Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Ultrahydrophobicity wikipedia , lookup
Microelectromechanical systems wikipedia , lookup
Strengthening mechanisms of materials wikipedia , lookup
Self-assembled monolayer wikipedia , lookup
Spinodal decomposition wikipedia , lookup
Sol–gel process wikipedia , lookup
Industrial applications of nanotechnology wikipedia , lookup
MORPHOLOGICAL STUDY OF DETONATION SPRAYED COATINGS OF CALCIUM HYDROXYAPATITE DEPOSITED ON A NANOSTRUCTURED TITANIUM SUBSTRATE A.A. Sitnikov, V.I. Yakovlev, Yu.P. Sharkeev 1, E.V. Legostaeva 1, A.A. Popova I.I.Polzunov Altai State Technical University, Barnaul [email protected] 1 Institute of Strength Physics and Materials Science SB RAS, Tomsk Biocompatible coatings are effectively formed by spraying of calcium hydroxyapatite Са10(РО4)(ОН)2 powders on a titanium substrate. Recently, along with the composition, macro- and microstructure development, the surface morphology of the coatings has received increasing attention. In a number of studies, the roughness of the coatings has been shown to significantly influence the induction processes of cells. As a substrate material, titanium VT1-0 has been chosen, which has several advantages being highly biocompatible, bioinert, practically non-toxic, corrosion-resistant and possessing low thermal conductivity and low coefficient of thermal expansion. The morphology of the gas-detonation sprayed calcium phosphate coatings deposited on ultrafine-grained and nanostructured titanium substrates and implant imitations has been studied. The substrates and implant imitations were produced in the Institute of Strength Physics and Materials Science SB RAS, Tomsk. It was shown that the detonation sprayed hydroxyapatite powders with particles ranging from 1 to 20 µm formed coatings non-uniform in thickness and phase composition. The roughness of the coatings was Ra=3,65-4,72 µm (class 5). When hydroxyapatite particles of 20-100 µm in size are sprayed, coatings more uniform in thickness and phase composition are formed (Fig.1) with an average roughness of Ra = 6,24 µm (class 4). Preliminary treatment of the titanium substrate by sanding and chemical etching allows increasing the adhesive strength of the coating up to 20MPa. 162 □ (522) □ (432) в □ (110) □ □ (002) (210) □ (300) □ (310) □ (222) □ (100)□ 312) □(320) □ (511) б □ (211) а 100 m 20 30 40 50 60 70 80 90 10 200 m 0 Fig.1. SEM images: hydroxyapatite powder (a), detonation sprayed hydroxyapatite coating (b), XRD pattern of the coating (c). Biological studies have demonstrated biocompatibility and bioactivity of the coatings. It was found that the calcium phosphate detonation sprayed coatings induce growth of tissue cells with 100% probability, which indicates that the relief of the coatings is optimal for fixation and aging of the cells. Comparative studies of calcium phosphate coatings produced by detonation spraying and those produced by micro-arc in an electrolyte containing phosphoric acid, hydroxyapatite and calcium carbonate have shown the advantages of detonation spraying for providing the required phase composition of the coating. This opens up a possibility of making two-phase coatings (hydroxyapatite and beta-calcium phosphate) ensuring the closest match in composition to the bone tissue. 163