Study of rhombohedral tricalcium phosphate in hexagonal crystal structure family on the sample prepared by the sol-gel route and the effect of calcination temperature

Abstract

The effect of the calcination temperature at 800 and 1000 °C on the stable formation of the tricalcium phosphate with rhombohedral structure in the system of the hexagonal crystal family was determined, while its precursor was made from limestone obtained from nature in the Lumajang district, Indonesia. The rhombohedral tricalcium phosphate samples were prepared by sol-gel routine, then examined by several tests, such as, Fourie transform infrared spectroscopy to study the deficiency of -OH, X-ray diffraction test to study the microstructure of the tricalcium phosphate with the rhombohedral structure in a hexagonal crystal system, differential scanning calorimetry and thermogravimetry tests to study thermal characteristics, scanning electron microscopy and energy dispersive spectroscopy to study the surface topography and to obtain the atomic ratio Ca/P ~1.5. Finally, the UV-vis test found the optical energy gap, E g , from ~5.34 to ~5.41 eV for the sample calcined at 800 °C and E g ~5.19 to ~5.21 eV at 1000 °C.

Probing the influence of strontium doping and annealing temperature on the structure and biocompatibility of hydroxyapatite nanorods

“…A novel phase denoted as [Sr 7 Ca 3.5 (PO 4 ) 7 ] emerges predominately in samples such as Sr5-800, Sr7-UA, Sr7-600 and Sr7-800 exhibiting the presence of a distinctive rhombohedral crystal structure within the hydroxyapatite structure. 45 Usually the rhombohedral structure has three equal axes at oblique angles to each other. The crystallographic directions and planes offer lower energy barriers for the attachment of new atoms.…”