Hydrochloric acid (HCl) may contain traces of impurities that will change the aggressiveness of the solution. This article discusses the effects of impurities such as fluorides, ferric salts, cupric salts, chlorine, and organic solvents, in HCl. It describes the corrosion resistance of various metals and alloys in HCl, including carbon and alloy steels, austenitic stainless steels, standard ferritic stainless steels, nickel and nickel alloys, copper and copper alloys, corrosion-resistant cast iron, zirconium, titanium and titanium alloys, tantalum and its alloys, and noble metals. The article illustrates the effect of HCl on nonmetallic materials such as natural rubber, neoprene, thermoplastics, and reinforced thermoset plastics. It also tabulates the corrosion of various metals in dry hydrogen chloride.

Natural and synthetic rubber linings are used extensively in many industries for their corrosion and/or abrasion resistance. These industries include transportation, chemical processing, water treatment, power, mineral processing, and mining. This article provides information on soft natural rubber, semihard natural rubber, hard natural rubber, neoprene or polychloroprene, chlorobutyl, three-ply linings, nitrile, and ethylene propylene with a diene monomer. Emphasis is placed on advantages, disadvantages, and common uses of each material discussed.

Rough grinding and polishing of specimens are required to prepare fiber-reinforced composite samples for optical analysis. This article discusses the consumables, process variables, and the equipment that influence the sample preparation procedure. It describes the hand and automated grinding methods. The article summarizes the rough and final polishing steps for both hand and automated techniques. Common artifacts that may be created during grinding and polishing steps of composite samples are reviewed. These include scratches, fiber pull-out, matrix smears, streaks, erosion of different phases, and fiber and sample edge rounding and relief.

Elastomers belong to a group of materials known as polymers that acquire their properties and strength from their molecular weight, chain entanglements, and crystalline regions. This article focuses on the use of elastomers as seals and describes its performance capabilities from the point of a sealant. The important technical concepts that define the performance capabilities of the elastomeric part include polymer architecture (molecular building blocks), compounding (the ingredients within the polymer), and vulcanization of the elastomer shape. The article discusses the aggressiveness of the chemical environment, temperature, and minor constituents in the environment and in the material itself that affect the chemical resistance of the elastomer. It provides a discussion on performance evaluation methods, namely, immersion testing and application specific testing that are determined using ISO and ASTM standards. The article concludes with information on elastomer failure modes and failure analysis.

This article presents a detailed discussion on the relative performance properties of principal rubber types used in lining applications together with their application, vulcanization and inspection techniques, and material and installation costs.

Microscopy is a valuable tool in materials investigations related to problem solving, failure analysis, advanced materials development, and quality control. This article describes the sample preparation techniques of composite materials. These techniques include mounting, rough grinding, and polishing. The preparation techniques of ultrathin sections are also summarized. The article explains the illumination methods used by reflected light microscopy to view a specimen. These consist of epi-bright-field illumination, epi-dark-field illumination, epi-polarized light, and epi-fluorescence. The article also provides information on transmitted light microscopy.

This article provides information on personal protective equipment (PPE), consistent with the Occupational Safety and Health Administration's Personal Protective Equipment Standard (29 CFR 1910.132-138). This standard is intended to protect individuals from the risk of injury by creating a barrier against workplace hazards. This article provides guidelines for establishing PPE programs with an overview of the responsibilities for employers, supervisors, and employees, assessing hazards associated with thermal spray operations, and training workers about PPE, as well as guidelines for selecting, using, and maintaining PPE. It presents an overview of eye, face, head, hand, foot, hearing, fall, and respiratory protection. Respiratory and hearing protection should be used in conjunction with industrial hygiene monitoring.

Adhesive bonding is a proven technology in the manufacture of automotive assemblies, helping carmakers achieve weight reduction goals without compromising body stiffness, crash performance, and noise-vibration-handling characteristics. This article discusses the advantages and limitations of adhesive-bonded aluminum joints and the procedures used to produce them. It addresses surface preparation, the addition of interfacial coatings and primers, and the application of thermoplastic and thermosetting resins. The article examines the nature and role of the various layers that constitute the joint and explains how each contributes to performance. It also discusses adhesive selection factors, joint design, and testing procedures.

