Fe-based amorphous coating prepared using high-velocity oxygen fuel and its corrosion behavior in static lead-bismuth eutectic alloy

The Fe 49.7 Cr 18 Mn 1.9 Mo 7.4 W 1.6 B 15.2 C 3.8 Si 2 amorphous coating was deposited on T91 steel substrate by using the high-velocity oxygen fuel (HVOF) spray technique to enhance the corrosion resistance of T91 stainless steel in liquid lead-bismuth eutectic (LBE). The corrosion behavior of the T91 steel and coating exposed to oxygen-saturated LBE at 400°C for 500 h was investigated. Results showed that the T91 substrate was severely corroded and covered by a homogeneously distributed dual-layer oxide on the interface contacted to LBE, consisting of an outer magnetite layer and an inner Fe−Cr spinel layer. Meanwhile, the amorphous coating with a high glass transition temperature ( T g = 550°C) and crystallization temperature ( T x = 600°C) exhibited dramatically enhanced thermal stability and corrosion resistance. No visible LBE penetration was observed, although small amounts of Fe 3 O 4 , Cr 2 O 3 , and PbO were found on the coating surface. In addition, the amorphicity and interface bonding of the coating layer remained unchanged after the LBE corrosion. The Fe-based amorphous coating can act as a stable barrier layer in liquid LBE and have great application potential for long-term service in LBE-cooled fast reactors.