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.

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.

This article discusses the methods for producing powder metallurgy (PM) nickel powders, including carbonyl process, hydrometallurgical process, hydrogen reduction process, and atomization process, as well as their applications. It describes three processes for producing nickel alloy powders: water atomization, high-pressure water atomization, and gas atomization. The article also provides information on the applications of PM hot isostatic pressing in the oil and gas industry.

This article discusses electrospinning as a method for obtaining nanofibers, some of the challenges and limitations of the technique, advancements in the field, and how it may be used in key functional applications. The key drawbacks of traditional electrospinning processes include relatively slow speed of nanofiber production, low product yield, and relatively high cost. The article also addresses novel high-throughput techniques and methods designed for the scalable synthesis of nanofibers and nanofibrous mats that are of reasonable cost.

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.

X-ray spectroscopy is generally accepted as the most useful ancillary technique that can be added to any scanning electron microscope (SEM), even to the point of being considered a necessity by most operators. While “stand-alone” x-ray detection systems are used less frequently in failure analysis than the more exact instrumentation employed in SEMs, the technology is advancing and is worthy of note due to its capability for nondestructive analysis and application in the field. This article begins with information on the basis of the x-ray signal. This is followed by information on the operating principles and applications of detectors for x-ray spectroscopy, namely energy-dispersive spectrometers, wavelength-dispersive spectrometers, and handheld x-ray fluorescence systems. The processes involved in x-ray analysis in the SEM and handheld x-ray fluorescence analysis are then covered. The article ends with a discussion on the applications of x-ray spectroscopy in failure analysis.

Nondestructive testing (NDT), also known as nondestructive evaluation (NDE), includes various techniques to characterize materials without damage. This article focuses on the typical NDE techniques that may be considered when conducting a failure investigation. The article begins with discussion about the concept of the probability of detection (POD), on which the statistical reliability of crack detection is based. The coverage includes the various methods of surface inspection, including visual-examination tools, scanning technology in dimensional metrology, and the common methods of detecting surface discontinuities by magnetic-particle inspection, liquid penetrant inspection, and eddy-current testing. The major NDE methods for internal (volumetric) inspection in failure analysis also are described.

Additive manufacturing (AM) has been adopted as one of the most versatile and rapid design-to-manufacturing approaches for printing a wide range of two- and three-dimensional parts, devices, and complex geometries layer by layer. This article provides insights into the current progress, challenges, and future needs of AM of electronics from the space, defense, biomedical, energy, and industry perspectives.

This article discusses the fracture and fatigue properties of powder metallurgy (P/M) materials depending on the microstructure. It describes the effects of porosity on the P/M processes relevant to fatigue and fracture resistance. The article details the factors determining fatigue and fracture resistance of P/M materials. It reviews the methods employed to improve fatigue and fracture resistance, including carbonitriding, surface strengthening and sealing treatments, shot-peening, case hardening, repressing and resintering, coining, sizing, and postsintering heat treatments. Safety factors for P/M materials are also detailed.

Rare earth metals belong to Group IIIA of the periodic table that includes scandium, yttrium, and the lanthanide elements which are lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. This article classifies the rare earth metals based on their purity level, which are designated as research grades (>99.8% pure) and commercial grades (95% - 98% pure), and describes the preparation and purification, including solid-state electrolysis. It further discusses physical, mechanical, and chemical properties; electronic configurations; crystal structures, and explains the alloy forming characteristics of rare earth elements. The article concludes by describing the various applications of commercial-grade rare earth elements and commercial alloys, which incorporates rare earth elements as additives.

This article discusses the influence of the materials, design, package type, and environment on corrosion in microelectronics. It describes the common sources and mechanisms of corrosion in microelectronics, including anodic, cathodic, and electrolytic reactions resulting in uniform corrosion, galvanic corrosion, pitting corrosion, creep corrosion, dendrite growth, fretting, stress-corrosion cracking, and whisker growth. The article presents effective measures for minimizing the moisture retention in hermetic packages and/or moisture ingress in plastic packages. It concludes with information corrosion tests.

The biocompatibility of a material relates to its immunological response, toxicity profile, and ability to integrate with surrounding tissue without undesirable local or systemic effects on a patient. This article underscores the transformation of the medical device design ecosystem engaged as an integral part of the device ecosystem. It discusses the applications of biomaterials, including orthopedic, cardiovascular, ophthalmic, and dental applications. The article describes four major categories of biomaterials such as metals, polymers, glass and ceramics, and composites. A discussion on natural materials, nanomaterials, and stem cells is also provided. The article concludes with examples of biomaterials applications, such as endovascular devices, knee implants, and neurostimulation.

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.

Compression molding is the single largest primary manufacturing process used for automotive composite applications. This article provides an overview of the compression molding process. It describes the basic design, materials, and processing equipment of three main groups of composite materials, namely, glass-fiber-mat-reinforced thermoplastics, long-fiber-reinforced thermoplastics, and sheet molding compounds. The article also presents information on the application examples and market volume of compression molding.

This article focuses on the significant fundamental powder characteristics, which include particle size, particle size distribution, particle shape, and powder purity, followed by an overview of general and individual powder production processes such as mechanical, chemical, electrochemical, atomizing, oxide reduction, and thermal decomposition processes. It also covers the consolidation of powders by pressing and sintering, as well as by high density methods. Further emphasis is provided on the distinguishing features of powders, their manufacturing processes, compacting processes, and consolidated part properties. In addition, a glossary of powder metallurgy terms is included.

This article provides crystallographic and engineering data for single oxide ceramics, zirconia, silicates, mullite, spinels, perovskites, borides, carbides, silicon carbide, boron carbide, tungsten carbide, silicon-nitride ceramics, diamond, and graphite. It includes data on crystal structure, density, mechanical properties, physical properties, electrical properties, thermal properties, and magnetic properties.

Adhesive-bonded joints are extensively used in aircraft components and assemblies where structural integrity is critical. This article addresses the problem of how to inspect bonded assemblies so that all discrepancies are identified. It describes several inspection techniques and presents drawbacks and limitations of these techniques. Generic flaw types and flaw-producing mechanisms are listed in a table. The article discusses metal-to-metal defects, adherend defects, honeycomb sandwich defects, repair defects, and in-service defects. It reviews the methods applicable to the inspection of bonded structures, including visual inspection, ultrasonic inspection, X-ray radiography, and neutron radiography. The evaluation and correlation of inspection results are also discussed. The article concludes with information on the effects of ultrasonic wave interference in the ultrasonic inspection of adhesive-bonded joints.

This article provides information on the microstructure of powder metal alloys and the special handling requirements of porous materials. It covers selection, sectioning, mounting, grinding, and polishing, and describes procedures, such as washing, liquid removal, and impregnation, meant to preserve pore structures and keep them open for analysis. The article compares and contrasts the microstructures of nearly 50 powder metal alloys, using them to illustrate the effect of consolidation and compaction methods as well as particle size, composition, and shape. It discusses imaging equipment and techniques and provides data on etchants and etching procedures.