Friction and wear behaviors of bare and diamond-like carbon/chromium bi-layer coated SKH51 steel at low temperatures

• Published in: Surface & coatings technology Vol. 412; p. 127018
• Main Authors: Khadem, Mahdi, Kim, Dae-Eun
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 25.04.2021; Elsevier BV
• Subjects: Bi-layer coating; Bilayers; Chromium; Coating; Degradation; Diamond-like carbon (DLC); Diamond-like carbon films; Friction; High resolution electron microscopy; High speed tool steels; Indentation; Low temperature; Magnetron sputtering; Mechanical properties; Mechanical systems; Microscopy; Photoelectrons; Raman spectroscopy; Reliability aspects; SKH51 steel; Spectrum analysis; Substrates; Temperature; Tribology; Wear; Wear mechanisms; Wear rate; X ray photoelectron spectroscopy; SKH51 steel; Bi-layer coating; Friction; Diamond-like carbon (DLC); Wear; Low temperature
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2021.127018

The durability and reliability of mechanical systems operating under low-temperature conditions are subject to degradation caused by abrupt changes in the tribological characteristics of contact pairs. In this regard, the friction and wear behaviors of bare and diamond-like carbon (DLC)/Chromium (DLC/Cr bi-layer) coated SKH51 steel at low temperatures were assessed comprehensively. The bi-layer coating was deposited onto the SKH51 substrate using a combination of pulsed DC and radio frequency magnetron sputtering. Tribological tests were conducted using a custom-built reciprocating tribo-tester installed inside a cooling unit with temperature-control capabilities. The nano-structural properties of the coating and governing wear mechanisms were investigated using high-resolution transmission electron microscopy (HR-TEM), laser confocal microscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and ultra-nano indentation. The results revealed a significant increase in the wear rate of SKH51 due to changes in wear mechanism and the degradation of mechanical properties as the temperature decreased. The DLC/Cr bi-layer coating significantly reduced the wear of SKH51, particularly at low temperatures. The formation of a thin layer of frozen water at subzero temperatures played a major role in determining the wear behaviors of the specimens. [Display omitted] •Reducing the temperature changed the wear mechanism of SKH51 steel.•Reducing the temperature increased the wear rate of SKH51 steel by 200%.•The wear rate of the DLC/Cr bi-layer coating was the lowest at 0 °C.•DLC/Cr bi-layer coating can effectively protect SKH51 steel at subzero temperatures.