Abstract

The frictional and wear performance of molybdenum disul=ide (MoS₂) is signi=icantly in=luenced by its intrinsic arrangement of crystals or crystallinity. In this study, we investigate the effect of crystallinty on coef=icient of friction (COF) and wear in MoS₂ using a suite of reactive molecular dynamics (MD) simulations. A range of con=igurations, from amorphous to crystalline, is modeled to capture the effect of structural order on the tribological behavior. To study friction and wear, we simulate the sliding of a spherical rigid carbon body over the MoS₂ surface under varying crystallinity conditions. Our results reveal a pronounced reduction in COF with decreasing crystallinity, with crystalline MoS₂ exhibiting superlubricity. This behavior is attributed to the preservation of a =lat sliding surface and frictional anisotropy, which enables lateral movement along low-resistance paths. In contrast, amorphous and polycrystalline MoS₂ with lower degrees of crystallinity displays a substantially higher COF, driven by increased surface roughness and atomic-scale energy dissipation. Furthermore, we examine the wear mechanisms under high normal loads, demonstrating that crystallinity enhances wear resistance by mitigating material deformation. These =indings provide atomic-scale insights into the tribological performance of MoS2, emphasizing the critical role of structural order in achieving ultralow friction. Our work corroborates with previous studies on superlubricity in MoS₂ and extends this understanding to rigid-body sliding conditions, offering valuable implications for designing low-friction and wear resistant solid lubricants.

Abstract

The frictional and wear performance of molybdenum disul=ide (MoS₂) is signi=icantly in=luenced by its intrinsic arrangement of crystals or crystallinity. In this study, we investigate the effect of crystallinty on coef=icient of friction (COF) and wear in MoS₂ using a suite of reactive molecular dynamics (MD) simulations. A range of con=igurations, from amorphous to crystalline, is modeled to capture the effect of structural order on the tribological behavior. To study friction and wear, we simulate the sliding of a spherical rigid carbon body over the MoS₂ surface under varying crystallinity conditions. Our results reveal a pronounced reduction in COF with decreasing crystallinity, with crystalline MoS₂ exhibiting superlubricity. This behavior is attributed to the preservation of a =lat sliding surface and frictional anisotropy, which enables lateral movement along low-resistance paths. In contrast, amorphous and polycrystalline MoS₂ with lower degrees of crystallinity displays a substantially higher COF, driven by increased surface roughness and atomic-scale energy dissipation. Furthermore, we examine the wear mechanisms under high normal loads, demonstrating that crystallinity enhances wear resistance by mitigating material deformation. These =indings provide atomic-scale insights into the tribological performance of MoS2, emphasizing the critical role of structural order in achieving ultralow friction. Our work corroborates with previous studies on superlubricity in MoS₂ and extends this understanding to rigid-body sliding conditions, offering valuable implications for designing low-friction and wear resistant solid lubricants.

Abstract

The frictional and wear performance of molybdenum disul=ide (MoS₂) is signi=icantly in=luenced by its intrinsic arrangement of crystals or crystallinity. In this study, we investigate the effect of crystallinty on coef=icient of friction (COF) and wear in MoS₂ using a suite of reactive molecular dynamics (MD) simulations. A range of con=igurations, from amorphous to crystalline, is modeled to capture the effect of structural order on the tribological behavior. To study friction and wear, we simulate the sliding of a spherical rigid carbon body over the MoS₂ surface under varying crystallinity conditions. Our results reveal a pronounced reduction in COF with decreasing crystallinity, with crystalline MoS₂ exhibiting superlubricity. This behavior is attributed to the preservation of a =lat sliding surface and frictional anisotropy, which enables lateral movement along low-resistance paths. In contrast, amorphous and polycrystalline MoS₂ with lower degrees of crystallinity displays a substantially higher COF, driven by increased surface roughness and atomic-scale energy dissipation. Furthermore, we examine the wear mechanisms under high normal loads, demonstrating that crystallinity enhances wear resistance by mitigating material deformation. These =indings provide atomic-scale insights into the tribological performance of MoS2, emphasizing the critical role of structural order in achieving ultralow friction. Our work corroborates with previous studies on superlubricity in MoS₂ and extends this understanding to rigid-body sliding conditions, offering valuable implications for designing low-friction and wear resistant solid lubricants.

Abstract

The frictional and wear performance of molybdenum disul=ide (MoS₂) is signi=icantly in=luenced by its intrinsic arrangement of crystals or crystallinity. In this study, we investigate the effect of crystallinty on coef=icient of friction (COF) and wear in MoS₂ using a suite of reactive molecular dynamics (MD) simulations. A range of con=igurations, from amorphous to crystalline, is modeled to capture the effect of structural order on the tribological behavior. To study friction and wear, we simulate the sliding of a spherical rigid carbon body over the MoS₂ surface under varying crystallinity conditions. Our results reveal a pronounced reduction in COF with decreasing crystallinity, with crystalline MoS₂ exhibiting superlubricity. This behavior is attributed to the preservation of a =lat sliding surface and frictional anisotropy, which enables lateral movement along low-resistance paths. In contrast, amorphous and polycrystalline MoS₂ with lower degrees of crystallinity displays a substantially higher COF, driven by increased surface roughness and atomic-scale energy dissipation. Furthermore, we examine the wear mechanisms under high normal loads, demonstrating that crystallinity enhances wear resistance by mitigating material deformation. These =indings provide atomic-scale insights into the tribological performance of MoS2, emphasizing the critical role of structural order in achieving ultralow friction. Our work corroborates with previous studies on superlubricity in MoS₂ and extends this understanding to rigid-body sliding conditions, offering valuable implications for designing low-friction and wear resistant solid lubricants.