Failure mode in which the coating breaks through its own thickness, between splats or layers, so both halves of the test show coating. It means the bond to the substrate was stronger than the coating's internal strength. Low cohesive strength points to unmelts, oxides, porosity or dusting between passes. In a two-layer system it is reported by which layer failed.
Cohesive failure in the zirconia at 3,500 psi, that's normal for this top coat, it passes.
Also heard as
- cohesive break
- intra-coating failure
Related terms
Bond strength
How hard you must pull to tear a coating off its substrate, measured by gluing and tensile testing.
Adhesive failure
A bond test break at the coating-substrate interface, meaning the coating let go of the base metal.
Unmelts
Lab shorthand for particles that hit the surface without fully melting and kept their round shape.
Dusting
Fine, cooled overspray that settles on a surface as loose powder and weakens the next layer sprayed over it.