This chapter covers coatings and treatments that are used to improve the friction and wear behaviors of materials. It describes modifications that work by hardening contacting surfaces, including heat treating, vacuum coating, thermal spray, and plating, and those that separate or lubricate surfaces, including solid film, chemical conversion, and vacuum coatings, surface oiling and texturing, and lubricating platings. It compares and contrasts methods based on thickness and depth and their relative effect on friction, erosion, and wear.

This chapter covers the friction and wear behaviors of carbon, alloy, and tool steels. It begins a review of commercially available shapes and forms. It then describes the metallurgy and microstructure of various designations and grades of each type of steel and explains how it affects their performance in adhesive and abrasive wear applications and in environments where they are subjected to solid particle, droplet, slurry, and cavitation erosion and fretting damage.

This chapter covers common types of erosion, including droplet, slurry, cavitation, liquid impingement, gas flow, and solid particle erosion, and major types of wear, including abrasive, adhesive, lubricated, rolling, and impact wear. It also covers special cases such as galling, fretting, scuffing, and spalling and introduces the concepts of tribocorrosion and biotribology.

This chapter covers the tribological properties of stainless steel and other corrosion-resistant alloys. It describes the metallurgy and microstructure of the basic types of stainless steel and their suitability for friction and wear applications and in environments where they are subjected to liquid, droplet, and solid particle erosion. It also discusses the tribology of nickel- and cobalt-base alloys as well as titanium, zinc, tin, aluminum, magnesium, beryllium, graphite, and different types of wood.

This chapter covers the friction and wear behaviors of cast irons. It describes the microstructure and metallurgy of gray, white, malleable, and ductile cast irons, their respective tensile properties, and their suitability for applications involving friction, various types of erosion, and adhesive and abrasive wear.

This chapter covers the friction and wear behaviors of copper alloys. It describes the compositions and forms of copper available and their suitability for applications involving friction, different types of erosion, and adhesive and abrasive wear.

This chapter provides guidelines and insights on the selection of materials, coatings, and treatments for friction and wear applications. It begins with a review of the system nature of tribological effects, the subtleties of friction, and the selection idiosyncrasies of the material systems and lubricants covered in prior chapters. It then presents a systematic approach for selecting tribomaterials, using an automotive fan motor as an example.

This chapter concerns itself with the tribology of ceramics, cermets, and cemented carbides. It begins by describing the composition and friction and wear behaviors of aluminum oxide, silicon carbide, silicon nitride, and zirconia. It then compares and contrasts the microstructure, properties, and relative merits of cermets with those of cemented carbides.

This chapter covers the tribological properties of different types of oil, greases, solid lubricants, and metalworking and traction fluids. It explains how lubricants are made, how they work, and how they are applied and tested. It also discusses the fundamentals of lubrication and friction control, the relationship between viscosity and breakaway friction, and the factors that affect load-carrying capacity and service life.

This chapter discusses the processes and procedures involved in tribotesting, the significance of test parameters and conditions, and practical considerations including test metrics and measurements and the interpretation of wear damage. It also describes the different types of erosion tests in use and common approaches for adhesive wear and abrasion testing.

This chapter covers the friction and wear behaviors of plastics and elastomers. It begins by describing the molecular differences between the two types of polymers and their typical uses. It then discusses the important attributes of engineering plastics and their suitability for applications involving friction, erosion, and adhesive and abrasive wear. It also discusses the tribology of elastomers and rubber along with their basic differences and the conditions under which they produce Schallamach waves. It includes information on polymer composites as well.

Cast irons, like steels, are iron-carbon alloys but with higher carbon levels than steels to take advantage of eutectic solidification in the binary iron-carbon system. Like steel, heat treatment of cast iron includes stress relieving, annealing, normalizing, through hardening, and surface hardening. This chapter introduces solid-state heat treatment of iron castings, covering general considerations for heat treatment and discussing the processes, advantages, and disadvantages of heat treatment of cast iron.

This chapter provides a practical understanding of heat treatments and how to employ them to optimize the properties and structures of cast irons and steels. It discusses annealing, normalizing, quenching, tempering, patenting, carburizing, nitriding, carbonitriding, and nitrocarburizing. It describes the primary objectives of each treatment along with processing sequences, process parameters, and related phase transformations. The chapter contains more than 100 images, including time-temperature diagrams, transformation curves, data plots, and detailed micro- and macrographs. It also discusses the concepts of hardenability, critical diameter, quench severity, and Jominy testing.

Mechanical components often require surface treatments to meet application demands. This chapter describes several surface hardening treatments for steel and their effect on microstructure, composition, and properties. It discusses flame hardening, induction heating, carburizing, nitriding, carbonitriding, and nitrocarburizing. The discussion on carburizing addresses several interrelated factors, including processing principles, alloying, surface oxidation, residual stresses, bending fatigue, contact fatigue, and fracture.

Induction heat treating is used in a wide range of applications. Typical uses, as described in this chapter, include the surface hardening of many types of shafts as well as gears and sprockets and the through-hardening of gripping teeth, cutting edges, and impact zones incorporated into various types of tools and track pins manufactured for off-highway equipment.

This chapter discusses the methods and procedures used for inspecting induction-hardened parts. It provides information on hardness and case depth measurements, nondestructive testing and surface analysis, the effect of various hardening errors, and relevant test standards.

The surface condition of metals can have a significant effect on the outcome of high-temperature processes and vice versa. This chapter discusses the general cleaning and surface treatment needs of work in-process both before and after induction hardening. It identifies contaminants and defects associated with various quenchants and processing atmospheres and provides insights on how they can be removed and, in some cases, prevented. It also recommends the application of a rust preventative shortly after parts have cooled.

This chapter discusses the basic principles of induction heating and related engineering considerations. It describes the design and operation of induction coils, the magnitude and distribution of magnetic fields, and the forces that generate eddy currents in metals. It explains how induced electrical current causes metal to heat in proportion to their electrical resistance and how it affects temperature dependent properties such as resistivity and specific heat and, in turn, heating rates and efficiencies. It also discusses the effect of hysteresis and explains why eddy currents tend to be confined to the outer surface of the workpiece, a phenomenon known as the skin effect. The chapter includes several data plots showing how the depth of heating varies with frequency and how heating time, power density, and thermal conduction rate correspond with hardening depth.

This chapter covers the fundamentals of heat treating. It begins with a review of the composition, classification, and properties of iron and steel, the phases of the iron-carbon system, and the basic types of heat treatments. It then discusses the topics of hardness and hardenability, the role of carbon in the hardening of steels, the process of austenitization, and the influence of cooling rate on subsequent transformations. The chapter also explains how induction heating affects residual stress, distortion, and grain size.