Si-enabled self-lubrication and wear resistance of CrCoNiSi medium-entropy alloy films

Young Mok Kim, Tae Jin Jang, Wansu Song, Hyeon Seok Do, Sang Ho Oh, Gyeongbeom Lee, Joungwook Kim, Eunsoo Yang, Byeong Joo Lee, Ho Jang, Seok Su Sohn

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

High- or medium-entropy alloys have gained attention in coatings attributed to high wear resistance, with the formation of an amorphous phase. However, tailoring the crystal structure has limitations in improving both friction and wear characteristics due to the uncertain influence of amorphization on friction coefficients. In this respect, Si, known to increase glass-forming ability, can reduce the friction coefficient as a self-lubricating tribo-film formed by tribochemical reactions. However, tailoring Si content also affects crystal structures, defects, and mechanical properties, which require systematical investigations. Therefore, in this study, CrCoNiSi alloy films are fabricated with controlling Si content (0–13 at%) and sputtering power (5.8–13.7 W/cm2). The increase in Si content and sputtering power both produce identical microstructural evolutions, shifting from a crystalline towards an amorphous phase. In an amorphous film of high sputtering power, the high SiO2 fraction leads to dominant adhesive wear with delamination, thus contributing to the increase in wear rate. However, the Si addition alters the Si ion fraction of post-wear, forming Si-induced tribo-film, retaining abrasive wear, and consequently reducing the friction coefficient and wear rate. This Si addition would offer control over crystal structure and self-lubricating properties, enabling tailored mechanical and tribological properties.

Original languageEnglish
Pages (from-to)5429-5443
Number of pages15
JournalJournal of Materials Research and Technology
Volume30
DOIs
Publication statusPublished - 2024 May 1

Bibliographical note

Publisher Copyright:
© 2024 The Authors

Keywords

  • Amorphous phase
  • Medium-entropy alloy
  • Self-lubrication
  • Thin films
  • Tribological properties

ASJC Scopus subject areas

  • Ceramics and Composites
  • Biomaterials
  • Surfaces, Coatings and Films
  • Metals and Alloys

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