Hydroxyapatite Coating on Thermal Titanium Substrate in Aqueous Solution

Abstract

A hydroxyapatite, HAP, film was deposited on a titanium substrate in an aqueous solution, at an ambient temperature and ambient pressure. The solution included 3 mmoldm-3 Ca(H2PO4)2 and 7 mmol dm-3 CaCl2 at pH 5.5. The temperature of the substrate surface was controlled in both methods of applying alternative current through the Ti foil and high frequency induction heating using Ti ingot. In these methods, the substrate was heated up and the temperature gradient was formed between the substrate and the solution. The effects of surface temperature, fluoride ions, additive inhibitor and heating time on the morphology of HAP crystals formed on Ti substrate were investigated in various conditions. The morphology changed from compact layer to dendrite layer with the HAP growing time in AC current method and the HAP film with the thickness of 200 μm can be obtained on Ti foil with cross section of 30 μm × 2mm by heating for 20 min at 20 A-AC. On the other hand, the deposits consisted of algae-like whisker in the induction heating method. The HAP formation is found to take place only on the substrate surface by these substrate heating methods without HAP precipitation in aqueous solution

Application of high magnetic fields in inorganic materials processing

“…A magnetic field has been introduced into a heat substrate method proposed by Okido et al [20,21]. A titanium foil was submerged in an aqueous solution with 0.3 mM Ca (H 2 PO 4 ) 2 and 0.7 mM CaCl 2 and heated by passing electric current through the titanium foil to precipitate HAp on the foil.…”

Control of Crystal Orientation of Hydroxyapatite by Imposition of a High Magnetic Field

“…In this study, the magnetic field has been introduced into a heat substrate method in an aqueous solution, proposed by Okido et al 18,19) The experimental apparatus of the method is shown in Fig. 7.…”

“…Especially Sakka et al 16,17) applied a high magnetic field to a colloidal filtration (slip casting) process to align crystals of Alumina and Titania etc. In this study, in order to control crystal orientations of the hydroxyapatite the colloidal filtration process has firstly been extended to hydroxyapatite and a new process has been developed which a high magnetic field is introduced in a heat substrate process developed by Okido et al 18,19) The usefulness of the two processes has been confirmed through the orientation index evaluated by X-ray diffraction patterns and scanning electron microscope (SEM) images of hydroxyapatite crystals.…”

Crystal orientation of non-magnetic materials by imposition of a high magnetic field

“…A magnetic field has been introduced into a heat substrate method proposed by Okido et al [21,22]. The experimental apparatus of the method is shown in Fig.…”