Search Results for aluminum coatings

The sealing of the anodized aluminum is a critical process in achieving the durability and extended functionality of anodizing. This article discusses the different methods for sealing the anodic coatings produced by using sulfuric acid, namely, hot deionized water, hot nickel acetate, midtemperature, cold, and dichromate sealing. It reviews the factors that affect seal quality: immersion time, chemistry concentration, temperature, pH, water quality, coating thickness, and contaminants/dye bleeding. The article describes the various tests that are used for determining the quality of the seal, namely, salt spray, modified dye stain, acid dissolution, impedance, copper accelerated acetic acid salt spray, high-alkaline resistance, SO 2 fog, and clorox tests.

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.

Vapor-deposition processes fall into two major categories, namely, physical vapor deposition (PVD) and chemical vapor deposition (CVD). This article describes major deposition processes such as sputtering, evaporation, ion plating, and CVD. The list of materials that can be vapor deposited is extensive and covers almost any coating requirement. The article provides a table of some corrosion-resistant vapor deposited materials. It concludes with an overview of the applications of CVD and PVD coatings and a discussion on coatings for graphite, the aluminum coating of steel, and alloy coatings for aircraft turbines, marine turbines, and industrial turbines.

This article describes the methods used for coloring anodized aluminum coatings: integral coloring, electrolytic coloring, chemical coloring, and organic dyeing. It discusses organic dye chemistry in terms of single-component organic dyes and multicomponent dyes. The article reviews optimal dyeing conditions, such as temperature, time, concentration, and pH. It concludes with a discussion on the factors considered for choosing a coloring method: the desired shade, light fastness, heat fastness, and contamination.

Pack carburizing is a process in which carbon monoxide derived from a solid compound decomposes at the metal surface into nascent carbon and carbon dioxide. In addition to discussing the pros and cons of pack carburizing, this article provides information on the carburizing medium, compounds, furnaces, and containers used in pack carburizing. The successful operation of the pack carburizing process depends on the control of principal variables such as carbon potential, temperature, time, case depth, and steel composition. The three types of furnaces most commonly used for pack carburizing are the box, car-bottom, and pit types. Carburizing containers are made of carbon steel, aluminum-coated carbon steel, or iron-nickel-chromium heat-resisting alloys. The article also provides information on the packing procedure of workpieces.

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.