Effects of sp2/sp3 ratio and hydrogen content on in vitro bending and frictional performance of DLC-coated orthodontic stainless steels

Takeshi Muguruma, Masahiro Iijima, Masahiro Kawaguchi, Itaru Mizoguchi

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

This study investigated a diamond-like carbon (DLC) coating formed on stainless steels (disk and wire specimens) using a plasma-based ion implantation/deposition method with two different parameters (DLC-1, DLC-2). These specimens were characterized using high-resolution elastic recoil analysis, microscale X-ray photoelectron spectroscopy and nanoindentation testing to determine the hydrogen content, sp2/sp3 ratio and mechanical properties of the coating. Three-point bending and frictional properties were estimated. DLC-1 had a diamond-rich structure at the external surface and a graphite-rich structure at the inner surface, while DLC-2 had a graphite-rich structure at the external surface and a diamond-rich structure at the inner surface. Mean mechanical property values obtained for the external surface were lower than those for the inner surface in both types of DLC-coated specimens. The hydrogen content of DLC-2 was slightly higher versus DLC-1. Both DLC-coated wires produced a significantly higher elastic modulus according to the three-point bending test versus the non-coated wire. DLC-2 produced significantly lower frictional force than the non-coated specimen in the drawing-friction test. The coating of DLC-1 was partially ruptured by the three-point bending and drawing-friction tests. In conclusion, the bending and frictional performance of DLC-coated wire were influenced by the hydrogen content and sp2/sp3 ratio of the coating.

Original languageEnglish
Article number199
JournalCoatings
Volume8
Issue number6
DOIs
Publication statusPublished - 2018 Jun 1
Externally publishedYes

Keywords

  • Diamond-like carbon
  • Frictional property
  • Hydrogen content
  • Sp2/sp ratio
  • Surface modification

ASJC Scopus subject areas

  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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