Plasma-sprayed hydroxyapatite coatings

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. 

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

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. 

Fahad Hasan, M., Wang, J., and Berndt, C. (2014) Evaluation of the mechanical properties of plasma sprayed hydroxyapatite coatings. Appl. Surf. Sci., 303, 155-162. 

Jaworski, R., Pierlot, C., Tomaszek, R., Pawlowski, L., Znamirowski, Z., and Zdanowski, J. (2007) Optimization of dielectric properties of suspension plasma sprayed hydroxyapatite coatings. Material-wiss. Werkstofftech., 38 (2), 125-130. 

Yeung, W.K., Reilly, G.C., Matthews, A., and Yerokhin, A.L. (2013) In vitro biological response of plasma electrolytically oxidized and plasma-sprayed hydroxyapatite coatings on li-6Al-4V alloy. /. Biomed. Mater. Res. B Appl. Biomater., 101 (6), 939—949. 

Table 6.1 Performance profile of plasma-sprayed hydroxyapatite coatings (Wintermantel and Ha, 1996 Callahan, Gantenberg and Sands, 1994).

A notable exception is a study by Hesse et al. (2008) who investigated the effect of powder grain size and grain size distribution on the spatial distribution of calcium phosphate phases in atmospheric plasma-sprayed hydroxyapatite coatings incubated in r-SBF (SBF-H, Table 7.8). Coatings were mechanically abraded under dry conditions in steps of 40 pm by abrasive SiC paper, and the newly created surfaces analysed by XRD with Rietveld refinement for their quantitative phase composition. The results of this depth profiling are shown in Figure 6.8. 

Figure 6.13 Non-linear last-squares fitting (Keller and Dollase, 2000) to determine the ACP content of a plasma-sprayed hydroxyapatite coating (Heimann, 2009).

Figure 6.14 shows that a plasma-sprayed hydroxyapatite coating on a porous titanium layer covering the titanium alloy surface (solid bars) will improve the interfacial bond strength compared to uncoated porous titanium (light bars)... 

Figure 6.14 Comparison of early stage interfacial bond strength of porous titanium with (solid bars) and without (light bars) a plasma-sprayed hydroxyapatite coating (Cook, 1991. (Modified after Hench (1991).)...

Carayon, M.T. and Lacout, J.L. (2003) Study of the Ca/P atomic ratio of the amorphous phase in plasma-sprayed hydroxyapatite coatings. J. Solid State Chem., 172, 339-350. 

Fazan, F. and Marquis, P.M. (2000) Dissolution behavior of plasma-sprayed hydroxyapatite coatings. J. Mater. Sci. Mater. Med., 11, 787-792. 

Grafimann, O. and Heimann, R.B. (2000) Compositional and microstructural changes of engineered plasma-sprayed hydroxyapatite coatings on Ti6A14V substrates during incubation in protein-free simulated body fluid. /. Biomed. Mater. 

Gross, K.A., Berndt, C.C., and Herman, H. (1998) Amorphous phase formation in plasma-sprayed hydroxyapatite coatings. / Biomed. Mater. Res., 39 (3), 407 -414. 

T., and Jennissen, H.P. (2001) Biomimetic processes during in vitro leaching of plasma-sprayed hydroxyapatite coatings for endoprosthetic applications. Materialwiss. Werkstofftech., 32, 913-921. 

Leali Tranquilli, R, Merolli, A., Gabbi, C., Cacchioli, A., and Gonizzi, G. (1994) Evaluation of different preparations of plasma-spray hydroxyapatite coatings on titanium alloy and duplex stainless steel... 

Tercero, J.E., Namin, S., Lahiri, D., Balani, K., Tsoukias, N., and Agarwal, A. (2009) Effect of carbon nanotube and aluminum oxide addition to plasma-sprayed hydroxyapatite coating s mechanical properties and biocompatibility. Mater. Sci. Eng. C, 29 (7), 2195-2202. 

Tsui, Y.C., Doyle, C., and Clyne, T.W. (1998a) Plasma sprayed hydroxyapatite coatings on titanium substrates. Part 1 mechanical properties and residual stress levels. Biomaterials, 19, 2015-2029. 

Wang, B.C., Chang, E., Yang, C.Y., Tsu, D and Tsai, C.H. (1993) Characteristics and osteoconductivity of three different plasma-sprayed hydroxyapatite coatings. Surf. Coat. Technol., 58 (2), 107—117. 

Attempts have been made to simulate the X-ray signal of the ACP in plasma-sprayed hydroxyapatite coatings by a Lorentz function added to the Rietveld refinement algorithm (Hesse et al., 2008). This provides a reasonable fit of the... 

Figure 7.7 (a) Laser-Raman spectrum of a plasma sprayed hydroxyapatite coating showing the four principal vibrational modes of the P043- tetrahedron, (b) The v-, Raman mode deconvoluted by a... 

Figure 7.16 2D-1 H/31 P-CP-HETCOR NMR spectrum (a) and a Lorentzian fit of the cross-section of the HETCOR spectrum at the proton frequency of band L (b) of a plasma-sprayed hydroxyapatite coating incubated in r-SBF for 12 weeks (Heimann, 2007). For details see text.

Cathodoluminescence Microscopy of Plasma-Sprayed Hydroxyapatite Coatings... 

Figure 7.22 Cathodoluminescence emission spectra of Mn2+ doped plasma-sprayed hydroxyapatite coatings in the as-sprayed state (KT) and immersed in HBSS for 7 (7KT) and 28 (28KT) days (Gotze, 2000).

Figure 7.23 Concentration of Ca2+ and P043 ions and pH development measured in protein-free SBF during incubation of plasma-sprayed hydroxyapatite coatings (Gotze et ai, 2001).

Adhesion of Plasma-Sprayed Hydroxyapatite Coatings 7.5.2.1 Modified Peel Test According to ASTM D3167-10... 

The procedure to evaluate adhesion strength of plasma-sprayed hydroxyapatite coatings has been described earlier. The presence of a thin plasma-sprayed titania bond coat (see Chapter 6.3.2.2) considerably enhances the adhesion strength to a Ti6Al4V substrate of titania/HAp tandem coatings compared to HAp coatings without a bond coat. 

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