Surface hardening of titanium by pulsed Nd:YAG laser irradiation at 1064- and 532-nm wavelengths in nitrogen atmosphere

Naofumi Ohtsu, Misao Yamane, Kenji Kodama, Kazuaki Wagatsuma

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


The surface hardness of titanium modified by laser irradiation at different wavelengths in nitrogen atmosphere was investigated. Further, surface characteristics such as morphology, chemical state, and chemical composition in the depth direction were also studied. The size and depth of the craters observed in the laser-irradiated spots increased monotonically with an increase in the laser power. Furthermore, the crater formed by the 532-nm laser was deeper than that formed by the 1064-nm laser for the same laser power. Laser power beyond a certain threshold value was required to obtain a titanium nitride layer. When the laser power exceeds the threshold value, a titanium nitride layer of a few tens of nanometers in thickness was formed on the substrate, whereas a titanium oxide layer containing small amounts of nitrogen was formed when the laser power is below the threshold value. Thus, it was shown that laser irradiation using appropriate laser parameters can successfully harden a titanium substrate, and the actual hardness of the titanium nitride layer, measured by nanoindentation, was approximately five times that of an untreated titanium surface.

Original languageEnglish
Pages (from-to)691-695
Number of pages5
JournalApplied Surface Science
Issue number3
Publication statusPublished - 2010 Nov 15


  • Depth profile
  • Laser nitridation
  • Laser wavelength
  • Nanoindentation

ASJC Scopus subject areas

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


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