Search Results for chemical industry

This article focuses on noble and neutral coatings and the requirements necessary to achieve successful industrial applications. These include corrosion and wear control and repair applications in processing and chemical industries, and valve and downhole drilling applications in the petrochemical industry. The article also discusses substrate chemistry and preparation; coating selection process and microstructure; sealing by chemical, post-heat treatments, and laser processing; and thermal spray process alternatives.

Inorganic chemical-setting ceramic linings are one of the most widely used construction materials in designing the protective linings for industrial installations. Monolithic linings can be applied by cast or gunite (shotcreting) methods over steel or concrete as well as brick and mortar masonry. This article provides a discussion on the function of monolithic linings, the advantages of these materials, the types of applications in which these materials can be successfully used, and the limitations of these linings. It describes the application procedures that should be followed to ensure proper installation of a dual-lining system. The industrial applications that illustrate the corrosion resistance and some uses of monolithic linings, as well as other applications in wastewater treatment systems and the chemical industry, are discussed.

This article describes the processes involved in the production of hafnium and its alloys. It discusses the physical, mechanical and chemical properties of hafnium. The aqueous corrosion testing of hafnium and its alloys is detailed. The article reviews the corrosion resistance of hafnium in specific media, namely, water, steam, hydrochloric acid, nitric acid, sulfuric acid, alkalis, organics, molten metals, and gases. Forms of corrosion, namely, galvanic corrosion, crevice corrosion, and pitting corrosion are included. The article explains the corrosion of hafnium alloys such as hafnium-zirconium alloys and hafnium-tantalum alloys. It also deals with the applications of hafnium and its alloys in the nuclear and chemical industries.

This article provides a discussion on the structural ceramics used in gas turbine components, the automotive and aerospace industries, or as heat exchangers in various segments of the chemical and power generation industries. It covers the fundamental aspects of chemical corrosion and describes the corrosion resistance characteristics of specific classes of refractories and structural ceramics. The article also examines the prevention strategies that minimize corrosion failures of both classes of materials.

Corrosion problems and materials selection for emissions control equipment can be difficult because of varied corrosive compounds present and the severe environments encountered. This article discusses the selection of materials for construction of flue gas desulfurization systems. It addresses the problems associated with materials for incinerator off-gas treatment equipment. The off-gases can be classified according to their corrosiveness as: industrial chemical, hospital, municipal solid, and sewage sludge. The article provides information on the selection of materials for the three most common types of dust collection equipment used in bulk solids processing, namely, fabric filters, electrostatic precipitators, and wet scrubbers. It also discusses a wide variety of corrosion problems encountered in chemical and pharmaceutical industries.

This article provides a discussion on the corrosion of industrial refractory materials and technical ceramics. These materials, which are used to minimize heat losses and provide a barrier between the vessel and its contents, are utilized in the metallurgical, chemical process, power generation, automotive, and aerospace industries. The article covers the fundamental principles of chemical corrosion of refractories and ceramics, and the use of thermodynamic calculations and kinetic models to evaluate the probability of the occurrence of corrosion-causing chemical reactions. It describes the corrosion resistance characteristics of specific classes of refractories and structural ceramics. The article also examines the prevention strategies that minimize corrosion failures of both classes of materials.

This article discusses the properties, primary and secondary production, product forms and applications of various grades of lead and lead-base alloys with the aid of several tables and illustrations. It lists the Unified Numbering System (UNS) designations for various pure lead grades and lead-base alloys grouped according to nominal chemical composition. The properties of lead that make it useful in a wide variety of applications are also discussed. The largest use of lead is in lead-acid storage batteries. Other applications include ammunition, cable sheathing, cast products such as type metals, terneplate, foils, and building construction materials. Lead is also used as an alloying element in steel and in copper alloys to improve machinability. The article concludes with information on the principles of lead corrosion, corrosion resistance of lead in water, atmospheres, underground ducts, soil and chemicals.

The primary fossil fuels are generally defined as coal, oil, natural gas, tar sands, and shale oil. This article discusses the characteristics and the types of fuels used in fossil and fuel industries. It describes the energy conversion in fuels and outlines the efficiency of a heat engine with the help of the Carnot equation.

The rate and form of corrosion that occur in a particular situation depend on many complex variables. This article discusses the rate of corrosion of lead in natural and domestic water depending on the degree of water hardness caused by calcium and magnesium salts. Lead exhibits consistent durability in all types of atmospheric exposure, including industrial, rural, and marine. The article tabulates the corrosion of lead in various natural outdoor atmospheres and the corrosion of lead alloys in various soils. It explains the factors that influence in initiating or accelerating corrosion: galvanic coupling, differential aeration, alkalinity, and stray currents. The resistance of lead and lead alloys to corrosion by a wide variety of chemicals is attributed to the polarization of local anodes caused by the formation of a relatively insoluble surface film of lead corrosion products. The article also provides information on the corrosion rate of lead in chemical environments.

