Microstructure and high temperature oxidation resistance of Si–Y co-deposition coatings prepared on TiAl alloy by pack cementation process

Autor: Yong-quan Li, Xiang-qing Wu, Fa-qin Xie
Rok vydání: 2015
Předmět:
Zdroj: Transactions of Nonferrous Metals Society of China. 25:803-810
ISSN: 1003-6326
DOI: 10.1016/s1003-6326(15)63666-4
Popis: In order to improve the high temperature oxidation resistance of TiAl alloy, Y modified silicide coatings were prepared by pack cementation process at 1030, 1080 and 1130 °C, respectively, for 5 h. The microstructures, phase constitutions and oxidation behavior of these coatings were studied. The results show that the coating prepared by co-depositing Si–Y at 1080 °C for 5 h has a multiple layer structure: a superficial zone consisting of Al-rich (Ti,Nb) 5 Si 4 and (Ti,Nb) 5 Si 3 , an out layer consisting of (Ti,Nb)Si 2 , a middle layer consisting of (Ti,Nb) 5 Si 4 and (Ti,Nb) 5 Si 3 , and a γ-TiAl inner layer. Co-deposition temperature imposes strong influences on the coating structure. The coating prepared by Si–Y co-depositing at 1080 °C for 5 h shows relatively good oxidation resistance at 1000 °C in air, and the oxidation rate constant of the coating is about two orders of magnitude lower than that of the bare TiAl alloy.
Databáze: OpenAIRE