Mohd Fadzli Bin Abdollah

Tribological Study of a Tetrahedral Diamond-Like Carbon Coating under Vegetable Oil–Based Lubricated Condition

Maintaining a clean environment is the major concern of industries that produce fuel and lubricants for automotive applications. Thus, vegetable-based oils are being explored for the preparation of biobased lubricants because of their biodegradability and nontoxicity. Despite their low thermal stability, vegetable oils show better tribological characteristics than mineral oils. Nonetheless, the thermal stability of vegetable oils could be improved by transesterification. In this study, three vegetable-based oils (sunflower, palm, and coconut) were used to investigate the tribological properties of ta-C diamond-like carbon (DLC) coating under DLC–steel contact condition. A BICERI ball-on-a plate tribotesting machine was used to conduct experiments. During the experiment, test contacts of tribopairs lubricated with sunflower oil exhibited better tribological characteristics than those using coconut oil as a lubricant.

Effect of hexagonal boron nitride nanoparticles as an additive on the extreme pressure properties of engine oil

Purpose This paper aims to investigate the effect of hexagonal boron nitride (hBN) nanoparticles on extreme pressure (EP) properties when used as an additive in lubricating oil. Design/methodology/approach The nano-oil was prepared by dispersing an optimal composition of 0.5 vol. per cent of 70 nm hBN in SAE 15W-40 diesel engine oil using a sonication technique. The tribological testing was performed using a four-ball tribometer according to the ASTM standard. Findings It was found that the nano-oil has a potential to decelerate the seizure point on the contact surfaces, where higher EP can be obtained. More adhesive wear was observed on the worn surfaces of ball bearing lubricated with SAE 15W-40 diesel engine oil as compared with the nano-oil lubrication. Originality/value The results of the experimental studies demonstrated the potential of hBN as an additive for improving the load-carrying ability of lubricating oil.

Improving Engine Oil Properties by Dispersion of hBN/Al2O3 Nanoparticles

This paper provides oil properties study of conventional diesel engine oil enriched with hBN/Al2O3 nanoparticles. In this study, an optimal composition (0.5 vol.%) of hBN and Al2O3 nanoparticles separately dispersed in SAE 15W40 diesel engine oil by sonication technique. The oil properties were studied by measuring the Viscosity Index (VI), Total Acid Number (TAN), Total Base Number (TBN) and flash point temperature. The results reveal that the nano-oil with hBN nanoparticles could improves or at least maintain the key lubrication properties, though the TAN value is slightly increased. The results presented here may facilitate improvements in the conventional diesel engine oil performance.

The effect of dimple size on the tribological performances of a laser surface textured palm kernel activated carbon-epoxy composite

Purpose The purpose of this study is to investigate the effect of dimple size on the tribological performances of laser surface-textured palm kernel-activated carbon-epoxy (PKAC-E) composite. Design/methodology/approach A PKAC-E disc 74 mm in diameter was fabricated using the hot compression moulding technique. Five different types of surface contacts were prepared using a CO2 laser surface-texturing machine: a non-textured surface, and surfaces with dimples between 500 and 1,200 μm in diameter. The area density, contact ratio and depth were kept constant. A sliding test was carried out using a ball-on-disc tribometer under boundary lubricated conditions with constant sliding speed, sliding distance and applied load. Findings In general, the results showed that the friction coefficient decreased with an increasing dimple diameter of surface-textured PKAC-E composite. However, the appropriate dimple diameter for maintaining low friction coefficient is proposed in the range of 800 to 1,000 μm. Originality/value This is the first study, to the authors’ knowledge, to investigate the effects of dimple size, which is larger than 500 μm, on the tribological performances of laser surface-textured PKAC-E composite.

Effect of operating parameters and chemical treatment on the tribological performance of natural fiber composites: A review

ABSTRACT The demand for high-performance engineering products made from natural resources is increasing because of the low-cost, low-density, biodegradability, renewable nature and lighter than synthetic fibers. With these characteristics, the tribological performance of natural fiber composite has become an important element to be considered in most industrial and manufacturing functions. This paper presents an overview of the factors that influence the tribological performance of natural fiber composites, which include applied load, sliding distance, sliding velocity and fiber orientation. Influences of chemical treatment is also reviewed and illustrated through scanning electron microscope (SEM) observations. This review will focus on kenaf fibers (KFs) and oil palm fibers (OPFs) which have been widely exploited over the past few years among the available natural resources. The results show that the operating parameter, fiber orientation and chemical treatment has significant effects on the tribological performance of natural composite. A clear understanding of the factors that affect the tribological performance is very essential in performance improvement on natural fibers reinforced polymer composite for potential applications.

