Yeoh Cheow Keat
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Preferred name
Yeoh Cheow Keat
Official Name
Cheow Keat, Yeoh
Alternative Name
Yeoh, C. K.
Yeoh, Cheow Keat
Yeoh, Cheow-Keat
Main Affiliation
Scopus Author ID
16231574200
Researcher ID
EGP-0633-2022

Research Output
Now showing 1 - 5 of 5
  • Publication
    A comparative study of microwave welding using multiwalled carbon nanotubes and silicon carbide nanowhiskers as microwave susceptors
    ( 2024-10)
    Phey Yee Foong
    ;
    Voon Chun Hong
    ;
    Lim Bee Ying
    ;
    Teh Pei Leng
    ;
    Yeoh Cheow Keat
    ;
    Mohd Afendi Rojan
    ;
    Nor Azizah Parmin
    ;
    Subash Chandra Bose Gopinath
    ;
    Foo Wah Low
    ;
    Muhammad Kashif
    ;
    Nor Azura Abdul Rahman
    ;
    Sam Sung Ting
    ;
    Veeradasan Perumal
    Recently, microwave welding has arisen as an advanced joining method due to its versatility and rapid heating capabilities. Among others, microwave susceptors play a crucial role in microwave welding, as different classes of microwave susceptors have distinct microwave heating mechanisms. In this work, polypropylene (PP) was utilized as a thermoplastic substrate and two types of microwaves susceptors, namely multiwalled carbon nanotubes (MWCNTs) and silicon carbide nanowhiskers (SiC NWs), were studied for microwave welding. The susceptor was first dispersed in acetone to form susceptor suspension. Next, the susceptor suspension was deposited onto the targeted area on substrate and paired with another bare PP substrate. The paired sample was then exposed to 800 W microwave radiation in a microwave oven. Afterward, the welded joint was evaluated using a tensile test and scanning electron microscopy to determine its joint strength and cross-section microstructure. The results showed that the joint strength increased as the heating duration increased. The welded joint formed using MWCNTs achieved a maximum strength of 2.26 MPa when 10 s was used, while the SiC NWs-formed welded joint achieved a maximum strength of 2.25 MPa at 15 s. This difference in duration in forming a complete welded joint can be attributed to the higher microwave heating rates and thermal conductivity of MWCNTs. However, increasing the heating duration to 20 s caused severe deformation at the welded joint and resulted in low joint strength. Overall, this study highlights the significance of understanding the microwave heating mechanism of different susceptors and provides essential insight into the selection of a microwave susceptor for microwave welding.
  • Publication
    Comparison study: The effect of unmodified and modified graphene nano-platelets (GNP) on the mechanical, thermal, and electrical performance of different types of GNP-filled materials
    ( 2021-09-01)
    Ka Wei K.
    ;
    Teh Pei Leng
    ;
    Yeoh Cheow Keat
    ;
    Hakimah Osman
    ;
    Sullivan M.
    ;
    Voon Chun Hong
    ;
    Lim Bee Ying
    ;
    Mohamad Syahmie Mohamad Rasidi
    Graphene nano-platelet (GNP) nano-fillers were successfully covalently functionalized with carboxylic and epoxide groups as proven by Fourier-transform infrared spectroscopy. This paper reports the effect of unmodified and modified GNP nano-fillers on the mechanical, thermal, and electrical performance of GNP-filled materials. The results show that the mechanical properties of GNP-filled materials were enhanced with a modified GNP nano-filler. Among the GNP-filled materials, the modified epoxy/NR/GNP compatibilized material shows higher flexural and toughness properties. The modified GNP nano-filler has reduced the thermal stability of the modified compatibilized material. This is because the oxygen-containing groups (C–O–C and –COOH) on the surfaces of modified GNP nano-fillers have lower thermal stability; which accelerates the thermal decomposition of the modified material. Modified compatibilized material shows higher electrical conductivity than the unmodified compatibilized material. X-ray diffraction results proved that d-spacing of modified GNP nano-fillers in modified compatibilized material was shortest when compared to unmodified GNP nano-fillers in unmodified compatibilized material, thus, allowing more electrons to travel at a faster rate through the conductive pathways.
  • Publication
    Microwave Welding of Thermoplastic using Silicon Carbide Nanowhiskers as Susceptor: Effect of Heating Duration
    ( 2024-06-01)
    Foong P.Y.
    ;
    Voon Chun Hong
    ;
    Lim Bee Ying
    ;
    Teh Pei Leng
    ;
    Yeoh Cheow Keat
    ;
    Mohd Afendi Rojan
    ;
    Nor Azizah Parmin
    ;
    Low F.W.
    ;
    Subash Chandra Bose Gopinath
    ;
    Kashif M.
    ;
    Rahman N.A.A.
    ;
    Sam Sung Ting
    ;
    Perumal V.
