Modification of electrochemically deposited apatite using supercritical water.
Supercritical water was used as a modification method of electrochemically deposited apatite on pure titanium. The apatites were coated on a commercially pure titanium plate using a hydrothermal-electrochemical method. A constant direct current at 12.5 mA/cm2 was loaded for 1 hr at 25, 60, 100, 150 and 200 degrees C in an electrolyte containing calcium and phosphate ions. The deposited apatite on the titanium substrate was stored in supercritical water at 450 degrees C under 45 MPa for 8 hr. With this treatment, the crystallinity of the apatites increased, sharp edges of the deposited apatites were rounded off, and the bonding strength of the titanium substrate to the deposited apatites significantly increased. On the other hand, weight loss in 0.01 N HCl decreased and the weight gain rate in a simulated body fluid also decreased with this treatment. It is suggested that the modification using supercritical water improved the mechanical strength of the deposited apatite, but worsened its bioactivity.
Ban
S
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Department of Biomaterials Science, Kagoshima University Dental School, 8-35-1, Sakuragaoka, Kagoshima 890-8544, Japan.
Hasegawa
J
J
D001031:Apatites / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry; D001826:Body Fluids / Q000737:chemistry; D002118:Calcium / Q000737:chemistry; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003460:Crystallization; D004563:Electrochemistry; D006801:Humans; D008855:Microscopy, Electron, Scanning; D010710:Phosphates / Q000737:chemistry; D011312:Pressure; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013816:Thermodynamics; D014025:Titanium / Q000737:chemistry; D014867:Water / Q000737:chemistry*; D014961:X-Ray Diffraction
D001031:Apatites; D001672:Biocompatible Materials; D020099:Coated Materials, Biocompatible; D010710:Phosphates; D014867:Water; D014025:Titanium; D002118:Calcium