Hydroxyapatite (HAp Ca10(PO4)6(OH)2) is very known to be a biomaterial and an absorbent for chromatography. In this study, HAp was agglomerated with anatase TiO2 to manufacture thermal spray powders to improve the absorption activity of TiO2 and then improve its photocatalytic activity. The microstructures and compositions of plasma sprayed TiO2, TiO2-10%HAp, TiO2-30%HAp and HAp coatings were investigated. Due to the low thermal conductivity of HAp compound, not all HAp particles fully melted even under the arc current of 800 A. Low temperature stable β-Ca3(PO4)2 was detected in the sprayed HAp coatings. The addition of HAp inhibited the phase transformation of anatase TiO2 to rutile. Under the arc current of 600 A, the anatase content in the TiO2, TiO2-10%HAp and TiO2-30%HAp coatings was 10.6%, 20% and 42%, respectively. Although slightly decomposition of HAp to α-Ca3(PO4)2 was found in the TiO2-30%HAp coatings, it did not decompose to CaO and P2O5 according to the XRD and EDAX analysis. With the increasing of the spraying distance from 70 mm to 110 mm, the anatase content in the TiO2-30%HAp coatings decreased from 34% to 17% under arc current of 700 A. The addition of the secondary gas of helium has no significant influence on the melting state of the TiO2-HAp feedstock powders.

This content is only available as a PDF.
You do not currently have access to this content.