2.4. X-Ray Diffraction (XRD)

XRD is a technique to determine crystal structure and, in these types of substrates, to differentiate apatitic crystals from other calcium phosphate minerals. Freeze-dried samples were analyzed with a Panalytical XPert Powder by placement atop an amorphous glass slide. Samples were scanned from 10° to 60° (2ϴ) with a step size of 0.01° and a dwell time of 10 s/step using Cu Kα x-rays (λ = 1.54 Å).