Effect of temperature on electrochemical deposition of calcium phosphate coatings in a simulated body fluid

Calcium phosphate coatings were deposited on titanium plate by an electrochemical method in simulated body fluid at 5–62 °C. X-ray diffractometry and FTIR studies demonstrated that the deposits at 5, 22 and 37 °C were amorphous and those at 52 and 62 °C contained Mg(OH)2, CaCO3 and carbonate apatite of low crystallinity. The calcium, magnesium and phosphorus contents of deposit increased in direct proportion to the square root of loading time of cathodic potential. Induction periods, which might be thought to be the time required to decrease the pH of the electrolyte around the cathode by the formation of H2 gas and to start deposition of calcium phosphate, were observed on all the regression lines. It is concluded that in the electrochemical synthesis of calcium phosphate in this temperature range the diffusion process is a rate-determining step.