| dc.description.abstract | Abstract
The final goal of this master thesis is to measure CoCrMo metal behaviour such as electrode potentials and corrosion rates in oxygen-depleted environments while inducing mechanical damage to them. To do this efficiently, laboratory equipment is needed (i.e. a tribometer). This master thesis builds up on a previous equipment did not give reproducible results, which is a demand when doing research and drawing conclusions.
The ambition of this project is to modify the previous laboratory equipment (tribometer equipped with an electrochemical cell, i.e. a tribocorrosionmeter) to do precise tests and provide reproducible results. This project will build knowledge on CoCrMo alloys in PBS electrolyte, to investigate corrosion and mechanical wear properties inside the human body as an implant.
The recipient of an implant will eventually reject it over time due to wear, and corrosion products accumulation around the implant area, as a result of corrosion and mechanical wear. The rejection process starts immediately after surgery. However, it is not noticeable to the recipient before the hip rejection developed into an inflammation. Inflammation is caused by an immune response and migrating immune cells to the affected area to restore balance by removal of foreign pathogens, which practically is the emission of implant wear particles from the hip.
Immune cells consume a lot of oxygen causing the inflicted area to experience local hypoxia (oxygen depletion). There is therefore a need to investigate the potentials and corrosion properties of the material when hypoxia occurs. However, there many other oxygen-depleted environments where tribocorrosion occurs, for example, deep waters oil installations, and other constructions in similar environments. The equipment developed should produce tests of any desired oxygen-depleted environments, by making a versatile test rig. The rig is compared against the previous results from CoCrMo in PBS solution.
Based on developing minimum viable products (MVP), this project used a 3D-printer for prototyping. Small prototypes are made throughout the project, small tests are made to give a quick feedback loop on equipment performance which will be evaluated against the equipment demands to verify each component that builds up the test rig throughout the project. To ensure reliable performance, overall quality, and reproducible tests.
Each idea, iteration, and feedback loop from each component tested in the development process is discussed with the supervisor orally to ensure that the project always continues in the right direction, both for the developer and the customer.
This method builds on the agile development manifesto, principles, and values. Where creativity and self-interpretation are valued, to design a new product. The whole process will be presented and defended orally. This report will cover problems linked to the implant failure process, potential drop of CoCrMo alloy under wear in extreme hypoxic environments to establish theories of material integrity, and potensiostatic tests to measure corrosion rate in the same extreme hypoxic environments. | |