Investigation On The Effect Of Monolayer Graphene On Tribological Behavior Of Soda Lime Glass

Soda-lime-glass(SLG)is widely used in fields such as construction,medical,photovoltaic,instrumentation,and nuclear engineering.During manufacturing,transportation,installation,and use,the glass surface inevitably undergoes physical contact processes,such as indentation,friction/shear,and wear,which cause surface and subsurface damage to the glass material,thereby affecting its mechanical and tribological properties.Many studies have improved the mechanical and chemical properties of glass materials by forming a surface layer with high compressive stress on the glass surface through thermal strengthening(tempering or quenching)and chemical strengthening(ion exchange).However,thermally strengthened glass exhibits lower scratch resistance and more debris in scratch tests,while ion-exchanged glass does not enhance mechanical-chemical wear in humid air.In this thesis,the influence of graphene on the mechanical properties of soda-lime-glass(SLG)surfaces and the mechanism of graphene-enhanced resistance to deformation in SLG glass are studied through nanoindentation and Vickers hardness testing.The effect of graphene on the deformation of the SLG glass surface and subsurface under frictional shear is investigated by experimental means such as nanoscratch testing and annealing,revealing the mechanism by which graphene affects surface deformation and subsurface damage of SLG glass.Based on the above research,the main conclusions of this thesis are as follows:(1)Under macro conditions,the Vickers hardness of both SLG and G/SLG(graphene/soda-lime)glass surfaces is not dependent on the load.Compared to the SLG glass surface,the Vickers hardness of the G/SLG glass surface is slightly higher,with a lower probability of crack initiation and increased fracture toughness.The reduction in crack initiation probability in G/SLG glass indicates that the graphene film inhibits radial crack propagation to some extent.Under micro conditions,the mechanical properties of soda lime glass glass are significantly enhanced by a single layer of graphene compared to macro conditions.Under the same normal load,the G/SLG glass surface has a higher hardness and elastic modulus than the SLG glass surface.Compared to SLG glass,the plastic deformation of G/SLG glass is slightly reduced.Research shows that the G/SLG glass surface can absorb more strain energy through an elastic process.Therefore,the proportion of elastic energy dissipated during nanoindentation is higher in G/SLG glass than in SLG glass.(2)Frictional behavior of monolayer graphene on soda lime glass glass surface was studied by nanoscratch experiments.Under given conditions,the wear amount of G/SLG glass was reduced by about 30%～44%compared to SLG glass,while the pile-up height increased by about 33%～46%.The modified Arrhenius kinetic model showed that the activation volumes of G/SLG and SLG glasses were 58.56?~3 and 65.05?~3,respectively.The lower activation volume and friction of G/SLG glass were the main reasons for its mechanical chemical wear resistance being lower than that of SLG glass.In addition,the subsurface deformation behavior of nanoindentation and nanoscratch was quantitatively analyzed in combination with annealing.The recovery rate of G/SLG glass after annealing(～56%)was lower than that of SLG glass(～64%).The study showed that the shear stress diffused to the subsurface was the direct cause of densification of the subsurface of soda lime glass glass.Graphene can promote interfacial shear,so during the nano-indentation test,graphene promoted the plastic flow of glass material along the sidewall of diamond probe,resulting in more plastic flow in G/SLG glass than in SLG glass.