METAL MICROGRAPHY

The microscopic metallography (or metal micrography) studies metallurgical products, with the aid of a microscope, so as to determine their constituents and their texture. As a whole, this study is performed on previously polished surfaces, generally etched by a proper reagent.
Nowadays, metallography is regarded one of the most important analytical method to ensure the quality of the materials in the manufacturing process and also to conduct studies in the formation new alloys of materials. This practice becomes more complex because materials present different morphologies depending on the Heat Treatments applied as well as the chemical composition employed.
Currently, Labmat has a highly-skilled professional team who not only works on the interpretation of the expert reports but also provides clients with comprehensive support .

Intergranular corrosion takes place when there is a preferential path for corrosion in the region of the grain boundaries. We can observe that the grains outstand as the corrosion propagates. The main factor responsible for the difference in the corrosion resistance of the ground mass (material inside the grain) and of the material surrounding the boundary is the difference that is found in the chemical composition of these places. Therefore, even if the change in the chemical composition is not enough to fully eliminate the formation of the passive layer, it can be verified that there is a corrosion current due to the difference in potential caused by the different characteristics of materials.

Intergranular Corrosion Test according to Standard A 262 practice A.