Spallation refers to the phenomenon where a surface coating, such as a layer of paint, thermal barrier coating, or protective film, breaks off, peels, or delaminates from the substrate. This typically occurs due to mechanical stress, thermal cycling, corrosion, or the presence of defects in the bond between the coating and the substrate. Spallation can compromise the coating's performance, leading to premature failure and exposure of the underlying material to environmental or operational hazards.
Common causes of spallation include: