Metal Materials and Metallography Lab.

This laboratory is used to prepare samples for microstructural analysis. The sample to be examined is cut to specific dimensions using a precision cutting device, then placed in a mold using either a hot bakelite device or cold bakelite equipment. Afterward, the samples are then subjected to grinding and polishing processes. If the sample is of a hand-holdable size, it can be ground and polished without molding. During the grinding process, samples are abraded from the coarsest to the finest abrasives, minimizing surface scratches. SiC paper or diamond abrasives are typically used in the grinding process. The samples are then passed through various abrasive grades under continuous running water before proceeding to the polishing step. In this process, polishing cloths of specific sizes (such as 6, 3, 1, and 0.25 µm) are used, along with liquids such as diamond paste, alumina paste, and colloidal silica. Polishing is performed on cloths fixed to rotating discs used in the grinding device. Once the sample surface is completely scratch-free and shiny, the etching process begins, if necessary. Once the necessary etching solutions have been prepared, the etched samples, or simply polished samples, can be examined using an optical microscope, and microstructure photographs can be taken of specific areas if desired.