STUDY OF BN FORMATION BY DUAL IMPLANTATION OF BORON AND NITROGEN IN A100CR6 BEARING STEEL

Boron nitride (BN) layers are well known to present interesting and va rious coating properties depending on their crystallographic structure . The aim of this work was to synthesize a surface layer containing BN compounds by dual implantations of boron and nitrogen in a 100Cr6 bea ring steel. So as to superimpose both profiles, the implantation energ ies were 65 and 110 keV for boron and nitrogen respectively. The impla ntation fluences were ranging between 2 x 10(17) and 3 x 10(17) ions c m(-2). Nuclear backscattering spectrometry at 6.04 MeV was used to det ermine the distribution profiles of the implanted elements as well as to control the concentrations of contaminants carbon and oxygen. X-ray photoelectron spectroscopy analyses were carried out in order to reve al the formation of BN and its crystallographic structure (hexagonal o r cubic). The effect of the current density as well as that of the imp lantation sequence (B + N or N + B) on the amount and structure of the BN phase were also investigated. It was shown that both these paramet ers have a combined influence on the BN phase structure. For the highe st current density and the N + B sequence, the cubic structure is pred ominant, whereas for the lowest current density and the other sequence , the hexagonal phase is mainly formed.