ISSN:
0021-9304
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Medizin
,
Technik allgemein
Notizen:
Bioglasses® form a double layer composed of apatite and a silica-rich layer when placed in a simulated physiological solution as well as in living tissue [A. E. Clark, C.G. Pantano, and L. L. Hench, „Auger spectroscopic analysis of bioglass corrosion films,“ J. Am. Ceram. SOC., 59(1-2), 37-39 (1976).]. In the present work, the mechanisms of the calcium phosphate layer and the silica-rich layer formation of fluoride Bioglassesm i n Tris-buffer solution are studied as a function of the SiOz content. Fourier Transform Infrared Reflection Spectroscopy (FTIRS) is used to investigate the mechanism of formation of calcium phosphate and silica-rich layers on the glass surface. Ion concentration in reacted solution and elemental depth profiles are obtained by Induced Coupled Plasma Atomic Emission Spectrometry (ICP) and Auger Elect on Spectroscopy (AES), respectGely. Si—O bonds with one nonbridging oxygen and Si—O—Si bonds form at the early stage of reaction. Strong phosphorus ion uptake occurs when an amorphous calcium phosphate layer crystallizes. Glasses with high silica content (conventional glass) form the silica-rich layer first followed by a calcium phosphate layer on top. However, glasses with low silica content (invert glass) form both layers simultaneously. The rate of apatite formation decreases with increasing SiOz content, especially in the region of conventional glass compositions. Ion release rates decreases as Si02 content increases, with a significant change occurring at the compositional boundary between invert and conventional glasses. © 1992 John Wiley & Sons, Inc.
Zusätzliches Material:
11 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jbm.820260905
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