Tribology Online (Dec 2019)

Effect of Pillar and Mesh Structure of Tetrahedral Amorphous Carbon (ta-C) Coatings on the Wear Properties and Fracture Toughness of the Coating

  • Mohd Muhyiddin Bin Mustafa,
  • Noritsugu Umehara,
  • Takayuki Tokoroyama,
  • Motoyuki Murashima,
  • Akinori Shibata,
  • Yoshiharu Utsumi,
  • Hideki Moriguchi

DOI
https://doi.org/10.2474/trol.14.388
Journal volume & issue
Vol. 14, no. 5
pp. 388 – 397

Abstract

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Wear by fracture is among the factors associated with the DLC coating failures in the tribological application. The current study investigated the link between the wear and the fracture-toughness on the novel Pillar and Mesh structure ta-C coatings, in addition to conventional ta-C coatings. The tribological properties of these coatings were examined under base-oil lubrication via ball-on-disk tribo-tester and micro indentation technique was used to characterize the fracture toughness. The wear track and the indentation mark were analyzed using the optical microscope, 3D laser microscope and FE-SEM. The friction coefficient for ta-C, Pillar ta-C and Mesh ta-C are within the range of 0.071 to 0.106. Mesh ta-C indicated the highest wear resistance, followed by the Pillar ta-C and conventional ta-C. Also, Mesh ta-C demonstrated the highest fracture-toughness value with 16.6 MPa·m1/2, followed by Pillar ta-C with 13.4 MPa·m1/2 in contrast to ta-C. Greater resistance to wear for ta-C with Pillar and Mesh structure was detected with an increased fracture-toughness and improvement in crack propagation inhibition. Moreover, the Pillar and Mesh ta-C provides superior rate of crack-energy dissipation as compared to the ta-C.

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