Stereology define
![stereology define stereology define](https://i.ytimg.com/vi/0ybTVNLsVb0/maxresdefault.jpg)
If the crystal structure is non-cubic (e.g., a metal with a hexagonal-closed packed crystal structure, such as Ti or Zr) the microstructure can be revealed without etching using crossed polarized light (light microscopy).
Stereology define free#
Typically, a specimen is polished with a slurry of alumina, silica, or diamond on a napless cloth to produce a scratch-free mirror finish, free from smear, drag, or pull-outs and with minimal deformation remaining from the preparation process.Īfter polishing, certain microstructural constituents can be seen with the microscope, e.g., inclusions and nitrides. After grinding the specimen, polishing is performed. Generally, polishing with diamond suspension gives finer results than using silicon carbide papers (SiC papers), especially with revealing porosity, which silicon carbide paper sometimes "smear" over. Diamond grit in suspension might start at 9 micrometres and finish at one micrometre.
![stereology define stereology define](http://acronymsandslang.com/acronym_image/212/506e1d71ba5aee992ec84176b3f7fe2e.jpg)
Many metallographers, however, prefer to use a diamond grit suspension which is dosed onto a reusable fabric pad throughout the polishing process. Silicon carbide abrasive paper was the first method of grinding and is still used today. The specimen is successively ground with finer and finer abrasive media. Mounting a specimen provides a safe, standardized, and ergonomic way by which to hold a sample during the grinding and polishing operations.Īfter mounting, the specimen is wet ground to reveal the surface of the metal. When specimens are very sensitive to temperature, "cold mounts" may be made with a two-part epoxy resin. A typical mounting cycle will compress the specimen and mounting media to 4,000 psi (28 MPa) and heat to a temperature of 350 ☏ (177 ☌). In the past, phenolic thermosetting resins have been used, but modern epoxy is becoming more popular because reduced shrinkage during curing results in a better mount with superior edge retention.
![stereology define stereology define](https://www.mbfbioscience.com/sites/default/files/CL.png)
Metallographic specimens are typically "mounted" using a hot compression thermosetting resin. Different materials with similar properties ( hardness and ductility) will respond alike and thus require the same consumables during preparation. Sample preparation must therefore pursue rules which are suitable for most materials. Many different machines are available for doing this grinding and polishing, which are able to meet different demands for quality, capacity, and reproducibility.Ī systematic preparation method is the easiest way to achieve the true structure. Successively finer abrasive particles are used to remove material from the sample surface until the desired surface quality is achieved. Mechanical preparation is the most common preparation method. Using only metallographic techniques, a skilled technician can identify alloys and predict material properties.
![stereology define stereology define](https://www.stereology.info/wp-content/uploads/2013/10/number-picture_300dpi.png)
After preparation, it is often analyzed using optical or electron microscopy. The surface of a metallographic specimen is prepared by various methods of grinding, polishing, and etching. A single magnetic platen is positioned on the grinding and polishing machine to support the preparation pads. Example of a reusable pad for use with diamond suspension.