Patent ID: 7341777

Claim:
A coating for the inspection of a crack in a structure wherein a first coating layer having dispersed therein microcapsules with a visualizing liquid sealed therein is formed on the surface of the structure and when a crack is developed in said structure and propagated to said coating layer, the microcapsules dispersed in said coating layer are ruptured and said visualizing liquid flows out from the ruptured microcapsules and reaches the surface of the coating layer along the crack in the coating layer, thereby making it possible to detect the occurrence of the crack in said structure, wherein at least one second coating layer not containing the microcapsules is formed over said first coating layer with the microcapsules dispersed therein, and said second coating layer being transparent and having an outermost layer capable of elongating at least seventeen times the amount of elongation of any other coating layer in said structure.