Mechanism of material removal during nanofinishing of aluminium in aqueous KOH: A reactive molecular dynamics simulation study

In this work, the atomic mechanism of tribo-chemical wear of aluminium at the interface of Si-Al in aqueous KOH environment was investigated using a reactive molecular dynamics simulation (R-MDS) for achieving nano-finished surface using the principle of chemically assisted mechanical finishing (CMAF) through chemo mechanical magnetorheological finishing (CMMRF) process. Three attributes of material removal mechanisms were detected in the finishing process. The first is caused by the destruction of parent bonds on the aluminium substrate surface and is assisted by the oxidation. The second is caused by the mechanical stress assisted chemical reaction to bridge new bonds between abrasive and workpiece. The third is caused by rupture of Al-Al bonds, as the newly formed bonds are relatively strong. This work shows that the removal of Al atoms from the substrate is a result of both chemical reaction and mechanical effects, and contributes to the understanding of tribo-chemical wear behaviour of CMMRF process. The finished surface shows free of any other contamination which is suitable to employ such surfaces for the micro-electronics fabrication. Experimental results also support the mechanism of CAMF for generating the surface finish of the order of few nanometers.