High resolution electron microscopy investigations of interface and other structure defects in some ceramics

Wen, Shulin; Liu, Qian

doi:10.1002/(sici)1097-0029(19980201)40:3<177::aid-jemt2>3.0.co;2-s

Cited by 18 publications

(9 citation statements)

References 49 publications

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“…11 In this study, the presence of an amorphous phase suggests that we would observe preferential dissolution from these less-crystalline triple junctions for Si-HA samples in vivo. 11,21 An important finding in this study was the difference in grain boundary structure observed between the different Si-HAs. In the 0.4 wt % Si-HA, "clean" grain boundaries were observed, with single grain boundaries in lower wt % Si-HA phase-pure and no extra phases present.…”

Section: Discussionmentioning

confidence: 62%

“…Our present findings in synthetic apatites take on particular significance, because grain boundary structure has been shown to have a predominant influence on the dissolution behavior of biological apatites. 11 Previous TEM studies on biological apatites have demonstrated the importance of amorphous grain boundary phases to calcium homeostasis. 11 In this study, the presence of an amorphous phase suggests that we would observe preferential dissolution from these less-crystalline triple junctions for Si-HA samples in vivo.…”

Section: Discussionmentioning

confidence: 99%

“…11 Previous TEM studies on biological apatites have demonstrated the importance of amorphous grain boundary phases to calcium homeostasis. 11 In this study, the presence of an amorphous phase suggests that we would observe preferential dissolution from these less-crystalline triple junctions for Si-HA samples in vivo. 11,21 An important finding in this study was the difference in grain boundary structure observed between the different Si-HAs.…”

Section: Discussionmentioning

confidence: 99%

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Ultrastructural comparison of hydroxyapatite and silicon‐substituted hydroxyapatite for biomedical applications

Porter

Best

Bonfield

2003

J Biomedical Materials Res

110

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Silicon-substituted hydroxyapatite (Si-HA) has been shown to lead to significantly increased rates of bone apposition when compared with phase-pure hydroxyapatite (HA) bioceramic implants (Patel N, et al. J Mater Sci Mater Med 2002;13:1199 -1206. However, uncertainty remains about the mechanism by which Si increases the in vivo bioactivity. In this study, defect structures in Si-HA were observed and characterized for the first time using highresolution transmission electron microscopy. Using tilting experiments and the g ⅐ b ϭ 0 criterion for invisibility, the Burgers vectors of dislocations in phase-pure HA and 0.8 wt % Si-HA were characterized to be screw and mixed in character. Dislocations were observed in both pure HA and 0.8 wt % Si-HA with no significant difference in dislocation density between HA and Si-HA. However, our findings suggest that an increased number of triple junctions in Si-HA may have a significant role in increasing the solubility of the material and the subsequent rate at which bone apposes Si-HA ceramics.

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Section: Discussionmentioning

confidence: 62%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Ultrastructural comparison of hydroxyapatite and silicon‐substituted hydroxyapatite for biomedical applications

Porter

Best

Bonfield

2003

J Biomedical Materials Res

110

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“…There are several reports on the mechanism of grain boundary dissolution in HA-based ceramics [18][19][20][21]. In particular, the presence of a TCP phase either by deliberate addition or a result of HA decomposition is a critical reason for HA dissolution in a liquid environment.…”

Section: Resultsmentioning

confidence: 99%

Sintering and dissolution of bone ash-derived hydroxyapatite

2010

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Bone ash-derived hydroxyapatite (HA) ceramics were prepared by pressureless sintering and hot pressing, and their dissolution behavior was examined in buffered water. HA powder was obtained by soaking bone ash in a 0.1 M NaOH solution at 80°C, followed by calcination at 1000°C to completely remove the organic material. The crystal structure of the HA powder with a particle size of approximately 1 µm was mainly hydroxyapatite with a minimal amount of α-tricalcium phosphate. To improve densification, the powder was hot-pressed at 1000°C for 0.5 h under a pressure of 30 MPa in an Ar atmosphere. The sintered density of the hot-pressed HA was 95 % of the theoretical density, which is much higher than the 70% obtained for the pressureless-sintered compact. In the porous HA ceramics obtained by pressureless sintering, dissolution occurred adjacent to the pores rather than in the dense part, which increased the residual porosity. On the other hand, the hot-pressed HA showed grain boundary dissolution followed by particle loosening.

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“…252 Takođe, u istraživanju Portera i saradnika utvrđeno je da supstitucija silicijuma unutar kristalne rešetke HA povedava broj strukturnih defekata, kao i da rastvorljivost opada sa smanjenjem stepena supstitucije. 253 U slučaju da je stepen bioaktivnosti uzrokovan predloženim mehanizmom rastvaranja i taloženja, pomenuta saznanja, kao i saznanja proistekla iz studije Patela i saradnika ukazuju na to da povedana rastvorljivost Si-HA dovodi do povedanja koštane apozicije u pomenutim biokeramičkim materijalima.…”

Section: Sl 1015 Rendgenski Difraktogrami Skafolda Sk-s150 Sk-s1unclassified

Investigation of formation processes of porous biocompatible materials based on silicon doped and undoped ?-calcium-phosphate and hydroxyapatite

Jokić¹

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High resolution electron microscopy investigations of interface and other structure defects in some ceramics

Cited by 18 publications

References 49 publications

Ultrastructural comparison of hydroxyapatite and silicon‐substituted hydroxyapatite for biomedical applications

Ultrastructural comparison of hydroxyapatite and silicon‐substituted hydroxyapatite for biomedical applications

Sintering and dissolution of bone ash-derived hydroxyapatite

Investigation of formation processes of porous biocompatible materials based on silicon doped and undoped ?-calcium-phosphate and hydroxyapatite

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