Zirconium and hafnium surfaces require cleaning and finishing for reasons such as preparation for joining, heat treatment, plating, forming, and producing final surface finishes. This article provides information on various surface treatment processes, surface soil removal, blast cleaning, chemical descaling, pickling or etching, anodizing, autoclaving, polishing, buffing, vapor phase nitriding, and electroplating. Applications of these surface treatment processes are also reviewed.

Metal surfaces must often be cleaned before subsequent operations to remove unwanted substances such as pigmented drawing compounds, unpigmented oil and grease, chips and cutting fluids, polishing and buffing compounds, rust and scale, and miscellaneous contaminants. The article describes common cleaning processes, including alkaline, electrolytic, solvent, emulsion, molten salt bath, ultrasonic and acid cleaning as well as pickling and abrasive blasting. It also explains how to select the appropriate process for a given soil type and surface composition.

Alkaline cleaning is a commonly used method for removing a wide variety of soils from the surface of metals. This article focuses on the composition, operating conditions, and test and control of alkaline cleaners, as well as equipment used and their application methods. It describes the mechanisms of alkaline cleaning, such as saponification, displacement, emulsification and dispersion, and metal oxide dissolution. The article concludes with information of the safety and environmental considerations in the usage of alkaline cleaners.

This article reviews cleaning and finishing operations that have proven to be effective on titanium, its alloys, and semi-fabricated titanium products. It explains how to remove scale, tarnish films, grease, and other soils and how to achieve required finishes and/or improve wear and oxidation resistance through the use of polishing, buffing, and wire brushing operations. The article also covers a wide range of surface modification and coating processes, including ion implantation, diffusion, chemical and physical vapor deposition, plating, anodizing, and chemical conversion coatings as well as sprayed and sol-gel coatings and laser and electron-beam treatments.

This article describes the basic attributes of the most widely used metal surface cleaning processes to remove pigmented drawing compounds, unpigmented oil and grease, chips, cutting fluids, polishing and buffing compounds, rust and scale from steel parts, and residues and lapping compounds from magnetic particle and fluorescent penetrant inspection. The cleaning processes include emulsion cleaning, electrolytic alkaline cleaning, acid cleaning, solvent cleaning, vapor degreasing, alkaline cleaning, ultrasonic cleaning, and glass bead cleaning. The article provides guidelines for choosing an appropriate process for particular applications and discusses eight well-known methods for determining the degree of cleanliness of the work surface.

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.

This article provides an overview of surface contaminants that may affect the heat treatment processes and end-product quality. It presents information on the chemicals used to clean different surface contaminants of steels. The article discusses three types of cleaning methods, namely, mechanical, chemical, and electrochemical and their effectiveness and applicability. The mechanical cleaning methods include grinding, brushing, steam or flame jet cleaning, abrasive blasting, and tumbling. Solvent cleaning, emulsion cleaning, alkaline cleaning, acid cleaning, pickling, and descaling are chemical cleaning methods. The electrochemical cleaning methods include electropolishing, electrolytic alkaline cleaning, and electrolytic pickling. The article provides information on cleanliness measurement methods such as qualitative tests and quantitative tests to ensure product quality. Health hazards that may be associated with each cleaning method and the general control measures to be used for each hazard are tabulated.

Solvent cleaning is a surface preparation process that can be accomplished in room temperature baths (cold cleaning ) or by condensing vapors of a solvent on a workpiece (vapor degreasing). This article provides a detailed discussion on solvents, equipment, process limitations and applications, and safety and health hazards of cold cleaning and vapor degreasing. It also includes information on control of contamination, conservation and recovery of solvent, and disposal of solvent wastes.

Emulsion cleaning is an industrial cleaning process that uses an organic solvent as the main active agent. This article provides information on the applications, concerns and limitations, and process parameters of emulsion cleaning. It describes the processing variables and equipment for three main stages of emulsion cleaning: immersion cleaning, secondary cleaning, and spray cleaning. In addition, the classifications, composition, and selection criteria are also discussed.

This article focuses on the various techniques for removing contaminants in the surface preparation of steel for hot-dip coatings: wet cleaning methods, including alkaline cleaning, electrolytic cleaning, chemical pickling, and electrolytic pickling; flame cleaning and furnace-atmosphere techniques, such as Sendzimir oxidation/reduction method; other specialized methods, namely, fluxes, mechanical cleaning, and ultrasonic methods; or a combination of these.

This article describes the test methods for evaluating the durability of a metal in soil. It provides useful information on soil characteristics such as soil electrical resistivity, pH value, and soil texture. Specimen design, preparation, burial, and retrieval techniques are discussed. The type of information sought during soil-induced corrosion evaluation controls the design configuration and the nature of the corrosion measurements. Consideration of these factors during the planning stage helps the corrosion engineer to obtain the maximum amount of information with the minimum number of problems.

