کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1661448 1008425 2008 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Nitrogen diffusion in medical CoCrNiW alloys after plasma immersion ion implantation
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد فناوری نانو (نانو تکنولوژی)
پیش نمایش صفحه اول مقاله
Nitrogen diffusion in medical CoCrNiW alloys after plasma immersion ion implantation
چکیده انگلیسی

CoCr alloys are widely used for medical applications, e.g. total hip replacements or coronary stents. Nevertheless, an increase in the surface hardness and a reduction of the wear rate is still desirable to improve the biocompatibility. Plasma immersion ion implantation (PIII) at different temperatures, acceleration voltages and working pressures is used to determine the nitrogen diffusivity in the CoCr alloys SY21med, L605 and HS188. Depending on the temperature, two different treatment regimes can be distinguished, independent of the ion energy. At low temperatures, a diffusion process with an activation energy of 1.0–1.1 eV is present, indicative of interstitial nitrogen diffusion. Beyond 350 °C, a reduced activation energy of 0.5–0.7 eV is observed. Additionally, a strong dependency of the layer thickness on the working pressure in the range 0.3–0.8 Pa was observed for the temperature dependent diffusion regime, which suggests a synergistic interplay of adsorption and implantation during PIII. Below 500 °C, an increase of the diffusion coefficient by three orders of magnitude was observed for PIII, compared with pure plasma nitriding.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Surface and Coatings Technology - Volume 202, Issue 15, 25 April 2008, Pages 3747–3753
نویسندگان
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