Passivation; pickling, that is, acid descaling; electropolishing; and mechanical cleaning are important surface treatments for the successful performance of stainless steel used for piping, pressure vessels, tanks, and machined parts in a wide variety of applications. This article provides an overview of the various types of stainless steels and describes the commonly used cleaning methods, namely, alkaline cleaning, emulsion cleaning, solvent cleaning, vapor degreasing, ultrasonic cleaning, and acid cleaning. Finishing operations of stainless steels, such as grinding, polishing, and buffing, are reviewed. The article also explains the procedures of electrocleaning, electropolishing, electroplating, painting, surface blackening, coloring, terne coatings, and thermal spraying. It includes useful information on the surface modification of stainless steels, namely, ion implantation and laser surface processing. Surface hardening techniques, namely, nitriding, carburizing, boriding, and flame hardening, performed to improve the resistance of stainless steel alloys are also reviewed.

Although stainless steel is naturally passivated by exposure to air and other oxidizers, additional surface treatments are needed to prevent corrosion. Passivation, pickling, electropolishing, and mechanical cleaning are important surface treatments for the successful performance of stainless steel. This article describes the surface treatment of stainless steels including abrasive blast cleaning, acid pickling, salt bath descaling, passivation treatments, electropolishing, and the necessary coating processes involved. It also describes the surface treatment of heat-resistant alloys including metallic contaminant removal, tarnish removal, oxide and scale removal, finishing, and coating processes.

Thermal inspection comprises all methods in which heat-sensing devices or substances are used to detect irregular temperatures. Inspection of workpieces can be used to detect flaws and undesirable distribution of heat during service. Though there are several methods of thermal inspection and many types of temperature-measuring devices and substances, this article focuses only on thermography, which is the mapping of isotherms, or contours of equal temperature, over a test surface, and on thermometry, which is the measurement of temperature. Thermography techniques can be classified as contact thermographic methods using cholesteric liquid crystals, thermally quenched phosphors, and heat-sensitive paints, and noncontact techniques using hand-held infrared scanners, high-resolution infrared imaging systems, and thermal wave interferometer systems. Contact thermometric inspection devices include bolometers, thermocouples, thermopiles, and meltable substances, whereas radiometers and pyrometers come under the noncontact category.

This article describes the various specimen preparation procedures for lead, lead alloys, and sleeve bearings, including sectioning, mounting, grinding, polishing, and etching. The microscopic examination and microstructures of lead and lead alloys are discussed. The article also provides information on the microstructures of sleeve bearing materials.

Spark source mass spectrometry (SSMS) is an analytical technique used for determining the concentration of elements in a wide range of solid samples, including metals, semiconductors, ceramics, geological and biological materials, and air and water pollution samples. This article discusses the basic principles of spark source technique; SSMS instrumentation such as ion source, electric sector, and magnetic sector; sample preparation; and test procedures of SSMS. Some of the related techniques to SSMS are laser ionization mass spectrometry and laser-induced resonance ionization mass spectrometry. The ions produced in SSMS are detected by either the photometric method or electrical detection method and quantitatively measured by techniques such as internal standardization techniques, isotope dilution, multi element isotope dilution, and dry spike isotope dilution. The detected spark source spectrum contains all the elemental data of the tested sample. Finally, the article exemplifies the applications of SSMS.

This article discusses the advantages and disadvantages of field metallography and describes the important material characteristics and other aspects to be considered before performing any metallographic procedure. It investigates the various stages of sample preparation in the metallographic laboratory: grinding, polishing, etching, preparing a replica, and obtaining a small sample. The article also illustrates the applications of field metallography with case studies.

Iron powders are the most widely used powder metallurgy (P/M) material for structural parts. This article reviews low to medium density iron and low-alloy steel parts produced by the pressing and sintering technology. It explains different powder production methods, including Hoeganaes process, Pyron process, atomization of liquid metal, thermal decomposition and the electrodeposition process for carbonyl and electrolytic iron powders. It describes the types of compaction and sintering, explaining their effects of processing with designations. Further, the article deals with the mechanical and physical properties of ferrous P/M materials, which may depend on certain factors, namely microstructure, porosity, density, infiltration, re-pressing, chemical composition, and heat treatment.

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.

Sputtering is a nonthermal vaporization process in which atoms are ejected from the surface of a solid by momentum transfer from energetic particles of atomic or molecular size. Ionized gases in plasma nitriding chambers often possess enough energy to sputter atoms from workload, fixturing, and racking surfaces that are then redeposited to the benefit or detriment of the nitriding process. This article explains how and why sputtering occurs during plasma nitriding and how to recognize and control its effects. It reviews the factors that influence the intensity of sputtering and its effects, whether positive or negative, on treated parts. It also provides recommendations for improving outcomes when nitriding titanium alloys, ferrous metals, particularly stainless steels, and components with complex geometries.

