Microstructure, hardness, and tribology properties of the (Cu/MoS₂)/graphene nanocomposite via the electroless deposition and powder metallurgy technique

Abstract

To increase the strength and to reduce the wear rate of the copper composite that used as a solid self-lubricant materials, Cu/10MoS2/ (0, 0.2, 0.4, 0.6, 0.8, and 1 wt.% graphene nanosheets) hybrid matrix nanocomposites were fabricated using the electroless copper precipitation process followed by the cold pressing and sintering in a hydrogen atmosphere furnace with a double-heating rate cycle. The microstructure of the as-received powders, as well as the produced samples, was examined using the scanning electron microscope. The chemical composition of the fabricated composites was evaluated by the energy dispersive spectrometry analysis. The effect of the graphene nanosheets (wt.%) addition on the densification, the hardness, the adhesive wear rate, the wear mechanism, and the coefficient of friction was investigated. The low heating rate of 5℃/min was the best for the fabrication process. The microstructure of the composites reveals the good distribution of the (graphene nanosheets and MoS2) in the copper matrix and good adhesion between graphene nanosheets and the (Cu-10MoS2) matrix as well. The 0.4 wt.% graphene nanosheets composite exhibits the highest hardness, the lowest wear rate, and the lowest coefficient of friction. The adhesive regions were dissipated by increasing the graphene nanosheets up to 0.6 wt.% then increased.

Direct Observation of Induced Graphene and SiC Strengthening in Al–Ni Alloy via the Hot Pressing Technique

“…Before the GNs and SiC powders were put in the aluminum matrix, they were cleaned of manufacturing contamination by stirring in a 10 wt% sodium hydroxide solution and acetone for 1 h, respectively. To improve the adhesion between the Al and the ceramic particle reinforcements, a 3 wt% nano-silver metal was precipitated by the electroless plating process onto the GN and SiC particles' surface individually [48][49][50][51][52].…”

“…An essential phenomenon was also observed in which the wear rate increased as the sliding speed increased. As the sliding speed increased, the track of the sample on the frictional parts increased and, consequently, the wear rate increased [51].…”

Studying the Effect of Process Controlling Agent on the Microstructure, Electrical and Thermal Conductivities of Copper /Graphene Composite Prepared by PM

“…The white grey area represents the Cu matrix, the grey area represents the Graphene nanosheets (GNSs) and the black ones are belonging to the pores. Generally, GNSs did not wet copper as the surface energy between them is high, so no good dispersion of the GNSs in the copper matrix takes place [13]. Addition of PCA and good milling parameters (milling time, ball to powder ratio and number of rotations rpm) are controllable to adjust the composite preparation.…”

Mussel-Inspired Interfacial Modification for Ultra-Stable MoS2 Lubricating Films with Improved Tribological Behavior on Nano-Textured ZnO Surfaces Using the AACVD Method

“…MoS 2 , a typical two-dimensional (2D) layered transition-metal dichalcogenide, has been widely used as a solid lubricant in the aviation field because of the excellent vacuum lubrication performance induced by its high interlayer anisotropy. − However, MoS 2 tends to be oxidized by oxygen and water vapor in the atmospheric environment, which reduces the friction properties and shortens the wear life. , Research has shown that metal doping − is a simple and economical method to improve the mechanical and tribological properties of MoS 2 solid lubricating materials. Meanwhile, the construction of micro-/nanotexture surfaces can not only improve the bearing capacity as power bearings but can also increase the storage capacity of lubricating materials and prolong the service life. − On the other hand, the poor adhesion between MoS 2 and a matrix has always been a perplexing problem. − Inspired by mussel adhesion proteins, polydopamine (PDA) formed by self-polymerization of dopamine is a polymer with outstanding adsorption performances, which can be adsorbed on various materials through strong covalent and non-covalent bonds to serve as an effective protective layer for nanostructures. − In particular, the rich functional groups (e.g., −NH 2 , −OH and catechol groups) on the surface of PDA have strong chelating ability for transition-metal ions (e.g., Zn 2+ , Fe 3+ , and Mo 4+ ), − which is beneficial to provide a reaction platform as a nucleation site to form a unique solid core–shell structure, thus improving the adhesion and load-bearing capacity of the film.…”