Electrochemical calcium phosphate coating

Electrochemical methods applied to deposit calcium phosphate coatings require an electrical conductor as a substrate as well as post-depositional heat treatment (Abe, Kokubo and Yamamuro, 1990). Hence, they are not well suited to coat non-conducting ceramics and heat sensitive polymers. 

Figure 5.10 Changes of calcium (a) and phosphorus (b) concentrations during immersion of electrochemically deposited calcium phosphate coatings in DMEM solution ([Ca]0 = 1.80 mmol Table 7.8) for up to 28 days. (After Drevet and Benhayoune (2012).)...

Table 5.2 Electrochemical parameters obtained by potentiodynamic measurements of calcium phosphate coatings deposited on Mg alloy.

Niinomi, M. Cyto-toxicity and fatigue performance of low rigidity titanium alloy, Ti-29Nb-13Ta-4.6Zr, for biomedical apphcations. Biomateiials, 24,2673-2683(2003). Niespodziana, K., Jurczyk, K., Jakubowicz, J., and Jurczyk, M. Fabrication and properties of titanium-hydroxyapatite nanocomposites. Mater. Chem. Phys., 123,160-165 (2010). Noort, R.V Titanium The implant material of today. J. Mater. Sci., 22,3801-3811 (1987). Narayanan, R., Seshadri, S.K., Kwon, T.Y., and Kim, K.H. Electrochemical nano-grained calcium phosphate coatings on Ti-6AMV for biomaterial apphcations. Scripta Mater., 56, 229-232 (2007). 

Narayanan R, SeshadriS, KwonT, Kim K. Electrochemical nano-grained calcium phosphate coatings on Ti-6A1-4V for biomaterial applications. Scr Mater 2007 56 229-32. 

RoBler S., Sewing A, StolzelM., Born R., Scharnweber D., Dard M., and Worch H. Electrochemically assisted deposition of thin calcium phosphate coatings at near-physiological pH and temperature. /. Biomed. Mater. Res. 2002 64A 655-663. 

SEM micrographs of the electrochemically deposited calcium phosphate coating (a) microporous structure, (b) nanometre-scale crystal grains (Hu etaL, 2007). 

Non-thermal deposition methods are defined as those ones carried out at temperatures much below the incongruent melting point of hydroxyapatite, in particular at or near ambient temperature. However, frequently post-depositional heat treatment must be applied to either crystallise amorphous calcium phosphate (ACP), transform (dehydrated/dehydroxylated) precursor phases such as octacal-cium phosphate (OCP) to hydroxyapatite, and/or to remove organic compounds used in coating preparation, for example during sol-gel, dip coating, electrochemical and EPD. 

Currently, a number of alternative applications of nanostructured calcium phosphate are under investigation, some of which will be introduced at this point. For example, Shirkhanzadehl [175] has synthesized a nano-HA coating via an electrochemical method and doping with silver ions (using silver nitrate solution at room... 

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