Boriding to improve the mechanical properties and corrosion resistance of steels

Boriding is a thermochemical surface treatment in which boron diffuses into and combines with a substrate material to form a single- or double-phase metal boride layer at the substrate surface. This chapter discusses the importance of boriding for ferrous materials in which the formation of boride layers, such as FeB and Fe₂B, improves hardness, wear resistance, temperature resistance and corrosion resistance at the surface of steels. The chapter includes a discussion of the growth kinetics of boride layers associated with traditional diffusion models. To understand the intended industrial applications, the chapter then reviews the physicochemical and mechanical characterisations of the different steels exposed to the boriding process.