This chapter describes surface modification processes that go beyond conventional heat treatments, including plasma nitriding, plasma carburizing, low-pressure carburizing, ion implantation, physical and chemical vapor deposition, salt bath coating, and transformation hardening via high-energy laser and electron beams. The chapter compares methods and includes several example applications.

Organic coatings (paints and plastic or rubber linings), metallic coatings, and nonmetallic inorganic coatings (conversion coatings, cements, ceramics, and glasses) are used in applications requiring corrosion protection. These coatings and linings may protect substrates by three basic mechanisms: barrier protection, chemical inhibition, and galvanic (sacrificial) protection. This chapter begins with a section on organic coating and linings, providing a detailed account of the steps involved in the coating process, namely, design and selection, surface preparation, application, and inspection and quality assurance. The next section discusses the methods by which metals, and in some cases their alloys, can be applied to almost all other metals and alloys: electroplating, electroless plating, hot dipping, thermal spraying, cladding, pack cementation, vapor deposition, ion implantation, and laser processing. The last section focuses on nonmetallic inorganic coatings including ceramic coating materials, conversion coatings, and anodized coatings.

Surface modification technologies improve the performance of tool steels. This chapter discusses the processes involved in oxide coatings, nitriding, ion implantation, chemical and physical vapor deposition processing, salt bath coating, laser and electron beam surface modification, and boride coatings that improve the performance of hot-work and high-speed tool steels.