Boriding is a thermochemical diffusion-based process of achieving ultra-hard surface on metals. Two distinct crystalline phases, i.e. tetragonal Fe2B and orthorhombic FeB can exist in the surface layer penetrated by boron ions.
In our contribution, we have studied the microstructure, the hardness, and the spatial distributions of both phase composition and residual stresses (RS) in samples exhibiting either single-phase Fe2B or duplex Fe2B-cum-FeB character.