AVS 47th International Symposium
    Surface Engineering Tuesday Sessions
       Session SE-TuM

Paper SE-TuM4
The Compressive Coating Stresses in the Scratch Adhesion Test

Tuesday, October 3, 2000, 9:20 am, Room 201

Session: Interface Engineering and Graded Films: Structure and Characterization
Presenter: Y. Xie, National Research Council Canada
Authors: Y. Xie, National Research Council Canada
H.M. Hawthorne, National Research Council Canada
Correspondent: Click to Email
Despite the widespread use of the scratch adhesion test, there is no model available to determine the critical coating stress for initiating interfacial failure, so that ranking the coating-substrate adhesion of coated systems with different mechanical properties is impossible. In this study, a mathematical model is developed to calculate the distribution of compressive stresses in a thin coating induced by a scratch indenter. For ease of use in practice, a simple equation, @sigma@@sub cm@ = 0.15 (P@sub c@H@sub f@/H)@super 0.5@ E@sub f@@super 0.3@ E@super 0.2@/R, is then derived from the model, where @sigma@@sub cm@ is the critical mean compressive stress in the coating for interfacial failure, P@sub c@ is the critical normal load measured from the scratch adhesion test, H@sub f@ and E@sub f@are the hardness and Young's modulus of the coating, H and E are the hardness and Young's modulus of the substrate, and R is the indenter radius. This equation is useful for ranking the coating-substrate adhesion of different coated systems, or, for estimating the critical mean coating stress for interfacial failure.