Polyether ether ketone (PEEK) is a high-performance thermoplastic, which is often selected for high-temperature tribological applications under chemically aggressive environments. The present work investigates the tribological behavior of a high-performance PEEK composite under conditions that are often found inside hermetic compressors. Therefore, an AMTI tribometer equipped with a hermetic chamber and a heating system was used to conduct sliding tests of PEEK cylinders on AISI 304 stainless...

Hydrostatic assistance is a commonly used method to improve limited load carrying ability of tilting-pad thrust bearings during transient states of operation of vertical shaft hydro-generators. Despite of special hydraulic equipment (as pumps, valves, etc.), it also requires manufacturing of special recesses/pockets at pad sliding surfaces, into which oil is injected under high pressure. It allows to lift the rotor before start-up of the machine and form a hydrostatic film between pads and co...

The oil viscosity specification for wind turbine gear oils is ISO VG 320, although there are quite different viscosity indexes oils for that viscosity specification. This work evaluates the behaviour of different base oil formulations, since polyalphaolefin (PAO), mineral, ester and polyalkeleneglycol (PAG) that withstand quite different viscosity indexes. The oils evaluation was done in rolling bearing tests and gear tests. Their behaviour was compared for operating conditions in the range o...

It has been shown before that liquids can slip at a solid boundary, which prompted the idea that parallel-surfaces bearings can be achieved just by alternating slip and non-slip regions in the direction of fluid flow. The amount of slip at the wall depends on the surface tension at the liquid–solid interface, which in turn depends on the chemical state of the surface and its roughness. In the present study a heterogeneous surface was obtained by coating half of a circular glass disc with a co...

Superlubricity means non-sticky and frictionless when two bodies are set contacting motion. Although this occurrence has been extensively investigated since 1859 when Faraday firstly proposed a quasiliquid skin on ice, the mechanism behind the superlubricity remains uncertain. This report features a consistent understanding of the superlubricity pertaining to the slipperiness of ice, self-lubrication of dry solids, and aqueous lubricancy from the perspective of skin bond-electron-phonon adapt...

This investigation reports on the effect of Jatropha oil doped with lube oil on tribological characteristics of Al-7%Si alloy. The factors involved were Jatropha oil percentages, sliding velocities and load which was optimized for weight loss, friction coefficient and specific wear rate characteristics. The conventional lubricant was SAE 40. It is observed that the Jatropha oil percentage factor had significant influence on the weight loss, friction coefficient and wear rate of the pin. The o...

Magnetorheological (MR) fluid damper which allows the damping characteristics of the damper to be continuously controlled by varying the magnetic field is extensively used in metal cutting to suppress tool vibration. Even though magnetorhelogical fluids have been successful in reducing tool vibration, durability of magnetorhelogical fluids remains a major challenge in engineering sector. Temperature effect on the performance of magnetorhelogical fluids over a prolonged period of time is a maj...

Since the term “superlubricity” was put forward at the beginning of 1990s, it has become one of the hottest researches in tribology due to it being close linked to the energy problems. Recently, the International Workshop on “Superlubricity: Fundamental and Applications” was successfully held on 19–20 October 2015 in Beijing, which has attracted many researchers in this field. The recent scientific results in both solid superlubricity and liquid superlubricity have been presented according to...