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 briefly introduces some commonly used methods for mechanical testing. It describes the test methods and provides comparative data for the mechanical property tests. In addition, creep testing and dynamic mechanical analyses of viscoelastic plastics are also briefly described. The article discusses the processes involved in the short-term and long-term tensile testing of plastics. Information on the strength/modulus and deflection tests, impact toughness, hardness testing, and fatigue testing of plastics is also provided. The article describes tension testing of elastomers and fibers. It covers two basic methods to test the mechanical properties of fibers, namely the single-filament tension test and the tensile test of a yarn or a group of fibers.

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.

This article reviews the factors that have a significant effect on the selection and interpretation of results of different hardness tests, namely, Brinell, Rockwell, Vickers, and Knoop tests. The factors concerned include hardness level (and scale limitations), specimen thickness, size and shape of the workpiece, specimen surface flatness and surface condition, and indent location. The article focuses on the selection for specific types of materials, such as steels, cast irons, nonferrous alloys, and plastics, and industrial applications, of hardness tests.

The article provides a discussion on the parameters influencing abrasive wear and the elements and standards of abrasion wear tests. It emphasizes the general test procedures, advantages, and limitations of various types of abrasive wear testing. Wear testing for scratch wear, dry abrasion against fixed particles, dry abrasion against loose particles, wet abrasion against fixed or loose particles, gouging-abrasion, small particle erosion, impact abrasion, slurry abrasion, and microabrasion, are also discussed.

This article reviews the general mechanical properties and test methods commonly used for ceramics and three categories of polymers, namely, fibers, plastics, and elastomers. The mechanical test methods for determining the tensile strength, yield strength, yield point, and elongation of plastics include the short-term tensile test, the compressive strength test, the flexural strength test, and the heat deflection temperature test. The most commonly used tests for impact performance of plastics are the Izod notched-beam test, the Charpy notched-beam test, and the dart penetration test. Two basic test methods for a group or strand of fibers are the single-filament tension and tow tensile tests. Room temperature strength tests, high-temperature strength tests, and proof tests are used for testing the properties of ceramics.

Independent verification of coating system performance can be based on laboratory testing and/or field exposure. Qualification testing is a critical component to coating system selection. This article focuses on performance evaluations that are used to prequalify coating systems, namely, facility-specific, industry-specific, coating-type-specific, or a combination of these. It describes the standard laboratory tests used to generate performance data, namely, physical, compositional, chemical exposure, and application characteristics tests. The pros and cons of using manufacturer-generated data versus independently generated data are discussed. The article provides information on accelerated corrosion/weathering testing and nuclear level 1/level 2 service coatings qualification. It also describes the procedures for establishing minimum performance requirements and for determining when requalification testing may be required.

This article discusses the concepts of quality control (QC) and quality assurance (QA), and clarifies the differences and similarities in the roles and responsibilities of QC and QA personnel. It describes the inspection procedures used to verify proper surface preparation and installation of the protective coating/lining system. Prior to beginning surface-preparation operations, many specifications will require a presurface-preparation inspection to verify the correction of fabrication defects and removal of surface contamination such as grease, oil, cutting compounds, lubricants, and chemical contaminants. When inspecting concrete prior to coating installation, three areas of concern exist: surface roughness, moisture content in concrete, and acidity/alkalinity of the surface. The article provides information on the industry standards for assessing surface cleanliness. It details postcoating application quality requirements, including measuring of dry-film thickness, assessing intercoat cleanliness, verifying minimum and maximum recoat intervals, performing holiday/pinhole detection, conducting cure/hardness testing, and assessing adhesion of the applied coating system.

Mechanical testing is an evaluative tool used by the failure analyst to collect data regarding the macro- and micromechanical properties of the materials being examined. This article provides information on a few important considerations regarding mechanical testing that the failure analyst must keep in mind. These considerations include the test location and orientation, the use of raw material certifications, the certifications potentially not representing the hardware, and the determination of valid test results. The article introduces the concepts of various mechanical testing techniques and discusses the advantages and limitations of each technique when used in failure analysis. The focus is on various types of static load testing, hardness testing, and impact testing. The testing types covered include uniaxial tension testing, uniaxial compression testing, bend testing, hardness testing, macroindentation hardness, microindentation hardness, and the impact toughness test.

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 is a compilation of terms related to mechanical testing and evaluation of metals, plastics, ceramics, and composites.

This article is an informative primer on sealants and the role they play in engineered assemblies. It discusses the physical, thermal, chemical, and electrical properties of sealant materials and the various forms in which they are applied, including liquids, pastes, and extruded tapes. It also describes classifications and types, comparing and contrasting sealants made from oil-based caulks, asphalts, coal tar resins, latex acrylic sealants, polyvinyl acetate caulks, solvent acrylics, butyl sealants, polysulfides, polyurethanes, modified silicones, anaerobics, vinyl plastisols, and polypropylenes. In addition, the article provides practical design insight, addressing application requirements, seal configurations, and joint stresses. It concludes with a brief discussion on the use of sealants in aerospace, automotive, electrical, and construction applications.

Material jetting (MJ) is a classification of additive manufacturing processes that involves the selective jetting and subsequent solidification of liquid droplets onto a substrate in a layerwise manner. This article focuses solely on MJ of polymers, providing a process overview and describing the functional characteristics that distinguish it from other AM technologies. It provides information on the properties and design considerations of both build and support materials. Process-related effects on final part properties and overall quality, as well as corresponding design considerations are also covered. The article also discusses the applications and future scope of polymer MJ systems.

This article describes the use of conventional machining techniques, laser cutting and water-jet cutting for producing finished composite parts. It explains two representative polymer-matrix composites--graphite and aramid composites--and discusses the machining and drilling problems such as delamination and fiber or resin pullout. The article describes machining and drilling techniques and the necessary tools and cutting parameters. It presents a description of laser cutting. The article also provides information on the advantages, disadvantages, cutting characteristics, and applications of water-jet cutting and abrasive water-jet cutting.

Polyvinylidene fluoride (PVDF)-based coatings are typically used in outdoor applications that require exceptionally high performance and excellent long-term exterior durability with little maintenance. This article provides a background of three fluoropolymers most commonly used for coatings, namely, PVDF, polyvinyl fluoride, and polytetrafluoroethylene. It focuses on general properties, polymerization, resin types, coating formulation, technology of organic coatings, coating properties, and health and related safety considerations of PVDF. The article describes the application and typical end uses of PVDF-based coatings and the opportunities for improvement in PVDF-based coatings as with all organic coatings.

This article discusses the properties, chemical structures, and applications of different types of elastomers grouped based on their resistance to aging (oxidative degradation), solvents, and temperature. These include butadiene rubber, natural rubber, isoprene rubber, chloroprene rubber, styrene-butadiene rubber, aerylonitrile-butadiene (nitrile) rubber, isobutylene-isoprene (butyl) rubber, ethylene-propylene (-diene) rubber, and silicone rubber. The article also provides an outline of the concerns related to the processing stages of rubbers or elastomers, including mixing or compounding, shaping, and vulcanizing or crosslinking.

This article is a compilation of definition of the terms related to thermal spray coating technology.

This article is a comprehensive collection of engineering tables providing information on the mechanical properties of and the techniques for processing and characterizing polymeric materials, such as thermosets, thermoset-matrix unidirectional advanced composites, and unreinforced and carbon-and glass-reinforced engineering thermoplastics. Values are also provided for chemical resistance ratings for selected plastics and metals, and hardness of selected elastomers.