Experimental growth and structural-morphological characteristics of co-tourmaline
Experimental growth and structural-morphological characteristics of co-tourmaline
复制标题
共碧玺的实验生长及结构形态特征
DOI：
10.1134/s1028334x09010176
复制
发表时间：
2009
影响因子：
0.9
通讯作者：
V. S. Balitskii
中科院分区：
文献类型：
--
作者：
T. Setkova;Y. Shapovalov;V. S. Balitskii
实验旨在研究co -电气石在含氯硼钴的水溶液中生长到种子晶体上的机会，温度为400 - 500℃，压力高达1000 bar。实验是在热梯度条件下在钛热压釜中进行的，并且在一些情况下使用了分隔隔膜。只有使用单独的碧玺形成成分（单晶刚玉和石英棒）作为熔化原料，碧玺才能生长到种子晶体上。铜碧玺生长的层（高达600微米）是深红色的，只出现在正单面体{+0001}的表面。随着单晶的生长，大量极细（尺寸为30 ~ 150微米）的自生成核电气石晶体出现在种子晶体和熔体中。它们的组成与生长层的组成没有差异，它们的单胞参数（a = 15.82638±0.00215 a, c = 7.09434±0.00186 a）对应于电气石族矿物橄榄石和榴辉石的中间值。电气石是一种复杂的硼硅酸盐，一般晶体化学式XYZ，其中X对应于充满Na， Ca， K或空位的大空隙；Y对应紧密排列的Mg、fe2 +、Li、Al、Mn和Cr的八面体；Z对应Al和fe3 +的变形八面体。在自然界中，电气石经常出现在花岗岩伟晶岩和气溶岩-热液和热液地层中。它的存在在这类花岗岩以及交代岩和变质岩中并不罕见。这表明电气石形成条件的多样性。对生长电气石单晶的兴趣与获得新的有前途的压电和热释电材料的任务有关，这些材料具有比已知材料更强的特性。此外，在珠宝行业中，合成电气石可以作为天然形式的替代品，类似于其他宝石的合成类似物。尽管进行了大量的地质、矿物学、地球化学、晶体化学等方面的研究，自然界中电气石的形成条件仍有许多问题尚不清楚。安全和可重复的单晶生长方法也尚未开发出来。这种情况通常与电气石复杂的化学成分有关，根据颜色的深浅，电气石有许多品种，即使在单晶中也经常发生变化。显然，这是由于这种矿物在其生长过程中复杂和不断变化的物化结晶条件，以及其结构的特殊倾向于广泛展示异价和异价同形。合成和生长领域的研究
Experiments aimed at investigating opportunities of Co-tourmaline growth onto a seed crystal in aqueous boron-chloride cobalt-containing solutions under temperatures of 400‐500 ° C and pressure up to 1000 bar were performed. Experiments were conducted under thermogradient conditions in titanium autoclaves, and in several cases with the help of a dividing diaphragm. Tourmaline growth onto a seed crystal occurs only with the use of separate tourmaline-forming components (monocrystal corundum and quartz rods) as the melting stock. The layer (up to 600 micron) of Co-tourmaline grown is intensively crimson-colored and occurs only at the face of positive monohedron {+0001}. Along with the monocrystal outgrowth, a great amount of very fine (30‐150 micron in size) tourmaline crystals of selfgeneration nucleation occurred on the seed crystals and in the melting stock. Their composition does not differ from the grown layer composition, and their unit cell parameters ( a = 15.82638 ± 0.00215 A, c = 7.09434 ± 0.00186 A) correspond to intermediate values of the tourmaline group minerals olenite and elbaite. Tourmaline is a complex borosilicate of the general crystal chemical formula XYZ , where X corresponds to large voids filled with Na, Ca, K, or a vacancy; Y corresponds to closely packed octahedrons of Mg, Fe 2+ , Li, Al, Mn, and Cr; and Z corresponds to deformed octahedrons of Al and Fe 3+ . In nature tourmaline rather often occurs in granite pegmatites and pneumatolyte‐hydrothermal and hydrothermal formations. Its presence is not unusual in such granites as well as in metasomatites and metamorphic rocks. This indicates the diversity of the tourmaline formation conditions. Interest in growing tourmaline monocrystals is connected with the task of obtaining new promising piezoelectric and pyroelectric materials possessing enhanced characteristics in comparison with those already known. Moreover, synthetic tourmaline can be used as a substitute for the natural form in the jewelry industry similar to other synthetic analogues of precious stones. There are many questions concerning the tourmaline formation conditions in nature that have remained unclear up until the present despite numerous geological, mineralogical, geochemical, and crystal chemical investigations. Safe and reproducible methods of growing its monocrystals have also not been developed. This situation is connected in general with the tourmaline complex chemical composition resulting in the existence of numerous varieties according to shades of color, which often change even within the single crystal. Obviously, this is a consequence of complex and changing physicochemical crystallization conditions of this mineral during its growth as well as special predisposition of its structure to a wide exhibition of iso- and heterovalent isomorphism. Investigations in the sphere of synthesis and growth