Liquid penetrant inspection is a nondestructive method of revealing discontinuities that are open to the surfaces of solid and essentially nonporous materials. This article provides information on physical principles, evolution, description, and processing parameters of liquid penetrant inspection as well as materials used. It discusses some of the more generally used types of equipment used in penetrant inspection and their requirements. The article describes various penetrant methods and their selection criteria and provides information on precleaning and postcleaning of workpieces before and after penetrant inspection. The quality assurance and maintenance of penetrant inspection materials are also discussed. The article concludes with information on specifications and standards applicable to penetrant inspection.

Liquid-penetrant inspection is a nondestructive method used to find discontinuities that are open to the surface of solid, essentially nonporous materials. This article describes the physical principles and the process of liquid-penetrant inspection. It also describes the basic penetrant systems, such as the water-washable system, the post-emulsifiable system, and the solvent-removable system. The article provides information on the liquid-penetrant materials, emulsifiers, solvent cleaners, and developers. It details the equipment requirements, selection of penetrant system, and specifications and standards for the liquid-penetrant inspection.

Corrosion is often thought of as rusting, the process of deterioration undergone by a metal when it is exposed to air or water. This article provides the fundamentals of joints corrosion and primarily addresses the various forms of corrosion observed in brazed and soldered joints and their causes. It describes the role of proper brazing procedures in controlling corrosion. The article concludes with information on the corrosion resistance of various brazing alloy systems.

This article provides an overview of surface contaminants that may affect the heat treatment processes and end-product quality. It presents information on the chemicals used to clean different surface contaminants of steels. The article discusses three types of cleaning methods, namely, mechanical, chemical, and electrochemical and their effectiveness and applicability. The mechanical cleaning methods include grinding, brushing, steam or flame jet cleaning, abrasive blasting, and tumbling. Solvent cleaning, emulsion cleaning, alkaline cleaning, acid cleaning, pickling, and descaling are chemical cleaning methods. The electrochemical cleaning methods include electropolishing, electrolytic alkaline cleaning, and electrolytic pickling. The article provides information on cleanliness measurement methods such as qualitative tests and quantitative tests to ensure product quality. Health hazards that may be associated with each cleaning method and the general control measures to be used for each hazard are tabulated.

This article describes the influences of the operational environments of U.S. Navy aircraft during corrosion-control process. The most widely used materials in airframe structures and components, such as aluminum, steel, titanium, and magnesium alloy systems, are reviewed. The article provides information on the inspections steps, corrosion-control issues, and corrosion-prevention strategies for naval aircraft. It contains a table that lists typical locations of corrosion on the aircraft. The article also provides examples of aircraft corrosion damage.

Cast irons and carbon steels are brazeable materials, although the brazeability of cast iron is lower than that of carbon steel. The article provides a detailed discussion on the brazeability of different types of cast iron (malleable iron, ductile iron, and gray iron), carbon steels, and dissimilar metals. It describes the factors considered in the selection of filler-metal for cast iron and carbon steel brazing, such as temperature and environment, brazed joint design, heat source, and heat-treatment requirements. The article also discusses the basic considerations in cleaning and fixturing procedures, filler metal and flux/atmosphere feeding procedures, and the heating methods of cast iron and carbon steel brazing.

Magnetic-particle inspection is a nondestructive testing technique used to locate surface and subsurface discontinuities in ferromagnetic materials. Beginning with an overview of the applications, advantages, and limitations of magnetic-particle inspection, this article provides a detailed account of the portable power sources available for magnetization, and the different ways of generating magnetic fields using yokes, coils, central conductors, prod contacts, direct-contact, and induced current. In addition, the article discusses the characteristics and classification, and properties of magnetic particles and suspended liquids. Finally, the article outlines the types of discontinuities (surface and subsurface) that can be identified by magnetic-particle inspection and the importance of demagnetization after inspection.

Nondestructive inspection (NDI) methods for cast iron are used to ensure that the parts supplied perform as required by the purchaser. This article focuses on the principal nondestructive methods used to inspect for anomalies in cast irons and to determine if the volume, shape, size, or number of these anomalies exceeds the maximum allowed by the purchaser. The nondestructive methods include visual inspection, dimensional inspection, liquid penetrant inspection, magnetic-particle inspection, eddy-current inspection, radiographic inspection, ultrasonic inspection, resonant testing, and leak testing. The technique, strengths, and weaknesses of each of the nondestructive methods are also discussed.

Brazing and soldering are done at temperatures below the solidus temperature of the base material but high enough to melt the filler metal and allow the liquid filler metal to wet the surface and spread into the joint gap by capillary action. This article discusses the common advantages of both brazing and soldering. It describes the brazing and soldering of cast irons, as well as the selection of brazing filler material. The article discusses various brazing methods: torch brazing, induction brazing, salt-bath brazing, and furnace brazing. It concludes with information on the application examples of brazing of cast iron.

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.

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.

This article addresses electrochemical methods for instantaneous rate determination and threshold determination as well as nonelectrochemical methods that can determine incremental or cumulative rates of corrosion. Electrochemical methods for the study of galvanic corrosion rates and localized corrosion and evaluation of corrosion rates under paints are also discussed. The article describes nonelectrochemical methods that can determine incremental or cumulative rates of corrosion. Methods presented include polarization methods, polarization resistance methods, electrochemical impedance methods, frequency modulation methods, electrochemical noise resistance, potential probe methods, cyclic potentiodynamic polarization methods, potentiostatic and galvanostatic methods, electrochemical noise (EN) methods, scratch-repassivation method, and electrochemical impedance spectroscopy (EIS) techniques. Gravimetric determination of mass loss, electrical-resistance methods, magnetic methods, quartz crystal microbalance method, solution analysis methods, and metrological methods are nonelectrochemical methods. The article presents an electrochemical test that examines the susceptibility of stainless steel alloys to intergranular corrosion.

Soldering technology has been used in applications ranging from the packaging of integrated circuit chips to the fabrication of industrial heat exchangers and consequently in structural or electronic applications. This article provides information on various soldering parameters, including types of solder alloy in terms of selection process; selection of substrate base material; flux selection based on adequate wettability by the solder; solder joint assembly; combined substrate, solder, and flux properties; and manufacturing procedures. Each of these parameters is explored using examples of both structural and electronic applications. The article concludes with a discussion on the environmental, safety, and health issues to be considered during soldering.

Magnetic-particle inspection is a method of locating surface and subsurface discontinuities in ferromagnetic materials. This article discusses the applications and advantages and limitations of magnetic-particle inspection. It describes magnetic fields in terms of magnetized ring, magnetized bar, circular magnetization, longitudinal magnetization, and effects of flux direction. General applications, advantages, and limitations of the various magnetizing methods used in magnetic-particle inspection are listed in a table. The article discusses the items that must be considered in establishing a set of procedures for the magnetic-particle inspection of a specific part: type of current, type of magnetic particles, method of magnetization, direction of magnetization, magnitude of applied current, and equipment. It concludes with a discussion on demagnetization after magnetic-particle inspection.