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1.
较详细地研究了V2O5-B2O3-TeO2三元体系的熔化温度、冷却熔体的相组成及玻璃形成规律;并测试分析了V2O5-B2O3-TeO2三元体系玻璃的热性能和特征温度。结果表明,V2O5-B2O3-TeO2三元体系具有较低的熔化温度,存在3个不同的结晶区域和一个较广阔的玻璃形成区,其玻璃形成区域为:V2O50%~70%、B2O30%~30%、TeO230%~100%(均为摩尔分数);V2O5-B2O3-TeO2系玻璃具有较低的熔化温度和封接温度,是无铅低温封接玻璃的理想体系之一。 相似文献
2.
采用溶胶-凝胶法制备了一种Bi2O3-B2O3-SiO2系玻璃粉体,在200 ℃、400 ℃、600 ℃和800 ℃温度下分别对凝胶玻璃粉体进行热处理,借助SEM、TEM、XRD、FT-IR、Raman、XPS、DSC、热膨胀仪及“纽扣”烧结实验分别测定了经不同温度热处理后玻璃粉体的结构与性能,分析了其结构变化对玻璃粉体转变温度Tg和烧结特性的影响。结果显示,在实验温度范围内,随热处理温度升高,Bi3+逐渐进入玻璃网络中,[BiO6]八面体和[BiO3]三角体、[BO4]四面体和[BO3]三角体分别与[SiO4]四面体以顶角相连的方式构建玻璃网络结构。O1s和Bi4f的电子结合能逐渐增大,B1s的电子结合能减小,玻璃网络结构稳定性增强,导致玻璃转变温度Tg及玻璃膨胀软化点温度Td升高、 润湿性降低且热膨胀系数略有降低。经600 ℃热处理后,玻璃粉体具有较优的烧结性能,Tg、Td分别约为485 ℃及542 ℃,热膨胀系数α约为7.067×10-6/℃。 相似文献
3.
利用溶胶凝胶法结合气氛控制方式合成了含Bi2O3纳米晶钠硼硅玻璃.利用X射线粉末衍射仪(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)、X射线能量色散谱(EDX)、扫描模式透射电子显微镜(STEM)、高分辨透射电子显微镜(HRTEM)以及选区电子衍射(SAED)对掺杂在钠硼硅玻璃中Bi2O3纳米晶的形貌和微结构进行了表征,同时,利用飞秒开孔Z-scan技术详细地研究了Bi2O3纳米晶玻璃在800 nm处不同激发光强度下的三阶非线性光吸收性质.结果表明,在钠硼硅玻璃中形成了尺寸小于10 nm的Bi2O3单斜晶系纳米晶.随着激发光强度的增强,该玻璃的三阶非线性光吸收性质产生由饱和吸收向反饱和吸收的转变.进一步,计算得到的该玻璃三阶非线性极化率χ(3)的数量级范围在10-19~10-18m2/V2之间.这一结果说明该玻璃具有良好的非线性光学性能,并且在光限幅器等非线性光学领域具有潜在的应用价值. 相似文献
4.
The subsolidus phase equilibria of the Li2O-Ta2O5-B2O3, K2O-Ta2O5-B2O3 and Li2O-WO3-B2O3 systems have been investigated mainly by means of the powder X-ray diffraction method. Two ternary compounds, KTaB2O6 and K3Ta3B2O12 were confirmed in the system K2O-Ta2O5-B2O3. Crystal structure of compound KTaB2O6 has been refined from X-ray powder diffraction data using the Rietveld method. The compound crystallizes in the orthorhombic, space group Pmn21 (No. 31), with lattice parameters a = 7.3253(4) Å, b = 3.8402(2) Å, c = 9.3040(5) Å, z = 2 and Dcalc = 4.283 g/cm3. The powder second harmonic generation (SHG) coefficients of KTaB2O6 and K3Ta3B2O12 were five times and two times as large as that of KH2PO4 (KDP), respectively. 相似文献
5.
