SAMPLE SURFACE POLISHING The goal of the surface polishing is to end up with a planar cross section. This process is a step-wise process that can be broken into three loosely separate parts: grinding, coarse polishing, and final polishing. Grinding, which is performed with an abrasive paper, is a firstly preparing sample step to ensure that a surface begin flat. A water-cooled abrasive grinder is available to form a flat initial surface from which to begin. The grinding should be start from the coarsest to the finest grit with a firm and uniform pressure. Rough and final polishing is performed with an Al2O3 abrasive particle suspended in water. It is a firstly step to ensure that a sample surface is flat. Apart from sample preparation, etching process (by acid solution) is also necessary for revealing a microstructure under optical microscope.