A New Specimen Preparation Technique for Metallographic Evaluation of Lead and Lead Alloys

Abstract Preparation of lead and lead alloy specimens for metallographic examination is more difficult than preparation of the majority of other metals and their alloys. The troublesome difference is that lead and lead alloys are soft (lead has a Vickers hardness of 4-5 [1,2]), and therefore readily develop a cold-worked surface layer and disturbances in the subsurface layers during mechanical polishing. The specimen softness also allows embedding of the abrasive particles. If not removed, these mechanically introduced artifacts obscure the true structure of the specimen, and in some cases could develop a pseudostructure, especially if excessive frictional heat is involved [1]. Usually etchpolishing, consisting of cycles of alternately etching, polishing, and microscopic examination, is required to remove the above artifacts. This treatment either might not completely remove these artifacts or it might overetch the sample. In addition, etching could introduce its own artifacts, such as tarnishing, etching pits, or both.