Date of Award

8-2019

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Bioengineering

Committee Member

Martine Laberge, Committee Chair

Committee Member

Guigen Zhang

Committee Member

Jeremy Mercuri

Committee Member

Fei Peng

Committee Member

Mark Roberts

Abstract

Ceramic and ceramic composites are gaining popularity over their metallic counterparts for orthopedic applications. Metallic biomaterials, like titanium alloys and CoCrMo alloy, exhibit good performance under concentrated loads but there have been plenty cases of implant failure due to release of metallic debris causing osteolysis. The wear debris release is caused by mechanically assisted electrochemical degradation of contacting surfaces at the joint. Ceramic based biomaterials have shown to exhibit superior wear performance, but they are prone to brittle fracture. Hence modern ceramic materials are reinforced with oxides, nitride and carbides too improve fracture resistance. However, nitrides and carbides reinforcement impart electrochemical activity to ceramic composite and facilitate electron transfer processes and participate in electrochemical interaction with aqueous environment. The electrochemical behavior of ceramic composites with electrochemically active reinforcement needs to be evaluated to account for any undesirable electrochemical activity for invivo applications. This research presents, a detailed investigation of electrochemical behavior of alumina-titanium Carbide (TiC) composite and valuable insights into the potential use of alumina-TiC as a biomaterial. A systematic analysis of electrochemical behavior under mechanical perturbation like abrasive wear was performed and related degradation mechanism was uncovered with combination of quantitative and qualitative methods.

For a better understanding of the reaction mechanism involved in the degradation process of alumina-TiC composite, studies in the forms of experimental, theoretical and computational investigation have been performed. Using the concepts of thermodynamics and electrochemical reaction kinetics like Butler-Volmer theory along with Nernst-Planck transport phenomenon, a great deal of insights into the reaction mechanism for oxidation of TiC was developed.

Moreover, a potential use of alumina-TiC composite as a biomaterial was assessed in biologically relevant environment. The electrochemical behavior and cytocompatible nature of the composite was investigated and compared with common metallic biomaterials like commercially pure titanium (Cp-Ti) and graphite covered CoCrMo alloy (GC-CoCrMo). After thorough analysis and supporting observations from surface and chemical analysis methods, it was concluded that alumina-TiC is electrochemically stable material than metallic biomaterials and it also favorably supports HB-MSC cell growth and proliferation.

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