The tribological properties of ultra-high-molecular-weight polyethylene (UHMW-PE) play a significant role in artificial joint materials. Graphite fluoride (GrF), a novel solid lubricant, was incorporated into ultra-high-molecular-weight polyethylene (UHMW-PE) at different concentrations via ball milling and heat pressing to prepare the GrF-UHMW-PE composites. The structure, hardness, and tribological behavior of the composites were investigated using X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectrometry, ball indentation hardness, and a reciprocating ball-on-plane friction tester, respectively. The results of FT-IR showed that hydrogen bonds (C-F···H-C) could be formed between GrF and UHMW-PE. The hardness of the composites was significantly enhanced by increasing the GrF concentrations. GrF in the composites displayed superior lubricant properties and the coefficient of friction (COF) of the composites was significantly decreased at lower concentrations of GrF viz. 0.1 and 0.5 wt%. The addition of GrF also significantly enhanced the anti-wear properties of the composites, which was a combined effect of lubrication as well as hardness provided by GrF. At 0.5 wt% GrF concentration, the COF and the wear rate were reduced by 34.76% and 47.72%, respectively, when compared to UHMW-PE. As the concentration of GrF increased, the wear modes of the composites transitioned from fatigue wear to abrasive wear. Our current work suggested that GrF-UHMW-PE composites could be a suitable candidate for artificial joint materials.

The distribution of substrate temperature plays a decisive role on the uniformity of polycrystalline diamond films on cemented carbide tools with a long flute, prepared by a hot filament chemical vapor deposition (HFCVD). In this work, the heat dissipation mode at the bottom of tools is a focal point, and the finite volume method (FVM) is conducted to simulate and predict the temperature field of tools, with the various materials of the holder placed under the tools. The simulation results show that the thermal conductivity of the holder affects the temperature difference of the individual tools greatly, but only affects the temperature of different tools at the same XY plane slightly. Moreover, the ceramic holder can reduce the difference in temperature of an individual tool by 54%, compared to a copper one. Afterwards, the experiments of the deposition of diamond films is performed using the preferred ceramic holder. The diamond coatings on the different positions present a highly uniform distribution on their grain size, thickness, and quality.

The friction coefficient versus time curve of PE-UHMW and PE-UHMW/GO composite materials treated differently under water lubrication.

As an advanced surface modification technology, laser cladding technology can significantly improve the hardness, wear resistance, and corrosion resistance of the base material by forming a high-performance composite coating on the surface of the substrate. In this paper, In718 nickel-based high-temperature alloy was used as the substrate, and laser cladding technology was used to prepare In718/(2Nb + 1SiC) composite coatings, and the effects of different laser powers (800 W, 1200 W, 1600 W, and 2000 W) on the microstructure and wear-resistant properties of the coatings were systematically investigated. Through SEM morphology observation, EDS elemental distribution analysis, wear behavior characterization, wear mechanism discussion, the regulatory mechanism of laser power on the microstructure evolution, the uniformity of reinforced phase distribution, and the coating properties were revealed. The results show that different melting powers significantly affect the phase structure and the generation of reinforcing phases in the In718/(2Nb + 1SiC) composite coatings. A 1200 W laser input power can make the coatings reach the optimal phase structure equilibrium. Both properties of the SiC-reinforced phase are retained, and a large number of NbC- and MoC-reinforced phases are generated. This results in excellent properties for the coating.