Theory 024/Materials Processing
Adhesion Is Roughness Wavelength
The claim
Coating adhesion is maximal at an intermediate substrate roughness wavelength rather than at maximum roughness.
01The mechanism
Mechanical keying requires features the coating can penetrate; features too coarse leave voids at valleys.
02Predictions
- P1Adhesion should peak at a roughness wavelength.
- P2Smoother and rougher substrates should both perform worse.
03Refutation
Monotonic adhesion with roughness would remove the optimum.