锂铝硅系光敏微晶玻璃的研究进展和应用

自Li₂O-Al₂O₃-SiO₂系光敏微晶玻璃诞生以来,人们便期望将其优秀的异向刻蚀能力应用于微型结构件的制造中。目前,对锂铝硅系光敏微晶玻璃材料的研究主要集中在成核机理、析晶过程和组分、性质间的关系等方面。光敏微晶玻璃的光敏性和结晶性能密不可分,光敏性决定了晶核的形成,而生成的偏硅酸锂晶体则决定了其异向刻蚀能力。因而对成核机理和析晶过程的研究至关重要,亦有利于了解玻璃的本质。而随着科学技术的发展进步,光敏微晶玻璃的某些性能已不能很好地满足应用要求,如介电损耗和化学稳定性,因此提高光敏微晶玻璃的性能变得必要。随着研究的日益深入,光敏微晶玻璃在实际应用中也暴露出一些问题,如刻蚀精度、壁角倾斜度、内壁光滑度、介电损耗高等,这些问题制约着该材料的发展,亟待解决。 本文阐述了锂铝硅系光敏微晶玻璃的光敏化诱导析晶原理,详细介绍了Li₂O-Al₂O₃-SiO₂系光敏微晶玻璃的研究进展以及在三维集成电路、微流控芯片和微通道板等方面的应用,分析了现阶段存在的问题,并指出了今后光敏微晶玻璃的研究方向。     

MgO/Al2O3比对MgO-Al2O3-SiO2系统玻璃分相与析晶的影响

采用高温熔融法制备了具有不同MgO/Al₂O₃比的堇青石微晶玻璃。采用差热分析仪(DTA)、X射线衍射仪(XRD)、扫描电子显微镜(SEM)等测试技术研究了MgO/Al₂O₃比对该系统玻璃分相和析晶的影响。结果表明:当SiO₂含量不变时,随着MgO/Al₂O₃比的减小,分相形貌由连通的蠕虫状逐渐变为孤立的球形结构,且分相粒子尺寸逐渐减小,从200~300 nm减小至30~50 nm。当MgO/Al₂O₃比从3降到1,析晶峰温度由997 ℃升至1 105 ℃,析晶的难度逐渐提高。当MgO/Al₂O₃比为3时,MgO-Al₂O₃-SiO₂系统玻璃经950 ℃热处理后即产生大量分相,经1 050 ℃热处理后在分相液滴中析出大量堇青石晶体,且堇青石优先在富Mg相中析出。提高MgO/Al₂O₃比有利于MgO-Al₂O₃-SiO₂系统玻璃在分相中析晶,反之,则会降低系统的分相和析晶能力。     

β-锂霞石负膨胀微晶玻璃的制备技术及结构特征

研究了β锂霞石微晶玻璃的制备技术、结构特征及其负膨胀特征。首先采用玻璃结晶法制备β锂霞石负膨胀微晶玻璃材料,然后通过XRD、SEM等测试手段,表征了β锂霞石微晶玻璃材料的结构特征。并讨论β锂霞石负膨胀微晶玻璃的膨胀系数及其与晶相组成和晶化温度及时间的依从关系,使其负膨胀系数在一定范围内连续可调。研究并制备出热膨胀系数可达到为-1.037×10-5/℃的β锂霞石微晶玻璃。     

锂铝硅微晶玻璃结构与性能热稳定性研究

以TiO₂、ZrO₂为形核剂制备了透明低膨胀锂铝硅系微晶玻璃, 通过测定其等温转变动力学曲线,讨论锂铝硅玻璃析晶及相变与热处理温度和时间的关系, 并采用DTA、XRD和SEM等方法研究锂铝硅微晶玻璃结构和性能的热稳定性. 结果表明, 以β-石英固溶体为主晶相的透明微晶玻璃能在750~900℃较宽的温度范围和较长的时间内保持主晶相和结构的稳定, 850℃保温5h仍具有较高的透光率和极低的热膨胀系数, 性能具有很好的高温稳定性. 材料结构和性能的稳定性均源自钛锆复合形核剂较高的形核效率.     

