An experimental investigation of the fabrication of biodegradable zinc–hydroxyapatite composite material using microwave sintering

The present work focuses on the fabrication of zinc–hydroxyapatite biodegradable composite with the use of pressureless microwave sintering for the orthopedic load-bearing application. The samples were prepared using the powder metallurgy process. The powders of both materials were homogeneously mixed in the quantified proportions to form the uniform mixture. For the fabrication of samples, the planning of experiments was done with the central composite design. The effect of process factors such as the weight percentage of hydroxyapatite, compaction pressure, and microwave sintering factors such as sintering temperature, heating rate, and soaking time on the compressive yield strength and sintered density was evaluated. Cylindrical samples were prepared for compression testing. The experimental results exhibited the increase in the compressive yield strength as well as the sintered density with the decrease in the hydroxyapatite percentage and an increase in the compaction pressure. The results also revealed that the compressive yield strength and sintered density were found to be increased as the heating rate and sintering temperature increased. Sample characterization was carried out for phase determination and composition of the elements. The optimum process factors were obtained after the regression analysis, and the results of the optimum process factors were also verified with the confirmation experiments. The in vitro corrosion testing of the sample prepared with optimum factors was also carried out in the simulated body fluid at a temperature of 37 ± 0.5 ℃. The fabricated sample showed a good agreement between the mechanical and degradation properties as required for a human bone.