The combination of high strength-to-weight ratio, excellent mechanical properties, and corrosion resistance makes titanium the best material choice for many critical applications. This article commences with a description of the historical perspective of titanium casting technology. It discusses the various types of molding methods, namely, rammed graphite molding, and lost-wax investment molding. The article provides information on the casting design, melting, and pouring practices, and describes the microstructure, hot isostatic pressing, heat treatment, and mechanical properties of Ti-6AI-4V alloy. It also talks about the chemical milling and weld repair, and describes the product applications of titanium alloy castings. Tensile properties, standard industry specifications, and chemical compositions of various titanium alloy castings are tabulated.

This article describes the classification of organic solvents, namely, aprotic and protic solvents and one-component and multi-component systems. It discusses the corrosion behavior in aprotic and protic solvents. The article contains a table that presents the relationship among solution conductivity, acidity, and the corrosion rates of type 304 stainless steel in protic and aprotic solvents. The article reviews important environmental variables that influence corrosion testing in organic liquids.

Stainless steels are iron-base alloys containing minimum of approximately 11% Cr, and owing to its excellent corrosion resistance, are used for wide range of applications. These applications include nuclear reactor vessels, heat exchangers, oil industry tubular, chemical processing components, pulp and paper industries, furnace parts, and boilers used in fossil fuel electric power plants. The article provides a brief introduction on corrosion resistance of wrought stainless steel and its designations. It lists the chemical composition and describes the physical and mechanical properties of five major stainless steel families, of which four are based on the crystallographic structure of the alloys, including martensitic, ferritic, austenitic, or duplex. The fifth is precipitation-hardenable alloys, based on the type of heat treatment used. The article further discusses the factors in the selection of stainless steel, namely corrosion resistance, fabrication characteristics, product forms, thermally induced embrittlement, mechanical properties in specific temperature ranges, and product cost.

This article analyzes the estimates of the cost of corrosion, made in various countries at various times. The data are extrapolated to a 2004 base and then projected to the global economy. The chronological order of the countries are the United States of America, the United Kingdom, Australia, Japan, Canada, Germany, Poland, South Africa, Czechoslovakia, Belgium, Netherlands, Sweden, Finland, the Union of Soviet Socialist Republics, Kuwait, India, and the Basque Region.

Phosphating is used in the metalworking industry to treat substrates like iron, steel, galvanized steel, aluminum, copper, and magnesium and its alloys. This article provides an overview of the types, uses, and theory of phosphate coatings and their formation. It also discusses the composition of phosphating baths, phosphate layers, and their analysis, as well as the process hardware necessary to realize these treatments. A summary of the different types of phosphate layers is tabulated, and the chemical formulas for a number of different phosphate compounds that are theoretically possible in crystalline phosphate layers are illustrated. The article presents four chemically important phosphating steps, namely, cleaning, activation or conditioning, phosphating, and posttreatment plus standard rinsing. It describes the physical and chemical properties by gravimetric analysis, chemical analysis, structure and morphology, thermal analysis, and alkaline resistance.

The electronic microcircuit industry has placed severe demands on metal suppliers to provide metals of the highest reproducible purity attainable as a result of the constant quest for the true values of physical and chemical properties of metals. This article describes the commonly used methods for ultrapurification of metals produced by electrolytic processes, including fractional crystallization, zone refining, vacuum melting, distillation, chemical vapor deposition, and solid state refining techniques. In addition, it describes the trace element analysis and resistance-ratio test methods used to characterize purity. Tables list the values for resistance ratios of zone-refined metals and their corresponding chemical compositions, and provide an example of the detection of impurities to concentrations in the parts per billion range, utilizing a combination of the glow discharge mass spectroscopy method and Leco combustion methods.

Chemical-mechanical planarization (CMP) of metals is described as mechanically accelerated corrosion, erosion corrosion, or metallic corrosion enhanced by wear. This article reviews the history, process, chemistry, electrochemistry, and defect issues for CMP. It provides an overview of CMP through a schematic illustration of CMP process equipment. The applications of CMP to tungsten and copper alloys are of prime interest in the semiconductor industry. The article discusses copper CMP and tungsten CMP in detail and analyzes polishing mechanism during CMP by application of direct current potentiodynamic polarization and alternating current impedance measurements. It concludes with information on chemically induced defects such as pitting corrosion, galvanic corrosion, and chemical etching.

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.

This article provides a summary of the concepts discussed in the Section “Corrosion in Specific Industries” in the ASM Handbook, Volume 13C:Corrosion: Environments and Industries. This Section applies the fundamental understanding of corrosion and knowledge of materials of construction to practical applications. The industries addressed are nuclear power, fossil and alternative fuel, land transportation, air transportation, microelectronics, chemical processing, pulp and paper, food and beverage, pharmaceutical and medical technology, petroleum and petrochemical, building, and mining and metal processing.