Turbulence-like Cu/MoS2 films: Structure, mechanical and tribological properties

Modifying tribological performances of AISI 316 stainless steel surfaces by laser surface texturing and various solid lubricants

Effect of boron content on the structure, mechanical and tribological properties of sputtered Mo–S–B films

An insight on the MoS2 tribo-film formation to determine the friction performance of Mo-S-N sputtered coatings

Effect of diesel-palm biodiesel fuel with plastic pyrolysis oil and waste cooking biodiesel on tribological characteristics of lubricating oil

The tribological properties of chemical-vapor-deposited (CVD) diamond films vary with the environment, possessing a Jekyll-and-Hyde character. CVD diamond has low coefficient of friction and high wear resistance in air but high coefficient of friction and low wear resistance in vacuum. Improving the tribological functionality of materials (such as achieving low friction and good wear resistance) was an aim of this investigation. Three studies on the surface design, surface engineering, and tribology of CVD diamond have shown that its friction and wear are significantly reduced in ultrahigh vacuum. The main criteria for judging whether diamond films are an effective wear-resistant, self-lubricating material were coefficient of friction and wear rate, which must be less than 0.1 and on the order of 10(exp 6) cu mm/N(dot)m, respectively. In the first study the presence of a thin film (less than 1 micron thick) of amorphous, nondiamond carbon (hydrogenated carbon, also called diamondlike carbon or DLC) on CVD diamond greatly decreased the coefficient of friction and the wear rate. Therefore, a thin DLC film on CVD diamond can be an effective wear-resistant, lubricating coating in ultrahigh vacuum. In the second study the presence of an amorphous, nondiamond carbon surface layer formed on CVD diamond by ion implantation significantly reduced the coefficient of friction and the wear rate in ultrahigh vacuum. Therefore, such surface layers are acceptable for effective self-lubricating, wear-resistant applications of CVD diamond. In the third study CVD diamond in contact with cubic boron nitride exhibited low coefficient of friction in ultra high vacuum. Therefore, this materials combination can provide an effective self-lubricating, wear-resistant couple in ultrahigh vacuum.

Synergistic effect of ceria-zirconia nanoparticles and hBN nanosheets incorporation on the corrosion resistance of MoS2 solid lubricant coatings

Wear and friction characteristics of PVD-coated roller bearings

This paper tests the friction between a popular design of rugby ball contacting the palm and three different designs of gloves. The gloves used were from the same manufacturer; one was made from synthetic leather, one had a round, pronounced silicon pattern of pimples and the final one had a silicon pattern with oval shapes cut into it. The friction of the contact was measured in dry conditions, with a small amount of water added to the palm/glove, a larger amount of water added to the palm/glove and finally a dry palm/glove contacting wet material. These tests showed the silicon designs of gloves gave a consistent measurement of coefficient of friction across all moisture levels. However, for the bare palm and the synthetic leather glove the coefficient of friction increased with a small amount of water and then decreased when more water was added. The synthetic leather glove was shown to have the highest coefficient of friction across all levels of water, with the silicon oval patterned glove having the lowest coefficient of friction in the majority of cases.

In this study, the tribological performance of polyamide‐6 (PA‐6), polypropylene (PP), polyamide‐6/polypropylene (PA‐6/PP) polymer blend, and nanoclay reinforced polyamide‐6/polypropylene composite are investigated. Nanoclay reinforced polymer composite is produced by melt compounding using co‐rotating twin screw extruder followed by injection moulding. Tribological studies are carried out using a pin‐on‐stainless steel disc configuration under dry sliding conditions. Tribological tests are carried out at sliding speed of 0.5 m s−1 and applied load values of 25, 50,100, 150 N. The friction coefficient and specific wear rate values are obtained and evaluated. The results show that the addition of nanoclay into the PA‐6/PP polymer blend reduced their coefficient of friction and specific wear rate values. The lowest coefficient of friction and specific wear rate values are for nanoclay reinforced PA‐6/PP blend. The highest coefficient of friction and specific wear rate values are for PA‐6 polymer.

Polydimethylsiloxane (PDMS) has many advantages, but the friction coefficient generated by contact with the counter material is high. The purpose of this study is to reduce the friction coefficient by forming hierarchical micro/nanopatterns on the PDMS surface using the imprinting method. In addition, the optimum conditions for reducing the friction coefficient by controlling the sliding speed and normal load were determined. After contacting flat bare PDMS and hierarchical micro/nanostructured PDMS with a counter tip made of polyurethane (PU), the change in friction with sliding speed and vertical load was evaluated. Under normal load conditions, the average friction coefficient of the bare PDMS decreased as the sliding speed increased, and that of the patterned PDMS slightly increased. Regardless of the sliding speed, the friction coefficient decreased as the normal load increased for both specimens. At a sliding speed of 4 mm/s under a load of 10 mN, the friction reduction effect of the pattern structure was the largest at 79%. Overall, the greatest friction reduction effect (84%) was confirmed in patterned PDMS with the lowest friction coefficient under the conditions of 4 mm/s, 50 mN, compared to bare PDMS with the highest friction coefficient under the conditions of 4 mm/s, 10 mN.

Effect of N+ ion implantation on micro/nanotribological properties of nanocrystalline diamond films

Low-friction diamond-like carbon (DLC)-layers for humid environment

The vulva's higher capacitance, or skin hydration, leads it to have a higher friction coeffi cient, µ, which can be measured by the Newcastle Friction Meter. The vulva has a higher friction coeffi - cient at 0.66 ± 0.03, compared with the forearm at 0.48 ± 0.01 (7). This higher friction coeffi cient leads to increased vulva skin friction irritation from mechanical trauma, such as occlusion, clothing, sexual activity, and moisture occlusion from incontinence, which increases skin moisture, resulting in an even higher friction coeffi cient (7,8). Of note, the higher incontinence-related friction coeffi cient comes even more onto the front stage in postmenopausal women who suffer from vulvar skin atrophy in addition to incontinence issues, predisposing them even more so to increased vulvar irritation and dermatitis (9).

Spark-anodization of titanium can produce adherent and wear-resistant TiO2 film on the surface, but the spark-anodized titanium has lots of surface micro-pores, resulting in an unstable and high friction coefficient against many counterparts. In this study, the diamond-like carbon (DLC) was introduced into the micro-pores of spark-anodized titanium by the magnetron sputtering technique and a TiO2/DLC composite coating was fabricated. The microstructure and tribological properties of TiO2/DLC composite coating were investigated and compared with the anodic TiO2 mono-film and DLC mono-film. Results show that the DLC deposition significantly decreased the surface roughness and porosity of spark-anodized titanium. The fabricated TiO2/DLC composite coating exhibited a more stable and much lower friction coefficient than anodic TiO2 mono-film. Although the friction coefficient of the composite coating and the DLC mono-film was similar under both light load and heavy load conditions, the wear life of the composite coating was about 43% longer than that of DLC mono-film under heavy load condition. The wear rate of titanium with protective composite coating was much lower than that of titanium with DLC mono-film. The superior low friction coefficient and wear rate of the TiO2/DLC composite coating make it a good candidate as protective coating on titanium alloys.

Design of low-friction and anti-corrosion a-C:H:SiOx films