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Author: search.filters.author.Oungpakornkaew, PitchapornSubject: search.filters.subject.Wear mechanism

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    Impact of soot nanoparticle size and quantity on four-ball steel wear characteristics using EDS, XRD and electron microscopy image analysis
    (2022-01-01)
    Karin, Preechar
    ;
    Chammana, Pattara
    ;
    Oungpakornkaew, Pitchaporn
    ;
    Rungsritanapaisan, Panyakorn
    ;
    Amornprapa, Warawut
    The effect of soot contamination on the tribological performance of engine oil was investigated. Carbon black is introduced to simplify diesel engine soot contamination. Besides, the tribological performance issue is verified by a four-ball tribometer. The steel ball worn surfaces were studied by Scanning Electron Microscopy (SEM), Optical Microscope (OM) and Energy Dispersive X-ray spectroscopy (EDX). In addition, Transmission Electron Microscopy (TEM) was used to investigate the morphology and nanostructure of soot and carbon black. According to the four ball test results, the average wear scar diameter of steel ball tested with engine oil blended with N220, N330, N550 and N660 by 1% by weight is larger than that of pure engine oil by 26%, 38%, 41%, and 39%, respectively. The wear scar diameter tends to increase after blended larger size of carbon black particle. The steel balls tested with formulated engine oil without soot contamination and with soot contamination by 0.5 wt%, 1 wt%, and 2 wt% have average wear scar diameters of 621, 567, 784 and 894 nm, respectively. On the other hand, wear scar roughness of steel balls tested with formulated engine oil without soot contamination and with soot contamination by 0.5 wt%, 1 wt%, and 2 wt% were 2.28, 0.25, 1.49 and 1.76 μm, respectively. Consequently, quantity of the soot nanoparticle approximately 0.5% by mass in engine oil significantly plays an important role in steel ball wear scar diameter and surface roughness reduction. Moreover, the agglomerated soot which is larger than the oil film thickness might block the lubricant from entering the contact. It leads to the breakdown of the oil film thickness resulting in increasing adhesive wear on the worn surface.
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    Characterization of biodiesel and soot contamination on four-ball wear mechanisms using electron microscopy and confocal laser scanning microscopy
    (2020-10-15)
    Oungpakornkaew, Pitchaporn
    ;
    Karin, Preechar
    ;
    Tongsri, Ruangdaj
    ;
    Hanamura, Katsunori
    Utilization of biodiesel as an alternative fuel has been increasing nowadays in term of quantity and ratio of bio-resource derived esters from B7 to B100. The tribological characteristic due to biodiesel application has been more interesting. Not only fuel dilution but also soot contamination in engine oil must be taken into account for the effect to the engine wear. This research employed carbon black as soot model and B7, B20 and B100 as contaminated fuel. Two blended grades of diesel engine oils (API CI-4 and CK4) were tested by a four-ball wear tester. Scanning electron microscopy (SEM) was used to investigate the wear characteristic. Three-dimensional images of wear scars and surface roughness were observed from confocal microscopy technique. The result shows that CK-4 has greater anti-wear performance and can maintain the lubricating performance when the oil is contaminated. For CI-4 cases, soot contamination causes increasing wear, but biodiesel fuel dilution shows wear reduction.