Corrosion, Pitting, and Surface Defects in Coatings

corrosion and aging-related defects impact the functional lifespan and aesthetic quality of both coated and uncoated engineering materials, particularly within industrial and biomedical contexts. A primary focus is on micro-pitting, a localised corrosion process that creates minute surface cavities, significantly compromising surface uniformity and protective capacity. The text explains that the microstructure of coatings, such as Ni-P and Ni-P-Cu layers, critically influences corrosion resistance, noting that the inclusion of elements like copper can introduce sites for galvanic corrosion. Furthermore, surface imperfections arising from wear or process defects, like those studied in TiBN thin films, accelerate susceptibility to corrosion by affecting charge transfer resistance. Ultimately, the text highlights that the synergistic effect of tribocorrosion (wear and corrosion) and environmental factors, such as hydrothermal aging, substantially hastens visible and functional surface degradation.