Fretting wear behavior of duplex PEO/chameleon coating on Al alloy

Abstract

Plasma electrolytic oxidation (PEO) is an attractive technology for improving resistance to wear, heat and corrosion of aluminum alloys. PEO results in a hard, well-adhered alumina ceramic coating with a morphology which is graded from a dense region near the substrate interface to a porous outer region. Such properties mean that PEO can be an ideal underlying layer for the application of solid lubricants which can be entrapped in outer pores and provide reservoirs for the tribological contact lubrication. This study investigates the fretting wear behavior and adaptive mechanisms for a PEO-produced alumina surface of about 11-12 GPa hardness with a top layer of an MoS2/Sb2O3/C chameleon solid lubricating coating, the

Fluorinated Graphene: A Promising Macroscale Solid Lubricant under Various Environments

“…For example, diamond-like carbon was widely used in mechanical systems as a coating material . Nanocomposite coatings were developed to reduce the friction and wear under various external environments, such as the cycling of the atmosphere and temperature in aerospace applications. − In recent years, two-dimensional (2D) materials were widely used as solid lubricants owing to their easy shear between lattice layers . They have been extensively investigated for a better adaptability to extreme environmental conditions and contact pressures.…”

Corrosion of the Welded Aluminium Alloy in 0.5 M NaCl Solution. Part 2: Coating Protection

“…There are numerous works dedicated to the modification of PEO-layers to improve their corrosion protection [22,23,24,25,26,27,28,29,30,31,32,33]. Zhang et al used PEO as a pretreatment method to form calcium stearate based hydrophobic coatings [22].…”

“…Ghafaripoor et al formed a composite coating on 7075 Al alloy via plasma electrolytic oxidation in silicate base electrolyte containing α-Al 2 O 3 particles [31]. In [32], a duplex coating was obtained using PEO treatment of AA 6082 Al alloy, with subsequent formation of MoS 2 /Sb 2 O 3 /C chameleon solid lubricating coating as a top layer. A TiO 2 - and Al 2 O 3 -dense composite PEO film was generated on the substrate of Al 6061 alloy in a sodium silicate electrolyte containing dissolved TiO 2 powder [33].…”

Surface characteristics underpinning fretting wear performance of heavily loaded duplex chameleon/PEO coatings on Al

“…Solid lubricants, in turn, constitute a viable alternative to provide sufficient tribological performance over a wider range of working environments. To overcome the variable and cycled environmental challenges of aerospace applications, adaptable duplex chameleon/PEO coatings were recently introduced [27]. The majority of chameleon materials are composed of transition-metal dichalcogenides and graphite, while some may have inclusions on low shear strength metals and oxide phases [28].…”