Binod Kumar 《Materials Research Bulletin》1984,19(3):331-338
Glasses from the SiO2-B2O3 binary system containing up to 25 mole percent B2O3 have been synthesized. These glasses have been characterized by x-ray diffraction, optical transmission measurement, and I.R. absorption spectroscopy. In order to obtain a homogeneous glass, it was determined that a certain degree of hydrolysis of Si(OC2H5)4 was essential before B(OC2H5)3 could be incorporated. Optical transmission data exhibit characteristic absorption bonds related to Si, B, and OH fundamental and combination frequencies. I.R. absorption spectra in the 620 – 1700 cm?1 range revealed presence of absorption bands related to vibrations of O-Si-O, Si-O-Si, B-O, and Si-O-B bonds. 相似文献
6.
在匹配封接中,为确保材料和结构在冷热反复循环的稳定性和耐久性,需考察封接材料与基体材料的膨胀系数在工作温度范围内的匹配性,以使封接应力尽可能小。一般来说,低熔点玻璃封接温度越低,膨胀系数越大。为满足低温封接,同时膨胀系数小的实际需求,常常在低温封接玻璃粉中添加低膨胀耐火填料,制成复合型低温焊料。本文对比研究了堇青石、锆英石、β-锂霞石及锂铝硅(LAS)微晶玻璃4种填料对Bi2O3-ZnO-B2O3低熔封接玻璃膨胀系数的影响,并估算了各自的有效模量。结果表明:在添加量相同的情况下,堇青石填料调节作用最为显著;β-锂霞石、锂铝硅微晶玻璃虽然本身的线膨胀系数为负,但调节效果不理想,与堇青石相比略差;锆英石的有效模量值最大,但因其自身密度大,膨胀系数也大,调节效果不及另外3种填料。 相似文献
7.
先用聚丙烯酰胺凝胶法制备出Bi2O3颗粒,然后用光还原法将粒径为6~18 nm的AuAg合金纳米颗粒修饰在Bi2O3颗粒表面,制备出AuAg/Bi2O3复合光催化剂。AuAg合金纳米颗粒的等离子体共振吸收效应(SPR)使AuAg/Bi2O3复合物能吸收波长为~577 nm的可见光,拓展了Bi2O3的光响应范围,还促进了Bi2O3中光生电荷的分离。以甲基橙(MO)、罗丹明(RhB)和铬离子(Cr(VI))作为目标反应物,在模拟太阳光和可见光照射下考察了AuAg/Bi2O3的光催化降解和还原活性,发现AuAg合金纳米颗粒修饰提高了Bi2O3的光催化性能。用模拟太阳光照射2 h后,RhB和MO的降解率以及Cr(VI)的还原效率分别提高了~34.2%,~38.0%和~56.7%。同时,AuAg/Bi2O3还具有良好的光催化和结构稳定性。基于以上结果,提出了AuAg合金纳米颗粒对Bi2O3光催化性能的改性机理。 相似文献
8.
Polymorphs of bismuth sesquioxide were studied by TG-DTA and X-ray diffraction methods and by electron microscopy. Phase transitions of the polymorphs are influenced not only by the temperature before cooling and the cooling rate but also by the duration of melting. New commensurate and incommensurate superstructure phases, observed under the electron microscope, are described as the Naxa types, where N is various value between 2 and 2.48. Here a stands for the cell dimension of the δ form, the fluorite-type structure. The superstructures can be derived by a scheme for ordering oxygen vacancies in the defective fluorite-type structure. 相似文献
9.
Tiefeng Xu Xiang Shen Shixun Dai Qiuhua Nie Xunsi Wang 《Materials Research Bulletin》2010,45(10):1501-82
Bi2O3-B2O3-SiO2 ternary glasses embedded with Ag nanoparticles were prepared by introducing AgCl into the bismuthate glasses using conventional melt quenching method and characterized by several experimental techniques. Scanning electron microscopic studies indicated the formation of Ag contained nanoclusters which crack and become regular with increase of AgCl content in these composites. Optical absorption spectra of the nanocomposites showed the presence of absorption band of surface plasmon resonance (SPR) due to Ag nanoparticles at ∼600 nm. Z-scan measurement with femtosecond laser was used to investigate third-order optical nonlinearities of the nanocomposites. The results show that the nonlinear refraction γ was dramatically increased up to 30 times by the appearance of Ag nanoparticles when excited within its SPR region, while nonlinear absorption due to two-photon absorption exhibited opposite tendency or even saturated behavior. The calculation of figure of merit suggests that the Ag particle embedded Bi2O3-B2O3-SiO2 glass composites are promising candidates for optoelectronic devices. 相似文献
10.
