Hydroxyapatite and hydroxyapatite-matrix ceramics: A survey

This survey deals with the features of hydroxyapatite (HA) production by we t, dry, and hydrothermal processes. The parameters of HA deposition from so lutions:of calcium chloride, ammonium hydrogen phosphate, and aqueous ammon ia were comprehensively studied. Alkoxide sol-gel and codeposition from sol ution methods were developed for producing HA and composite powders of HA w ith zirconium, yttrium, and aluminum hydroxides for use in reinforced ceram ics manufacture. The details of isomorphous substitutions in HA are discuss ed. Quantum-chemical simulations of the electronic structure and the dynami cs of isomorphous substitution in HA are described. Dielectric properties a nd thermostimulated exoelectron emission measurements were used to characte rize structure alterations in HA. The character of the interaction between HA and collagen was studied by IR spectroscopy and NMR. The principles of t he technology of porous and dense HA ceramics with controlled mechanical pr operties and of HA-matrix composites with improved mechanical properties ar e considered. The tendencies of dissolution and corrosion under stress for HA ceramics are discussed.