Search Results for organic zinc-rich coatings

The use of zinc in corrosion-protective coatings is due to its higher galvanic activity relative to that of steel. Pure zinc dust provides the best sacrificial protection to steel in a galvanic couple. Zinc-rich coatings can be subcategorized according to the type of binder material used, namely, inorganic and organic zinc-rich coatings. Common inorganic binders such as post-cured water-based alkali metal silicates, self-cured water-based alkali metal silicates, and self-cured solvent-based alkyl silicates, are reviewed. The article also compares inorganic and organic zinc-rich coatings, and discusses the concerns regarding zinc-rich coatings.

This article describes the characteristics of zinc-rich coatings that can be subcategorized according to the type of binder material used. It discusses the formulations of zinc-rich coatings with organic binders. The three major groups of inorganic zinc-rich coatings categorized by the Society for Protective Coatings are also discussed. These include postcured water-based alkali metal silicates, self-cured water-based alkali metal silicates, and self-cured solvent-based alkyl silicates. The article concludes with information on comparisons of inorganic with organic zinc-rich coatings.

A coating can be defined as a substance spread over a surface to provide protection or to serve decorative purposes. This article discusses two industrial coating components, namely, nonvolatile components such as the resin or binder, pigments, and any additives that may be incorporated into the formulation; and volatile components such as solvents, or water in emulsions and their composition. It provides general information on volatile organic compounds. The article describes the film-forming mechanisms of various coating types, namely, lacquers, chemically converting coatings, latex coatings, alkyds and other resins, which cure by oxidation, moisture-curing polyurethanes and inorganic zinc primers, and powder coatings. The article concludes with a discussion on the functions of the primer, intermediate coat, and topcoat in coating systems.

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.

Organic coatings are the principal means of corrosion control for the hulls and topsides of ships and for the splash zones on permanent offshore structures. This article describes surface preparation which is the most important consideration in determining the performance of organic coating systems. It contains a table that lists the uses and applicable standards for various surface preparation techniques. The article provides information on organic coatings in topside coating systems and reviews the importance of primers in the protection of steel substrates. It also explains the property requirements and the common types of immersion coatings.

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.

Coating of cast irons is done to improve appearance and resistance to degradation due to corrosion, erosion, and wear. This article describes inorganic coating methods commonly applied to cast irons. The coating methods include plating, hot dip coating, conversion coating, diffusion coating, cladding, porcelain enameling, and thermal spray. Organic coatings have a wide variety of properties, but their primary use is for corrosion resistance combined with a pleasing colored appearance. The article discusses the various types of organic coatings applied to cast irons. Practically any degree of smoothness or roughness and requirement for color and gloss can be filled by organic coatings. The article describes abrasive blast cleaning, abrasive waterjet cleaning and finishing, vibratory finishing, barrel finishing, and shot peening for processing iron castings.

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.

This article focuses on those areas of coatings technology where silicon-based technology (SBT) is the primary enabling technology and where SBT is used as an additive to provide unique properties to the coating film. It describes the chemistry and the uses of alkoxy silanes. The uses of silicates, siliconates, silicone fluids, and silicone resins in coatings are reviewed. The article discusses the various applications of SBT, namely, primers, heat-resistant coatings, industrial maintenance coatings, hygienic coatings, and abrasion-resistant coatings, and for marine biofouling control. It also provides information on the benefits of silicon-base additives.

This article provides an overview of the electrochemical nature of corrosion and analyzes corrosion-related failures. It describes corrosion failure analysis and discusses corrective and preventive approaches to mitigate corrosion-related failures of metals. These include: change in the environment; change in the alloy or heat treatment; change in design; use of galvanic protection; use of inhibitors; use of nonmetallic coatings and liners; application of metallic coatings; use of surface treatments, thermal spray, or other surface modifications; corrosion monitoring; and preventive maintenance.