以CaO-B2O3-SiO2(CBS)玻璃粉体和Al2O3陶瓷粉体为原料,通过在CBS与Al2O3的质量比固定为50:50的玻璃-陶瓷复合材料中添加适量的Bi2O3作为烧结助熔剂,探讨了Bi2O3助熔剂对CBS/Al2O3复合材料的烧结性能、介电性能、抗弯强度和热膨胀系数的影响规律.研究表明:Bi2O3助熔剂能通过降低CBS玻璃的转变温度和黏度促进CBS/Al2O3复合材料的致密化进程,于880 ℃下烧结即能获得结构较致密、气孔较少的CBS/Al2O3复合材料.然而,过量添加Bi2O3将使玻璃的黏度过低,从而恶化CBS/Al2O3复合材料的烧结性能、介电性能及抗弯强度.当Bi2O3的添加量为CBS/Al2O3复合材料的1.5wt%时,于880 ℃下烧结即能获得最为致密的CBS/Al2O3复合材料,密度为2.82 g·cm-3,这一材料具有良好的介电性能(介电常数为7.21,介电损耗为1.06×10-3),抗弯强度为190.34 MPa,0~300 ℃的热膨胀系数为3.52×10-6 K-1. 相似文献
11.
Low temperature co-fired ceramic (LTCC) is prepared by sintering a glass selected from CaO-SiO2-B2O3 system, and its sintered bodies are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). It is found that the optimal sintering temperature for this glass-ceramic is 820 °C for 15 min, and the major phases of this material are CaSiO3, CaB2O4 and SiO2. The glass-ceramic possesses excellent dielectric properties: ?r = 6.5, tan δ < 2 × 10−3 at 10 MHz, temperature coefficient of dielectric constant about −51 × 10−6 °C−1 and coefficient of thermal expansion about 8 × 10−6 °C−1 at 20-400 °C. Thus, this material is supposed to be suitable for the tape casting process and be compatible with Ag electrode, which could be used as the LTCC materials for the application in wireless communications. 相似文献
12.
Au/Bi3:54Nd0:46Ti3O12/Bi2Ti2O7/Si structure has been fabricated with a preferentially (111)-orientated Bi2Ti2O7 seeding layer as a ferroelectric gate of metal-ferroelectric-insulator ¯eld e®ect transistor. Bi3:54Nd0:46Ti3O12 and Bi3:54Nd0:46Ti3O12/Bi2Ti2O7 ¯lms are both well-crystallized when annealed at 680±C for 40 min, and have smooth, dense and crack-free surfaces. The width of memory window of the ferroelectric gate increases with increasing electric ¯eld applied to the Bi3:54Nd0:46Ti3O12 thin ¯lms. The width of memory window of Au/Bi3:54Nd0:46Ti3O12/Bi2Ti2O7/Si with seeding layer is relatively wider than that of Au/Bi3:54Nd0:46Ti3O12/Si at the same bias voltage, and the counterclockwise hysteresis curve of Au/Bi3:54Nd0:46Ti3O12/Bi2Ti2O7/Si is referred to as polarization type switching at di®erent voltages. Bi2Ti2O7 seeding layer plays an important role in alleviating the element interdi®usion between Bi3:54Nd0:46Ti3O12 and Si. 相似文献
13.
14.
An alternative two-step method has been proposed for the synthesis of Bi2O3 nanowires with a diameter of about 40 nm from common and cost-effective Bi(NO3)3·5H2O, Na2SO4, and NaOH. That is, first, Bi2O(OH)SO4 nanowires were prepared through the precipitation reaction of Bi(NO3)3·5H2O and Na2SO4 in distilled water under the ambient condition and second, monoclinic phase Bi2O3 nanowires were prepared via the hydrothermal reaction of Bi2O(OH)SO4 and NaOH at 120 °C for 12 h. The resultant products were characterized by X-ray diffraction, field emission scanning electron microscope, and high resolution transmission electron microscopy. In addition, the photocatalytic studies indicated that the as-synthesized Bi2O3 nanowires were a kind of promising photocatalyst in remediation of water polluted by some chemically stable azo dyes. 相似文献
15.
