Painting is a generic term for the application of a thin organic coating to the surface of a material for decorative, protective, or functional purposes. This article provides a detailed account of the types and selection factors of paints and the various application methods, including conventional air atomized, airless, and electrostatic spray; roller coating; dip coating; flow coating; curtain coating; tumble coating; electrocoating; and powder coating. Surface preparation methods and prepaint treatments for coating systems are also discussed. The article includes information on quality control procedures, causes of paint film defects, cost calculation, and safety and environmental precautions. The composition and characteristics of organic coatings, coating system selection factors, the types of paints for structural steel, and the applications of paint on structural steel are also reviewed.

This article describes the paint systems generally used to protect steel structures, steel sheet, and bridges from corrosion, and how they deter corrosion. It provides a discussion on the basic design criteria of steel structures for corrosion protection. The article also explains the differences between prepaint and postpaint, and the steps involved in prepaint processing of steel. It presents the selection guideline for paint system evaluation. The advantages of corrosion protection are also discussed.

Steel sheet is often coated in coil form prior to fabrication to save time, reduce production costs, and streamline operations. This article examines the most common precoating methods and provides a metallurgical understanding of how they impact the manufacturability, performance, and service life of the host material. The article covers metallic coatings, including zinc, aluminum, zinc-aluminum alloys, tin, and terne; pretreatment or phosphate coatings; and preprimed and painted finishes based on organic coatings.

This article discusses the classifications, compositions, properties, advantages, disadvantages, limitations, and applications of the most commonly used methods for surface engineering of carbon and alloy steels. These include cleaning methods, finishing methods, conversion coatings, hot-dip coating processes, electrogalvanizing, electroplating, metal cladding, organic coatings, zinc-rich coatings, porcelain enameling, thermal spraying, hardfacing, vapor-deposited coatings, surface modification, and surface hardening via heat treatment.

There are various coating techniques in practice to prevent the deterioration of steels. This article focuses on dip, barrier, and chemical conversion coatings and describes hot-dip processes for coating carbon steels with zinc, aluminum, lead-tin, and other alloys. It describes continuous electrodeposition for steel strip and babbitting and discusses phosphate and chromate conversion coatings as well. It also addresses painting, discussing types and selection, surface preparation, and application methods. In addition, the article describes rust-preventive compounds and their application. It also provides information on weld-overlay and thermal spray coating, porcelain enameling, and the preparation of enamel frits for steels. The article closes by describing methods and materials for ceramic coating.

Ferrous metals are metals that contain primarily iron and may have small amounts of other elements added to give the desired properties. This article discuses the characteristics of steel products used in most industries, including construction, automotive, energy, shipping, and agriculture. These products include bars, rods, wires, hot and cold rolled sheets, strip plates, tin mill products, steel tubes, castings, and forgings. The article also provides information on the methods used to prevent or control the rusting of ferrous materials, namely, alloying, coating, and covering.

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.

This article focuses on the types, composition, and applications of phosphate coatings and describes the characteristics of phosphate-coated ferrous and nonferrous materials, including steel and aluminum. It addresses five successive process fundamentals: cleaning, rinsing, phosphating, rinsing after phosphating, and chromic acid rinsing. The article describes the techniques for controlling the chemical composition of various phosphating solutions. It discusses the equipment and factors that influence equipment requirements in immersion and spray systems. The article also describes the controlling procedures of coating weight and crystal size. It provides guidelines for choosing phosphate coatings based on application, coating weight requirements, and recommended process parameters. The article concludes with a discussion on safety precautions and the treatment of effluents from phosphating plants.

Low-carbon steel sheet and strip are used primarily in consumer goods. This article discusses quality descriptors and mechanical properties of low-carbon steel sheet and strip and carbon and low-alloy steel plate. Alloy steel sheet and strip are used primarily for those special applications that require the mechanical properties normally obtained by heat treatment. Steel sheet is coated in coil form before fabrication either by the steel mills or by specialists called coil coaters. Porcelain enamels are glass coatings applied primarily to products or parts made of sheet steel, cast iron, or aluminum to improve appearance and to protect the metal surface.

