Erosion of a solid surface can be brought about by liquid droplet impingement (LDI), which is defined as "progressive loss of original material from a solid surface due to continued exposure to erosion by liquid droplets." In this article, the emphasis is placed on the damage mechanism of LDI erosion under the influence of a liquid film and surface roughness and on the prediction of LDI erosion. The fundamentals of LDI and processes involved in initiation of erosion are also discussed.

Erosion is the progressive loss of original material from a solid surface due to mechanical interaction between that surface and a fluid, a multicomponent fluid, an impinging liquid, or impinging solid particles. The detrimental effects of erosion have caused problems in a number of industries. This article describes the processes involved in erosion of ductile materials, brittle materials, and elastomers. Some examples of erosive wear failures are given on abrasive erosion, liquid impingement erosion, cavitation, and erosion-corrosion. In addition, the article provides information on the selection of materials for applications in which erosive wear failures can occur.

This article discusses the basic principles of inductively coupled plasma mass spectrometry (ICP-MS), covering different instruments used for performing ICP-MS analysis. The instruments covered include the sample-introduction system, ICP ion source, mass analyzer, and ion detector. Emphasis is placed on ICP-MS applications in the semiconductor, photovoltaic, materials science, and other electronics and high-technology areas.

Copper and copper alloys are widely used in many environments and applications because of their excellent corrosion resistance, which is coupled with combinations of other desirable properties. This article lists the identifying characteristics of the forms of corrosion that commonly attack copper metals as well as the most effective means of combating each. General corrosion, galvanic corrosion, pitting, impingement, fretting, intergranular corrosion, dealloying, corrosion fatigue, and stress-corrosion cracking (SCC) are some forms of corrosion. The article also lists a galvanic series of metals and alloys valid for dilute aqueous solutions, such as seawater and weak acids. It provides useful information on the effects of alloy compositions, selection for specific environments, and atmospheric corrosion of selected copper alloys. The article also tabulates the corrosion ratings of wrought copper alloys in various corrosive media.

This article provides a general introduction on casting processes and design. It discusses the process steps and methods of the main categories of shape casting methods, namely, expendable molds with permanent patterns, expendable molds with expendable patterns, and metal or permanent mold processes. The article lists general guidelines of geometry in casting design. It describes the factors, such as mold complexity and casting solidification, in casting design. The solidification of a casting can involve as many as three separate contractions as a result of cooling: liquid-liquid contraction, solid-solid contraction, and liquid-solid contraction. The article discusses the factors influencing the solidification sequence of simple shapes, such as T-sections, X-sections, and L-sections. It also provides an overview of geometric factors that influence heat transfer and transport phenomena. The article concludes with a description of the structure and properties of a casting.

This article focuses on the concepts involved in heat-transfer modeling, thermomechanical modeling, and microsegregation modeling of hot tearing. It discusses the modeling of solidification defects, namely, inclusion entrapment, segregation, shrinkage cavities, gas porosity, mold-wall erosion, and hot-tear cracks.

Titanium alloys are often used in highly corrosive environments because they are better suited than most other materials. The excellent corrosion resistance is the result of naturally occurring surface oxide films that are stable, uniform, and adherent. This article offers explanations and insights on the most common forms of corrosion observed with titanium alloys, including general corrosion, crevice corrosion, anodic pitting, hydrogen damage, stress-corrosion cracking, galvanic corrosion, corrosion fatigue, and erosion-corrosion. It also provides practical strategies for expanding the useful application range for titanium and includes a comprehensive overview of available corrosion data.

This article considers the main characteristics of wear mechanisms and how they can be identified. Some identification examples are reported, with the warning that this task can be difficult because of the presence of disturbing factors such as contaminants or possible additional damage of the worn products after the tribological process. Then, the article describes some examples of wear processes, considering possible transitions and/or interactions of the mechanism of fretting wear, rolling-sliding wear, abrasive wear, and solid-particle erosion wear. The role of tribological parameters on the material response is presented using the wear map concept, which is very useful and informative in several respects. The article concludes with guidelines for the selection of suitable surface treatments to avoid wear failures.

High-temperature corrosion can occur in numerous environments and is affected by various parameters such as temperature, alloy and protective coating compositions, stress, time, and gas composition. This article discusses the primary mechanisms of high-temperature corrosion, namely oxidation, carburization, metal dusting, nitridation, carbonitridation, sulfidation, and chloridation. Several other potential degradation processes, namely hot corrosion, hydrogen interactions, molten salts, aging, molten sand, erosion-corrosion, and environmental cracking, are discussed under boiler tube failures, molten salts for energy storage, and degradation and failures in gas turbines. The article describes the effects of environment on aero gas turbine engines and provides an overview of aging, diffusion, and interdiffusion phenomena. It also discusses the processes involved in high-temperature coatings that improve performance of superalloy.

This article provides a brief review of the classification and characteristics of cast irons. It describes the processes used to clean iron castings, including mechanical cleaning and finishing and nonmechanical cleaning. The article discusses surface treatments used to extend casting life when resistance to corrosion, wear, and erosion is required. The common methods include electroplating, electroless plating, hardfacing, weld cladding, surface hardening, porcelain enameling, and organic coatings.

Portland cement concrete has low environmental impact, versatility, durability, and economy, which make it the most abundant construction material in the world. This article details the types and causes of concrete degradation. Concrete can be degraded by corrosion of reinforcing steel and other embedded metals, chlorides, carbonation, galvanic corrosion, chemical attack, alkali-aggregate reaction, abrasion, erosion, and cavitation as well as many other factors. The article addresses the durability of concrete by two approaches, namely, the prescriptive approach and the performance approach. In the former, designers specify materials, proportions, and construction methods based on fundamental principles and practices that exhibit satisfactory performance. In the latter, designers identify functional requirements such as strength, durability, and volume changes and rely on concrete producers and contractors to develop concrete mixtures to meet those requirements.

