Lubricant-enhanced fatigue crack growth in silicon nitride

Daping Yao, J. K. Shang

Research output: Contribution to journalArticlepeer-review

Abstract

Effect of a fluorinated lubricant on the subcritical crack growth behavior of a Si3N4ceramic was examined under cyclic loading condition. The fatigue lifetime of the specimens tested in the oil was shorter, particularly in the low stress regime, compared to that in air. The growth rate of the surface crack was measured in the oil and compared with that in humid air. Crack growth rate in the oil was twice that in the air. XPS analysis of the fatigue fracture surfaces revealed that F had reacted with yttria-containing grain boundary phase, while the fraclographical examination indicated that the oil had caused the dissolution of the grain boundary phase. ‘The dissolution was shown to reduce the extent of crack bridging behind the crack tip, resulting in a higher fatigue crack growth rate in the oil.

Original languageEnglish (US)
Pages (from-to)973-979
Number of pages7
JournalTribology Transactions
Volume38
Issue number4
DOIs
StatePublished - Oct 1995

Keywords

  • Fluorocarbons
  • Silicon nitride
  • Wear and failure

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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