Buhagiar, Joseph (2008)
Ph.D. thesis, University of Birmingham.
Low temperature plasma surface alloying with nitrogen (nitriding), carbon (carburising) and both (carbonitriding) has been successfully employed in hardening medical grade ASTM F138, ASTM F1586 and ASTM F2581 as well as engineering grade AISI 316 by the formation of a modified layer better known as S-phase or expanded austenite. In this study, systematic plasma treatments and characterisation were performed on medical grade stainless steel in order to establish the optimised treatment conditions, especially temperature, which can maximise the hardened case depth without any detriment in corrosion resistance. The surface of a biomaterial must not adversely affect its biological environment and return the material surface must not be adversely affected by the surrounding host tissue and fluids. Experimental results have shown that this duality of concern can be addressed by creating S-phase. It has been shown that low-temperature nitriding (430°C), carburising (500°C) and carbonitriding (430°C) improved the localised corrosion, corrosion-wear and fretting-wear resistance of these medical grade stainless. Also biocompatibility studies have proved that these hardened surfaces were biocompatible under the realms of the tests conducted in this study therefore the use of hardened medical grade austenitic stainless steel might be suitable in implant applications.
|Type of Work:||Ph.D. thesis.|
|Supervisor(s):||Dong, Hanshan and Bell, Tom|
|School/Faculty:||Colleges (2008 onwards) > College of Engineering & Physical Sciences|
|Department:||School of Metallurgy and Materials |
|Keywords:||biocompatibility; S-phase; Expanded austenite; Plasma nitriding; Plasma carburising; Plasma nitrocarburising; Corrosion-wear; Stainless steel; Pitting corrosion; Hardening; Crevice corrosion; Low Temperature Plasma; Carbo-Nitriding; Hybrid; Austenitic Stainless Steel; Corrosion; Wear-Corrosion; Medical Grade; ASTM F138; ASTM F1586; ASTM F2581; AISI 316; Ringer's Solution; surface engineering; biomedical; corrosion; Nickel free austenitic stainless steel; Medical austenitic stainless steel; Fretting-wear; Intergranular corrosion; Low temperature plasma alloying; Tribocorrosion; TEM; XTEM; tribology; Fretting wear; wear |
|Subjects:||Q Science (General)|
TN Mining engineering. Metallurgy
|Institution:||University of Birmingham|
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