Study of damage evolution in 316L stainless steel composite enamel coatings by in situ scanning electron microscopy and acoustic emissions analyses

Ceramics and glass ceramics are used in many demanding applications due to their exceptional properties including wear resistance, thermal stability, and corrosion resistance. However, sizable efforts are spent to improve their low fracture toughness, by, for example, modification of microstructure, and fiber-reinforcement. The addition of metallic particles also represents a well-known approach to solve this issue. Metal-reinforced glass-ceramics also emerge as a potential solution providing the desirable ability of crack bridging and absorption of energy by ductile deformation. This concept was in this study applied to the production of novel composite enamel coatings with different amount of 316L stainless steel flakes. This study aims to evaluate the steel-enamel composite coatings’ mechanical properties, using flexural tests and in-situ techniques. Acoustic Emission is introduced as a valuable method to monitor damage evolution and the quantitative results are compared to combined SEM in-situ flexural tests carried out on the same samples. The addition of stainless-steel flakes resulted to effectively counteract the nucleation and propagation of cracks and the AE technique was demonstrated to be a first-choice method for assessing the mechanical properties of composite enamel coatings.