Investigation of acoustic emission source of Fe-based sprayed coating under rolling contact

Acoustic emission (AE) technique was used to monitor rolling contact fatigue (RCF) experiments of plasma sprayed coatings. AE signal response was investigated. Worn morphologies of the coating were observed. Results show that typical AE signal mode owns three stages, i.e. running-in, stable and jump stage. Observations of worn coating release there are three kinds of AE signal sources, i.e. the crack initiated from surface, cracks embedded within the coating and cracks on the coating/substrate interface. The combined effect of orthogonal shear stress (OSS) and radial stress (RS) is main reason of the initiation and propagation of cracks within the coatings.