Boronizing of alloy steels

Boronizing of iron aluminide Fe72Al28

“…The surface hardness of the resulting boride layer can exceed 2000 HV and has a good resistance to abrasive and adhesive wear. In particular, surface hardening of steels by boriding treatments have found wide applications in industries [2][3][4].…”

Oxidation stability of boride coatings

“…This type of layer growth is typically observed for low alloy steels [3,33]. The presence of particular alloying elements, most importantly Cr, Ni, Mo or Si, is known to reduce the layer thickness [3,33]. These elements act as a diffusion barrier to boron, leading to flattening out the layer microstructure at the boride-metal substrate interface.…”

“…The acicular type of layer microstructure is related to the preferred orientation of boron diffusion in (002) crystallographic direction [32]. This type of layer growth is typically observed for low alloy steels [3,33]. The presence of particular alloying elements, most importantly Cr, Ni, Mo or Si, is known to reduce the layer thickness [3,33].…”

“…These elements have not been present in the steel (Table 2). Mn, the major alloying element in S235JRG1 (Table 1), is less efficient in retarding the boride layer growth compared to Cr or Ni [3].…”

“…During this process, temperatures of 973-1273 K and processing times of 1-10 h are typically used [1][2][3]. Since boron is a relatively small size element, it easily diffuses into a variety of metals, including Fe and Co-based alloys and refractory materials [4][5][6][7][8].…”