This article reviews the various substrates for coatings, namely, steel, cast iron, galvanized steel, aluminum, stainless steel, nonferrous metals, concrete, and wood. General guidance for surface preparation and coating selection is provided along with unique requirements for the particular substrate(s).

Although aluminum alloys are inherently corrosion resistant, there are many operating environments where they require additional protection. This article describes the conditions under which aluminum is prone to corrode and explains how to prevent it through the addition of conversion coatings and paints. It addresses some of the more common corrosion mechanisms, including corrosion driven by pH extremes, pitting corrosion, crevice corrosion, galvanic corrosion, and filiform corrosion. The article also describes in-plant as well as field application procedures for cleaning and coating, and discusses the advantages and limitations of the various materials and chemicals used.

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.

Filiform corrosion has been observed to occur under a wide range of organic coatings and proceeds with the same general characteristics on steel, aluminum, and magnesium. This article describes the standard tests for filiform corrosion, characteristics and mechanisms of filiform corrosion in steels, as well as coated aluminum and magnesium. It concludes with information on the prevention and mitigation of filiform corrosion accomplished through the adjustment of the environment and changes in the substrate and coating systems.

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.

This article discusses the processes involved in continuous hotdip coating of steel sheets, namely, hot and cold line processing, surface preparation, and post treatment. It outlines the properties and microstructures of metals and their alloys used in this process. The coatings considered in this article include metal coatings, such as zinc coatings, and alloy coatings, such as zinc-iron, types 1 and 2 aluminum, Zn-5AI, Zn-55AI, and lead-tin coatings.

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.

Surface treatments are used in a variety of ways to improve the material properties of a component. This article provides information on surface treatments that improve service performance so that the design engineer may consider surface-engineered components as an alternative to more costly materials. It describes solidification surface treatments such as hot dip coatings, weld overlays, and thermal spray coatings. The article discusses deposition surface treatments such as electrochemical plating, chemical vapor deposition, and physical vapor deposition processes. It explains surface hardening and diffusion coatings such as carburizing, nitriding, and carbonitriding. The article also tabulates typical characteristics of carburizing, nitriding, and carbonitriding diffusion treatments.

This article provides an overview of some common sheet steel coatings available. It discusses the formability differences between coated and bare steel and provides some general guidelines on the forming of coated steels. Coated steels are classified according to the nature of the substrate, the type of coating, and the method used for its application. The article describes various coating types for steels such as zinc-coated steels, aluminum-coated steels, tin-coated steels, terne-coated steels, and organic-coated steels.

This article provides information on the properties, compositions, designations, and applications of zinc and zinc alloys. It discusses the principal areas of application of zinc: in coatings and anodes for corrosion protection of irons and steels; in zinc casting alloys; as an alloying element in copper, aluminum, magnesium, and other alloys; in wrought zinc alloys; and in zinc chemicals. The zinc coating applications of hot dip galvanizing, electrogalvanizing, plating, and thermal spray are presented. The use of zinc alloys in both gravity and pressure die castings is discussed as well as the three main types of wrought products: flat-rolled products, wire-drawn products, and extruded and forged products. The article also provides a section on the corrosion resistance of zinc and zinc coatings in various atmospheres.

Rust-preventive compounds are removable coatings used for the protection of the surfaces of iron, steel, coated or galvanized products, and other alloys. This article describes the basic parts of rust-preventive compounds, namely, carrier, film former, polar materials, and specialty additives. It explains types of rust-preventive compounds, including dry films and water-based dry films. The article also discusses the methods of application of various compounds, such as petrolatum compounds and emulsion compounds. It contains tables that provide information on the characteristics, applications, and physical properties of rust-preventive materials covered by military specifications. Finally, the article describes the various considerations and parameters for selecting rust-preventive materials.