Boriding is a thermochemical diffusion-based surface-hardening process that can be applied to a wide variety of ferrous, nonferrous, and cermet materials. It is performed on metal components as a solution for extending the life of metal parts that wear out too quickly in applications involving severe wear. This article presents a variety of methods and media used for boriding of ferrous materials, and explains their advantages, limitations, and applications. These methods include pack cementation boriding, gas boriding, plasma boriding, electroless salt bath boriding, electrolytic salt bath boriding, and fluidized-bed boriding. The article briefly describes the chemical vapor deposition process, which has emerged to be dominant among metal-boride deposition processes.