TITLE:
Tribo-Mechanical and Electrochemical Properties of Carbonitrided 316 Austenitic Stainless Steel by rf Plasma for Biomedical Applications
AUTHORS:
F. M. El-Hossary, M. Raaif, A. M. Abd El-Rahman, M. Abo EL-Kassem
KEYWORDS:
Plasma-Material Interactions 52.40.Hf, Surface Hardening 81.65.Lp, Mechanical Properties 62.20.Qp, Surface Energy 68.35.Md, Biocompatibility 87.85.Jj
JOURNAL NAME:
Advances in Materials Physics and Chemistry,
Vol.8 No.9,
September
14,
2018
ABSTRACT: AISI 316 austenitic stainless steel was
carbonitrided using rf plasma with purpose of using low-cost orthopedic implant
materials in biomedical applications besides the manufacturing requests. The
plasma treatment process was accomplished at low working gas pressure of 0.075
mbar in nitrogen-acetylene gaseous mixture. The plasma-processing time was
fixed at 10 min while the plasma-processing power was varied from 450 to 650
watt. The effect of plasma treatment power on the structure, tribological,
mechanical, electrochemical and biocompatibility of AISI 316 has been investigated.
The structural results demonstrated the formation of nitrogen and carbon solid
solutions, chromium nitride, iron carbide and iron nitride phases in the
treated samples. The microhardness of the treated layer increases with
increasing the processing power to reach a maximum value of approximately 1300 HV0.1 at 600 W which represents more than 6-folds increase in
microhardness in comparison with the untreated matrix. The wear and corrosion
resistance of the treated AISI 316 were enhanced compared to the untreated one.
The friction coefficient was reduced from nearly 0.5 for the untreated
substrate to nearly 0.3 for the carbonitrided sample. The surface energy and
wettability of the carbonitrided samples were augmented as the plasma-processing power
increased. Furthermore, the numbers of grown mesenchymal stem cells are higher
for carbonitrided samples compared to the untreated one. The formation of
nitrogen and carbon solid solution, chromium nitride, iron nitride and iron
carbide hard phases after carbonitriding process is responsible for achieving
good mechanical, tribological, biocompatibility and electrochemical properties
for AISI 316 alloys.