The crystallization of fluorapatite in the presence of hydroxyapatite seeds and of hydroxyapatite in the presence of fluorapatite seeds
The crystallization of fluorapatite in the presence of hydroxyapatite seeds and of hydroxyapatite in the presence of fluorapatite seeds
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DOI：
10.1006/jcis.1996.4621
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发表时间：
1997-02-01
影响因子：
9.9
通讯作者：
Grynpas, M
中科院分区：
文献类型：
--
作者：
Liu, Y;Sethuraman, G;Grynpas, M
用等组份方法研究了羟基磷灰石(HAP)晶种在氟磷灰石过饱和溶液中诱导晶体生长的动力学，以及氟磷灰石(FAP)晶种晶体在羟基磷灰石过饱和溶液中的生长动力学。在pH 6.5的相对过饱和度为Sigma(FAP)=0.99-12.0，在pH为7.4的HAP的相对过饱和度为Sigma(HAP)=3.6-12.6。在FAP-过饱和溶液中，该相在HAP表面成核，其生长速度是在等比表面积的FAP晶种上的三倍以上。透射电子显微镜和电子衍射成像清楚地表明，新的针状HAP相起源于FAP表面，HAP的002晶面在FAP表面生长。相反，不能确定FAP在HAP晶种上结晶的相互取向。采用薄层芯吸技术测定了FAP、HAP和磷酸八钙(OCP)微晶与水溶液的界面能。在纯水溶液中测得FAP、HAP和OCP的界面能分别为18.5、9.0和4.3mJ·m(-2)。与其他相相比，OCP的值要小得多，这可能解释了为什么这一相经常被认为是磷灰石形成的可能先驱，特别是在生物矿化反应中。(C)1997年学术出版社
The kinetics of growth of crystals induced by hydroxyapatite (HAP) seed crystals in supersaturated solutions of fluorapatite and of fluorapatite (FAP) seed crystals in supersaturated solutions of hydroxyapatite have been studied using the constant composition method. The reactions were investigated at relative supersaturations ranging from sigma(FAP) = 0.99 to 12.0 at pH 6.5 and for HAP, sigma(HAP) = 3.6 to 12.6 at pH 7.4. In FAP-supersaturated solutions, this phase was nucleated at the HAP surfaces and underwent growth at a rate more than three times greater than that on FAP seed crystals of equivalent surface area. Transmission electron microscopy (TEM) and electron diffraction imaging clearly demonstrated that the new needle-like HAP phase originated at the FAP surface with the 002 planes of HAP growing on FAP. In contrast, the mutual orientation of FAP crystallization on HAP seed crystals could not be established. Interfacial energies of FAP, HAP, and octacalcium phosphate (OCP) microcrystals against aqueous solutions were obtained by using a thin-layer wicking technique. The interfacial energy values measured in pure aqueous solutions were 18.5, 9.0, and 4.3 mJ m(-2) for FAP, HAP, and OCP, respectively. The much smaller value for OCP as compared with the other phases may explain why this phase has been so frequently implicated as a possible precursor to the formation of apatite, especially in biological mineralization reactions. (C) 1997 Academic Press