共查询到18条相似文献,搜索用时 125 毫秒
1.
本文用差热分析和X射线衍射等方法研究了BaO-Na 2O-B 2O 3三元系的两个截面:BaB 2O 4-Na 2B 2O 4和BaB 2O 4-Na 2O赝二元系的相平衡关系。BaB 2O 4-Na 2B 2O 4属共晶体系,其共晶温度为826±3℃。在BaB 2O 4-Na 2O体系中发现一个新化合物BaB 2O 4·Na 2O,该化合物在846±3℃同成分熔化。BaB 2O 4·Na 2O对BaB 2O 4和Na 2O均为共晶体系,其共晶温度分别为755±3℃和573±3℃。并根据所得的结果,分别以15mol%Na 2O和13mol%Na 2B 2O 4为助熔剂,用提拉法培养出2×4×6mm 3和2×4×8mm 3的低温相BaB 2O 4单晶体。
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2.
用X射线衍射和差热分析方法研究了BaB 2O 4-K 2O和BaB 2O 4-K 2B 2O 4赝二元系的相平衡关系。BaB 2O 4-K 2B 2O 4属共晶体系,共晶温度为850±3℃,共晶点成分为45mol%K 2O。在Ba
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3.
本文用差热分析和X射线衍射方法对Li 2SO 4-Li 2B 2O 4和Li 2SO 4-[NH 4] 2SO 4两个赝二元系相图进行了研究。Li 2SO 4-Li 2B 2O 4是共晶体系,共晶温度为720℃
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4.
本文在室温到300℃的温度范围内研究了Li 4SiO 4-Li 3VO 4和Li 4GeO 4-Li 4SiO 4-Li 3VO 4体系中的离子导电性,发现γ II相固溶体Li 3+xV 1-xSi xO 4是好的锂离子导体。所研究的成分中Li 3.3V 0.7Si 0.3O 4的离子电导率最高,室温下为1×10 -5Ω -1·cm -1,在42—192℃的电导激活能为0.36eV,电子电导率可以忽略,因而这是迄今所发现的最好的锂离子导体之一。粗略确定了Li 4GeO 4-Li 4SiO 4-Li 3VO 4三元系中电导率高的范围,发现在Li 3.5V 0.5Ge 0.5O 4中Si部分取代Ge可以使电导率进一步提高,Li 3.5V 0.5Ge 0.4Si 0.1O 4的室温电导率可达1.3×10 -5Ω -1·cm -1,电导激活能为0.40eV。
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5.
本文用差热分析法和高温、室温X射线衍射法对Li 3VO 4,Li 4SiO 4的相变过程,Li 3VO 4-Li 4SiO 4,Li 3O 4-Li-4GeO 4赝二元系相图以及Li 3VO 4-Li 4SiO 4-Li 4GeO 4赝三元系相图室温截面进行了研究。发现在Li 3VO 4-Li 4SiO 4,Li 3VO 4-Li 4GeO 4赝二元系中,由于Li 4SiO 4或Li 4GeO 4的加入而使Li 3VO 4的高温γ II相稳定存在于室温,从而得到一种新的具有高电导率的锂离子导体。作者认为探寻使高温态稳定存在于室温的方法是探索新的离子导体研究中有效途径之一。
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6.
本文用X射线粉末法测定了Li 2K(IO 3) 3与Li 2NH 4(IO 3) 3的晶体结构和原子参数。发现Li 3K(IO 3) 3,Li 2NH 4(IO 3) 3与Li 2Rb(IO 3) 3同晶型,属单斜晶系,空间群为P2 1/α,每个单胞含有四个化合式量。室温的点阵常数分别为α=11.198?,b=11.046?,c=8.254?,β=111.53°,及α=11.327?,b=11.078?,c=8.341?,β=111.87°。讨论了二元化合物的形成与离子半径的关系。
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7.
我们用Raman光谱研究了Li 2O(LiCl) 2B 2O 3-Al 2O 3系玻璃的结构,着重研究了Al 2O 3的影响。对于Li 2O-B 2O 3系玻璃,Li 2O含量增加使玻璃中存在的BO 3三角体转变为BO 4四面体,
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8.
