Meaning
Standardized specimen preparation procedures outline the sequential steps of grinding, polishing, and etching required to expose the true microstructure of metals for analysis. This protocol, designated as ASTM E3, prevents the alteration of surface features by minimizing deformation and scratching during cutting and mounting operations. It provides the base method for inspecting welds, battery terminal connections, and current collectors.
Metallographic Preparation
The process begins with securing the sample in a mounting resin to protect fragile edges, followed by progressive grinding with silicon carbide papers. High-purity alumina or diamond suspensions are then applied on polishing cloths to achieve a mirror finish. This step is followed by chemical etching when the grain structure of terminal welds or tab joins must be revealed for quality audit.
Sourcing Standard
Quality agreements for cell terminal welds often mandate inspection protocols that comply with these preparation standards to ensure weld depth measurements are accurate. Inaccurate sample preparation can smear soft copper or aluminum layers, hiding defects or cracks from the inspection microscope. Suppliers must present polished cross-sections processed under these guidelines to prove the structural integrity of the electrical joints.
Material Limit
Very soft or ductile metals like raw lithium foils require alternative preparation methods because standard abrasive polishing causes excessive deformation. Such active materials must be processed in an inert gas glovebox.
