The optical glass materials are used in various industries due their optical properties but these need to have an ultra-smooth surface to correctly work [1]. Although the polishing process is a common method for ultra-smooth surface creation, it may still cause damage in glass material [2]. The polishing process begins at nanoscale, hindering its evaluation in real time with experimental analyses, currently. Molecular Dynamic (MD) simulation is a powerful tool that permits to scrutinise the phenomena of the polishing at atomic scale in real time. The chemical reaction during the polishing is a key factor of this process. The reactive force-field (Reaxff) interatomic potential can simulate the physical and chemical phenomena [3]. For the fused silica (a-SiO2) optical glass materials, α-alumina (α-Al2O3) and ceria (CeO2) abrasives are usually employed in the polishing [2]. The influence of the grain chemical composition on a-SiO2 polishing in water at nanoscale in real time was studied with Reaxff-MD in this work. The simulation was made with vector movements (Horizontal and normal motion) with 45o penetration angle to assess the friction and normal force of the plastic transition. The material removal rate for ceria grain simulation was larger than that for α-Al2O3 grain simulation while the plastic transition normal, compression and tension stress force were lower. The chemical reactions during the polishing process weakened the fused silica materials. The highest chemical reactivity of the CeO2 weakened the a-SiO2 more than that of α-Al2O3. The polishing friction force was higher in the simulation carried out with CeO2 grain because of the larger material removal rate.

Refences

[1]. Rajaramakrishna R, Kaewkhao J. Glass material and their advanced applications. KnE Social Sciences. 2019;2019:kss. v3i18. 4769.

[2]. Suratwala TI, Steele WA, Wong LL, Tham GC, Destino JF, Miller PE, et al. Subsurface mechanical damage correlations after grinding of various optical materials. Optical Engineering. 2019;58(9):092604.

[3]. Liu J, Li X, Guo L, Zheng M, Han J, Yuan X, et al. Reaction analysis and visualization of ReaxFF molecular dynamics simulations. Journal of Molecular Graphics and Modelling. 2014;53:13-22.