Chemical brightening (bright dipping) and electrolytic brightening (electropolishing) are essentially selective-dissolution processes, in which the high points of a rough surface of aluminum are attacked more rapidly than the depressions, and the peaks and valleys are smoothed to produce a bright and beautiful finish. This article discusses the metallurgical factors, optical factors, and applications of the chemical and electrolytic brightening. It compares the chemical brightening and electrolytic brightening, and presents the advantages of the chemical and electrolytic brightening processes in terms of performance and economy. The article describes the phosphoric-nitric acid baths and phosphoric-sulfuric acid baths used for chemical brightening. Solution compositions and operating conditions for three commercial electropolishing processes, as well as for suitable post-treatments, are presented in a table.

This article is a comprehensive collection of tables listing: dangerous reactions of chemicals and designations of etchants; chemical-polishing solutions for irons and steels and nonferrous materials; attack-polishing solutions, macrostructure etchants for iron and steel; and major microstructure etchants for common phases and constituents in ferrous materials.

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.

Metallographic preparation of a material involves the elimination of artifacts or scratches from fine polishing and may be achieved by methods such as attack polishing, vibratory polishing, chemical polishing, electrolytic polishing, and electromechanical polishing. This article discusses the mechanism, operating procedure, advantages, and limitations of chemical and electrolytic polishing of samples for metallographic preparation. It provides information on the specimen preparation, apparatus used, and safety precautions to be followed during the polishing process. The various groups of electrolytes used in electropolishing of several metals and alloys are reviewed. The article concludes with a discussion on local electropolishing.

This article describes the methods and equipments involved in the preparation of specimens for examination by light optical microscopy, scanning electron microscopy, electron microprobe analysis for microindentation hardness testing, and for quantification of microstructural parameters, either manually or by the use of image analyzers. Preparation of metallographic specimens generally requires five major operations: sectioning, mounting, grinding, chemical polishing, and etching. The article provides information on the principles of technique selection in mechanical polishing, and describes the procedures, advantages, and disadvantages of electrolytic and chemical polishing. It also provides a detailed account of procedures, precautions, and composition for preparation and handling of etchants.

Aluminum or aluminum alloy products have various types of finishes applied to their surfaces to enhance appearance or improve functional properties. This article discusses the procedures, considerations, and applications of various methods employed in the cleaning, finishing, and coating of aluminum. These include abrasive blast cleaning, barrel finishing, polishing, buffing, satin finishing, chemical cleaning, chemical brightening, electrolytic brightening, chemical etching, alkaline etching, acid etching, chemical conversion coating, electroplating, immersion plating, electroless plating, porcelain enameling, and shot peening.