Coatings, bioceramic

When high-impact resistance is needed, bioceramic materials such as hydroxyapatite can be coated by plasma spraying on to metals like titanium. Plasma-sprayed calcium phosphate coatings on to steel pins, when used with implants, greatly reduce pain experienced in hip joints. Bone adhesion is also improved [68,69], 

An alternative method of coating titanium with calcium phosphates is to anodise the metal in a solution containing sodium glycerophosphate and calcium acetate [37], 

In reverse, the porosity of Ni/P alloys obtained by electroless plating on to bioceramic materials, may allow the temporary housing of drugs, and so on [70], 

Applying a glass or ceramic coating onto the surface of a substrate allows us to have the best of both worlds. We have the bulk properties of the substrate and the surface properties of the coating. There are three main reasons for applying a coating  

Bioceramic coatings are often used on metallic substrates in which the fracture toughness of the metal is combined with the ability of the coating to present a bioactive surface to the surrounding tissue. The use of a bioceramic coating on a metal implant can lead to earlier stabilization of the implant in the surrounding bone and extend the functional life of the prosthesis. Under the proper conditions a cementless prosthesis should remain functional longer than a cemented device in which stability is threatened by fracture of the bone cement. 

Hydroxyapatite coatings prepared by plasma spraying typically contain considerable amounts of amorphous calcium phosphate and small amounts of other crystalline phases. Heat treating the coating can increase crystallinity and also improve the adhesion to the substrate. However, this process is not usually done because of economic factors and concerns about the adverse effects it might have on the mechanical properties of the substrate. 

In addition to plasma spraying other methods have been used to apply HA coatings  

Electrophoretic deposition (see Section 27.6 for a description of the technique) can be used to coat porous surfaces that caimot be completely coated by line-of-sight techniques such as plasma spraying. But the adhesion of the HA particles to the substrate and each other is weak and high-temperature sintering after deposition is usually necessary. 

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Bioceramic Coatings for Medical Implants Trends and Techniques, First Edition. 

Heimann, R.B. (2013) Structure, properties, and biomedical performance of osteocon-ductive bioceramic coatings. Surf. Coat. Technol., 233, 27-38. 

The present authors are very conscious about the skimpiness of this account and hence the perceived need to expand on this important subject. They feel, however, that within the general context of this treatise biochemical exactitude has to take second place to an account on technological developments of bioceramic coatings that are designed to prepare a nurturing bed for bone apposition and cell ingrowth controlled by the principles of biomineralisation. To somewhat remedy this deficiency, the interested reader is referred to an excellent and necessarily much more detailed overview of biomineralisation by Weiner and Dove (2003). 

Ali, Hung and Yongyi (2010) reviewed the application of focused ion beam (FIB) sputtering for micro/nano fabrication. Although less relevant for discussion of bioceramic coatings, treatment of basic principles of FIB, and evaluation of empirical and fundamental models for sputtering yield, material removal rate and surface roughness were presented and compared. Fabrication of various micro- and nanostructures was discussed. 

A limited number of contributions dealing with HVSF-sprayed alumina coatings exist. While these contributions appear to have no direct bearing to bioceramic coatings, alumina is considered a bioinert ceramic and, in the future, applications may arise for such coatings in the biomedical realm. 

Borisov, Y., Vojnarovich, S.G., Ulianchich, N.V., Jansen, J., and Wolke, J. (2002) Investigation of bioceramic coatings produced by microplasma spraying. Paton Welding /, 9, 4-6. 

Durdu, S. and Usta, M. (2014) The tribological properties of bioceramic coatings produced on Ti6A14V alloy by plasma electrolytic oxidation. Ceram. Int., 40 (2), 3627-3635. 

Heimann, R.B., Kurzweg, H., Ivey, D.G., and Wayman, M.L. (1998) Microstructural and in vitro chemical investigations into plasma-sprayed bioceramic coatings. / Biomed. Mater. Res., Appl. Biomater., 43, 441-450. 

Heimann, R.B. and Vu, T.A. (1997) Low-pressure plasma-sprayed (LPPS) bioceramic coatings with improved adhesion strength and resorption resistance. /. 

Melero, H., Madrid, C., Fernandez, J., and Guilemany, J.M. (2014a) Comparing two antibacterial treatments for bioceramic coatings at short culture times. J. Therm. Spray Technol., 23 (4), 684-691. 

J., Diez-Perez, A., and Guilemany, J.M. (2014c) Comparison of the in vitro behaviour of as-sprayed, alkali-treated and collagen-treated bioceramic coatings obtained by high velocity oxy-fuel spray. Appl. Surf Sci., 307, 246-254. 

Komath, M., and Varma, H. (2012) Preparation and analysis of chemically gradient functional bioceramic coating formed by pulsed laser deposition. /. Mater. Sci. Mater. Med., 23 (2), 339-348. 

Vu, T.A. and Heimann, R.B. (1996) Improvement of the adhesion strength of plasma-sprayed bioceramic coatings. DVS-Ber.,... 

Zeng, H.T. and Lacefield, W.R. (2000) XPS, EDX and FTIR analysis of pulsed laser deposited calcium phosphate bioceramic coatings the effects of various process parameters. Biomaterials, 21 (1), 23-30. 

Deposition, Structure, Properties and Biological Function of Plasma-Sprayed Bioceramic Coatings... 

General Requirements and Performance Profile of Plasma-Sprayed Bioceramic Coatings 255... 

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