Effect of Temperature on Morphology of Electrochemically-Deposited Calcium Phosphates

Abstract

Calcium phosphates were electrochemically deposited on titanium plates at temperatures from 4°C to 92°C in a solution of NaCl, K2HPO4 and CaCl2 · 2H2O. Scanning electron microscopic studies showed that granular deposits formed on the electrode at electrolyte temperatures of 4°C, 22°C, and 37°C; needle-like deposits formed at 52°C-92°C. The width and length of the needles increased with the temperature of the electrolyte. Based on the results of characterization by electron diffractometry, Fourier transform infrared spectroscopy and X-ray diffractometry, the granular deposits were identified as carbonate-containing calcium phosphate with low crystallinity, and the needle-like deposits as carbonate-containing apatite crystals elongated along the c-axis. Crystallinity of the deposits increased with the temperature of the electrolyte, whereas the orientation indices of the apatite increased with temperature up to 82°C and slightly decreased at 92°C.