Tribology in Malaysia: General perspective

Tribology was first coined in 1966 as documented in ‘Jost Report’. The word ‘tribology’ has since gained a common usage for matters related to friction, wear, and lubrication in machine in-teractions. Since tribology is an engineering issue that goes beyond national boundaries, many tribology societies have emerged across the continents partly motivated by the pursuit for green-er world via waste reduction. The move for improved tribology practices in industry has reached Malaysia and in 2007, Malaysian Tribology Society (MYTRIBOS) was established by local tribol-ogists [1]. MYTRIBOS is responsible to promote proper practices in research and development related to the field of tribology in Malaysia and to facilitate collaborations between academia and industry in all possible endeavors. MYTRIBOS eventual vision and mission is to help reduce en-ergy consumption by making machineries more energy efficient in order to reduce greenhouse gas emission. MYTRIBOS is contributing towards the improvement of the environment and to achieve a better quality of life and more sustainable world by creating awareness of the impor-tance of practicing proper tribology

Deformation–wear transition map of DLC coating under cyclic impactloading

A new deformation–wear transition map of hydrogen-free amorphous carbon coating(commonly known as Diamond-Like Carbon(DLC)coating)on tungsten high speed steel(SKH2)substrate under cyclic impact loading has been proposed to clarify the interactions of the operating parameters,deformation and wear. The study was carried out using an impact tester,under lubricated conditions over a wide range of impact cycles, and applied normal loads. SKH2 discs were coated with thin DLC films using a Physical Vapor Deposition (PVD) method. Tungsten (W) was used as an interlayer material. The DLC coated disc was impacted repeatedly by a chromium molybdenum steel(SCM420) pin. All impacttests were conducted at room temperature. It has been suggested that the deformation–wear transition map is an easy way to illustrate the impact wear mechanisms of DLC coating, as shown by its transition zones. Initially,the DLC coating only follows the plastic deformation of the substrate until several impact cycles. Then, a suppression of plastic deformation of the substrate is taking place due to the decreasing contact pressure with impact cycles to the yield point.Wear ofthe DLC coating becomes dominant when the critical limit of maximum normal impactload and impact cycles is exceeded. From experimental observations, some degradation ofthe DLC coating occurs within the wear zone

Phase transformation studies on the a-C coating under repetitive impacts

The phase transformation of hydrogen-free amorphous carbon (a-C) coating on tungsten high speed steel (SKH2) substrates under repetitive impact testing has been studied. The a-C coated disc was impacted by the chromium molybdenum steel (SCM420) pin at several different impact loads and impact cycles (up to 100,000) under lubricated conditions. The results show that the sp3 fractions of impacted a-C coating obtained from the surface of impact craters are significantly increased with impact cycles due to decreasing ID/IG ratio. This means that the amorphization of a-C coating also increased after several impact cycles. As for the full-width at half maximum (FWHM) of G peak characterization, it is shown that the hardness of impacted a-C coating is higher than the as-received. From the observation of surface roughness using atomic force microscopy (AFM), it is supposed that increasing sp3 fractions and the hardness of the impacted a-C coating during impact correlate to the reduction of surface roughness. In addition, the tribochemical reaction to the environment during impact occurred at the mating material, where the transfer layer adhered, as well as in the wear debris. This is due to the oxidation of ferrum (Fe) to magnetite (Fe3 O4) and hematite (α-Fe2 O3) phases with predominant peak at about 680 cm−1 and 1317 cm−1 , respectively. The formation of Fe3 O4 and α-Fe2 O3 phases was revealed from Raman spectroscopy and the existence of oxide elements was verified by energy dispersive X-ray spectroscopic (EDS) analysis. Increasing the G peak position, together with a concomitant decrease of their width, it is believed that the structural transformation from sp3 to sp2 is taking place within the wear debris and leads to the graphitization process at a higher contact pressure. It was suggested that the high contact pressure is not just only corresponding to the applied normal impact load, but it is also exerted by an oil lubricant during impact. A high contact pressure can significantly reduce the graphitization temperature and substantially accelerate the graphitization process. However, a significant phase transformation of the transfer layer on the SCM420 pin does not intensely occur because it is mainly coming from the surface layer of the impacted aC coating, where the sp3 content increases and no wear debris is observed inside it

Preliminary Design of Side Door Impact Beam for Passenger Cars using Aluminium Alloy

