Effect of thermal oxidation on corrosion resistance of Ti-8Mo4Nb-2Zr alloy for biomedical application
<p>Titanium and titanium alloys are widely used in a variety of engineering applications.</p><p>Medical device manufacturers have also benefited from the outstanding properties of</p><p>titanium alloys. However, titanium alloys ar...
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| Format: | thesis |
| Language: | eng |
| Published: |
2021
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| Subjects: | |
| Online Access: | https://ir.upsi.edu.my/detailsg.php?det=7330 |
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| Summary: | <p>Titanium and titanium alloys are widely used in a variety of engineering applications.</p><p>Medical device manufacturers have also benefited from the outstanding properties of</p><p>titanium alloys. However, titanium alloys are weak in meeting all of the clinical</p><p>requirements for biomedical implants. Issues such as metal sensitivity associated with</p><p>high levels of metal ion release triggered by corrosion effects remain critical concerns.</p><p>Hence, the implant material surface has a strong role in the responses to the biological</p><p>environment the implant can be stimulated in contact with the bone. In order to</p><p>improve the biological and tribological properties of implant materials, surface</p><p>modification needed to be made. Thermal oxidation is one of the surface modification</p><p>techniques to enhance the corrosion performance of titanium alloys. This technique is</p><p>excellent for forming a thicker oxide layer on Ti and its alloys to achieve optimum</p><p>corrosion resistance. In the present study, thermal oxidation of Ti-8Mo-4Nb-2Zr alloy</p><p>was explored. Hence, experiments were carried out to investigate the effective</p><p>combination of surface modification parameters and evaluate performance corrosion</p><p>behaviour in terms of their suitability with the Ti-8Mo-4Nb-2Zr alloy surface for</p><p>biomedical implants applications. Process thermal oxidation was carried out at 500,</p><p>600 and 700C for three different durations of 6, 12 and 24 hours. It was found that</p><p>particles of oxides formed were noticeably larger after oxidation at an increased</p><p>temperature of 600C and 700C. The increase in temperature resulted in the</p><p>formation of compact particles in the oxide layer. A phase analysis showed that the</p><p>phase contents of the oxide layer showed a strong dependence on treatment conditions</p><p>with a predominance of the rutile phase over the anatase phase at temperatures ></p><p>500C and for time periods > 6h. Improved corrosion resistance had been achieved of</p><p>these alloys using thermal oxidation. EIS was employed to measure the corrosion</p><p>resistance of the Ti-8Mo-4Nb-2Zr alloys in simulated physiological solutions of a</p><p>wide pH range (namely 7.4 pH) at 37C, and the best results were obtained for the</p><p>alloys at 700C. A more positive Ecorr value (-0.125 V) and a lower Icorr value</p><p>(2.583 A x 10-6) were observed for the thermally oxidized Ti-8Mo-4Nb-2Zr alloys</p><p>when compared with the untreated alloy. This finding, the oxide scale on the</p><p>examined alloy efficiently enhances can increase the corrosion resistance of the</p><p>implant material.</p> |
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