Effect of temperature on morphology of electrochemically-deposited calcium phosphates

Calcium phosphates were electrochemically deposited on titanium plates at temperatures from 4 degrees C to 92 degrees C in a solution of NaCl, K2HPO4 and CaCl2 x 2H20. Scanning electron microscopic studies showed that granular deposits formed on the electrode at electrolyte temperatures of 4 degrees C, 22 degrees C, and 37 degrees C; needle-like deposits formed at 52 degrees C-92 degrees 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 degrees C and slightly decreased at 92 degrees C.