An in-operando evaluation identified the oxidative failure mechanism of TiN hard coatings during extreme thermal cycling

Mehdi Rouhani, Sai Bhavani Sravan Metla, Jonathan Hobley, Yeau-Ren Jeng

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

We determine the definitive failure mechanism of passivated TiN films by in-operando monitoring extreme temperature (650 °C) induced microstructure, chemical, and mechanical changes. Films were in-operando characterized using Raman and optical microscopy, in air and argon, and post-mortem using nanoindentation, XPS, XRD, and microscopy. Initially, TiO2 anatase forms from pre-existing anatase-rich nucleation centers. These develop into domed bulges of condensed N2 gas in the sub-surface. This initial oxidation is limited to the surface. However, during cooling, cracks propagate from the bubbles, leading to wide-area delamination of the films. These cracks provide a pathway for further destructive bulk oxidation to rutile. This insight into failure mechanism provides deposition protocol for coatings operated under demanding conditions.

Original languageEnglish
Article number158375
JournalApplied Surface Science
Volume640
DOIs
Publication statusPublished - 2023 Dec 15

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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