Softening of hydroxyapatite by vacancies: A first principles investigation

Jiang, Shuyun; Song, Yan; Wen, Guangwu; Wang, Y.; Yang, Rui

doi:10.1016/j.msec.2012.12.001

Cited by 36 publications

(21 citation statements)

References 51 publications

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“…Furthermore, a direct correlation between the Ca deficiency and the mechanical properties of the crystals was found: calcium deficiency lead to an 80 % reduction in the hardness and elastic modulus and at least a 75 % reduction in toughness in plate-shaped HA crystals (Viswanath et al 2010). More recently, using first-principles calculations, a reduction in the elastic constants and moduli of CDHA due to vacancies was reported (Sun et al 2013;Bhat et al 2014). Theoretical investigations of the defect formation mechanism relevant to non-stoichiometry in CDHA are available elsewhere (Matsunaga 2008b Rey et al 2006;O'Neill 2007).…”

Section: Acpmentioning

confidence: 92%

Calcium orthophosphates (CaPO 4 ): Occurrence and properties

Dorozhkin¹

2017

Morphologie

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Section: Acpmentioning

confidence: 92%

Calcium orthophosphates (CaPO 4 ): Occurrence and properties

Dorozhkin¹

2017

Morphologie

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“…Furthermore, a direct correlation between the Ca deficiency and the mechanical properties of the crystals was found: calcium deficiency lead to an 80 % reduction in the hardness and elastic modulus and at least a 75 % reduction in toughness in plate-shaped HA crystals (Viswanath et al 2010 ). More recently, using first-principles calculations, a reduction in the elastic constants and moduli of CDHA due to vacancies was reported (Sun et al 2013 ; Bhat et al 2014 ). Theoretical investigations of the defect formation mechanism relevant to non-stoichiometry in CDHA are available elsewhere (Matsunaga 2008b ).…”

Section: The Members Of Capo 4 Familymentioning

confidence: 97%

Calcium orthophosphates (CaPO4): occurrence and properties

Dorozhkin¹

2015

Prog Biomater

214

141

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The present overview is intended to point the readers’ attention to the important subject of calcium orthophosphates (CaPO4). This type of materials is of the special significance for the human beings because they represent the inorganic part of major normal (bones, teeth and antlers) and pathological (i.e., those appearing due to various diseases) calcified tissues of mammals. For example, atherosclerosis results in blood vessel blockage caused by a solid composite of cholesterol with CaPO4, while dental caries and osteoporosis mean a partial decalcification of teeth and bones, respectively, that results in replacement of a less soluble and harder biological apatite by more soluble and softer calcium hydrogenorthophosphates. Therefore, the processes of both normal and pathological calcifications are just an in vivo crystallization of CaPO4. Similarly, dental caries and osteoporosis might be considered as in vivo dissolution of CaPO4. In addition, natural CaPO4 are the major source of phosphorus, which is used to produce agricultural fertilizers, detergents and various phosphorus-containing chemicals. Thus, there is a great significance of CaPO4 for the humankind and, in this paper, an overview on the current knowledge on this subject is provided.

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“…Previously, we reported that the total DOS of HA shows a 5.7 eV band gap between the valence and conduction bands, and four bonding areas in the valence band which are mainly contributed by PO 4 unit. 35 On the contrary, the total DOS of the HA/Ti interface shows a metallic characteristic in both the Ca atom and PO 4 -terminated interfaces. The PDOSs indicate that the metallic nature mainly comes from Ti.…”

Section: Work Of Adhesionmentioning

confidence: 99%

Affinity of the Interface between Hydroxyapatite (0001) and Titanium (0001) Surfaces: A First-Principles Investigation

Jiang

Dai

Song

et al. 2014

ACS Appl. Mater. Interfaces

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A basic understanding of the affinity between the hydroxyapatite (HA) and α-Ti surfaces is obtained through electronic structure calculations by first-principles method. The surface energies of HA(0001), HA (011̅0), HA (101̅1), and Ti(0001) surfaces have been calculated. The HA(0001) presents the most thermodynamically stable of HA. The HA/Ti interfaces were constructed by two kinds of interface models, the single interface (denoted as SI) and the double-interface (denoted as DI). Two methods, the full relaxation and the UBER, were applied to determine the interfacial separation and the atomic arrangement in the interfacial zone. The works of adhesion of interfaces with various stoichiometric HA surfaces were evaluated. For the HA(0001)/Ti(0001) interfaces, the work of adhesion is strongly dependent on the chemical environment of the HA surface. The values are -2.33, -1.52, and -0.80 J/m(2) for the none-, single-, and double-Ca terminated HA/Ti interfaces, respectively. The influence of atomic relaxation on the work of adhesion and interface separation is discussed. Full relaxation results include -1.99 J/m(2) work of adhesion and 0.220 nm separation between HA and Ti for the DI of 1-Ca-HA/Ti interface, while they are -1.14 J/m(2) and 0.235 nm by partial relaxation. Analysis of electronic structure reveals that charge transfer between HA and Ti slabs occurs during the formation of the HA/Ti interface. The transfer generates the Ti-O or Ti-Ca bonds across the interface and drives the HA/Ti interface system to metallic characteristic. The energetically favorable interfaces are formed when the outmost layer of HA comprises more O atoms at the interface.

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Softening of hydroxyapatite by vacancies: A first principles investigation

Cited by 36 publications

References 51 publications

Calcium orthophosphates (CaPO 4 ): Occurrence and properties

Calcium orthophosphates (CaPO 4 ): Occurrence and properties

Calcium orthophosphates (CaPO4): occurrence and properties

Affinity of the Interface between Hydroxyapatite (0001) and Titanium (0001) Surfaces: A First-Principles Investigation

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