Transition and post-transition metal ions in borate glasses: Borate ligand speciation, cluster formation, and their effect on glass transition and mechanical properties
Transition and post-transition metal ions in borate glasses: Borate ligand speciation, cluster formation, and their effect on glass transition and mechanical properties
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DOI：
10.1063/1.4962323
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发表时间：
2016-09-28
影响因子：
4.4
通讯作者：
Wondraczek, L.
中科院分区：
文献类型：
--
作者：
Moencke, D.;Kamitsos, E. I.;Wondraczek, L.
研究了一系列过渡和后过渡金属离子（Mn、Cu、Zn、Pb、Bi）二元硼酸盐玻璃，特别考虑了阳离子对硼酸盐结构的影响、阳离子的交联能力以及更普遍的结构-性能相关性。红外（IR）和拉曼光谱用于结构表征。这些互补的技术是敏感的短程顺序，如在四面体和三方硼酸盐单元的分化或关于每单位的非桥接氧离子的数量。此外，振动光谱也是敏感的中程秩序和超结构单元的存在，如环和链，或环的组合。为了澄清各种硼酸盐实体的频带分配，给出了从纯玻璃质B2 O3到Meta位、焦位、邻位甚至过度改性的硼酸盐玻璃组合物的实例。对于二元偏硼酸盐玻璃，显示了改性剂阳离子对硼酸盐形态的影响。高场强阳离子如Zn 2+增强偏硼酸盐向聚硼酸盐和焦硼酸盐单元的反硝化。Pb 2+和Bi 3+诱导团簇形成，导致PbOn-和BiOn-假相。铅和铋的硼酸盐玻璃也显示出一种倾向，以二硼酸盐聚阴离子的形式稳定非常大的超结构单元。远红外光谱反映了玻璃中改性剂阳离子的成键状态。测量的阳离子位点振动带的频率用于获得金属-氧键合的平均力常数FM-O。偏硼酸盐玻璃系列的玻璃化转变温度（T-g）和FM-O之间的线性相关性。玻璃的机械性能也与力常数FM-O相关，尽管对于类似力常数的阳离子，四面体硼酸盐单元（N-4）的分数强烈影响热性能和机械性能。对于顺磁性的Cu-和Mn-硼酸盐玻璃，在使用抗磁性玻璃的NMR文献数据推导出硼四面体与硼三角单元的相对吸收系数α = α（4）/α（3）之后，从IR光谱确定N-4。出版社：AIP Publishing
A series of transition and post-transition metal ion (Mn, Cu, Zn, Pb, Bi) binary borate glasses was studied with special consideration of the cations impact on the borate structure, the cations cross-linking capacity, and more generally, structure-property correlations. Infrared (IR) and Raman spectroscopies were used for the structural characterization. These complementary techniques are sensitive to the short-range order as in the differentiation of tetrahedral and trigonal borate units or regarding the number of non-bridging oxygen ions per unit. Moreover, vibrational spectroscopy is also sensitive to the intermediate-range order and to the presence of superstructural units, such as rings and chains, or the combination of rings. In order to clarify band assignments for the various borate entities, examples are given from pure vitreous B2O3 to meta-, pyro-, ortho-, and even overmodified borate glass compositions. For binary metaborate glasses, the impact of the modifier cation on the borate speciation is shown. High field strength cations such as Zn2+ enhance the disproportionation of metaborate to polyborate and pyroborate units. Pb2+ and Bi3+ induce cluster formation, resulting in PbOn- and BiOn-pseudophases. Both lead and bismuth borate glasses show also a tendency to stabilize very large superstructural units in the form of diborate polyanions. Far-IR spectra reflect on the bonding states of modifier cations in glasses. The frequency of the measured cation-site vibration band was used to obtain the average force constant for the metal-oxygen bonding, FM-O. A linear correlation between glass transition temperature (T-g) and FM-O was shown for the metaborate glass series. The mechanical properties of the glasses also correlate with the force constant FM-O, though for cations of similar force constant the fraction of tetrahedral borate units (N-4) strongly affects the thermal and mechanical properties. For paramagnetic Cu- and Mn-borate glasses, N-4 was determined from the IR spectra after deducing the relative absorption coefficient of boron tetrahedral versus boron trigonal units, alpha = alpha(4)/alpha(3), using NMR literature data of the diamagnetic glasses. Published by AIP Publishing.