Surface analysis of nitride layers formed on Fe-based alloys through plasma nitride process

Shigeo Sato, Koji Omori, Sawa Araki, Yohei Takahashi, Kazuaki Wagatsuma

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

Nitriding phenomena that occur on the surfaces of pure Fe and Fe-Cr alloy (16 wt% Cr) samples were investigated. An Ar + N2 mixture-gas glow-discharge plasma was used so that surface nitriding could occur on a clean surface etched by Ar+ ion sputtering. In addition, the metal substrateswere kept at a low temperature to suppress the diffusion of nitrogen. Theseplasmanitriding conditions enabled us to characterize the surface reaction between nitrogen radicals and the metal substrates. The emission characteristics of the band heads of the nitrogen molecule ion (N2+) and nitrogen molecule from the glow-discharge plasma suggest that the active nitrogen molecule is probably the major nitriding reactant. AES and angle-resolved XPS were used to characterize the thickness of the nitride layer and the concentration of elements and chemical species in the nitride layer. The thickness of the nitride layer did not depend on the metal substrate type. An oxide layer with a thickness of a few nanometers was formed on the top of the nitride layer during the nitriding process. The oxide layer consisted of several species of Nx-Fey-O, NO+, and NO 2-. In the Fe-Cr alloy sample, these oxide species could be reduced because chromium is preferentially nitrided.

Original languageEnglish
Pages (from-to)496-501
Number of pages6
JournalSurface and Interface Analysis
Volume41
Issue number6
DOIs
Publication statusPublished - 2009 Jun 1

Keywords

  • AES
  • Angle-resolved XPS
  • Glow-discharge plasma
  • Plasma nitriding

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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