Tribometer

About: Tribometer is a research topic. Over the lifetime, 4330 publications have been published within this topic receiving 74248 citations.

A Conditional approach to the tribology of RNLI marine systems.

Abstract: Lubricant degradation mechanisms in the 4-stroke heavy duty diesel engines of RNLI lifeboats were investigated. These mechanisms lead to the increased wear of main engine components, such as cylinder liners. The lifeboat application is distinct from the other marine applications from an engine lubrication perspective, since it involves infrequent engine running conditions and is often subjected to either under or over engine maintenance due to the unpredictable usage of lifeboats. This research has demonstrated the key lubricant properties which were affected by the lifeboat operations. Analysis of used lubricants was conducted such as Wear Debris Analysis (Analytical Ferrography) to identify the wear mechanism of affected tribological contacts and Nuclear Magnetic Resonance (NMR) analysis to analyse the trend in reduced effectiveness of antiwear additives. Other standard lubricant analysis technique were also performed to supplement the information about the lubricant condition. The experimental test rig involved the modification of a high frequency reciprocating tribometer (Plint TE77) to simulate piston ring and cylinder liner configuration. Boundary lubrication conditions that exist near the top dead centre region of cylinder liner were simulated in order to evaluate the tribological performance of lubricant additives. Also real-time condition monitoring of engine lubricant samples was carried out using a commercially available on-line sensing system. The obtained results from oil sensor were sufficiently promising to conduct engine level tests in lifeboat to monitor lubricant performance in real-time and build the system as part of the planned maintenance strategies of the RNLI. The work also involved recovering the tribological performance of used engine lubricants for further use at the end of their service life. Ionic Liquids (ILs) were tested as performance improving additives in used engine lubricants at engine start and running conditions using the modified Plint TE77 experimental test setup. Additional tests were conducted with different fully-formulated and mineral base oils with ILs as additives. Post-test surface analysis for wear mechanism and surface chemistry analysis of boundary antiwear films were performed to relate the chemical composition of films with its tribological performance. Obtained results demonstrated significant improvement in tribological performance of used engine lubricants. Also interference between Phosphonium ILs and existing additives in engine oils was noted. ILs effectively contributed to the boundary film formation when already present additives (such as ZDDP) are substantially depleted as seen in the case of used engine oil. The extension of service life of used engine oils can be achieved and has potential of significant savings in terms of fuel economy, engine reliability and by reduced oil consumption and drainage into the environment.

Accurate measurement of Kinetic Friction Coefficient by using two types of tribometer

Abstract: Tribological tests are adopted to estimate the kinetic friction coefficient of the material of interest according to the ASTM standard. Typically, for the measurement process, several replicas as well as a post-processing data treatment are necessary to take into account the observed casual variability of the measurand. The paper describes a statistical approach for both Time and Frequency Domain analysis, aiming to highlight the most significant time intervals during each test replica. Experimental activity has been carried out by performing multiple tests through two different tribometers (ball-on-flat and ball-on-disk configurations) in order to verify the improvement allowed by the authors’ proposal about the dry friction coefficient measurement in terms of both accuracy and reliability.

Wear behaviour of the PLA and Cu2O composite under different temperature

Abstract: Tribological behaviour of the Poly lactic acid (PLA) and copper (I) oxide (Cu2O) composite under two different temperature were studied using the pin on disk tribometer under dry sliding condition. Comparative wear studies of the unreinforced PLA and PLA/Cu2O-10 volume percentage composite is made under the low sliding velocity (1 m/s) for the distance of 2000m at room temperature (35°C) and elevated temperature (65°C) under low loading condition (10 N). The worn-out samples were examined using the optical microscope. The wear trend were analysed in the plain PLA and the blend of PLA/ Cu2O compressed composite. The study showed differing trends of wear at different temperatures.

Wear and Corrosion Properties of Cold Sprayed 420 Stainless Steel/WC-17Co Coating on Magnesium Alloy

Abstract: 420/WC-17Co coating was deposited on AZ80 magnesium alloy substrate by cold spraying technology. SEM was used to characterize the original powder morphology and coating microstructure. The microhardness and bonding strength of as-sprayed coating were tested by microhardness tester and universal material testing machine. Moreover, friction and wear property of the coating was also investigated by a ball-on-disk tribometer. Corrosion behaviours of coatings and magnesium alloy were characterized by electrochemical measurements. The results show that high quality 420/WC-17Co coating can be deposited on AZ80 magnesium alloy by cold spraying technology. The microhardness of cold sprayed 420/WC-17Co coating is (615 ± 62) HV, bonding strength is (57 ± 11) MPa and wear rate is only 3.3 × 10–6 mm3·N·m. The wear resistance of cold sprayed 420/WC-17Co coating is improved by two orders of magnitude, and the corrosion current density is reduced by one order of magnitude than magnesium alloy substrate. In conclusion, the present research demonstrates that cold sprayed 420/WC-17Co coating can significantly improve the surface performance of magnesium alloy substrate without evident heating output.