Surface hardening of age-hardenable Cu-Ti alloy by plasma carburization

S. Semboshi, Akihiro Iwase, T. Takasugi

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Plasma carburization was performed on specimens of a commercially used age-hardenable Cu-Ti alloy, in order to improve its surface hardness and wear toughness. Specimens of a Cu-4mol% Ti alloy were carburized in a methane gas glow discharge plasma at temperatures of 1073K and 1123K for 6h. The plasma-carburization treatment resulted in the formation of two layers of crystalline compounds on the surfaces of the Cu-4mol% Ti alloy specimens: (i) a TiC top layer containing 11at.% oxygen and (ii) a Cu3Ti3O sublayer. The thicknesses of the TiC and Cu3Ti3O layers were approximately 100nm and 900nm, respectively, in the case of the specimen plasma-carburized at 1073K. This led to significant improvements in the surface hardness and wear toughness of the specimen. It was interesting to note that the presence of a carbon-friendly alloying element (Ti) at a concentration of only 4mol% resulted in the formation of a hard TiC layer, leading to the surface hardening of the Cu-based alloy. Furthermore, plasma carburization at a higher temperature of 1123K resulted in the formation of thicker layers of hard TiC and Cu3Ti3O, causing a greater degree of surface hardening. Thus, it was demonstrated that plasma carburization is highly suitable for the surface modification of age-hardenable Cu-Ti dilute alloys.

Original languageEnglish
Pages (from-to)262-267
Number of pages6
JournalSurface and Coatings Technology
Publication statusPublished - 2015 Dec 15


  • Cu-Ti alloy
  • Hardness
  • Plasma carburization
  • Surface hardening
  • TiC
  • Wear toughness

ASJC Scopus subject areas

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


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