采用高温原位拉曼光谱技术,研究了Li 2B 4O 7从常温至1 373 K温度范围内的拉曼光谱。在升温过程中,晶体的拉曼光谱出现展宽和红移现象,且强度降低。晶体熔化时,由2个[BO 4]和2个[BO 3]组成的[B 4O 9]环状结构转变成(B 3O 6)3- 六元环和[BO 3]结构,[BO 4]结构减少直至消失。基于密度泛函理论,计算了Li 2B 4O 7晶体的拉曼光谱,对其振动模式进行了分析归属。利用量子化学从头计算法计算了由[B 3O 6-BO 3]为基础相互连接形成的 x(Li 2B 4O 7)( x=2, 3, …, 9)的环状团簇模型的拉曼光谱,对Li 2B 4O 7熔体的结构进行了模拟分析。计算结果表明Li 2B 4O 7熔体的阴离子基元为三个(B 3O 6-BO 3)组成的大三元环超级结构。 相似文献
9.
采用分子动力学模拟方法,研究了β-BaB 2O 4晶体生长母液BaB 2O 4-Na 2O二元系熔体的结构,Na 2O摩尔浓度分别为12.5%,20%,25%,30%.模拟给出的不同组分比下的B-O径向分布函数表明,随着Na 2O浓度的增加,第一峰峰值更高,峰形更尖锐.在模拟产生的一系列瞬态构型基础上,采用键序参数方法,结合环链统计,研究了母液溶体的局部结构.结果表明
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10.
本文报道了非晶态离子导体Li 2B 2O 4的 7Li核磁共振研究。测量了 7Li核磁共振谱与温度的关系。实验中发现,Li 2B 2O 4的晶态、非晶态和部分晶化样品的 7Li核磁共振谱有很大的不同,且在部分晶化样品的 7Li核磁共振谱上有附加的小峰,它与LiCl(Al 2O 3)的 7Li核磁共振谱上附加的小峰相类似。我们也对非晶态离子导体B 2O 3-0.7Li 2O-0.7LiCl进行了 7Li核磁共振研究,其结果与上面的类似。研究结果表明,它们都起因于非晶母体与微晶的界面效应。
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11.
The lithium insertion characteristics of lithium vanadate, Li 4V 3O 8, were investigated using LiV 3O 8 prepared by the precipitation technique as the starting material. The Li 4V 3O 8 phase was formed by lithiation over x=1.5 in Li 1+xV 3O 8, and the diffusion of lithium in this phase determined the reaction rate of insertion more than x=1.5. Improvement of insertion kinetics in the Li 4V 3O 8 phase extended the lithium insertion limit from x=3.2 to x=4.0, compared with the case of LiV 3O 8 by conventional high temperature synthesis. Lithium insertion proceeds as the single-phase reaction in the range of 3.2< x<4.0. 相似文献
12.
The solid–solid interactions between cobalt and ferric oxides to produce CoFe 2O 4 were followed up using XRD investigation. The effect of Li 2O-doping on the ferrite formation was also studied. The electrical and dielectric parameters of pure and doped mixed solids precalcined at 1273 K were measured using d.c and a.c instruments.The dopant concentration was varied between 0.5 and 6 mol% Li 2O. The results obtained revealed that Li 2O doping much enhanced the ferrite formation due to an increase in the mobility of the reacting species. The addition of the smallest amount of Li2O (0.5 mol%) resulted in measurable variations in the electrical constants (ρ, Ea, ′, ″ and tan δ). Resistivity increased upon increasing the dopant concentration up to 1.5 mol% exceeding the values measured for the undoped sample. Furthermore, the presence of 6 mol% Li2O brought about a significant decrease of electrical resistivity. Also, the activation energy decreased with increasing the dopant concentration. The dielectric constant behaves according to ε=const. 1/ρ1/2. The Li2O-doping modified the values of different dielectric constants, the change in these constants was found to be strongly dependent on the amount of Li2O added.These results have been discussed in terms of the potentiality of Li2O in increasing the mobility of the reacting species involved in the ferrite formation. 相似文献
13.
本文首次观察到具有单斜I(P2 1/c)的DyP 5O 14晶体,并用光学显微镜,X射线结构分析和红外光谱等方法予以证明。DyP 5O 14在室温下存在着mmmF 2/m类铁弹体的单斜I结构,其铁弹相变温度为159±3℃。单斜I的DyP 5O 14的晶胞参数,a=8.62?,b=8.84?,c=12.82?,β=90.28°。这一发现是L
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14.