    Microwave welding is becoming more popular than conventional joining methods due to its advantages such as rapid and localised heating as well as applicable to components with complicated geometry. Previously reported susceptor, such as carbonaceous materials and conductive polymers, are toxic and the welding process involving these susceptors is time-consuming. Because of its exceptional microwave absorption and biocompatibility, silicon carbide nanowhiskers (SiCNWs) was employed as the microwave susceptor for microwave welding. Microwave welding in this study comprises of only three simple steps: SiCNWs suspension preparation, SiCNWs application and microwave heating. The weld strength of welded joint was then characterised using tensile test and energy dispersive x-ray spectroscopy equipped scanning electron microscopy (EDS-SEM) to study its mechanical properties and cross-section microstructure. The influence of microwave irradiation time was studied in this study, and it is found that the weld strength rose with the extension of microwave irradiation time, until a maximum weld strength of 1.61 MPa was achieved by 17 s welded joint. The development of SiCNWs reinforced PP nanocomposite welded joint layer is responsible for the enhanced weld strength. Prolonged heating duration may also result in flaws such as void formation at the welded joint, which subsequently lowered the weld strength to 0.60 MPa when the heating duration was extended to 20 s. In sum, a strengthen welded joint can be formed with rapid microwave heating under the proper control of heating duration.
      1
  • Publication
    Microwave welding of thermoplastic using silicon carbide nanowhiskers as susceptor effect of heating duration
    ( 2024-06)
    Phey Yee Foong
    ;
    Voon Chun Hong
    ;
    Lim Bee Ying
    ;
    Teh Pei Leng
    ;
    Yeoh Cheow Keat
    ;
    Mohd Afendi Rojan
    ;
    Nor Azizah Parmin
    ;
    Subash Chandra Bose Gopinath
    ;
    Foo Wah Low
    ;
    Muhammad Kashif
    ;
    Nor Azura Abdul Rahman
    ;
    Sam Sung Ting
    ;
    Veeradasan Perumal
    Microwave welding is becoming more popular than conventional joining methods due to its advantages such as rapid and localised heating as well as applicable to components with complicated geometry. Previously reported susceptor, such as carbonaceous materials and conductive polymers, are toxic and the welding process involving these susceptors is time-consuming. Because of its exceptional microwave absorption and biocompatibility, silicon carbide nanowhiskers (SiCNWs) was employed as the microwave susceptor for microwave welding. Microwave welding in this study comprises of only three simple steps: SiCNWs suspension preparation, SiCNWs application and microwave heating. The weld strength of welded joint was then characterised using tensile test and energy dispersive x-ray spectroscopy equipped scanning electron microscopy (EDS-SEM) to study its mechanical properties and cross-section microstructure. The influence of microwave irradiation time was studied in this study, and it is found that the weld strength rose with the extension of microwave irradiation time, until a maximum weld strength of 1.61 MPa was achieved by 17 s welded joint. The development of SiCNWs reinforced PP nanocomposite welded joint layer is responsible for the enhanced weld strength. Prolonged heating duration may also result in flaws such as void formation at the welded joint, which subsequently lowered the weld strength to 0.60 MPa when the heating duration was extended to 20 s. In sum, a strengthen welded joint can be formed with rapid microwave heating under the proper control of heating duration.
      3  24
  • Publication
    Effect of dispersing agents on the electrical and mechanical performance of GNPs filled epoxy nanocomposite
    ( 2023-07)
    Wong Wee Chun
    ;
    Teh Pei Leng
    ;
    Yeoh Cheow Keat
    ;
    Azlin Fazlina Osman
    ;
    Lim Bee Ying
    ;
    Mohamad Syahmie Mohamad Rasidi
    In this work, graphene nanoplatelets (GNPs) filled epoxy nanocomposites with the addition of different dispersing agents were fabricated using a method combines mechanical mixing and tip sonication. The loading of GNPs used is 0.8 vol% determined previously as the amount required to achieve the percolation threshold to conduct electricity. Three dispersing agents were used in this work: Sodium dodecyl sulphate (SDS), ethanol and Phenyl glycidyl ether (PGE), with loadings varying from 2 vol% to 10 vol%. The incorporation of dispersing agent enhanced the electrical bulk conductivity of GNPs filled nanocomposites. The mechanical performance (flexural properties and fracture toughness) of the nanocomposite were evaluated and compared. The optimum loading of SDS to obtain the highest flexural strength and fracture toughness is 2 vol%, where further increases will deteriorate the performance of nanocomposites. On the other hand, the optimum loading of ethanol and PGE are 4 vol%. The fracture toughness of GNPs filled nanocomposites improved with the addition of 2 vol% SDS and deteriorated with increasing loadings of SDS up to 10 vol%. By incorporating 4 vol% of ethanol, the optimum fracture toughness of the nanocomposite is achieved. Fracture toughness is then dropped with further increases in ethanol. The addition of PGE caused deterioration in fracture toughness of GNPs filled epoxy nanocomposite.
      1  6