The shear testing machine is suitable to determine the strength of the bond between a thermally sprayed coating and the substrate (adhesive strength) and/or the cohesive strength of the coating.
With the shear test a hard metal shear plate is used to apply a force parallel and close to the interface coating/substrate. The force is increased until the coating fails either at the interface or within the coating itself. The load displacement measurements provide information about cracking of the coating, coating thickness, delamination, rupture and other adhesion or cohesion properties.
European Standard EN 15340 was developed within a European Joint Research Project together with: • EMPA - Materials Science & Technology and • walter+bai ag Testing Machines
The test is conducted to determine the strength of the bond between the spray deposit and the parent material (adhesive strength) and/or the strength of the coating (cohesive strength).
If adhesive strength to the base material supersedes cohesive strength of the sprayed coating primarily the cohesive strength of the deposit is determined.
The specimen / coating are loaded parallel to the interface coating / substrate. The test is used to evaluate the effects of parent material and spray material, surface preparation of the work piece before spraying, and the spraying conditions on the adhesive strength of thermally sprayed coatings, or for quality control and routine supervision of the spray works.