Effects of sintering temperature on the physical, structural, mechanical and antimicrobial properties of extracted hydroxyapatite ceramics from Anabas testudineus bone and head scull for biomedical applications

In this experimental investigation, Hydroxyapatite (HAp) is extracted from bone and head scull of Anabas testudineus by thermal calcination at 800 °C for 5 h under ambient air conditions. Ceramic samples were prepared through compaction and followed by sintering at 1200 °C, 1250 °C, and 1300 °C temperatures for 2 h from the calcined HAp powder. Both the calcined powder and sintered ceramic samples were characterized using X-ray Diffraction (XRD), Energy dispersive X-ray spectroscopy (EDS) and Scanning Electron Microscopy (SEM) to explore the potentiality of the extracted ceramics for biomedical applications. Moreover, the elemental composition, phase structure, compressive strength, Vicker hardness, and antimicrobial characteristics of the ceramic samples have been investigated. The XRD analysis confirmed the presence of hydroxyapatite in both the calcined powder and ceramic samples. Various types of trace elements were observed in HAp ceramics including a noteworthy 1.57 atomic percent of magnesium (Mg). Additionally, the XRD spectrum indicated the existence of the β-tricalcium phosphate (TCP) phase. Upon sintering at a temperature of 1250 °C, the ceramic sample underwent a phase shift to α-TCP. Our results show that the phase transition has a significant effect on the crystallinity of HAp. The ceramics sample sintered at 1300 °C exhibited the highest compressive strength and Vicker Hardness due to its high relative density, well-packed grains, and larger particle size. The sintered sample did not exhibit notable zone of inhibition against Escherichia coli and Staphylococcus aureus bacteria.