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 elec trochemical method in simulated body fluid at 5-62 degrees C. X-ray di ffractometry and FTIR studies demonstrated that the deposits at 5, 22 and 37 degrees C were amorphous and those at 52 and 62 degrees C conta ined Mg(OH)(2), CaCO3 and carbonate apatite of low crystallinity. The calcium, magnesium and phosphorus contents of deposit increased in dir ect proportion to the square root of loading time of cathodic potentia l, induction periods, which might be thought to be the time required t o decrease the pH of the electrolyte around the cathode by the formati on of H-2 gas and to start deposition of calcium phosphate, were obser ved on all the regression lines. It is concluded that in the electroch emical synthesis of calcium phosphate in this temperature range the di ffusion process is a rate-determining step.