Chemical Specification

1. SCOPE

Calcium Hydroxylapatite intended for thermal spraying applications. 'CAPTAL' grades

2. CHEMICAL SPECIFICATION

After heating for 2 hours @1250 (-0 +50) °C the specification shall be :-

Calcium Hydroxylapatite as Ca₁₀(PO₄)₆.(OH)₂ greater than 97.5% by XRD

3. LIST of ELEMENTAL COMPONENTS & LIMITS

Element	Formulae	Concentration	Method of Analysis
Calcium	CaO	54.5-55.2 %	XRF
Phosphorus	P₂O₅	41.0-41.2 %	XRF
Silicon	SiO₂	0.6% max	XRF
Carbon	Co₃^--	1.5% max	IRS
Sulphur	SO₄^--	150ppm max	GM
Chlorine	Cl^-	20ppm max	SE
Fluorine	F^-	50ppm max	SE
Iron	Fe₂O₃	700 ppm max	XRF
Magnesium	MgO	3000 ppm max	XRF
Aluminium	Al₂O₃	500 ppm max	PE
Strontium	SrO	500 ppm max	AAS
Sodium	Na₂O	300 ppm max	XRF
Potassium	K₂O	100 ppm max	XRF
Chromium	Cr₂O₃	20ppm max	AAS
Nickel	NiO	30 ppm max	AAS
Manganese	Mn₃O₄	100 ppm max	XRF
Copper	CuO	10 ppm max	AAS
Cadmium	CdO	2ppm max	PG
Arsenic	As₂O₃	1ppm max	AAS
Mercury	HgO	1 ppm max	AAS
Titanium	TiO₂	100 ppm max	XRF
Hafnium	HfO₂	50 ppm max	XRF
Barium	BaO	50 ppm max	XRF
Tin	SnO₂	50 ppm max	XRF
Zirconium	ZrO₂	50 ppm	XRF
Zinc	ZnO	500 ppm max	XRF
Lead	PbO	5 ppm max	PG

NOTE:-

The Calcium (CaO) to Phosphorus (P₂O₅) Ratio = 1.33 ± 0.05 by GM corresponding to 1.68 (Ca/P)

Key to methods used for chemical analyses

PG = Polography.
SE = Ion Specific Electrode.
AAS = Atomic Absorption Spectroscopy.
XRF = X ray Fluorescence.
IRS = Infrared Spectroscopy.
PE = Plasma Emission Spectroscopy.
GM = Gravimetric Analysis.
XRD = X ray Diffraction.