With regard to documentation and photography of a catastrophic event, the field investigator's duties are fundamentally different from those of the laboratory-based analyst, even though both share the same goals. This article presents a case study on documentation considerations during the field investigation. It provides a detailed discussion on the general procedure to downselect from a multicomponent assemblage to a set of potential primary failed components. The article describes visual examination in macrofractography.

Certain metal products can be produced only by powder metallurgy; among these products are materials whose porosity is controlled. Successful production by powder metallurgy depends on the proper selection and control of process variables: powder characteristics; powder preparation; type of compacting press; design of compacting tools and dies; type of sintering furnace; composition of the sintering atmosphere; choice of production cycle, including sintering time and temperature; and secondary operations and heat treatment. When the application of a powder metallurgy part requires high levels of strength, toughness, or hardness, the mechanical properties can be improved or modified by infiltration, heat treatment, or a secondary mechanical forming operation such as cold re-pressing or powder forging. The article also discusses the effect of the secondary processes on P/M mechanical properties.

This article focuses on the various coatings used on Department of Defense (DoD) systems. These include electroplated coatings; conversion coatings; supplemental oils, waxes, and lubricants; organic paint coatings; and other finishes such as vacuum deposits, mechanical plating, thermal spray coatings, and hot-dip coatings. The article also lists the test requirements and time to failure of the coatings.

Low-energy ion-scattering spectroscopy (LEISS) is used extensively to analyze solid surfaces. The LEISS process relies on binary elastic collisions between an incident ion beam and the atoms in a sample to obtain information on the surface atoms. The velocity of the scattered ions is used to determine the mass of the atoms that are struck. This article introduces LEISS and its principles. It describes the use of LEISS spectra in qualitative and quantitative analyses, and reviews the instrumentation and applications of LEISS.

This article reviews various segments of the powder metallurgy (PM) process from powder production and powder processing through the characterization of the materials and their properties. It covers the processing methods for consolidating metal powders including options for processing to full density. The article outlines the freeform fabrication process, also known as additive manufacturing and describes finishing operations of PM parts. It concludes with information on the applications of PM parts.

The selection of surface treatments for copper and copper alloys is generally based on application requirements for appearance and corrosion resistance. This article describes cleaning, finishing, and coating processes for copper and copper alloys. These processes include pickling and bright dipping, abrasive blast cleaning, chemical and electrochemical cleaning, mass finishing, polishing and buffing, electroless plating, immersion plating, electroplating, passivation, coloring, and organic coatings.

This article describes the surface modification treatments used to modify the tribological properties of titanium alloys. These include physical vapor deposition and thermochemical conversion treatments. The physical vapor deposition includes ion implantation, sputtering, evaporation, and ion plating surface modification treatments. The thermochemical conversion surface treatments include nitriding, carburizing, boriding, and solid lubrication.

The primary market for metal powder is the production of powder metallurgy (PM) parts, which are dominated primarily by iron and copper powders. This article reviews the chemical and pyrotechnics applications of ferrous and nonferrous powders. It describes the characteristics of iron powder used in oxygen scavengers and chemical reactive warmers and heaters. Metal powders used as fuels in solid propellants, pyrotechnic devices, explosives, and similar applications are reviewed. Atomized aluminum, magnesium, tungsten, and zirconium powders are also discussed.

Fracture surfaces can provide an important and indispensable record of many factors in simple or complex failures. Visual examination of fracture surfaces can reveal the type and direction of loading, with fracture-surface features often providing definitive evidence of torsion, tension, bending, and compressive loads. This article discusses tools and techniques of visual examination and characteristic features of fracture features. A brief review of ductile and brittle fracture-surface features is provided. The article also describes macroscopic features that can be used to identify fracture-initiation sites, locations of final overload, and the directions of crack propagation. In addition, the use of these features to characterize loading at the time of failure is also described.

This article provides a historical review of corrosion problems in military electronic equipment. It describes the importance of design for corrosion control of an electronic black box used to contain electrical equipment that provides various functions. The article illustrates corrosion control aspects, such as the position of printed circuit boards (PCBs) and proper location of connectors for insertion of the PCBs. It discusses various materials and alloys considered for connectors, PCB contacts, and circuits. The article concludes with a discussion on the effects of contaminants on the electronic black box.