ELECTROLYTIC DEPOSITIONS OF CALCIUM PHOSPHATES ON SUBSTRATE

Calcium phosphate deposition layers on cathode substrates were prepared by electrolysing acidic Ca(H2PO4)2 . H2O (MCP) solutions of 0.02-0.21 mol dm-3 added with and without NaNO3 at cathode currents of 2-200 mA CM-2 at 20-90-degrees-C. At relatively high MCP concentrations and low currents, CaHPO4 . 2H2O and CaHPO4 plate-like crystals were deposited below and above approximately 30-degrees-C, respectively. With increasing current, the deposits became fine. On further increasing the current and/or decreasing the MCP concentration, apatite deposition occurred. The addition of NaNO3 facilitated the formation of apatite. Deposited apatites were very fine grains and had a calcium-deficiency of approximately 1.50 in the Ca/P molar ratio.