Calcium-Titanium-Zirconium Phosphates

This atomic arrangement results in a hexagonal skeleton of space group R3c, with large structural vacancy sites per unit cell of octahedral symmetry (Ml) occupied by cations with the coordination number (6), such as titanium or zirconium and trigonal-prismatic symmetry (M2) occupied by vacancies as in Nb2(P04)3, by two-valent ions as in Cao.sTi2(P04)3 or three-valent ions as in Lao.33Ti2(P04)3. These vacancies account for the structural variability of the NASICON family, as well as their ionic conductivity. 

Reports of quantitative data of the electric conductivity of NASICONs are few in number, and appear to differ considerably depending on the chemical composition and preparation conditions. SUva et al (2006) measured the d.c. conductivity of CaTi4(P04)6 produced by high-energy dry ball-milling for 15 h of a mixture of 

Ti6Al4V substrate (b) Higher magnification of the coating interior. Note the absence of microcracks and larger interconnected pores. 

Acceleration of Bone Growth by an Electric Field Electrical currents have been used to heal bone fractures since the mid-1800s (Julius Wolff, 1835-1902 James Prescott Joule, 1818-1889), and the effect of electrical stimulation on bone has long been studied and well documented (Bassett and Becker, 1962 Bassett, 1968 Bassett et al, 1974). It has also long been known that the growth of bone is affected by the presence of materials with different dielectric behavior, as suggested by the so-called bioelectric phenomenon in bone (Fukada, 1957 Shamos et al, 1963  

Toluidine blue-stained histological section (b) MIcroradlographIc Image of the same sample (Helmann, 2006). 

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Calcium (titanium, zirconium) orthophosphate ceramics show solubility in SBF at least one order of magnitude lower than that of other calcium orthophosphates including hydroxyapatite and, in particular P-tricalcium phosphate (TCP) and tetracalcium phosphate (TTCP) (Figure 4.20). 

The rare earths (see table II) have a marked geochemical affinity for fluorine, calcium, titanium, niobium, zirconium, and the phosphate and carbonate ions. The most important, from an economic viewpoint, are the carbonatites and the phosphates. 

Allan (A7) during his studies of ashed plant materials also investigated interferences. Using an air-acetylene flame, sodium, potassium, calcium, magnesium, and phosphate had no effect. In the air-coal gas flame, as employed by Elwell and Gidley (E2), recoveries of iron were only 80-90% when the test solutions contained an excess of calcium, copper, aluminum, titanium, and zirconium. With silicon added, iron recovery was 26%. Owing to incomplete vaporization of iron in the flame, sensitivities attained are higher in the air-acetylene flame and lower in the air-coal gas flame. Since iron is subject to oxidation in the flame, fuel-rich flames are preferable. 

A large number of inorganic layer crystals such as micas, sodium silicates, niobate, uranate, vanadate, titanate, zirconium phosphate, graphitic acids, crystalline silicic acids, vanadium oxyhydrate, calcium phosphoric acid esters, and titanium disulfide develop alkyl crystals between their rigid crystal layers by ion exchange with, for example, alkyl ammonium salts and by intercalation inorganic... 

Major constituents (greater than 5 mg/L) Minor constituents (O.Ol-lO.Omg/L) Selected trace constituents (less than 0.1 mg/L) Bicarbonate, calcium, carbonic acid, chloride, magnesium, silicon, sodium, sulfate Boron, carbonate, fluoride, iron, nitrate, potassium, strontium Aluminum, arsenic, barium, bromide, cadmium, chromium, cobalt, copper, gold, iodide, lead, Uthium, manganese, molybdenum, nickel, phosphate, radium, selenium, silver, tin, titanium, uranium, vanadium, zinc, zirconium... 

For pressing as well as extrusion, the solid electrolyte precursor particles (e.g., zirconia) are often mixed or reacted with an inorganic cementing substance. It is preferred that such adhesive materials also have ion permselective properties as the precursor particles. Phosphates of zirconium, titanium and zinc are examples of such cements although other materials such as calcium aluminate and calcium aluminosilicates are candidates as well [Arrance et al., 1969]. For these cementing materials to be effective, the metal oxides must be only partially hydrated so that they are reactive with the bonding compounds. 

Legostaeva, E.V., Kulyashova, K.S., Komarova, E.G., Epple, M., Sharkeev, Y.P., and Khlusov, I.A. (2013) Physical, chemical and biological properties of micro-arc deposited calcium phosphate coatings on titanium and zirconium-niobium alloy. Materialwiss. Werkstofftech., 44 (2-3), 188-197. 

If those particles had been of moderate solubility, like the calcium phosphate, iron oxide, or zinc oxide particles, they would have been suspended sufficiendy long to be dissolved. Alternatively, if they had been nearly insoluble, as were the titanium oxide, cerium oxide, and zirconium oxide particles, we would expect them to persist. Thus, the particles could either dissolve direcdy or persist as insoluble particles. Previous work with titanium dioxide has shown it to be virtually insoluble in vitro and to persist in vivo. 

Additives used in final products Fillers barium titanate, calcium carbonate, carbon black, carbon black coated with conductive polymer, copper powder, hafnium powder, lead zirconium titanate, silica, tantalum powder, titanium dioxide, zeolite, zinc sulfide plasticizers adipic polyester, dibutyl phthalate, dibutyl sebacate, glyceryl tributyl-ate, tricresyl phosphate Antistatics carbon black, glycerol monooleate ... 

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