This article focuses on the mineral and organic acid cleaning of iron and steel. It begins with a discussion on the application methods, process selection criteria, solution composition, equipment used, and control of process variables in mineral acid cleaning. The article then describes the advantages and disadvantages of organic acid cleaning. Applications, including boiler cleaning, stainless steel cleaning, and removal of iron- and copper-bearing deposits, are discussed. The article concludes with an overview of acid cleaning of nonferrous alloys.

The corrosion processes of metals during burial are affected by environmental pollutants, other archaeological material, geography, microorganisms in the soil, vegetation, land use, soil chemistry, soil physical properties, and the presence or absence of water and air. This article discusses the key environmental variables that affect the corrosion of buried metal artifacts. These include water (including dissolved salts and gases), sulfate-reducing bacteria, pH (acidity), and potential (oxidizing or reducing capacity). The article contains tables that list some corrosion products identified on archaeological tin and pewter, lead, iron alloys, silver alloys, and copper alloys. It also discusses the corrosion problems after excavation and the techniques followed by archaeological department for conserving metal artifacts.

This article discusses the occupational health hazards related to industrial protective coating application and removal. It explains the health hazards associated with coating constituents such as lead, cadmium, chromium, arsenic, silica, and asbestos. The article also discusses hazard evaluation, hazard controls, Occupational Safety and Health Administration standards, and industry consensus standards. It concludes with a description of containment systems to prevent environmental exposures from industrial paint removal projects.

This article describes the features, benefits and limitations of petrolatum and microcrystalline wax. It provides a detailed discussion on the steps to be followed before applying the various forms of the wax-based coatings. The wax-based coating forms include petrolatum and microcrystalline tapes, marine petrolatum-based pile systems; cold-applied petrolatum-based paste coating systems; hot-applied microcrystalline wax flood coating systems; wax-based dips, brushons, and sprays; and wax-impregnated fabrics and wax-coated papers. The article also discusses the applications and limitations of these wax-based coatings. It concludes by highlighting the steps involved in the installation of wax-based casing fillers.

This article discusses surface engineering of nonferrous metals including aluminum and aluminum alloys, copper and copper alloys, magnesium alloys, nickel and nickel alloys, titanium and titanium alloys, zirconium and hafnium, zinc alloys, and refractory metals and alloys. It describes various techniques to improve functional surface properties and enhance the appearance of product forms. The article discusses various cleaning and finishing techniques such as abrasive blast cleaning, polishing and buffing, barrel burnishing, chemical cleaning, pickling, etching and bright dipping, electrochemical cleaning, mechanical cleaning, and mass finishing. It also examines coating processes such as plating, anodizing, chemical conversion coating, and thermal spray, and concludes with a discussion on oxidation-resistant coatings for refractory metals.

Zinc and zinc alloys require surface engineering prior to coating or use to improve adhesion and corrosion resistance. Die-cast zinc parts, in addition, must be trimmed and finished to remove flash and parting lines. This article covers zinc cleaning procedures as well as coating and finishing processes. It explains how to remove parting lines and presents several mechanical finishing methods, including surface polishing, brushing, controlled shot peening, and buffing. It also provides information on solvent cleaning, emulsion cleaning, aqueous detergent or alkaline cleaning), electrocleaning, acid dipping, and zinc conversion coating treatments.

Corrosion of metals is defined as deterioration caused by chemical or electrochemical reaction of the metal with its environment. This article provides information on corrosion of iron and steel by aqueous and nonaqueous media. It discusses the corrosive environments of carbon and alloy steels, namely atmospheric corrosion, soil corrosion, corrosion in fresh water and seawater. The article describes the corrosion process in concrete, which tends to create conditions that increase the rate of attack. The focus is on the stress-corrosion cracking of steels; an environmentally induced crack propagation that results from the combined interaction of mechanical stress and corrosion reactions. The article tabulates a guide on corrosion prevention for carbon steels in various environments. It also discusses protection methods of steel from corrosion, including coatings, such as temporary protection, cleaning, hot dip coating, electroplating, thermal spray coatings, conversion coatings, thin organic coatings, and inhibitors.

This article provides a discussion on the two basic steps of the batch hot dip galvanizing process: surface preparation and galvanizing. It describes the factors affecting coating thickness and coating structure. The mechanical properties of the coating and steel substrate are also discussed. The article also provides information on the various factors that should be considered before galvanizing a material. It examines the performances of galvanized coatings in corrosion service. The joining of galvanized structural members by bolting and welding is also discussed. The article describes the synergistic effects of galvanized and painted systems. It explains the applications of hot dip galvanized steel. The article concludes with information on pertinent galvanizing specifications under the authority of the American Society for Testing and Materials.

The chemicals that have been used in traditional vapor degreasing have serious health and environmental hazards that have prompted the search for modified and alternative techniques. This article provides a detailed discussion on the regulatory mandates that affect the use of industrial degreasing methods. It describes the aqueous degreasing technique, which forms an attractive alternative to the traditional vapor degreasing process. The article includes information on the materials and equipment used in the process, and discusses the advantages and disadvantages of hot and dip tank systems of aqueous degreasing. It explains how to convert an existing vapor degreaser to an aqueous cleaning system.