Mechanical plating is a method for coating ferrous metals, copper alloys, lead, stainless steel, and certain types of castings by tumbling the parts in a mixture of glass beads, metallic dust or powder, promoter or accelerator chemicals, and water. It offers a straightforward alternative method for achieving desired mechanical and galvanic properties with an extremely low risk of hydrogen embrittlement. This article provides a detailed description of the equipment, process steps, process capabilities, applicable parts, specific characteristics, advantages, limitations, post treatments, and waste treatment of mechanical plating.

Miscellaneous hardness tests encompass a number of test methods that have been developed for specific applications. These include dynamic, or "rebound," hardness tests using a Leeb tester or a Scleroscope; static indentation tests on rubber or plastic products using the durometer or IRHD testers; scratch hardness tests; and ultrasonic microindentation testing. This article reviews the procedures, equipment, and applications associated with these alternate hardness test methods.

This article describes the steps, bath composition and characteristics, equipment, plating rate, deposit thickness, and applications for different types of nonelectrolytic deposition processes, including electroless nickel plating, electroless copper plating and mechanical plating.

This article provides a brief discussion on the common types of overlayers that can be used on a metal surface to protect it from corrosion. These overlayers include phosphate, chromate, and chromate-free conversion coatings; hot dip galvanizing; cementitious linings; glass and porcelain enamels; electroplating; thermal spray coatings; and rubber linings.

Lead has been deposited from a variety of electrolytes, including fluoborates, fluosilicates, sulfamates, and methane sulfonic acid baths. This article provides a discussion on these electrolytic baths and includes information on the process sequence, equipment requirements, and applications of lead plating.

Gas chromatography/mass spectrometry (GC/MS) is useful in analyzing mixtures of organic compounds. This article commences with a description of the principles of mass spectrometry and gas chromatography. It provides information on the procedures of mass spectrum interpretation, and describes the experimental procedure of and sample preparation for GC/MS. The article also discusses complementary techniques, such as high-performance liquid chromatography/mass spectrometry and mass spectrometry/mass spectrometry, and concludes with the applications of GC/MS.

Wipe solvents are used to remove contaminants from a workpiece before it undergoes manufacturing operations that require clean surfaces, such as bonding, sealing, painting, welding, plating, specialized surface treatment procedures, and others. This article describes the evaluation parameters for wipe solvent cleaners, including methyl ethyl ketone, methyl isobutyl ketone, trichloroethene, tetrachloroethylene, acetone, toluene, dichloromethane, benzene, xylene, and other alternate wipe solvent cleaners. It contains a table that lists the compositions and properties of wipe solvent cleaners.

This article describes the selection of materials for the production and handling equipment of concentrated sulfuric acid, depending on factors such as the allowable corrosion rate, desired mechanical and physical properties, fabrication requirements, availability, and cost. Materials such as carbon steel, cast irons, austenitic stainless steels, higher austenitic stainless steels, higher chromium Fe-Ni-Mo alloys, nickel-base alloys, non-metals, and specific other metals and alloys are also discussed.

This article describes the unique aspects of cold isostatic pressing (CIP) in comparison with die compaction, for powder metallurgy parts. It details the components of CIP equipment, including pressure vessels, pressure generators, and tooling material. The article reviews the part shapes and their influence in determining tap density of the filled mold. It provides a discussion on process parameters, such as dwell time, depressurization rate, evaluation of green strength and density, and thermal processing, and illustrates a process flowchart for the production of CIP parts.

Beryllium is a metal with an unusual combination of physical and mechanical properties that make it particularly effective in optical components, precision instruments, and specialized aerospace applications. Almost all of the beryllium in use is a powder metallurgy (P/M) product. Beginning with an overview of the mining and refining processes of beryllium, this article discusses powder production and consolidation methods, beryllium grades and their designations, and the protective measures that have been enacted to reduce exposure to beryllium.

Curing is the irreversible change in the physical properties of a thermosetting resin brought about by a chemical reaction, condensation, ring closure, or addition. This article discusses the material types and functions of various components considered in the preparation for curing. It presents a discussion on the major elements of an autoclave system, namely, pressure vessel, gas stream heating and circulation sources, gas stream pressurizing systems, loading systems, and vacuum systems. The article describes a computerized approach to the simultaneous control of materials reaction behavior and consolidation dynamics, using an autoclave as the reaction vessel.