The growing demand for more fuel efficient vehicles to reduce energy consumption and air pollution provides a challenge for the automotive industry. The best way to increase fuel efficiency, without sacrificing safety, is to employ aluminium alloy within the body of cars, due to its higher strength to weight ratio than that of conventional steel. In this study, during the early design stage, structural modifications were studied using Finite Element Analysis (FEA), to determine a suitable cross-section shape for the side-door impact beam. The impact energy absorption characteristics of aluminium alloy and high-strength steel were investigated using a Charpy impact test. The fracture and surface contour of both materials were observed after impact testing. The preliminary results showed that a square hollow cross-section type was suitable for side-door impact beam use, due to its yield at the highest bending load. Both materials exhibited differential fractures and surface contours after impact testing, which directly indicates that aluminium alloy experienced a ductile fracture and had higher impact energy absorption than the high-strength steel

Proposal for hybrid passive cooling system of batteries In the electric car

This paper addresses the challenges faced by Electric Vehicle (EV) thermal management system and proposed a method to overcome them. Due to the non existence of internal combustion engine (ICE) in EV, the driving mechanisms of conventional cooling system need to be revamped. Therefore, in this paper a combination of liquid cooled, air cooled and phase change material (PCM) cooling system was introduced. The main heat dissipation from EV was identified coming from electric motor, battery module and the electronics controller and components. As this is a preliminary study, the reliability and sustainability of the system need to be further investigated. The investigation would include the, simulation and modeling of heat dissipated from the EV and also the cooling capacity of the proposed cooling system

Experimental Study on Friction and Wear Behaviors of Bearing Material under Gas Lubricated Conditions

Friction and wear behaviors of ball bearings made from carbon-chrome steel were experimentally simulated using a modified ball-on-disc tribometer. The test was performed over a broad range of applied loads (W), sliding velocities (v) and sliding distances (L) under gas lubricated conditions using a Taguchi method. The results found that gas blown to the sliding surfaces in air effectively reduced the coefficient of friction as compared with the air lubrication at higher applied load, sliding speed and sliding distance. In addition, a specific wear rate is constant throughout the tests under gas lubricated conditions. However, under air lubrication, the specific wear rate decreases with increasing applied load, sliding speed and sliding distance. By using the optimal design parameters, a confirmation test successfully verify the N2-gas lubrication reduced average coefficient of friction and simultaneously improved wear resistance about 24% and 50%, respectively. This is in accordance with a significant reduction of wear scar diameter and smoother worn surface on a ball

Effect of Lubrication Environments on Wear Performance of Ball Bearing Materials

From the past researches, wear of materials are effectively reduced by different gas lubrications. However, researches on this topic are not much explored. Thus, in this study, the wear performance of a ball bearing material sliding in air with O2- or N2-gas blows were investigated using a systematic approach, which is Taguchi method

Frictional behavior of bearing material under gas lubricated conditions

In this study, a Taguchi method is employed to determine statistically the optimal design parameters, and investigate the effect of gas lubrication on friction behavior of bearing material, which is carbon chromium steel. By selecting L9 Taguchi's orthogonal arrays, nine sliding tests were carried out in air, O2- and N2-gas lubrication in accordance with the ASTM standard G99-95a. The test was performed over a broad range of applied loads (W), sliding velocities (v) and sliding distances (L) using a ball-on-disc tribometer. At higher applied load, sliding speed and sliding distance, it was found that gas blown to the sliding surfaces in air effectively reduced the coefficient of friction as compared with the air lubrication. In addition, based upon the mean of signal-to-noise (SN) ratio analysis, the sliding speed is the most influencing factor for minimizing coefficient of friction. In this study, the optimal design parameters for a lower coefficient of friction () are: lubricant = N2, W = 10N, v = 1000rpm, L = 1km. By using the optimal design parameters, a confirmation test successfully verify the N2-gas lubrication reduced coefficient of friction by 24%. This is in accordance with a significant reduction of wear scar diameter and smoother worn surface on a ball

Pre-Materials Selection for Eco-Aware Lightweight Friction Material

In the automotive industry, non-asbestos based components, such as brake pads, have been in high demand due to environmental and human health concerns. Therefore, the purpose of this study is to design and select an alternative friction material, which is desired to eco-aware lightweight, cost effective, and non-toxic. This will be accomplished using Cambridge Engineering Selector (CES) Edupack software, embedded within an Eco-Audit Tool. The results show that Kenaf, which is a commodity plant in Malaysia, is the most suitable alternative friction material that passes all of the design stages and consumes less energy, compared to asbestos and other potential materials. Keywords