Frictional wear stability mechanisms of an activated carbon composite derived from palm kernel by phase transformation study

Purpose The purpose of this paper is to investigate the mechanisms of frictional wear stability of an activated carbon composite derived from palm kernel using phase transformation study. Design/methodology/approach The unlubricated sliding test was executed using a ball-on-disc tribometer at different loads with a constant speed, sliding distance and temperature. Findings Results of this paper suggest that stability of friction and wear of the test materials are primarily due to the phase transformation of the composite surface layer. Research limitations/implications However, the effectiveness of the transfer layer as a medium for low friction and wear is only limited at certain applied loads. Originality/value This is the first study, to the authors’ knowledge, to find out the mechanisms of low frictional wear properties of an activated carbon composite derived from palm kernel using phase transformation study.

A brief review on the wear mechanisms and interfaces of carbon based materials

Abstract The demand for reducing wear and friction has become the chief aim in the automotive industry nowadays. The usage of lubricant is not considered enough as there is still room for improvements. As a solution, much research has arisen towards what we called self-lubricating ideas, in order to reduce friction better than lubricant. This paper presents an overview wear mechanism and the interface of carbon-based materials. This paper will also discuss the interfaces by carbon as substrate and coating layer. The findings show that for metals, the predominant wear mechanisms were abrasion and fatigue. Meanwhile, for polymers and coating (DLC), they were abrasive along with adhesive wear. The surface roughness of the substrate plays a crucial role in increasing the excellent performance of the DLC coating. The interfaces of carbon elements definitely give huge impact on both self-lubricant materials and coatings where the coefficient of friction and wear rate changes drastically even with 1 wt.% addition. Nevertheless, a clear understanding of the factors that affect the tribological performance is very essential in performance improvement for potential applications.

Statistical models for predicting wear and friction coefficient of palm kernel activated carbon-epoxy composite using the ANOVA

Purpose The purpose of this study was to propose statistical models for predicting wear and friction coefficient of the palm kernel activated carbon-epoxy composite using the analysis of variance (ANOVA). Design/methodology/approach All the specimens were formed into 10-mm diameter pins of 30-mm length each. The tribological test was conducted using a pin-on-disc tribometer. The results of the coefficient of friction (COF) and the wear rate were then analysed using the ANOVA. Regression analysis was used to derive the predictive equations for both friction coefficient and wear rate. Findings It was found that the most significant parameter that affects the COF is the weight composition, while for the wear rate, it is the operating temperature. The proposed statistical models have 90-94 per cent reliability. Research limitations/implications The equation models are only limited within the tested parameters and ranges in the plastic deformation region. Originality/value These models can be very useful for material design engineers in avoiding the component failures occurring prematurely.

Optimization of friction properties of kenaf polymer composite as an alternative friction material

Purpose The aim of this study is to determine the optimal parameters for friction coefficient of kenaf/epoxy (KE) composite as an alternative friction material. Design/methodology/approach The design of experiment was constructed using the Taguchi method. KE specimens were formed into 10 mm diameter pins using hot compression technique with different types, weight concentrations and treatments of kenaf. The samples were tested using a pin-on-disc tribometer at different applied loads, speeds and operating temperatures with a constant sliding distance of 3 km under dry sliding conditions. Findings The sample with 45 wt.% of non-treated kenaf fibre, tested at 19.62 N, 500 rpm and 100°C was found to be the optimized combination to obtain higher friction. From the confirmation test, the experimental friction coefficient is acceptable because of fall within 95 per cent confidence interval. Predominant wear mechanisms are identified as micro-crack and debonding of fibre. Originality/value KE composite can be considered as an alternative friction material, as the tested friction coefficient is within the suggested range for the friction material applications.

Tribological effects of nano-based engine oil diluted with biodiesel fuel

The aim of this study was to investigate the tribological effects of nano-based engine oil diluted with biodiesel fuel. The nano-oil was prepared by disperse an optimal composition 0.5 vol.% of 70 nm hexagonal boron nitride (hBN) nanoparticles in diesel engine oil using sonication technique. Sample was diluted by difference percentages of B100 biodiesel fuel in range of 5-20 vol.%. The tribological test was performed using a four-ball tribometer. It was found that the addition of biodiesel fuel increases the coefficient of friction (COF) and seizure wears as compared with nano-oil. However, there is no significant effect on the extreme pressure (EP) properties, where the seizure for all tested samples starts to occur at 981 N.