The formation and mechanism of oxides film on GCr15 bearing steel under indoor atmospheric exposure

Available studies on atmospheric corrosion of steels are mainly targeted to develop corrosion resistant steels and protection strategies for outdoor structural applications, and little attention has been laid on the indoor atmospheric corrosion of steel parts, which are usually vital components for industrial equipment. In this work, the indoor atmospheric exposure formed thin oxides film on GCr15 bearing steel substrate has been investigated. On exposure to atmosphere with 25 degrees C and 45 % RH, XPS results find that the oxides film thickens fast during the initial 24 h aging, and then stabilizes as the aging proceeds to 120 h. EIS results find that the corrosion resistance of the thin oxides film initially enhances fast as the aging time proceeds to 24 h and then stabilizes with an extended aging time of 120 h. Such an evolution behavior is different from that often observed for steels undergoing outdoor atmospheric corrosion. Besides, the composition and formation mechanism of such an oxides film has been discussed, and it follows that the composition of this oxides film is alpha-FeOOH.

Automated summary

Current studies on atmospheric corrosion of steel mainly focus on outdoor structural applications and pay little attention to the indoor atmospheric corrosion of steel parts. This work investigates the formation of thin oxide film on GCr15 bearing steel substrate in indoor atmospheric exposure. The results show that the oxide film thickens rapidly during the initial aging period and then stabilizes with extended aging time. The corrosion resistance of the oxide film initially enhances and then stabilizes as well. The composition of the oxide film is determined to be alpha-FeOOH.