Study on the Evaluation of Coating Adhesion and Strength of Metal Coated with Ceramic Thin Film

4. The rotating bending fatigue tests were conducted in air and in 3.0% NaCl solution using the pre-flawed coating specimens. The fatigue life of pre-flawed coating specimen remarkably decreased as compared with that of an uncoated specimen. It was explained by the observation of fracture surface and the estimation of fatigue life based on the small fatigue crack propagation law that many cracks occured along the flaw of film are coalesced in each other and grow to large one crack at the early stage of fatigue process.