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

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 ◦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 α-FeOOH.