The ultramicrostructure of phases with n = 1, 2 and 3 in the hypothetical series Bi2WnO3n+3 has been investigated by high resolution electron microscopy and energy dispersive X-ray emission spectroscopy. For n = 1 and 2, well ordered phases with the predicted compositions have been obtained, but for n = 3, a severely disordered assemblage containing intergrowths of the two known structures and strips of the n = 3 member is produced. No evidence for ordered structures with n > 2 has yet been obtained. 相似文献
16.
Solid solution series, (Bi2O3)1−x (Y2O3)x and (Bi2O3)1−x (Gd2O3)x, forx = 0.10, 0.20, 0.30 and 0.40 were synthesized by standard ceramic technique. The structural phase characterization was carried
out using X-ray powder diffraction technique. It was found that the solid solution containing 20–40 mole% of Y2O3 had face-centred cubic structure. All samples of the solid solution series, (Bi2O3)1−x (Gd2O3)x, had rhombohedral single phase in the concentration range 0.10 ≤x ≤ 0.40. Lattice parameters offcc phase of Y2O3 doped samples were calculated from the X-ray diffraction data. The lattice constant ‘a’ gradually decreases with increasing content of dopant concentration (x) for the Y2O3 doped system and obeys Vegard’s rule. The unit cell parameters for the (Bi2O3)1−x (Gd2O3)x doped samples showing rhombohedral phase were obtained on hexagonal setting. 相似文献
17.
In order to obtain CO2-absorbents to eliminate CO2 concentration locally, Bi2O3-La2O3 mixed powders were prepared by mechanical alloying (MA) method using a planetary ball-milling machine. CO2-absorption and desorption properties were checked by TG-DTA for the obtained powder samples. As a result, the sample shown by (Bi2O3)1−x(La2O3)x [x≤0.50] was found to form α-Bi2O3-solid solution with repeated CO2-adsorption and desorption around 400- 500 °C. Absorbed and desorbed CO2 contents varied with MA time: the 72 h MA’ed sample had a larger CO2 content than the 24 h MA’ed sample. The performance depended on the sample composition, and (Bi2O3)0.70(La2O3)0.30 was found to have the highest performance in the present system. 相似文献
18.
A preparation method is described of monophasic yttria stabilized zirconia doped with Bi2O3. This material is prepared from a homogeneous power which, after pressing, is sintered in a Bi2O3 atmosphere. The resulting ceramic has a composition of 0.78rO2-0.206 YO1.5-0.014BiO1.5. The grain boundaries are enriched with bismuth. A relative density of 95% of the theoretical one is attained at a considerably lower temperature than the bismuth free sample. The electrical conductivities of the monophasic Bi doped and the Bi-free electrolyte material do not differ significantly. 相似文献
19.
L.H. Brixner 《Materials Research Bulletin》1978,13(6):563-566
Green luminescence (peaking at 490 nm) is described for Bi2Al4O9 at 300°K. Bi2Ga4O9 is isomorphous with the Al compound, and the lattice parameters are reported. Its fluorescence is totally quenched at room temperature. The corresponding In compound does not exist. 相似文献
20.
以Bi(NO3)3·5H2O为原料,天然棉花为模板结合热处理工艺,成功合成了具有网状结构的三斜晶相Bi2O3光催化材料,利用XRD、SEM、TG-DTA和UV-Vis漫反射等技术对样品的晶型结构、形貌及吸光性能等进行了表征。以亚甲基蓝染料分子模拟环境污染物,考察了样品的光催化性能。结果表明,棉花纤维在网状Bi2O3的制备中起到了充分的诱导作用,这种网状结构是由一些直径不一的Bi2O3扁平状网线交错排列、稀疏盘结而形成。TGA分析结果表明,适当的热处理在去除棉花模板的同时可以实现Bi 3+→Bi2O3的转化。在可见光照射下,网状Bi2O3的光催化活性及重复使用性能均优于粉体Bi2O3,反应100min后,对MB的脱色率可达到93%左右,并且重复使用4次后仍可使MB的脱色率保持在85%以上。此外,对网状Bi2O3的形成机理进行了探讨。 相似文献