for heat treatment was 10 mg. Samples were heated from room temperature to

1000 ^C at a heating rate of 10 ^C/min. On heating, as-synthesized HA nanopowders

exhibited weight loss to different extents (Table 23.7). In general, the weight loss

occurred in three steps: the first weight loss is due to dehydration, elimination of

nitrogenated substances, and conversion of HPO4

2
into P2O5; the second weight

loss is owing to reaction of OH
and P2O7 at temperatures between 400 ^C and

700 ^C, and the third weight loss above 700 ^C is suggested due to phase

transformations. HA nanopowder showed a total weight loss of 13.98%. There

was a small weight loss of about 2.31% above 700 ^C, which indicated its high

thermal stability. The thermal stability of HA was affected by ionic substitution.

Substitution of Zn or Mg in HA showed a decreased thermal stability due to the

Fig. 23.7 FTIR patterns of heat-treated nanopowders (HA8 and FHA8, HA10 and FHA10, and

HA12 and FHA12: powders heat-treated at 800 ^C, 1000 ^C, and 1200 ^C)

23

Unleashing Potential of Bone Mimicking Nanodimensional Hydroxyapatites and. . .

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