Friction-wear properties of nitrogen-ion-implanted nickel-free Co-Cr-Mo alloy

Takao Hanawa, Kozo Nakazawa, Kazuto Kano, Sachiko Hiromoto, Yoshiaki Suzuki, Akihiko Chiba

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Nitrogen ions were implanted in a Co-29 mass%Cr-6 mass%Mo alloy (ASTM F799-95) with reducing the amount of nickel in order to improve the friction-wear properties. The friction-wear properties of unimplanted and nitrogen-ion-implanted Co-Cr-Mo alloys were evaluated using a pin-on-flat-type reciprocating friction tester in air and phosphate-buffered saline, PBS(-), as a quasi-biological environment under applied stress of 3.54 MPa to understand the performance of this alloy for metal-on-metal-type artificial hip joints. As a result, the wear loss in PBS(-) was much smaller than that in air and increased with the increase of applied stress in both air and PBS(-), while the friction coefficient in a steady state during the test was larger in PBS(-) than in air, according to the lubrication behaviors of wear debris and PBS(-). Nitrogen-ion implantation is effective to decrease the friction coefficient in PBS(-) at the sliding interface between mutual Co-Cr-Mo alloys as well as to decrease the wear debris in PBS(-). Both in air and PBS(-), the surface of a N 2+-implanted flat specimen was smoother than that of an unimplanted flat specimen. Cobalt phosphate was precipitated as a corrosion product on the pin during the friction-wear test.

Original languageEnglish
Pages (from-to)1593-1596
Number of pages4
JournalMaterials Transactions
Volume46
Issue number7
DOIs
Publication statusPublished - 2005 Jul

Keywords

  • Biomaterials
  • Cobalt-chromium-molybdenum alloy
  • Friction-wear property
  • Nitrogen ion implantation

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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