纳米-Al2O3/SiO2加入量对MgO-Al2O3-SiO2复相陶瓷烧结机理的影响

为了探究纳米-Al₂O₃/SiO₂加入量对MgO-Al₂O₃-SiO₂复相陶瓷烧结行为的作用机理。以微米级MgO、纳米级Al₂O₃和SiO₂为主要原料制备陶瓷基复合材料。通过XRD和 SEM等检测手段对烧后试样的物相组成和微观结构进行测试与表征,重点研究Al₂O₃/SiO₂的加入对复相陶瓷物相组成、微观结构及烧结性能的影响。结果表明:随着Al₂O₃/SiO₂加入量的增大,试样烧后相对密度和烧后线变化率呈先增大后减小再增大的趋势,加入15%Al₂O₃/SiO₂(质量分数)的试样经1 500 ℃烧结后,其相对密度可以达到94%。引入的Al₂O₃/SiO₂与基体中的MgO生成镁铝尖晶石与镁橄榄石相,原位反应伴随的体积膨胀,抵消部分烧结过程中的体积收缩。Al₂O₃/SiO₂加入量为75%(质量分数)的试样经1 400 ℃烧结后,基体中有大量堇青石相生成,随着煅烧温度提高到1 500 ℃,堇青石分解所产生的高温液相促进了试样的烧结收缩。     

添加铅硅玻璃对烧结堇青石基微晶玻璃性能的影响

研究了铅硅玻璃在堇青石基微晶玻璃烧结中的作用及其添加量对微晶玻璃性能的影响．结果表明：铅硅玻璃的加入可以促进微晶玻璃的烧结致密化;随着铅硅玻璃加入量的增加,烧结样品的介电常数亦增加,且与密度变化曲线相似;微晶玻璃烧结样品的热膨胀系数符合加和性规律．     

以钾长石制备α-堇青石微晶玻璃及其性能研究

以钾长石为主要原料,制备了α-堇青石微晶玻璃。采用差热分析(DSC)、X射线衍射仪(XRD)及场发射扫描电子显微镜(FESEM)分别研究了微晶玻璃的烧结和晶化行为、晶相组成及显微结构。探讨了晶化温度对微晶玻璃晶相、显微结构及性能的影响。结果表明,随着温度的升高,微晶玻璃中α-堇青石含量先增加后减小,而微晶玻璃孔隙先变少后增多;微晶玻璃抗折强度(最高达到131 MPa)高,介电常数(最低为4.56,200kHz)及介电损耗(最低为0.030,200kHz)低,晶化温度低于1000℃,可以用作低温共烧陶瓷材料。     

低熔封接玻璃的研究进展

低熔封接玻璃是一种先进的焊接材料,由于其具有低的熔化温度和封接温度,优良的机械强度和化学稳定性,而在很多领域中得到广泛的应用,实现了玻璃、陶瓷、金属、半导体间的相互封接.综述了低熔封接玻璃的研究现状,展望了低熔封接玻璃向无铅化发展的趋势,指出了无铅低熔封接玻璃今后的研究方向.     

绿色无铅低熔点封接玻璃研究进展

传统的封接玻璃由于含有重金属元素铅,对环境和人类健康有着极大的损害,目前已经被世界各国限制使用或者禁止使用,因此,低熔点封接玻璃的无铅化将会是今后的主要发展方向。本文以低熔点封接玻璃的无铅化为出发点,归纳总结低熔点封接玻璃的主要性能。首先介绍了包括磷酸盐玻璃,钒酸盐、硼酸盐、铋酸盐玻璃在内的低熔点封接玻璃的组成、结构特点、性能以及研究现状。其次,提出了封接玻璃的封接低温化和无铅化的发展方向。最后,针对低熔点封接玻璃研究中存在的不足,对玻璃粉添加颗粒进行复合改性、加强玻璃理论研究、研发制备新工艺,是今后研究应该着力的突破点。     

