A fracture mechanics approach is applied to measuring the adhesion of plasma and flame sprayed coatings of mild steel, nickel-aluminum composite and alumina applied to a mild steel substrate. The experimental method essentially involves incorporating the coating into either a double torsion or double cantilever beam geometry. The results show that the coating adhesion can be quantitatively determined and several trends are discerned and related to the fracture morphology. The metal coatings exhibit a high adhesion when compared to the ceramic coating and this may be related to plastic deformation of the individual lamellae, of which the coating is made up, during failure. The testing technique described is applicable to adhesion measurements on other metal-ceramic coatings.
National Conference Publications,
Vol. 80, no. (1980), pp. 387-392