Sintered hydroxyapatite

Ruys, A.J., Sorrell, C.C., Brandwood, A., and Milthorpe, B.K. (1995) Hydroxyapatite sintering characteristics correlation with powder morphology by high resolution spectroscopy. J. Mater. Sci., 14, 744-747. 

Negami S (1988) Histological observations on muscle tissue reactions to porous hydroxyapatite sintered bodies in rats. J Japan Orthop Assoc 62 85-94... 

Watanabe Y, Ikoma T, Monkawa A, Suetsugu Y, Yamada H, Tanaka J et al (2005) Fabrication of transparent hydroxyapatite sintered body with high crystal orientation by pulse electric current sintering. J Am Ceram Soc 88 243-245... 

Fig. 11.17 XRD patterns of bone hydroxyapatite and sintered stoichiometric hydroxyapatite. (Bone hydroxyapatite was obtained by heating bone of pig at 600°C).

In France, a number of researchers have explored the washing, phosphate stabilization, and sintering or calcination of residues (Derie 1996 Iretskya et al. 1999 Nzihou Sharrock 2002 Piantone et al. 2003). The formation of more crystalline hydroxyapatite reaction products helps reduce leachability of metals incor-... 

Hydroxyapatite (HAP), with basically the same crystal structure as Ca-deficient, carbonate-containing hydroxyapatite, is compatible with and reactive in a live human body. However, sintered HAP prepared by treating fine HAP particles under elevated temperature and pressure has insufficient mechanical properties, in particular fracture toughness, which greatly limits its commercial applicability. It is rarely implanted alone. On the other hand, zirconia, particularly partially stabilized zirconia (PSZ),... 

The major interest in calcium phosphate cements has always been in their potential for biomedical applications. This is because bone contains hydroxyapatite (Ca5(P04)30H), a calcium phosphate mineral. Any material that could be used to bond bone or produce an artificial graft should contain this mineral for compatibility. In fact, much of the research in producing calcium phosphate-based cements or sintered ceramics was motivated by their biomedical applications. We will discuss applications of calcium phosphate cements in detail in Chapter 18. This section describes their materials development. 

Property Natural Biomaterials Cortical bone Dentine Sintered hydroxyapatite Dense CBPCs... 

Laquerriere. P. et ah. Correlation between sintering temperature of hydroxyapatite particles and the production of inflammatory cytokines by human monocytes. Colloids Surf. B, 30, 207, 2003. 

Rambo et al. (2006) produced highly porous biomorphous alumina scaffolds by pyrolysis of natural cellulosic sponges that afterwards were infiltrated by aluminium vapour, and subsequently oxidised and sintered. These alumina scaffolds were immersed in highly supersaturated SBF for 4 days to yield a thin (2 pm) calcium phosphate layer with a Ca/P ratio of 1.62, indicating the formation of a Ca-deficient bone-like hydroxyapatite layer. Kim et al. (2003a) had performed similar work on biomorphous zirconia scaffolds previously. 

Figure 5.26 Microporosity of hydroxyapatite particle precursors (SEM images of polished powder particles), (a) As-purchased (AMDRY 6021, Sulzer Metco Deutschland), (b) Sintered for 1 h at 1000°C. (c) Sintered for 1 h at 1300°C (Heimann and Vu, 1997).

Table 5.4 Tensile adhesion strength (ASTM C633-13) of LPPS (VPS) hydroxyapatite coatings Cl (deposited from as-received powder) and C2 (deposited from powder sintered for 1 h at 1300°C) as a function of immersion time in HBSS (n = 5) (Heimann and Vu, 1997).

Goudarzi, M., Batmanghelich, F., Afshar, A., Dolati, A., and Mortazavi, G. (2014) Development of electrophoretically deposited hydroxyapatite coatings on anodized nanotubular IK), structures corrosion and sintering temperature. Appl. Surf. Sci. doi 10.1016/j.apsusc.2014.02.055... 

Tamari, N., Mouri, M., and Kondo, I. (1987) Mechanical properties and existing phases of composite ceramics obtained by sintering of a mixture of hydroxyapatite and zirconia. J. Ceram. Soc. Jpn., Int. Ed., 95, 758-761. 

Vu, T.A. and Heimann, R.B. (1997) Effect of CaO on thermal decomposition during sintering of composite hydroxyapatite-zirconia mixtures for monolithic implants. J. Mater. Sci. Lett., 16, 437-439. 

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