Fe2+、Fe3+对CaO-Al2O3-SiO2-MgO系微晶玻璃析晶性能的影响规律

为了利用大量的含铁铝硅酸盐固体废弃物制备具有高附加值的微晶玻璃,采用DTA、XRD、SEM、 EDS等手段研究了Fe₂₊、Fe₃₊对CASM系微晶玻璃析晶性能的影响,结果表明,Fe₂₊在微晶玻璃中与Mgz+的 作用相同,取代以网络外体形式存在的Al₃₊,使得微晶玻璃的析晶温度逐渐下降,而对析晶能力几乎没有影 响,并当Fe₂₊掺入量为2%时,主晶相由铝黄长石转变为镁黄长石,在7.5%时,进一步转变为透辉石．Fe₃₊掺 量小于7.5%时,起到补充S14不足的作用,当大于7.5%时,部分Fe₃₊起到与Fe₂₊、Mg₂₊相同的作用,使得 析晶温度呈先升后降的变化,在掺量为7.5%时,铝黄长石主晶相才开始转变为镁黄长石,在10%对,转变为 透辉石,且析晶能力得到大幅提升．随着Fe₂₊和Fe₃₊含量增加,虽然微晶玻璃中主晶相的变化顺序相同,但 Fe₂₊具有降低微晶玻璃析晶温度的作用,而一定量的Fe₃₊可作为晶核剂提高微晶玻璃的析晶能力     

Bi2O3助熔剂对CaO-B2O3-SiO2/Al2O3玻璃陶瓷复合材料性能的影响

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.     

Thermal expansion studies of Gd2Mo3O12 and Gd2W3O12

Simultaneous thermogravimetric/differential thermal analysis of Gd₂Mo₃O₁₂ showed an irreversible phase transition at 1178 K where as Gd₂W₃O₁₂ showed reversible phase transition at 1433 K, which were confirmed by powder X-ray diffraction. The thermal expansion behavior of α-Gd₂Mo₃O₁₂ (room temperature phase), β-Gd₂Mo₃O₁₂ (phase obtained by heating Gd₂Mo₃O₁₂ at 1223 K) and Gd₂W₃O₁₂ have been investigated using high temperature X-ray diffractometer. The cell volume of α-Gd₂Mo₃O₁₂, β-Gd₂Mo₃O₁₂ and Gd₂W₃O₁₂, fit into polynomial expression with respect to temperature, showed positive thermal expansion up to 1073, 1173 and 1173 K, respectively. The average volume expansion coefficients for α-Gd₂Mo₃O₁₂, β-Gd₂Mo₃O₁₂ and Gd₂W₃O₁₂ are 39.52 × 10⁻⁶, 21.23 × 10⁻⁶ and 37.96 × 10⁻⁶ K⁻¹, respectively.     

Varistor properties of ZnO-Pr6O11-CoO-Cr2O3-Y2O3-In2O3 ceramics

The varistor properties of the ZnO-Pr₆O₁₁-CoO-Cr₂O₃-Y₂O₃-In₂O₃ ceramics were investigated for different concentrations of In₂O₃. The increase of In₂O₃ concentration slightly increased the sintered density (5.60-5.63 g/cm³) and slightly decreased the average grain size (3.4-2.9 μm). The breakdown field increased from 6023 to 14822 V/cm with increasing concentration of In₂O₃. The nonlinear coefficient increased from 17.6 to 44.6 for up to 0.005 mol%, whereas the further doping caused it to decrease to 36.8. In₂O₃ acted as an acceptor due to the donor concentration, which decreases in the range of 1.02 × 10¹⁷ to 0.24 × 10¹⁷/cm³ with increasing concentration of In₂O₃.     

Properties of (0.5−x)Zn-xFe2O3-0.5P2O5 glasses

Experimental determination of the properties of less studied zinc-iron-phosphate glasses was investigated. Glasses of the general composition (50−x)ZnO-xFe₂O₃-50P₂O₅, mol%, with x=0, 10, 20, 30 and 40, was chosen for these investigations. These studies included, glass forming, glass density, thermal expansion coefficient, dilatometric softening temperature, an initial test of chemical durability and vibrational properties. It is shown that an Fe/P ratio of the compositions at about 0.6 and 0.8 and the O/P ratio at 3.4 and 3.8 could be considered as chemically durable phosphate candidates.     

Determination of the thermo-optic coefficient dn/dT of ytterbium doped ceramics (Sc2O3, Y2O3, Lu2O3, YAG), crystals (YAG, CaF2) and neodymium doped phosphate glass at cryogenic temperature

In this paper, we report the measurements of the thermal expansion coefficient and the thermo-optic coefficient dn/dT for the ytterbium doped cubic sesquioxides (Sc₂O₃, Y₂O₃, Lu₂O₃) at cryogenic temperature. These materials appear to have very interesting properties for setting up high average power laser chains useful for plasma physics and for inertial fusion energy drivers. Measurements have also been done on YAG ceramic and crystal, CaF₂ crystal, and neodymium phosphate glass (Hoya, LHG-8).     

