Barbieri Thesis - BioMedical Materials program (BMM)

Chapter 5 – Alkali surface treatment effects
5.2. Materials and Methods
5.2.1. Apatite preparation and characterization
Nano–apatite powder was synthesized by adding (NH4)2HPO4 (Fluka, Steinheim,
Germany) aqueous solution (c=63.1 g L –1 ) to Ca(NO3)2·4H2O (Fluka) aqueous
solution (c=117.5 g L –1 ) at the controlled speed of 12.5 mL min –1 and 80±5ºC and
keeping the reaction pH above 10 by dropwise adding ammonia (Fluka). After
precipitation, the resulting powder was aged overnight, washed with distilled water to
remove ammonia, dehydrated in acetone (Fluka) and finally dried at 60±1°C. Its
chemistry was then investigated with X–ray diffractometry (XRD, MiniFlex II, Rigaku,
Japan) using Cu K radiation (=1.54056 Å) operating at 30 kV and 15 mA. Spectra
were collected at 0.083 deg sec –1 in the 2 range 5–90 deg. Unit cell parameters of
the powder were determined from XRD data using the software Jade (v6.5.26,
Materials Data Inc., Livermore, CA, USA). Following background subtraction (cubic
spline method) and pattern smoothing (parabolic Savitzky–Golay filter set at 15
points), individual diffraction peaks were fitted (R