A Study on the Characterisation and Mechanical Properties of Alumina-Based Bioceramics for Medical Applications

Ng, Zhong Kang (2020) A Study on the Characterisation and Mechanical Properties of Alumina-Based Bioceramics for Medical Applications. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

First and foremost, alumina is an advanced bioceramics that is mostly used in the biomedical application such as bone replacement and dental implantations due to its excellent and superior mechanical properties such as high hardness and toughness, non-toxicity, corrosion resistance and high abrasion resistance. Therefore, the sintering behavior and mechanical stability of the six types of different samples and parameter were evaluated in this project which is the 3 types of pure alumina samples sintered at 1200°C, 1300°C, 1400°C and hold them for 2 hours, another one type is the pure alumina samples which is send to two-steps sintering sintered at 1500°C hold for 3 minutes then follow by 1300°C hold for 5 hours, another 2 types is the manganese-doped alumina and vanadium oxide-doped alumina sintered at 1400°C. These sintering powders were synthesized by the process of ball milling mixing. The pure alumina was acquired to compare with the alumina-doped. In this present study, powder morphology of these ceramic materials was also examined using SEM in terms of different sintering temperature, sintering methods and dopant for alumina. On the other hand, XRD was also conducted to the pure alumina and doped-alumina to study its characterization such as its phase stability in which the crystal structure of each specimens was examined by using the X-Ray diffractometer. In additional, the mechanical properties such as relative density, hardness and toughness of the alumina and the doped-alumina was also studied through the density test, Vickers Hardness test and Fracture Toughness test by using the different sintering temperature, sintering methods and dopant for alumina. The results show that as the sintering temperature used on the pure alumina increase from 1200℃ (A1) to 1400℃ (A3), the relative density increase from 50.82% to 68.34%, Vickers Hardness increase from 0.9134GPa to 7.3937Gpa and fracture toughness increase from 0.30884MPa.m0.5 to 1.16346 MPa.m0.5 is due to the specimen is more compact, dense and less porous. In additional, the results show that the two-steps sintering sintered at 1500°C hold for 3 minutes then follow by 1300°C hold for 5 hours has the relative density of 71.22%, Vickers Hardness of 9.44GPa, and fracture toughness of 1.22MPa.m0.5 is higher than all the pure alumina that conventional sintered at 1200°C (A1), 1300°C (A2) and 1400°C (A3) for 2 hours holding time due to the specimen that is sintering at longer time is more compact, dense and less porous. The results show that the conventional sintering ball-milled 1%wt Manganese-doped alumina has the highest relative densities of 84.72%, toughness of 2.15MPa.m0.5 and hardness value of 14.12GPa as compare to other pure alumina. However, conventional sintering ball-milled 1%wt Vanadium-doped alumina has the lower relative densities of 59.15%, toughness of 0.35MPa.m0.5 and hardness value of 1.34GPa as compare to the pure alumina and the results still can be improved by selecting a suitable sintering temperature and increasing the holding time.