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Establishing multilayered coating on Mo–12Si–8.5 B alloy by Si pack cementation and its oxidation behavior at 900°C–1300°C
Author(s) -
Wang Juan,
Li Bin,
Li Rui,
Chen Xuan,
Zhang Guojun
Publication year - 2021
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.202012146
Subject(s) - materials science , cementation (geology) , alloy , layer (electronics) , coating , internal oxidation , composite material , substrate (aquarium) , metallurgy , oceanography , cement , geology
A multilayered oxidation protection coating consisting of MoSi 2 outer layer, Mo 5 Si 3 internal layer, and Mo 5 SiB 2 /MoB inner layer was developed on the surface of Mo–12Si–8.5B 1.0 wt% ZrB 2 alloy via Si pack cementation. The multilayered coating significantly enhanced the oxidation resistance of the alloy at 900°C, 1100°C, and 1300°C in the air by exhibiting negligible oxidation recession. MoSi 2 outer layer provided admirable oxidation protection for the alloy at high temperatures by forming a thin and protective SiO 2 ‐rich glass scale on its surface. This was supplemented by the Mo 5 Si 3 internal layer and Mo 5 SiB 2 /MoB inner layer that reduced the thermal expansion mismatch between the MoSi 2 outer layer and substrate, and therefore no obvious cracks were found in the MoSi 2 outer layer. More importantly, the Mo 5 SiB 2 /MoB layer as an in situ barriers of Si interdiffusion ensured the stable existence of MoSi 2 and Mo 5 Si 3 layers without obvious thickness change during oxidation at 900°C and 1100°C. Mechanical property test indicated that the formation of the coating layers could not affect the fracture toughness of the alloy.