Refractories based on 3Er2O3-Ta2O5

Refractory Er₂O₃-Ta₂O₅ compositions in the high Er₂O₃ region were prepared by coprecipitation as hydroxides, followed by calcination. Based on x-ray diffraction and wet chemical and electron microanalysis, the fluorite phase was found at 17.3–34.2 (±0.5) mole percent Ta₂O₅. This fluorite phase was stable to at least 2140 C in reducing atmospheres; although measurable vaporization occurred above 1975 C. Above 2100 C minor Ta reduction with preferential vaporization of Er and O was observed.     

Structural studies of Fe2O3-Bi2O3-CdO glass system

xFe₂O₃·(100 − x)[Bi₂O₃·CdO] system with 0 ≤ x ≤ 50 mol% was prepared and investigated by X-ray diffraction, density, FT-IR and Raman spectroscopies. The XRD patterns confirm the formation of a vitreous structure for x < 35 mol% Fe₂O₃. The evolution of density and molar volume with the addition and increasing of iron content indicates structural changes in the structure of Bi₂O₃·CdO glass matrix. The FT-IR spectrum of the glass matrix reveals a structure realized from BiO₃ pyramidal and BiO₆ octahedral units. With the addition of iron the structure proposed by the glass matrix is changing by the appearance of FeO₄ units. Also the existence of FeO₆ units cannot be excluded. The Raman spectra suggest a structure build from BiO₆ octahedral units. By Raman scattering the presence of structural units characteristic to Fe₂O₃ was not directly observed but the evolution of the spectra is dependent of the iron content.     

Hygroscopicity and bulk thermal expansion in Y2W3O12

Negative thermal expansion material, Y₂W₃O₁₂ has been synthesized by the solid-state method and bulk thermal expansion of the material has been investigated from 300 to 1100 K. The material reversibly forms a trihydrate composition whose X-ray diffraction pattern can be indexed to an orthorhombic unit cell with a = 10.098(1) Å, b = 13.315(3) Å, c = 9.691(4) Å. The cell volume of the hydrated pattern is 7% smaller than the unhydrated cell volume. According to the dilatometric studies, the material shows a 3-6% increase in the linear strain at about 400 K, which can be attributed to the removal of water. Sintering the material at 1473 K leads to large grain size of >100 μm, which results in a large hysteresis in the bulk thermal expansion behavior. Hot pressing at 1273 K under a uniaxial pressure of 25 MPa results in a fine-grained (2-5 μm) ceramic. Glazing the ceramic prevents moisture pick up and a linear thermal expansion over the entire temperature range 1100-300 K and an average linear thermal expansion co-efficient of −9.65 × 10⁻⁶/K is observed. The effect of water on the thermal expansion behavior of this system is discussed.     

Properties and Structures of Bi2O3-B2O3-TeO2 Glass

Glass formation range of Bi₂O₃—B₂O₃—TeO₂ system has been investigated（B₂O₃ < 40 mol%）.Four glasses with compositions xBi₂O₃—3OB₂O₃—（70—x）TeO₂（x = 40,50,60 and 70 mol%） have been prepared by using melt quenching technique.The effect of Bi₂O₃ content on thermal stability,optical properties and structures of these four Bi₂O₃—B₂O₃—TeO₂ glasses is systematically investigated by inductive coupled plasma emission spectrometer（ICP）,differential scanning calorimetry（DSC）,Raman spectra and X-ray photoelectron spectroscopy（XPS）.It is found that the density,refractive index and optical basicity increase with increasing Bi₂O₃.The Raman spectra and XPS spectra show that the glass network is mainly constituted by the[BiO₆] octahedron,[TeO₄]trigonal bipyramidal,[TeO₃]trigonal pyramid,[BO₃]trigonal pyramid and[BO₄]tetrahedron structural units.With increasing Bi₂O₃,the coordination number around B atom changes from 3 to 4 and [TeO₄]units are converted to[TeO₃]units.Bi⁵⁺ ions may exist in Bi₂O₃—B₂O₃—TeO₂（BBT） system and their amount grows with increasing Bi₂O₃ content.     

Phase relations of the Li2O-Ta2O5-B2O3 and Li2O-WO3-B2O3 systems and promising nonlinear optical compounds in K2O-Ta2O5-B2O3 system

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 D_calc = 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.