This article provides an overview of the identification systems for various grades of wrought stainless steels, namely, the American Iron and Steel Institute numbering system, the Unified Numbering System, and proprietary designations. It elaborates on five major families of stainless steels, as defined by the crystallographic structure. These include ferritic stainless steels, austenitic stainless steels, martensitic stainless steels, and precipitation-hardening stainless steels. The mechanism of corrosion protection for stainless steels is reviewed. The article examines the effects of composition, processing, design, fabrication, and external treatments on the corrosion of stainless steels. Various forms of corrosion, namely, general, galvanic, pitting, crevice, intergranular, stress-corrosion cracking, erosion-corrosion, and oxidation, are reviewed. Corrosion testing for; corrosion in atmosphere, water, and chemical environments; and the applications of stainless steels in various industries are also discussed.

This article provides a description of the classification, industrial applications, microstructures, physical, chemical, corrosion, and mechanical properties of zirconium and its alloys. It discusses the formation of oxide films and the effects of water, temperature, and pH on zirconium. The delayed hydride cracking of zirconium is also described. The article provides information on the resistance of zirconium to various types of corrosion, including pitting corrosion, crevice corrosion, intergranular corrosion, galvanic corrosion, microbiologically induced corrosion, erosion-corrosion, and fretting corrosion. The article explains the effects of tin content in zirconium and effects of fabrication on corrosion. Corrosion control measures for all types of corrosion are also highlighted. The article concludes with information on the safety precautions associated with handling of zirconium.

Analysis of the failure of a metal structure or part usually requires identification of the type of failure. Failure can occur by one or more of several mechanisms, including surface damage (such as corrosion or wear), elastic or plastic distortion, and fracture. This leads to a wide range of failures, including fatigue failure, distortion failure, wear failure, corrosion failure, stress-corrosion cracking, liquid-metal embrittlement, hydrogen-damage failure, corrosion-fatigue failure, and elevated-temperature failure. This article describes the classification of fractures on a macroscopic scale as ductile fractures, brittle fractures, fatigue fractures, and fractures resulting from the combined effects of stress and environment.

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.

No-bake sand molds are based on curing of inorganic or organic binders with either gaseous catalysts or liquid catalysts. This article reviews the major aspects of no-bake sand bonding in terms of coremaking, molding methods, and sand processing. It discusses the points to be noted in handling sand-resin mixtures for no-bake molds or cones and lists some advantages of no-bake air-set cores and molds. The article describes the process procedures, advantages, and disadvantages of gas curing and air-setting hardening of sodium silicates. It discusses the members of the air-setting organic binders, namely, furan no-bake resins, phenolic no-bake resins, and urethanes. The article provides an overview of gas-cured organic binders. It also illustrates the three commercial systems for sand reclamation: wet reclamation systems, dry reclamation systems, and thermal reclamation.

Sintering provides the interparticle bonding that generates the attractive forces needed to hold together the otherwise loose ceramic powder mass. It also improves hardness, strength, transparency, toughness, electrical conductivity, thermal expansion, magnetic saturation, corrosion resistance, and other properties. This article discusses the fundamentals of sintering and its effects on pore structures and particle density. It addresses some of the more common sintering methods, including solid-state, liquid-phase, and gas pressure sintering, and presents alternative processes such as reaction sintering and self-propagating, high-temperature synthesis. It also describes several pressure densification methods, including hot isostatic pressing, gas pressure sintering, molten particle deposition, and sol-gel processing. The article concludes with a section on grain growth that discusses the underlying mechanisms and kinetics and the relationship between grain growth and densification.

This article presents a detailed account on the process flow, composition, alternative sources, and the advancement of ironmaking, steelmaking and secondary steelmaking practices. Some steels, such as bearing steels, heat-resistant steels, ultrahigh strength missile and aircraft steels, and rotor steels have higher quality requirements and tighter composition control than plain carbon or ordinary low-alloy steels. The production of special-quality steels requires vacuum-based induction or electric remelting and refining capabilities. The article explores the types and characteristics of various steel manufacturing processes, such as ingot casting, continuous casting, and hot rolling. It provides an outline of specialized processing routes of producing ultralow plain carbon steels, interstitial-free steels, high strength low-alloy steels, ultrahigh strength steels, stainless steels, and cold-rolled products, and briefly explains the analytical techniques for liquid steels.

Advanced thermoplastics are stiff, moldable plastics that compete with traditional engineering thermoplastics and thermosets owing to their good tensile, compressive, impact, and shear strength, electrical properties, and corrosion resistance. This article discusses commercial forms, family characteristics, properties and applications of the following advanced thermoplastics: homopolymer and copolymer acetals, fluoropolymers, ionomers, polyamides, polyamide-imides, polyarylates, polyketones, polyaryl sulfones, polybutylene terephthalates, polycarbonates, polyether-imides, polyether sulfones, polyethylene terephthalates, thermoplastic polyimides, liquid crystal polymers, polyphenylene ether blends, polyphenylene sulfides, and polysulfones.

Wear is mechanically-induced surface damage that results in the progressive removal of material. Because different types of wear occur in machinery, many different types of wear tests have been developed to evaluate its effects on materials and surface treatments. This article provides an explanation on mechanisms, forms (sliding, impact, and rolling) and the causes of wear. It describes the wear measuring methods, including the mass loss method, wear width method, and scar depth method. The units used to report wear vary with type of wear and with the purpose for which the data are to be used. Listing the considerations of tribosystem analysis, the article provides information on selection of ASTM wear test methods grouped by wear type. The article concludes by tabulating the testing geometries and parameters that are commonly controlled and reported when conducting wear tests.