الفهرس 
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Abstract
This work was initiated to obtain a thick carbonitrided layer
into the surface of AISI 321 and AISI 316 with high tribological,
mechanical and biocombatibility performance. The samples were
tested and characterized using X-ray diffraction, optical microscopy,
microhardness tester, Form Talysurf 50 profilometer, oscillating
ball-on-disk tribometer, contact angle analyzer and Gill AC
instrument. Further, in order to preliminary evaluate the
biocompatibility performance, bio-tests including blood and cell
culture, protein adsorption were applied to the untreated and
carbonitrided samples.
The current work is classified into two main groups of
samples. The first one was devoted to study the effect of rf plasma
carbonitriding on the biocompatibility and mechanical properties of
AISI 321 austenitic stainless steel. Rf plasma-processing time was
varied from 4 to 20 min, while the plasma power was fixed at 500
W. In this study, rf plasma carbonitriding is succeeded to treat the
AISI 321 with a high rate of 1.1 μm2/s for plasma-processing time of
8 min. The structural results demonstrate the formation of nitrogen
and carbon solid solution phases beside the chromium nitride and
iron nitride phases as chemical compounds. The microhardness of
the treated layer increased with increasing the processing time to
reach a maximum value of 1468 HV0.1 at 16 min. That represents
approximately 7-folds increment in the microhardness in comparison
with the untreated AISI 321. Further, the wear and corrosion
resistance were improved. The friction coefficient decreased from
nearly 0.5 for the untreated AISI 321 to nearly 0.25 for the
carbonitrided one. Furthermore, .the results reported an agreement