Boriding of Steels. Some Notes on the Boron Diffusion Mechanism

The aim of this work was to ascertain if the alloying elements in steels influence the diffusion mechanism of the boron during boriding treatment and to relate the characteristics of the borided layer with the chemical composition of the matrix. Steels, Armco iron and some ferrous alloys containing Cr and/or Ni were borided for 7-24 hours at 1173-1223K using powders of composition B//4C equals 20 30%, KBF//4 equals 5%, SiC equals 65 75%. The borided samples were analysed by an X-ray diffractometer, electron microscope, EDS spectrometer, optical microscope and Vickers microdurometer. Because boron diffusion through the carbides and boron carbides is difficult, the surface layer becomes thinner, has a more homogeneous chemical composition and therefore becomes harder.