Effects of vibro-milling time and sintering temperature on the formation and selected properties of nano-hydroxyapatite ceramics derived from bovine bone

Hydroxyapatite (HA) bioceramics require nanoscale powders to achieve the mechanical strength necessary for load-bearing implants. The impact of vibro-milling on HA derived from bovine bone remains unclear. This study hypothesized that varying vibro-milling duration and sintering temperature could optimize the nano-HA characteristics and ceramic performance. Natural bovine bone was processed into HA powder through boiling, calcination at 800 °C, and initial ball milling. The resulting HA powder was then vibro-milled for 0, 1, 2, 4, and 8 hours to generate nanopowders and sintered between 1150 °C and 1300 °C. A 2 hours vibro-milling treatment produced uniform nano-HA (<100 nm) with good crystallinity. Sintering temperature had a greater influence than milling time, with 1250 °C treatment yielding the highest densification and a maximum bending strength of ∼112 MPa. These findings demonstrate that a 2 hours vibro-milling step combined with 1250 °C sintering produces HA ceramics suitable for load-bearing applications.