Long-Term Strength of Ceramics for Biomedical Applications

Yu Zhang, Brian Lawn

Research output: Contribution to journalArticle

Abstract

The influence of slow crack growth on the initiation of radial cracks at the lower surfaces of ceramic layers bonded to polymeric substrates is studied, with particular relevance to biomechanical systems, e.g., dental crowns and hip replacement prostheses. Critical loads are measured as a function of loading rate (dynamic fatigue) for model bilayers fabricated by epoxy-bonding selected clinical ceramics to polycarbonate bases. Radial crack initiation is observed in situ by viewing from below the transparent base during loading. Declines in the critical loads with diminishing load rate are consistent with slow crack growth of intrinsic flaws prior to radial crack pop in. A simple fracture mechanics relation incorporating a crack velocity function is used to analyze the data. Extrapolation beyond the data range enables long-lifetime (10 yr) estimates of sustainable loads. The procedure provides a basis for ranking ceramic types, and in particular for eliminating vulnerable candidate materials, for use in biomechanical systems. While slow crack growth is an important factor in failure, other mechanisms could operate in concert and even dominate under severe testing conditions, especially under cyclic loading.

Original languageEnglish (US)
Pages (from-to)166-172
Number of pages7
JournalJournal of Biomedical Materials Research - Part B Applied Biomaterials
Volume69
Issue number2
DOIs
StatePublished - May 15 2004

Keywords

  • Bilayers
  • Brittle coatings
  • Crack velocity
  • Critical loads
  • Dental crowns
  • Fracture
  • Lifetime

ASJC Scopus subject areas

  • Biomaterials
  • Biomedical Engineering

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