Failure of ceramic coatings on cast and selective laser melted Co-Cr dental alloys under tensile test: Experiment and finite element analysis

Present paper deals with investigation the failure of ceramic coatings on cast and selective laser melted (SLM) Co-Cr dental alloys by tensile test and finite element analysis (FEA). It is established that the failure mode of porcelain coatings is mixed/cohesive in SLM alloy and mixed/adhesive in cast. In both alloys, maximum shear and normal stresses are concentrated at coating free edge on the porcelain-metal interface. Stresses distribution indicates the possible sites of coating fracture initiation and the way it will start - adhesively in the cast alloy due to lower bond strength and cohesively for SLM alloy. Coating failure is cohesive along the sample's length, due to change of maximum stresses location from the coating free edge through its thickness to the surface. The FEA gave an adequate explanation of the failure mechanism of porcelain coatings on cast and SLM Co-Cr dental alloys upon tensile test.