Nanocrystalline Hydroxyapatite/Si Coating by Mechanical Alloying Technique

Table 1

Unit cell parameters of the mechanical milled HA.

Sample	Lattice constant (Å)	Standard deviation	𝑅𝑤𝑝 (%)
Standard card (24–0033)	𝑎=𝑏=9.432; 𝑐=6.881	—
1∶60 ratio	𝑎=𝑏=9.443; 𝑐=6.898	0.0014	7.6
1∶90 ratio	𝑎=𝑏=9.430; 𝑐=6.898	0.0018	8.9

𝑅_{𝑤𝑝(weightedresidualerror)}.