Hydroxyapatite plasma-sprayed

Hydroxyapatite Plasma Sprayed Coatings on Ti Substrate for Biomedical Applications... 

Bertrand, G., Collonges, G., Combes, C., Parco, M., Braceras, I., Alexis, J., Balcaen, Y., and Rey, C. (2014b) Comparison of physical-chemical and mechanical properties of chlorapatite and hydroxyapatite plasma sprayed coatings. Open Bioeng. J., in press. 

Yang, C.Y., Wang, B.C., Chang, W.J., Chang, E., and Wu, J.D. (1996) Mechanical and histological evaluation of cobalt-chromium alloy and hydroxyapatite plasma-sprayed coatings in bone. J. Mater. Sci. Mater. 

Fig. 10. Scanning electron microscope (SEM) micrograph of the surface of vacuum plasma sprayed hydroxyapatite (HA) coating after treatment in the fluoridating solution (KF 0.05 M KH2PO4 0.15 M pH 7, temperature 100 C). A layer of thin needle-like fluorhydroxyapatite crystals (0.5-3 m long, 0.1-0.3 m width) can be observed. (With kind permission of Springer Science and Business Media).

L. Sun, C.C. Berndt, K.A. Gross, A. Kucuk, Material fundamentals and clinical performance of plasma-sprayed hydroxyapatite coatings A review, J. Biomed. Mater. Res. 58 (2001) 570-592. 

P. Cheang, K.A. Khor, Addressing processing problems associated with plasma spraying of hydroxyapatite coatings. Biomaterials 17 (1996) 537-544. 

In the field of metallic powder applications, a method of plasma spray coating suitable for biomedical materials has been developed using titanium and calcium phosphate composite powder. By means of the mechanical shock process, the appropriate composite powder was prepared, and plasma sprayed on Ti substrate under a low-pressure argon atmosphere. A porous Ti coating layer was obtained in which the surface and the inside of the pores were covered thinly with hydroxyapatite. This surface coating is expected to show excellent bone ingrowth and fixation with bone (21). 

Figure 9.43 Raman spectra of plasma sprayed calcium phosphate coating shows the difference in hydroxyapatite content by comparing intensity of the OH stretching band at (a) near substrate (b) in the middle and (c) near the surface of the coating layer.

Some examples of applications of neutron and synchrotron radiation diffraction applied to the determination of residual stresses in various industrial and technological components have been presented. The reliability of the technique has been shown, being able to determine residual stresses induced by various thermomechanical treatments, such as shrink-fit joints, welds and surface treatments in automotive and aerospace materials. It has been shown how, by this method, it is possible to determine stresses both in the coating and in the substrate of plasma-spray deposed hydroxyapatite layers on Ti alloy for biomedical applications. 

Muzzarelli et al. (2000) described a method for coating prosthetic articles with chitosan-oxychitin. Plates of titanium (Ti) and its alloys were plasma sprayed with hydroxyapatite and glass layers, and subsequently a chitosan coat was deposited on the plasma-sprayed layers using chitosan acetate. These layers were treated with 6-oxychitin to form a polyelectrolytic complex. This complex was optionally contacted with l-ethyl-3-(3-dimethylami-nopropyl) carbodiimide at 4°C for 2 hours to form amide links between the two polysaccharides, or acetylation with acetic anhydride in methanol to obtain a chitin film. In all cases, the modified coats were insoluble, uniformly flat, and smooth. Prosthetic materials coated with chitosan-oxychitin were capable of provoking colonization by cells, osteogenesis, and osteointegration. 

During plasma spraying of hydroxyapatite onto titanium alloy substrate surfaces minor amounts of highly reactive CaO are being formed by thermal decomposition that react with the native titanium oxide layer to form calcium titanate, CaTiOs. This thin reaction layer has been implicated to be an important... 

ASTM F 2024. (2010) Practice for X-ray Diffraction Determination of Phase Content of Plasma-sprayed Hydroxyapatite Coatings, ASTM International, West Conshohocken, PA. 

Cattini, A., Bellucci, D., Sola, A., Pawlowski, L., and Cannillo, V. (2014) Microstructural design of functionally graded coatings composed of suspension plasma sprayed hydroxyapatite and bioactive glass. /. Biomed. Mater. Res. B Appl. Biomater., 102 (3), 551-560. 

Heimann, R.B. (2009) Characterization of as-plasma-sprayed and incubated hydroxyapatite coatings with high resolution techniques. Materialwiss. Werkstofftech.,... 

Table 5.3 Plasma spray parameter used to optimise deposition of hydroxyapatite by LEPS (Garcia-Alonso, 2009).

Figure 5.25 Contour plots of the depen- hydroxyapatite (Garcia-Alonso, 2009). (Images dence of coating thickness in micrometres (a) courtesy of Dr Diana Garcfa.Alonso Garcia, and crystallinity in percent (b) on statistically Dept of Appl. Phys., Technische Universiteit significant plasma spray parameters selected Eindhoven, The Netherlands.) for low power plasma spraying (LEPS) of...

Figure 5.32 SEM images of conventional atmospheric plasma sprayed (APS, left) and suspension plasma sprayed (SPS, right) hydroxyapatite coatings, (a, b) Top view and (c, d) coating cross-sections (Gross and Saber-Samandari, 2009). ( With permission by Elsevier.)...

Nanocrystalline hydroxyapatite coatings were deposited by plasma spraying of sols formed from various precursor solutions by Coyle et al. (2007). The coatings were designed to possess improved resorption in vivo and thus reduced the risk of forming larger debris particles that may give rise to particle disease . 

Barry, J.N. and Dowling, D.P. (2011) Comparison between the SBF response of hydroxyapatite coatings deposited using both a plasma-spray and a novel coincident micro-blasting technique. Key Eng. Mater., 493/494, 483-488. 

Chang, C., Shi, J., Huang, J., Hu, Z., and Ding, C. (1998) Effects of power level on characteristics of vacuum plasma sprayed hydroxyapatite coating. J. Therm. Spray Technol., 7 (4), 484-488. 

L. (2007) Plasma spray deposition of hydroxyapatite coatings from sol precursors. Mater. Sci. Forum, 539-543, 1128-1133. 

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