Polishing cloths from Denmark-based Akasel have a layer of water, ethanol and oil resistant polymer barrier attached to the cloth to protect against wear. Additionally, glue keeps the polishing cloth securely attached. There are various types of polishing cloth available for diamond polishing.
If there are any scratches on the material following the polishing process, the polishing cloth may be contaminated. Contamination can come from foreign substances as well as particles from earlier stages in the sample preparation process. It may be possible to clean the debris from the cloth with lukewarm water. Once the cloth has dried, it can be reused. It is also essential the surface of the sample is not contaminated; debris may become trapped in a mounting gap.
There are a multitude of materials used for polishing cloths, such as nylon, polyester, silk, acetate, foam, and wool. Silk polishing cloths, for example, are used in the fine grinding of ferrous metals, as well as polishing. Chemal, on the other hand, sourced from synthetic foam is ideal for chemical final polishing of materials involving oxide suspension.
Why is polishing a stage in metallography?
The sample preparation stages included sectioning, cutting, mounting, grinding, and finally polishing. All these stages must occur prior to microscopic observation, imaging, and documentation of quantitative data.
Metal polishing is essential for deformation removal and the production of a reflective surface that allows for examination under a microscope. Polishing generally involves polishing cloths and finer abrasives.
The overall goals of sample preparation are retaining structural elements, a surface free of scratches and deformation, no foreign particles on the surface or within the mould, a highly reflective surface and a process that can be replicated exactly. Beyond metallography, polishing processes can also be used to restore the appearances of particular metal components on vehicles, cookware, architectural metal and so forth.