This article addresses the cobalt and cobalt-base alloys most suited for aqueous environments and those suited for high temperatures. The performance of cobalt alloys in aqueous environments encountered in commercial applications is discussed. The article provides information on the environmental cracking resistance of the cobalt alloys. Three welding processes that are used for hardfacing with the high-carbon Co-Cr-W alloys, namely, oxyacetylene, gas tungsten arc, and plasma-transferred arc are also discussed. The article examines the effects of various modes of high-temperature corrosion. It describes the applications and fabrication of cobalt alloys for high-temperature service.

Porcelain enamels are glass coatings applied primarily to products or parts made of sheet steel, cast iron, and aluminum to improve appearance and to protect the metal surface. This article describes the types of porcelain enamels, and details enamel frits for these materials. It provides a list of steels suitable for porcelain enameling and discusses the most important factors considered in the selection of steel for porcelain enameling. The article briefly presents the preparation methods of these materials for porcelain enameling and covers the methods, and furnaces of porcelain enameling. It examines the role of coating thickness, firing time and temperature, metal substrate, and color on the performance of enameled surfaces. The article concludes with a discussion on the properties of enameled surfaces, factors considered in process control, and test procedures for evaluating the quality of enameled surfaces.

Cobalt finds its use in various applications owing to its magnetic properties, corrosion resistance, wear resistance, and its strength at elevated temperatures. This article discusses the mining and processing of cobalt and cobalt alloys. It describes the types of cobalt alloys, including wear-resistant alloys, high-temperature alloys, corrosion-resistant alloys, and special-purpose alloys. The article provides data on the chemical composition, mechanical properties, and physical properties of these alloys. Further, it provides information on the uses of cobalt in superalloys, cemented carbides, magnetic materials, low-expansion alloys, and high-speed tool steels.

This article contains a table that lists the electrical conductivity and resistivity of selected metals, alloys, and materials at ambient temperature. These include aluminum and aluminum alloys; copper and copper alloys; electrical heating alloys; instrument and control alloys; relay steels and alloys; thermostat metals; electrical contact materials; and magnetically soft materials.

Cobalt is used as an alloying element in alloys for various applications. This article provides a detailed account of the metallurgy of cobalt-base alloys. It focuses on the compositions, properties, and applications of cobalt-base alloys, which include wear-resistant cobalt alloys, heat-resistant cobalt alloys, and cobalt-base corrosion-resistant alloys. The article also describes the heat treatments such as annealing and aging, for these alloys.

Hardfacing is defined as the application of a wear-resistant material, in depth, to the vulnerable surfaces of a component by a weld overlay or thermal spray process Hardfacing materials include a wide variety of alloys, carbides, and combinations of these materials. Iron-base hardfacing alloys can be divided into pearlitic steels, austenitic (manganese) steels, martensitic steels, high-alloy irons, and austenitic stainless steel. The types of nonferrous hardfacing alloys include cobalt-base/carbide-type alloys, laves phase alloys, nickel-base/boride-type alloys, and bronze type alloys. Hardfacing applications for wear control vary widely, ranging from very severe abrasive wear service, such as rock crushing and pulverizing to applications to minimize metal-to-metal wear. This article discusses the types of hardfacing alloys, namely iron-base alloys, nonferrous alloys, and tungsten carbides, and their applications and advantages.

The refractory metals include niobium, tantalum, molybdenum, tungsten, and rhenium. They are readily degraded by oxidizing environments at moderately low temperatures. Protective coating systems have been developed, mostly for niobium alloys, to permit their use in high-temperature oxidizing aerospace applications. This article discusses the properties, processing, applications, and classes of refractory metals and its alloys, namely molybdenum, tungsten, niobium, tantalum and rhenium. It also provides an outline of the coating processes used to improve their oxidation resistance.