The Li oxides species formed on Li over-deposited V 2O 5 thin film surfaces have been studied by using X-ray and UV induced photoelectron spectroscopy (XPS and UPS). The photoelectron spectroscopic data show that the Li over-deposited V 2O 5 system itself is not stable. Further chemical decomposition reactions are taken place even under UHV conditions and lead to form Li 2O and Li 2O 2 compounds on the surface. The formation of Li 2O 2 causes to arise an emission line at about 11.3 eV in the valence band spectra. 相似文献
15.
作者用水热法对TeO 2-K 3PO 4-H 2O体系作了初步的合成与结晶尝试。在给定的条件和组成范围内除了能形成TeO 2晶体外,还能生成一种点阵参数为a=b=10.734?,c=21.041?,α=β=90°,γ=120°的三方晶系的化合物γ,其分子式为K 2Te 4O 9·3H 2O。结晶区的产物主要取决于原料的k=TeO 2/K 3PO 4(克分子比:当k≤1.9时,仅生成γ晶体;k≥2.22时,单独生成TeO 2晶体;而当1.9 2晶体出现,本文还给出了γ晶相的DTA曲线和X射线粉末衍射谱线的相对强度与相应面间距的详细数据。
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16.
The TL glow curve of X-ray irradiated pure and Cu-doped Li 2B 4O 7 shows that the most intense TL peak is at 160°C. In the present work the characteristics of the TL and PTTL glow curves from gamma irradiated pure Li 2B 4O 7 single crystal samples (prepared by Mitui Kinzoku Kougyo, Japan) have been studied. The samples were irradiated with different gamma doses (from 0.5 up to 500 Gy) using a 60Co gamma ray source at a dose rate of 78 Gy h −1. The TL glow curve shows three intense peaks (at 160°C, 260 and 305°C) and three weak ones (at 110, 140 and 220°C). The most intense TL peak is at 160°C, which agrees with the TL glow curve from X-ray irradiated samples [Kutomi Y. and Tomita A. (1990) TSEE and TL of Li 2B 4O 7:Cu single crystals. Radiat. Prot. Dosim. 33, 347–350]. The 305°C peak in gamma irradiated samples also appears to be very intense, which indicates its possible use in high-dose high-temperature dosimetry. Further, the characteristics of the PTTL glow curve have been studied as a function of ultraviolet exposure and number of repeated PTTL cycles. 相似文献
17.
本文用X射线衍射、热处理及差热分析等方法测定了SrNb 2O 6-NaNbO 3-LiNbO 3赝三元系的室温截面及相应的SrNb 2O 6-NaNbO 3,SrNb 2O 6-LiNbO 3和NaNbO 3-LiNbO 3等三个赝二元系相图;粗略地研究了Sr 0.42Na 0.16NbO 3-LiNbO 3系的纵截面;含5mol%LiNbO 3及10mol%LiNbO 3的SrNb 2O 6-NaNbO 3的纵截面。确定了室温Sr 2Na(NbO 3) 5(以下略为S 2N)相为四方钨青铜结构。其点阵常数为a=12.36?,c=3.906?.LiNbO 3在S 2N相内的溶解度可达~10mol%,当LiNbO 3含量超过5mol%时,S 2N相畸变为S 2N′相。S 2N′相为正交晶系。实验确定室温S 2N(S 2N′)相系亚稳相。在900-1100℃长时间退火即分解为SrNb 2O 6和以NaNbO 3为基的固溶体的混合物。
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18.
Induced absorption spectra in the range 200–900 nm at 77 and 290 K for Li 2B 4O 7 single crystals, isotopically Li and B enriched are presented after irradiation of these crystals by thermal neutrons with fluence 1.8×10 16 cm −2. The dependence of induced absorption spectra on the isotope composition was revealed: for 6Li 210B 4O 7 and 7Li 210B 4O 7 crystals intensive band in the region of 280–294 nm was observed. Under substitution of 7Li isotope by 6Li in the lithium tetraborate lattice no changes in the absorption spectra were observed. The nuclear reaction 10B(n,) 7Li is proposed to be the main mechanism of formation of the radiation defects. 相似文献
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