Contact-induced Damage in Ceramic Coatings on Compliant Substrates: Fracture Mechanics and Design

Authors

  • Young-Woo Rhee,

    1. Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899
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    • Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Yusong, Taejon 305-701, Korea.

  • Hae-Won Kim,

    1. Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899
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    • School of Materials Science and Engineering, Seoul National University, Seoul 151-742, Korea.

  • Yan Deng,

    1. Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899
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    • §

      Department of Materials and Nuclear Engineering, University of Maryland, College Park, MD 20742.

  • Brian R. Lawn

    1. Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899
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    • **

      Fellow, American Ceramic Society.


  • G.M. Pharr—contributing editor

  • Supported by grants from the Korean Science and Engineering Foundation (author YWR) and the U.S. National Institute of Dental Research.

Abstract

Simple explicit relations are presented for the onset of competing fracture modes in ceramic coatings on compliant substrates from Hertzian-like contacts. Special attention is given to a deleterious mode of radial cracking that initiates at the lower coating surface beneath the contact, in addition to traditional cone cracking and quasiplasticity in the near-contact area. The critical load relations are expressed in terms of well-documented material parameters (elastic modulus, toughness, hardness, and strength) and geometrical parameters (coating thickness and sphere radius). Data from selected glass, Al2O3 and ZrO2 coating materials on polycarbonate substrates are used to demonstrate the validity of the relations. The formulation provides a basis for designing ceramic coatings with optimum damage resistance.

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