This article reviews the corrosion behavior in various environments for seven important nickel alloy families: commercially pure nickel, Ni-Cu, Ni-Mo, Ni-Cr, Ni-Cr-Mo, Ni-Cr-Fe, and Ni-Fe-Cr. It examines the behavior of nickel alloys in corrosive media found in industrial settings. The corrosive media include: hydrochloric acid, sulfuric acid, phosphoric acid, hydrofluoric acid, hydrobromic acid, nitric acid, organic acids, salts, seawater, and alkalis. The modes of high-temperature corrosion include oxidation, carburization, metal dusting, sulfidation, nitridation, corrosion by halogens, and corrosion by molten salts. Applications where the corrosion properties of nickel alloys are important factors in materials selection include the petroleum, chemical, and electrical power industries. Most nickel alloys are much more resistant than the stainless steels to reducing acids, such as hydrochloric, and some are extremely resistant to the chloride-induced phenomena of pitting, crevice attack, and stress-corrosion cracking (to which the stainless steels are susceptible). Nickel alloys are also among the few metallic materials able to cope with hot hydrofluoric acid. The conditions where nickel alloys suffer environmentally assisted cracking are highly specific and therefore avoidable by proper design of the industrial components.

This article contains a table that lists the thermal conductivity of selected metals and alloys near room temperature. These include aluminum and aluminum alloys; copper and copper alloys; iron and iron alloys; lead and lead alloys; magnesium and magnesium alloys; nickel and nickel alloys; tin and tin alloys; titanium and titanium alloys; zinc and zinc alloys; and pure metals.

This article contains tables that present engineering data for the following metals and their alloys: aluminum, copper, iron, lead, magnesium, nickel, tin, titanium, zinc, precious metals, permanent magnet materials, pure metals, rare earth metals, and actinide metals. Data presented include density, linear thermal expansion, thermal conductivity, electrical conductivity, resistivity, and approximate melting temperature. The tables also present approximate equivalent hardness numbers for austenitic steels, nonaustenitic steels, austenitic stainless steel sheet, wrought aluminum products, wrought copper, and cartridge brass. The article lists conversion factors classified according to the quantity/property of interest.

Cast nickel-base alloys are used extensively in corrosive-media and high-temperature applications. This article briefly reviews the common types of heat treatments of nickel alloy castings: homogenization, stress relieving, in-process annealing, full annealing, solution annealing, quenching, coating diffusion, and precipitation. It describes the three general strengthening mechanisms, namely, solid-solution hardening, age hardening, and carbide precipitation. The article summarizes the typical heat treatment of the general families of nickel-base castings used in industrial applications. It focuses on the solution treatment and age hardening of cast nickel-base superalloys and the heat treatment of cast solid-solution alloys for corrosion-resisting applications. The article also discusses the typical types of atmospheres used in annealing or solution treating: exothermic, endothermic, dry hydrogen, dry argon, and vacuum.

Low-expansion alloys are materials with dimensions that do not change appreciably with temperature. Alloys included in this category are various binary iron-nickel alloys and several ternary alloys of iron combined with nickel-chromium, nickel-cobalt, or cobalt-chromium alloying. Low-expansion alloys are used in various applications such as rods and tapes for geodetic surveying, moving parts that require control of expansion (such as pistons for some internal-combustion engines), bimetal strip, components for electronic devices etc. This article discusses the properties, composition, and applications of iron-nickel low-expansion alloys (Invar), as well as other special alloys, including iron-nickel-chromium alloys, iron-nickel-cobalt alloys, iron-cobalt-chromium alloys, and high-strength, controlled-expansion alloys. It covers the factors affecting coefficient of thermal expansion of iron-nickel alloys, including heat treatment and cold drawing. Magnetic, physical, thermal, electrical and mechanical properties of iron-nickel alloys are also covered.

This article addresses two issues on thermodynamics, namely, the calculation of solubility lines and the calculation of the activity of various components. It discusses alloying elements in terms of their influence on the activity of carbon. The article describes the desulfurization and deoxidation of cast iron and steel. It illustrates the thermodynamics of the iron-carbon system and the iron-silicon system. The article examines solubility and saturation degrees of carbon in multicomponent iron-carbon systems. One of the main applications of the thermodynamics of the iron-carbon system is the calculation of structure-composition correlations. The article concludes with information on the structural diagrams, such as Maurer diagram and Laplanche diagram, for cast iron.

