This article describes the classification of fuel cells depending on the operating temperature and type of electrolytes used. This classification includes alkaline fuel cells, phosphoric acid fuel cells, polymer electrolyte membrane fuel cells (PEMFCs), molten carbonate fuel cells (MCFCs), and solid oxide fuel cells (SOFCs). The article explains the corrosion processes in fuel cells due to solid-gas interactions, solid-liquid interactions, and solid-solid interactions. It discusses the long-term performance stability and long-term degradation processes of PEMFCs, MCFCs, and SOFCs. The article reviews the development of chemically and structurally compatible component materials in PEMFCs, MCFCs, and SOFCs.

Batteries and fuel cells are popular forms of portable electrical energy sources. This article discusses the operation and corrosion problems inherent in batteries and fuel cells. Batteries are classified into two groups: primary or nonrechargeable batteries and secondary or rechargeable batteries. Fuel cells are classified into five types: phosphoric acid fuel cell (PAFC), solid polymer electrolyte fuel cell, alkaline electrolyte fuel cell, molten carbonate fuel cell (MCFC), and solid oxide fuel cell. The article presents reactions that occur during charging and discharging of lead-acid batteries, PAFCs, and MCFCs.

Thermal spray processes involve complete or partial melting of a feedstock material in a high-temperature flame, and propelling and depositing the material as a coating on a substrate. This article describes the properties of sprayed electronic materials, including dielectrics, conductors, and resistors, and discusses their implications and associated limitations for device applications and potential remedial measures. The article presents specific examples of electrical/electronic device applications, including electromagnetic interference/radio-frequency interference shielding, planar microwave devices, waveguide devices, sensing devices, solid oxide fuel cells, heating elements, electrodes for capacitors and other electrochemical devices.

This article describes the ideal performance of various low-temperature and high-temperature fuel cells that depends on the electrochemical reactions that occur between different fuels and oxygen. Low-temperature fuel cells, such as polymer electrolyte, alkaline, and phosphoric acid, and high-temperature fuel cells, such as molten carbonate and solid oxide, are discussed. The article contains tables that provide information on the evolution of cell-component technology for these fuel cells. It concludes with information on the advantages and limitations of the fuel cells.

The use of renewable energy has grown strongly in all end-use sectors such as power, heat, and transport. This article describes thermal spray applications that improve efficiency, lower maintenance costs, and prolong operational life in the renewable energy technologies, including wind power, hydro power, biomass and biofuels, solar energy, and fuel cells.

Ceramic materials serve important insulative, capacitive, conductive, resistive, sensor, electrooptic, and magnetic functions in a wide variety of electrical and electronic circuitry. This article focuses on various applications of advanced ceramics in both electric power and electronics industry, namely, dielectric, piezoelectric, ferroelectric, sensing, magnetic and superconducting devices.

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.

Molten salts, in contrast to aqueous solutions in which an electrolyte (acid, base, salt) is dissolved in a molecular solvent, are essentially completely ionic. This article begins with an overview of the thermodynamics of cells and classification of electrodes for molten salts: reference electrodes and indicator electrodes. It explains that corrosion in molten salts can be caused by the solubility of the metal in the salt, particularly if the metal dissolves in its own chloride. The article describes the factors that affect the corrosion of titanium, namely, the titanium chloride content of the magnesium chloride melt, magnesium or sodium content, and oxygen content of the product. It concludes with a discussion on the oxygen activity in the titanium metal product.

This article examines constructive corrosion that occurs in power-generating devices, specifically batteries. It discusses the kinetic aspects of constructive corrosion in batteries and provides examples to illustrate how the kinetics of a corrosion process varies among different battery systems. The article illustrates the constructive roles played by corrosion at anodes in batteries through the use of a zinc anode in a mercury battery and a lithium metal anode in a rechargeable lithium battery. It also outlines the destructive role played by corrosion by illustrating shelf reactions in zinc-carbon batteries and lead grid corrosion in lead-acid batteries.

Ores, which consist of the primary valuable mineral, predominant gangue content, valuable by-products, and detrimental impurities, are extracted and directed to mineral processing. This article describes the mineral processing facilities, such as crushers, grinders, concentrators, separators, and flotation devices that are used for particle size reduction, separation of particles according to their settling rates in fluids and dewatering of concentrate particles. It explains the basic principles, flow diagrams, ore concentrate preparation methods, and equipment of major types of metallurgical processes, including pyrometallurgical, hydrometallurgical, and electrometallurgical processes.

This article provides a summary of the concepts discussed in the articles under the Section “Fundamentals of Corrosion” in ASM Handbook, Volume 13A: Corrosion: Fundamentals, Testing, and Protection. In this section, the thermodynamic aspects of corrosion are descried first followed by a group of articles discussing the fundamentals of aqueous corrosion kinetics. The fundamentals of gaseous corrosion are addressed next. The fundamental electrochemical reactions of corrosion and their uses are finally described.

This article discusses three types of powder-feeder systems that are commonly used throughout the thermal spray (TS) industry: gravity-based devices, rotating wheel devices, and fluidized-bed systems. It provides information on the various mechanical methods for producing powders, namely, crushing, milling, attriting, and machining. The article describes two prime methods of agglomeration. One method uses a binder by way of agglutination, while the other relies on a sintering operation. The article discusses the technology and principles of the processes that relate to thermal spraying, and offers an understanding for choosing particular feedstock materials that are classified based on the thermal spray process, material morphology, chemical nature of the material, and applications. Sieving, the most common method of separating powders into their size fractions, is also reviewed. The article also provides information on the topical areas and precautions to be undertaken to protect the operator from safety hazards.

This article describes various methods of electrochemical analysis, namely coulometry, electrogravimetry, voltammetry, electrometric titration, and nanometer electrochemistry. The discussion covers the general uses, sample requirements, application examples, advantages, and limitations of these methods. Some of the factors pertinent to electrochemical cells are also provided. In addition, the article provides information on various potentiometric membrane electrodes used to quantify numerous ionic and nonionic species.

This article describes the corrosion mechanisms, challenges, and control methods in service water distribution systems. It provides a discussion on typical designs and water qualities for distribution systems used in fossil-fueled and nuclear power plants. The article also explains the techniques for controlling corrosion in service water systems.