Characterization of borided AISI 316L stainless steel implant

The present study reports on characterization of borided AISI 316L stainless steel implant. Boronizing heat treatment was performed on a cylindrical bar of AISI 316L austenitic surgical stainless steel with a diameter of 2mm and a length of 10 mm using slurry salt bath consisting of borax, boric acid and ferro-silicon. The susbstrate AISI 316L was essentially containing 0.022wt% C, 0.79wt% Si, 1.6wt% Mn, 0.25wt% P, 0.002wt% S, 15.30wt% Cr 14.09wt% Ni, 2.63wt% Mo and 0.05wt% Cu, respectively. Boronizing treatments were conducted at 850degreesC, 900degreesC, 950degreesC, and 1000degreesC, for 2, 4 and 6 h, respectively. Depending on process time and temperature, the thickness of boride layer formed on substrate ranged from 12 to 40 mum. The hardness of borides formed on the surface of substrate was over 1500 VHN. The presence of borides (e.g. Fe2B, CrB, Ni3B) formed on the surface of borided AISI 316L stainless steel was confirmed by classical metallographic technique combined with X-ray diffraction analysis. The distribution of alloying elements was determined by means of energy dispersive X-ray spectroscopy spectrum from surface and line-scan analysis from surface to interior. (C) 2002 Published by Elsevier Science Ltd.