Copper and copper alloys are widely used because of their excellent electrical and thermal conductivities, outstanding resistance to corrosion, and ease of fabrication, together with good strength and fatigue resistance. This article provides an overview of property and fabrication characteristics, markets, and applications of copper and its alloys. It contains several tables that provide helpful information on the chemical composition, classification, designation, uses, and mechanical properties of wrought copper and copper alloys.

This article reviews some concepts considered important for an understanding of processes used for preparing cobalt-chromium alloy implants, the microstructures resulting from this processing, and the resulting material properties. The review includes the solidification of alloys, diffusionless (martensitic) phase transformation as occurs with face-centered cubic to hexagonal close-packed transformation in cobalt-chromium alloys, stacking faults and twins and their role in this transformation. It also includes strengthening mechanisms that are responsible for the mechanical properties of cast and wrought cobalt alloys. The article contains tables that list the commonly used cobalt alloys and their biomedical applications and chemical compositions. It discusses the mechanical and corrosion properties of cobalt alloys, and provides a description of the microstructure of cobalt alloys.

This article provides information on nickel alloying elements, and the heat treatment processes of various nickel alloys for applications requiring corrosion resistance and/or high-temperature strength. These processes are homogenization, annealing, solution annealing, solution treating, stabilization treatment, age hardening, stress relieving, and stress equalizing. Discussion of furnaces, fixtures, and atmospheres is included. Nickel alloys used for the heat treatment processes include corrosion-resistant nickel alloys, heat-resistant nickel alloys, nickel-beryllium alloys, special-purpose alloys such as nitinol shape memory alloys, low-expansion alloys, electrical-resistance alloys and soft magnetic alloys. Finally, the article focuses on heat treatment modeling for selecting the appropriate heat treatment process.

Electrical resistance alloys used to control or regulate electrical properties are called resistance alloys, and those used to generate heat are referred to as heating alloys. This article covers both alloy types, describing the construction and use of resistors as well as heating elements. It also discusses soldering and joining methods, sensitivity and stability factors, and various design coefficients. In addition, it provides a detailed account of the properties and applications of thermostat metals and discusses the design of resistance heaters and their operating ranges.

Nickel and nickel-base alloys are vitally important to modern industry because of their ability to withstand a wide variety of severe operating conditions involving corrosive environments, high temperatures, high stresses, and combinations of these factors. This article discusses the mining and extraction of nickel and describes the uses of nickel. It discusses the categories of nickel-base alloys, including wrought corrosion-resistant alloys, cast corrosion-resistant alloys, heat-resistant alloys (superalloys), and special-purpose alloys. The article covers the corrosion resistance of nickel with the inclusion of varying alloying elements. It provides useful information on the behavior of nickel and nickel alloys in specific environments describes its corrosion resistance in certain acids, alkalis, and salts.

For chemical processing, niobium resists a wide variety of corrosive environments. These environments include mineral acids, many organic acids, liquid metals, and most salt solutions. This article focuses on the mechanisms of corrosion resistance of niobium alloys in these environments. The niobium alloys include Nb-1Zr, Nb-55Ti, Nb-50Ta, and Nb-40Ta. The article describes the use of these corrosion resistant niobium alloys. It provides information on applications of niobium in various industries.

This article describes the different types of precipitation and transformation processes and their effects that can occur during heat treatment of various nonferrous alloys. The nonferrous alloys are aluminum alloys, copper alloys, magnesium alloys, nickel alloys, titanium alloys, cobalt alloys, zinc alloys, and heat treatable silver alloys, gold alloys, lead alloys, and tin alloys. It also provides a detailed discussion on the effects due to precipitation and transformation processes in these non-ferrous alloys.