Challenges in the Metallographic Preparation of Brittle Materials and Ceramics

The preparation of both hard and brittle materials can present a challenge to even the most experienced metallographer. Avoiding fracture damage during sectioning and grinding stages can be particularly difficult. Damaged material can interfere with subsequent preparation stages and obscure the true structure. In addition, porosity analysis is a key measurement for many ceramic materials and some of these can be particularly difficult to prepare using traditional techniques. Surface preparation damage can be easily mistaken for porosity in granular structures and can also inhibit etching. Flatness may be difficult to control, making accurate feature measurement impossible. Sub-surface damage can create inaccuracy in mechanical testing such as indentation fracture toughness. Best practice recommendations are given both for how to recognize these problems and how to address them, for a variety of materials and for all stages of preparation from sectioning to analysis.