Protonic conduction in yttrium-substituted hydroxyapatite ceramics and their applicability to H2-O2 fuel cell

Yamashita, Kimihiro; Owada, Hitoshi; Umegaki, Takao; Kanazawa, Takafumi; Katayama, Keiichi

doi:10.1016/0167-2738(90)90153-i

Cited by 43 publications

(34 citation statements)

References 3 publications

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“…However, fluorapatite2 chemical analysis does not support the presence of more than 1% vacancies. This interpretation is consistent with anion conductivity in apatite ceramics (Yamashita et al 1988(Yamashita et al , 1990Maiti and Friedemann 1981), where conductivity of the protons or anions is thought to occur along the c-axis when a high enough vacancy concentration exists.…”

Section: Resultssupporting

confidence: 77%

Dielectric constants of apatite, epidote, vesuvianite, and zoisite, and the oxide additivity rule

Shannon

Rossman

1992

Phys Chem Minerals

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Abstract. The dielectric constants and dielectric loss values of 4 Ca-containing minerals were determined at 1 MHz using a two-terminal method and empirically determined edge corrections. The results are: The deviation (A) between measured dielectric polarizabilities as determined from the Clausius-Mosotti equation and those calculated from the sum of oxide polarizabilities according to eo (mineral) = ~ eD (oxides) for vesuvianite is ~ 0.5%. The large deviations of epidote and zoisite from the additivity rule with A= +10.1 and +11.7%, respectively, are attributed to "rattling" Ca ions. The combined effects of both a large F thermal parameter and possible F-ion conductivity in fluoraparite are believed to be responsible for A = + 2-3 %. Although variation of oxygen polarizability with oxygen molar volume (Vo) is believed to affect the total polarizabilities, the variation of Vo in these Ca minerals is too small to observe the effect.

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Section: Resultssupporting

confidence: 77%

Dielectric constants of apatite, epidote, vesuvianite, and zoisite, and the oxide additivity rule

Shannon

Rossman

1992

Phys Chem Minerals

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“…It is worthwhile to notice that a high ionic conductivity appears to enhance the electrical induced osteoconductivity and osseointegration of HA implants [43 45], which is favored by the presence of anion va cancies in the HA lattice [31,46,47]. Then, it is expected that the addition of Y 2 O 3 to HA improves osteoblast adhesion and bone bonding to the HA implants besides increasing its thermal stability and improving other properties related with the processing conditions such as the elastic constants, mechanical strength and microhardness.…”

Section: Xrd and Ftir Measurementsmentioning

confidence: 99%

Effect of highly dispersed yttria addition on thermal stability of hydroxyapatite

Parente

Savoini

Ferrari

et al. 2013

Materials Science and Engineering: C

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Abstract:The capability of the colloidal method to produce yttria (Y 2 O 3 ) dispersed hydroxyapatite (HA) has been in vestigated as an alternative method to the conventional method of mechanical mixing and sintering for de veloping HA based materials that could exhibit controllable and enhanced functional properties. A water based colloidal route to produce HA materials with highly dispersed Y 2 O 3 has been applied, and the effect of 10 wt.% Y 2 O 3 addition to HA investigated by thermal analysis, X ray diffraction and Fourier transform in frared spectroscopy. These measurements evidence a remarkable effect of this Y 2 O 3 addition on decomposi tion mechanisms of synthetic HA. Results show that incorporation of Y 2 O 3 as dispersed second phase is beneficial because it hinders the decomposition mechanisms of HA into calcium phosphates. This retardation will allow the control of the sintering conditions for developing HA implants with improved properties. Be sides, substitution of Ca 2+ with Y 3+ ions appears to promote the formation of OH − vacancies, which could improve the conductive properties of HA favorable to osseointegration.

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“…Besides these alkali ions, some apatite-type materials are also proton conductors [2,3]. Hydroxyapatite Cal0(POa)6(OH)2 (HAp) is a typical proton conductor as protons may be transported through the OH ions located in the 2a sites.…”

Section: Cation Conductionmentioning

confidence: 99%

“…etc.) conduction [2][3][4][5]7,8]. In these apatite-type materials, the 4f and 6h sites for cations are normally fully occupied (Fig.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and ionic conduction of apatite-type materials

Tao

Irvine

2000

Ionics

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Abstract. Apatite is a mineral with general formula Ml0(XO4)6Z2, where M are metallic elements such as Li § Na +, K*, Ca 2 § Sr z+, Ba 2 § Ln 3 § etc.; X = P, V, S, Si, Ge, Re, Cr etc; Z = F-, CI-, I-, OH-, O z-, S a-etc. Some materials with apatite structure (S.G. P63/m) exhibit quite high cationic (Li § H § etc.) and/or anionic (F-, C1-etc.) conduction. Recently, it was reported that some rare earth silicates, e.g., Lam(SiO4)603, exhibit quite high oxide-ion conductivity. In this paper, we discuss chemical composition, structure, synthetic procedure and ionic conduction of apatite-type materials. Recent improvements are briefly reviewed. High ionic conductivity has been observed for both cation deficient, oxygen stoichiometric La9.33(5iO4)60 a and cation stoichiometric, oxygen excess Lalo(SiO4)603 compositions. Grain boundary conductivity is usually low, which tends to dominate the impedance response. The resistance, particularly the grain boundary resistance is also found to depend on pO a.

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Protonic conduction in yttrium-substituted hydroxyapatite ceramics and their applicability to H2-O2 fuel cell

Cited by 43 publications

References 3 publications

Dielectric constants of apatite, epidote, vesuvianite, and zoisite, and the oxide additivity rule

Dielectric constants of apatite, epidote, vesuvianite, and zoisite, and the oxide additivity rule

Effect of highly dispersed yttria addition on thermal stability of hydroxyapatite

Synthesis and ionic conduction of apatite-type materials

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