Characterization and Sintering Properties of Hydroxyapatite Bioceramics Synthesized from Clamshell Biowaste

Abstract

Hydroxyapatite (HA) is a type of calcium phosphate-based bioactive ceramic that resembles the mineral phase of bone and teeth with great potential for bone substitution and biomedical implants. Biogenic-derived HA emerges as a cheap and eco sustainable alternative to improve waste utilization. However, hydroxyapatite has limited applications due to its apparent brittleness, thus prompting investigation for enhanced sintering properties. In the present study, the combination of calcination and chemical precipitation technique was used to extract hydroxyapatite (HA) from ark clamshells (Anadara granosa). The method successfully produced HA powder with a Ca/P ratio of 1.6 and characteristic bands corresponded to pure HA via Fourier Transform Infrared Spectroscopy (FTIR). The synthesized HA powder was then sintered at temperatures ranging from 1200 °C to 1300 °C, followed by mechanical evaluation of the density, Vickers hardness, fracture toughness and grain size. It was revealed that the samples sintered at 1250 °C achieved a relative density of 88%, Vickers hardness of 5.01  0.39 GPa, fracture toughness of 0.88  0.07 MPa.m1/2 and average grain size of 3.7 µm. Overall, the results suggest that ark clamshell synthesized HA (ACS) had the potential to be used as functional bioceramics for biomedical applications.