Stability of nanometer-thick layers in hard coatings

Scott A. Barnett*, Anita Madan, Ilwon Kim, Keith Martin

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

66 Scopus citations

Abstract

This article reviews two topics related to the stability of hard coatings composed of nanometer-thick layers: epitaxial stabilization and high-temperature stability. Early work on nanolayered hard coatings demonstrated large hardness increases as compared with monolithic coatings, but it was subsequently found that the layers interdiffused at elevated temperatures. More recently, it has been shown that nanolayers exhibit good stability at elevated temperatures if the layer materials are thermodynamically stable with respect to each other and are able to form low-energy coherent interfaces This article discusses metal/nitride, nitride/nitride, and nitride/boride nanolayers that exhibit good high-temperature stability and hardness values that are maintained (or even increase) after high-temperature annealing Epitaxial stabilization of nonequilibrium structures in thin layers is a well-known phenomenon that has been applied to hard nitride materials in particular, AIN, which crystallizes in the hexagonal wurtzite structure in bulk form, was stabilized in the rock-salt cubic structure in nitride/nitride nanolayers (e.g., AIN/TiN). These results and the current understanding of epitaxial stabilization in hard nanolayers are discussed.

Original languageEnglish (US)
Pages (from-to)169-172+165-167
JournalMRS Bulletin
Volume28
Issue number3
DOIs
StatePublished - Mar 2003

Keywords

  • Annealing
  • Hardness testing
  • Superhard coating materials
  • Thin films

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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