What is Metallurgical Analysis in  Sample Preparation

Metallurgical Sample Preparation Using SEM and Optical Magnification

Precision sample preparation, also known as metallographic specimen preparation, is an essential step in performing accurate metallurgical testing. This type of testing often entails examining the material’s microstructure using optical magnification or scanning electron microscopy (SEM). To obtain clear images, it is crucial that all microscopy sample preparation, including SEM sample preparation, be done correctly and thoroughly.

Method

When preparing metallographic specimens or metallurgical samples, several steps must be taken. It is important to select a representative sample of the material to accurately define the microstructure or characteristics of interest. Depending on the test, the sample must be cut into sections to prevent altering the material’s structure. It is essential to use lubrication or coolant to keep the sample cold when using an abrasive saw. Then, the specimen must be mounted in plastic or epoxy to facilitate handling during grinding and polishing. A water-lubricated abrasive wheel is used to grind the sample to create a flat, smooth, and scratch-free surface. A sequence of increasingly finer abrasive grits is used throughout the process. The polishing stage removes the final thin layer of deformed metal to create a flat reflecting surface. This produces a sample that is now ready to be examined for features that have not been etched, such as inclusion content or porosity. The microstructural details of the test sample can be highlighted by etching it in an appropriate acidic or basic solution as the final step.