Anodizing refers to conversion coating of the surface of aluminum and its alloys to porous aluminum oxide. This article provides the reasons for performing anodizing and discusses the three principal types of anodizing processes, namely, chromic acid process, sulfuric acid process, and hard anodic process. It describes the limitations imposed by variables, such as alloy composition, surface finish, prior processing, temper or heat treatment, and the use of inserts, on the anodizing processes. The article explains the causes and means adopted for correcting several specific problems in anodizing aluminum. It also discusses the process control techniques and equipment used for anodizing. The article reviews the sealing processes for anodic coatings and the method for coloring the coatings. It concludes with a discussion on the effects of anodic coatings on the surface and mechanical properties of aluminum and its alloys.

This article presents a brief history and the uses of the anodic protection technique. It compares anodic and cathodic protection and describes the design considerations of the anodic protection system. The article discusses the specific requirements of equipment required for anodic protection. It also explains the applications and economic aspects of anodic protection, with examples.

The high-temperature corrosion processes that are most frequently responsible for the degradation of furnace accessories are oxidation, carburization, decarburization, sulfidation, molten-salt corrosion, and molten-metal corrosion. This article discusses each corrosion process, along with the corrosion behavior of important engineering alloys. It describes the corrosion of plating, anodizing, and parts of pickling equipment such as tanks, wirings and bus bars, racks, anode splines, pumps, and heaters.

Selective plating, also known as brush plating, differs from traditional tank or bath plating in that the workpiece is not immersed in a plating solution (electrolyte). Instead, the electrolyte is brought to the part and applied by a handheld anode or stylus, which incorporates an absorbent wrapping for applying the solution to the workpiece (cathode). This article focuses on the selective plating systems that include a power pack, plating tools, anode covers, specially formulated plating solutions, and any auxiliary equipment required for the particular application. It provides a detailed account of the applications of selective plating, with examples. The article describes the advantages, limitations, key process elements, and health and safety considerations of selective plating. It also includes the most important industrial, government, and military specifications.

Tantalum is one of the most versatile corrosion-resistant metals known. The outstanding corrosion resistance and inertness of tantalum are attributed to a very thin, impervious, protective oxide film that forms on exposure of the metal to slightly anodic or oxidizing conditions. This article provides a discussion on the mechanism of corrosion resistance and on the behavior of tantalum in different corrosive environments, namely, acids; salts; organic compounds; reagents, foods, and pharmaceuticals; body fluids and tissues; and gases. It contains several tables that summarize the effects of acids, salts, and miscellaneous corrosive reagents on tantalum and applications for tantalum equipment in chemical, pharmaceutical, and other industries. Finally, the article presents a discussion on hydrogen embrittlement, the galvanic effects, and cathodic protection of tantalum and describes the corrosion resistance of different types of tantalum-base alloys.

Electrodeposits of cadmium are used to protect steel and cast iron against corrosion. This article provides an overview of the surface preparation of, and brighteners used in, cyanide baths. It focuses on the anode system, current density, deposition rates, and bath temperature of cadmium plating with attention to the materials of construction and equipment used. The article provides a description of the selection of plating method with examples, applications, and several postplating processes of cadmium plating.

Mechanical finishes usually can be applied to aluminum using the same equipment used for other metals. This article describes the two types of grinding used in mechanical finishing: abrasive belt grinding and abrasive wheel grinding. It reviews the binders and fluid carriers used in buffing, and discusses satin finishing and barrel finishing. It also describes lapping and honing techniques that are of special interest in treating aluminum parts that have received hard anodic coatings. Honing recommendations for aluminum alloys are presented in a table.

Lead has been deposited from a variety of electrolytes, including fluoborates, fluosilicates, sulfamates, and methane sulfonic acid baths. This article provides a discussion on these electrolytic baths and includes information on the process sequence, equipment requirements, and applications of lead plating.

Pulsed-current plating can be defined simply as metal deposition by pulsed electrolysis, which involves using interrupted direct current to electroplate parts. This article discusses the advantages and limitations of pulsed-current plating and provides information on the process principles and control, solution composition, operating conditions, and necessary equipment modifications.

Electrodeposition of tin alloys is used to protect steel against corrosion or wear, to impart resistance to etching, and to facilitate soldering. This article focuses on the compositions, operating conditions, advantages, and limitations of methane sulfonic acid plating solutions and fluoborate plating solutions for tin-lead. It briefly describes the solution compositions and operating conditions of tin-bismuth, tin-nickel, and tin-zinc.

This article provides a detailed account of the various alkaline and acid plating baths used for electrolytic copper plating. Dilute cyanide and Rochelle cyanide baths, high-efficiency sodium and potassium cyanide baths, alkaline noncyanide copper plating baths, and alkaline copper pyrophosphate baths, are discussed. The article reviews acid plating baths such as copper sulfate bath and copper fluoborate bath. It also presents information on the surface preparation considerations, bath composition, and operating variables of copper plating as well as the equipment used.

Copper alloys are widely used as electroplated coatings. They can also be used with practically any substrate material that is suitable for electroplating. This article focuses on the solution composition and operating conditions for brass and bronze plating solutions. It describes the decorative and engineering applications of brass and bronze plating. The article also provides information on the treatment of waste water from brass and bronze plating operations.

The major benefit of the implementation of the corrosion-control technologies at Army installations is the extension of the service life of buildings and other structures. This article reviews the exposure of military facilities and equipment to a wide variety of environmental conditions, including soils, waters, or atmospheres of varying corrosivity. It presents the case studies illustrating typical examples of the types of corrosion problems found on military installations. The article describes the various corrosion-control technologies used in military facilities. These include protective coatings and linings, cathodic protection, advanced materials selection and design, water treatment, equipment inspection and monitoring, and below-grade moisture mitigation.

The necessary precursor to a proper and durable finish is the preparation of the active aluminum surface to receive the desired protective finish that will allow it to have a long and attractive service life. This article helps those who work with aluminum in the many varieties of applications of such products. It describes the two main categories of cleaning that can be used with most any metal, namely, mechanical cleaning and chemical cleaning. The article provides a discussion on the laboratory evaluation of cleaners, field testing of cleaners, and cleaner types and procedures. It also describes the special cleaning procedures for aluminum alloys, such as steam cleaning and rotary wire-brush cleaning. The article reviews the use of temporary coatings and the use of maintenance coatings on aluminum. It provides information on the handling and storage procedures of aluminum alloys and the cleaning of specific applications of aluminum.

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.

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.

A tin deposit provides sacrificial protection to copper, nickel, and many other nonferrous metals and alloys. Tin also provides good protection to steel. Tin can be deposited from either alkaline or acid electrolytes. This article explains the compositions and operating conditions of these electrolytes.