Abstract: The elastic contact models for two-dimensional and three-dimensional multi-asperity coating surface with rigid plane are studied. The changes of elastic modulus ratio, coating thickness, spacing of asperity and indentation depth are studied for the stress distribution on asperity surface, coating/substrate interface and substrate surface by using finite element method. The results show that the indentation depth has the greatest influence on the maximum surface stress of 3D coating asperity. The influence of coating thickness, coating/substrate elastic modulus ratio, and spacing of asperity on the stress value decreases gradually in 3D contact model. Decreasing elastic modulus ratio, indentation depth, spacing of asperity and increasing coating thickness will obviously reduce the maximum equivalent stress value of the 3D contact model. Increasing coating asperity number and coating thickness while reducing coating elastic modulus will help to improve the coating/substrate interfacial bonding strength. Equivalent stresses of 3D contact model are greater than 2D model. These changes are ascribed to the stress superposition between the asperities. The research provides basis for the stress analysis of coating surface asperities and coating/substrate interfacial strength.

Key words: Coatings, Equivalent stress, Finite element method, Surface asperities, Three dimensional