AU  - Müller, Michael
AU  - Naumenko, Dmitry
TI  - Role of Temperature in Na 2 SO 4 –K 2 SO 4 Deposit Induced Type II Hot Corrosion of NiAl Coating on a Commercial Ni‐Based Superalloy
JO  - Advanced engineering materials
VL  - 22
IS  - 6
SN  - 1527-2648
CY  - Frankfurt, M.
PB  - Deutsche Gesellschaft für Materialkunde
M1  - FZJ-2020-01947
SP  - 1901244
PY  - 2020
AB  - The life span of gas turbine coatings may be restricted by type II hot corrosion when exposed at elevated temperatures in aggressive environments during service. Herein, the temperature dependence of corrosion morphologies and kinetics of NiAl coating on a second‐generation single crystalline Ni‐based superalloy is studied to provide an insight into the possible corrosion mechanisms. A series of tests are performed at 600–800 °C in air‐300 ppm SO2 atmosphere with Na2SO4–20% K2SO4 salt mixture as deposit. Severe attack is observed at both 700 and 750 °C after 24 h exposure, whereas at 600 and 800 °C, only a minor attack is found. The results indicate that the corrosion rate is strongly governed by Na2SO4–NiSO4 liquid formation, and temperature affects the attack rate of the outer coating (mainly β‐NiAl phase) primarily by changing the required minimum SO3 partial pressure to stabilize this liquid. The influence of temperature and 𝑝SO3 on phase equilibrium of the salt and oxide mixture is calculated with an in‐house developed thermodynamic database. The predicted minimum 𝑝SO3 for liquid formation calculated with the database is consistent with the experimental results. 
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000514743600001
DO  - DOI:10.1002/adem.201901244
UR  - https://juser.fz-juelich.de/record/875316
ER  -