This article presents information regarding the use of protective coatings in municipal potable water systems, including raw water collection and transmission, water treatment plants, and treated water distribution. It provides useful guidance for the selection and use of protective coatings in these municipal water systems. The most commonplace corrosion-damage mechanisms are highlighted. The article describes the most common materials of construction found in municipal water systems, namely, cast iron, ductile iron, carbon steel, precast concrete cylinder pipe and reinforced concrete pipe, prestressed concrete tanks, and stainless steel. It provides information on the most common generic coating systems used for new steel tanks and water storage tanks. It concludes with a discussion of quality watch-outs when selecting or using protective coatings in municipal water systems.

From the standpoint of corrosion protection of iron and steel, metallic coatings can be classified into two types: noble coatings and sacrificial coatings. This article focuses on hotdipped zinc, aluminum, zinc-aluminum alloy and aluminum-zinc alloy coatings. It discusses the Sendzimir process and the Cook-Norteman process, which are the two commercial processes that are used for almost all hot-dip galvanized sheet steel in the United States. The article provides a discussion on the aqueous corrosion and atmospheric corrosion of galvanized steel and aluminized steel, as well as the intergranular corrosion of galvanized steel.

This article explains the applications of continuous electroplated steel. For each category of application, the type of coating needed and the key attributes of the coating are discussed. The bulk of the article describes electrodeposition technology, including plating line components and process classification.

This article provides a brief discussion on the common types of overlayers that can be used on a metal surface to protect it from corrosion. These overlayers include phosphate, chromate, and chromate-free conversion coatings; hot dip galvanizing; cementitious linings; glass and porcelain enamels; electroplating; thermal spray coatings; and rubber linings.

Zinc is one of the most used metals, ranking fourth in worldwide production and consumption behind iron, aluminum, and copper. This article commences with an overview of the applications of zinc that can be divided into six categories: coatings, casting alloys, alloying element in brass and other alloys, wrought zinc alloys, zinc oxide, and zinc chemicals. It discusses the corrosion and electrochemical behavior of zinc and its alloys in various environments, particularly in atmospheres in which they are most widely used. The article tabulates the corrosion rates of zinc and zinc coatings immersed in various types of waters, in different solutions in the neutral pH range, and in soils at different geographic locations in the United States. It concludes with information on the forms of corrosion encountered in zinc coatings, including galvanic corrosion, pitting corrosion, and intergranular corrosion.

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.

This article provides a basic overview of bridge corrosion, where it occurs on steel and concrete bridge structures, and how to prevent corrosion by using coatings. It describes types of bridge designs, with illustrations, and presents information on how corrosion occurs in different bridge zones and areas, with illustrations. The article concludes with a discussion on the common methods of coating systems applications on bridge structures and key elements in coating condition assessment.

Independent verification of coating system performance can be based on laboratory testing and/or field exposure. Qualification testing is a critical component to coating system selection. This article focuses on performance evaluations that are used to prequalify coating systems, namely, facility-specific, industry-specific, coating-type-specific, or a combination of these. It describes the standard laboratory tests used to generate performance data, namely, physical, compositional, chemical exposure, and application characteristics tests. The pros and cons of using manufacturer-generated data versus independently generated data are discussed. The article provides information on accelerated corrosion/weathering testing and nuclear level 1/level 2 service coatings qualification. It also describes the procedures for establishing minimum performance requirements and for determining when requalification testing may be required.

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.

Surface coatings are essential in all facilities that process nuclear materials or use nuclear fission for power generation. This article describes the coatings used in two basic types of Generation 3 nuclear reactor designs in the United States and their containment size. These reactors are the boiling water reactor (BWR) and pressurized water reactor (PWR). The article provides information on the loss-of-coolant accident (LOCA) identified as the design basis accident (DBA), which can rapidly de-water the core of an operating nuclear reactor. To avoid LOCA, both the BWR and the PWR include emergency core cooling systems. The article describes a DBA test and other coating performance parameters necessary for safety-related coating systems. It provides a detailed account of the selection criteria of coating types in a nuclear plant. The article concludes by highlighting protective coating strategies in Generation 3 Plants.