Total joint replacement remains one of the most successful treatments for arthritis.  The most common materials used for artificial joints are metals (e.g., cobalt-chrome alloys or titanium alloys), which articulate against ultra-high molecular weight polyethylene.  Wear related failures of artificial joints may be reduced with the use of novel micro-textured carbide surfaces.  The micro-textured carbide surfaces were deposited on a CoCrMo alloy using microwave plasma-assisted chemical vapor deposition.  Wear tests were conducted to determine wear mechanisms and properties of the micro-textured surfaces.  The research presented in this thesis addresses: (1) rheolgoical behavior of bovine calf serum with and without antibacterial agents to determine whether they can be used as appropriate models for synovial fluid, (2) the wear behavior of the micro-textured CoCrMo surface system, and (3) the mechanical and material properties of the micro-textured CoCrMo alloy surface relevant to wear performance. The rheological studies showed that the apparent viscosity of bovine calf serum increased with an increase in concentration before and after the serum was used for wear testing.  The wear analysis showed that the processing conditions (2hr deposition vs. 4hr deposition times) affected the wear properties.  The 2hr carbide-on-carbide lubricated in 50% BCS produced the lowest wear factor and rate for the five wear couple systems containing the carbide disk or plate material.   Greater wear was produced in serum without penicillin/streptomycin (P/S) compared to the serum containing P/S. A greater carbide coating thickness 10 (micrometers) was produced during the 4hr deposition time than for the 2hr deposition ~3 (micrometers).  The nano-hardness value was higher than the micro-hardness for both the 4hr and 2hr carbide surfaces.  The micro-hardness results of the worn carbide surfaces showed that an increase in BCS concentration from 0% to 100% increased the micro-hardness (HV) for carbide surfaces (from 873 to 1344 HV).
Creators: name: Ettienne-Modeste, Geriel
Publisher: name: Maryland Shared Open Access Repository
Year: 2009

description: Total joint replacement remains one of the most successful treatments for arthritis.  The most common materials used for artificial joints are metals (e.g., cobalt-chrome alloys or titanium alloys), which articulate against ultra-high molecular weight polyethylene.  Wear related failures of artificial joints may be reduced with the use of novel micro-textured carbide surfaces.  The micro-textured carbide surfaces were deposited on a CoCrMo alloy using microwave plasma-assisted chemical vapor deposition.  Wear tests were conducted to determine wear mechanisms and properties of the micro-textured surfaces.  The research presented in this thesis addresses: (1) rheolgoical behavior of bovine calf serum with and without antibacterial agents to determine whether they can be used as appropriate models for synovial fluid, (2) the wear behavior of the micro-textured CoCrMo surface system, and (3) the mechanical and material properties of the micro-textured CoCrMo alloy surface relevant to wear performance. The rheological studies showed that the apparent viscosity of bovine calf serum increased with an increase in concentration before and after the serum was used for wear testing.  The wear analysis showed that the processing conditions (2hr deposition vs. 4hr deposition times) affected the wear properties.  The 2hr carbide-on-carbide lubricated in 50% BCS produced the lowest wear factor and rate for the five wear couple systems containing the carbide disk or plate material.   Greater wear was produced in serum without penicillin/streptomycin (P/S) compared to the serum containing P/S. A greater carbide coating thickness 10 (micrometers) was produced during the 4hr deposition time than for the 2hr deposition ~3 (micrometers).  The nano-hardness value was higher than the micro-hardness for both the 4hr and 2hr carbide surfaces.  The micro-hardness results of the worn carbide surfaces showed that an increase in BCS concentration from 0% to 100% increased the micro-hardness (HV) for carbide surfaces (from 873 to 1344 HV).