Trends in Physical Techniques of Boriding

Abstract

All the specified physical techniques of boriding, i.e. carried out under glow discharge conditions, boron ion implantation and high-energy techniques were characterized and compared in this chapter based on the available literature data. The technological aspects of boriding processes were analyzed, taking into consideration the advantages and disadvantages of each method. The effects of the boriding methods on the microstructure of borided materials were shown. The mechanism of formation of active boron atoms or ions and the phenomena during re-melting of alloying material together with the substrate were described. The three main groups of physical techniques of boriding were specified: boriding under glow discharge conditions, boriding by ion implantation and the high-energy methods of boriding. The most intensively developed physical techniques were put in the boxes drawn in a broken line in Fig. 2.1. They were described in more detail, taking into account the current trends in boronizing. Hence, the most attention was devoted to the boriding under glow discharge conditions, especially plasma gas (or paste) boriding, and surface alloying with boron, especially, laser (or plasma) surface alloying.