Search Results for etching

Etching aluminum can be a pretreatment step for anodizing, chemical conversion coating, metal-to-rubber bonding, and a host of other processes. Chemical etching, using either alkaline or acid solutions, produces a matte finish on aluminum products. This article describes the alkaline etching and acid etching of aluminum. Alkaline etching reduces or eliminates surface scratches, nicks, extrusion die lines, and other imperfections. Acid etching can be done without heavy smut problems, particularly on aluminum die castings. Hydrochloric, hydrofluoric, nitric, phosphoric, chromic, and sulfuric acids are used in acid etching. The article presents a flow chart of the operations used in acid etching.

Metallographic contrasting methods include various electrochemical, optical, and physical etching techniques, which in turn are enhanced by the formation of a thin transparent film on the specimen surface. This article primarily discusses etching in conjunction with light microscopy and describes several methods for film formation, namely, heat tinting, color etching, anodizing, potentiostatic etching, vapor deposition, and film deposition by sputtering. It provides information on the general procedures and precautions for etchants and reagents used in metallographic microetching, macroetching, electropolishing, chemical polishing, and other similar operations.