ZnO-Al2O3-B2O3-SiO2系微晶玻璃的研究

研究了能与可伐合金匹配封接的ZnO-Al2O3-B2O3-SiO2系微晶玻璃,其膨胀系数为5.2×10-6/℃,采用该微晶玻璃的封接器件绝缘电阻可达1×1013Q·cm.通过对该微晶玻璃的差热曲线分析,确定了其热处理制度;用X射线衍射仪和扫描电镜研究了该系统的主晶相,其主晶相为ZnAl2 O4、ZnB2O4和少量的NaSiAl2O4晶体.通过控制碱金属离子进入晶格,可明显提高微晶玻璃的绝缘电阻.     

氧化锌对MgO-Al2O3-SiO2系玻璃结构和性能的影响

采用熔融法制备不同氧化锌含量的MgO-Al2O3-SiO2系玻璃,采用差热分析法研究氧化锌含量对MgO-Al2O3-SiO2系玻璃转变温度和晶化峰值温度的影响,利用红外光谱技术研究氧化锌对玻璃结构的影响,并验证玻璃的差热分析结果,采用粉末X射线衍射分析对950℃烧结后的微晶玻璃样品进行晶相分析。结果表明:少量氧化锌的加入(w(ZnO)≤3%)能够促进玻璃粉体的烧结致密化,过多的氧化锌将阻止样品的烧结。样品的介电常数和膨胀系数随着氧化锌的增加而增加。样品的介电损耗随氧化锌的增加呈先降后升的变化,与密度的变化规律相反。     

氧化铋低熔玻璃介质粉的热学性能

制备了Bi2O3质量分数为30%~50%的Bi2O3-B2O3-BaO玻璃介质粉,分析了Bi2O3含量对玻璃膨胀系数(α)、体积电阻率(Rv)的影响以规律,结果表明:玻璃膨胀系数随Bi2O3含量的增加而增大,体积电阻率随温度上升而下降;利用差热分析(DTA)确定该体系玻璃介质粉的特征温度以及特征温度随组分的变化;运用红外光谱分析了玻璃的结构变化,结果表明,随着Bi2O3含量的增加使[BO4]四面体向[BO3]三角体转变,导致体系中非桥氧数增多和玻璃介质粉热学性能的变化。     

Na2O含量对BaO-SrO-Nb2O5-B2O3-SiO2系玻璃陶瓷微结构和性能的影响

采用熔融法制备NaO-BaO-SrO-Nb2Os-B2O3-SiO2玻璃陶瓷.借助DSC、XRD、SEM和电学性能测试研究不同含量的Na2O对其相组成、显微结构、介电性能、体积电阻率及击穿强度的影响.结果表明随着Na2O含量(摩尔分数)的增加,玻璃转变温度(Tg)和第一析晶放热峰(Tg1)温度逐渐降低,而第二析晶放热峰温度(Tg2)呈先降低后升高再降低的变化.经(800℃,3h)+(900℃,3h)热处理后,未添加Na2O的样品析出单相四方钨青铜结构的Ba0.5Sr0.5Nb2O6,而添加5%Na2O(摩尔分数)的样品变为单相Ba0.25Sr0.75Nb2O6.当Na2O为10%时,样品的主晶相仍为Ba0.25Sr0.75Nb2O6,但析出NaSr1.2Ba0.8Nb5O15和Na2Ba2Si2O7相;继续增加Na2O量到15%时,样品的晶相种类不变而衍射峰强度有所增强.样品的介电常数随Na2O含量的增加呈“N”字形变化,样品的体积电阻率和击穿强度随Na2O含量的增加而降低,未添加Na2O试样的击穿强度最大为1500kWcm,其储能密度达3J/cm3.     

Na2O-CaO-SiO2系透明微晶玻璃制备及其微观结构

制备了Yb3+掺杂的Na2O-CaO-SiO2系高结晶度、透明微晶玻璃。用差热分析(DSC)初步确定基础玻璃的核化及晶化温度范围,用X射线衍射(XRD)测定微晶玻璃析出晶相,用扫描电镜(SEM)研究微晶玻璃的微观结构。结果表明:组成为53SiO2-30CaO-17Na2O(摩尔分数,%)的基础玻璃经热处理析出了Na4Ca4Si6O18晶相;合适热处理制度为:595℃核化5 h,730℃晶化1 h;所制备的微晶玻璃析晶度高,晶粒尺寸约100μm,微晶玻璃仍具有较高的透明度。     

F-对 CBN磨具用陶瓷结合剂的结构与性能的影响

采用传统熔体淬法制备了R2O-MO-B2O3-Al2O3-SiO2多元系统玻璃(R为碱金属,M为碱土金属).将制得的玻璃与Na3AlF6混合均匀制成陶瓷结合剂.测试了结合剂的耐火度、润湿性、抗弯强度和热膨胀系数,分析了F-对玻璃结构和性能的影响.结果表明:在低熔陶瓷结合剂中引入适量的F-可以降低结合剂的耐火度,提高结合剂对CBN的润湿性以及结合剂本身的抗折强度.F-在玻璃网络中起断网作用,因此F-加入量不能大于5%,否则会影响结合剂的综合性能.     

Al2O3对CaO-B2O3-SiO2系玻璃陶瓷材料介电性能和微观结构的影响

Al2O3具有优异的电性能和物理性能,将Al2O3作为CaO-B2O3-SiO2系微晶玻璃陶瓷材料的烧结助剂,能够起到良好的助烧作用.用X-Ray,SEM,TG-DTA和介电频谱测试等方法系统研究了Al2O3含量对CaO-B2O3-SiO2系微晶玻璃陶瓷材料烧结性能、介电性能和微观结构等的影响.结果表明,有适量的Al2O3添加的该体系陶瓷材料能够在低温(＜900℃)烧结.烧结体在高频下具有低介电常数和低介电损耗(ε＜5,tg＜0.0013;1MHz～1.8GHz).Al2O3含量的增加使得CaO-B2O3-SiO2系玻璃陶瓷材料的烧结温度发生变化,而对烧结体的介电性能影响不大.     

CBN磨具用玻璃结合剂的结构与性能研究

采用传统熔体淬法制备了R2O—MO—B2O3-Al2O3-SiO2多元系统玻璃结合剂（R为碱金属,M为碱土金属）。利用红外光谱技术研究了玻璃的结构。测试了玻璃结合剂的抗弯强度和热膨胀系数,分析了玻璃组成及结构变化对玻璃性能的影响。结果表明：所有玻璃网络中均存在[SiO4]、[AlO4]四面体和[BO3]三角体结构单元。当SiO2增加到58．95mol％时,玻璃网络中出现[BO4]四面体,此时玻璃的抗折强度急剧下降,而膨胀系数由增大变成减小。SiO2含量为55．09mol％的样品适合用作CBN磨具玻璃结合剂。     

火焰喷淬制备BaO-TiO2和La2O3-Nb2O5玻璃微球及性能研究

分别以BaO、TiO2和La2O3、Nb2O5为原料采用火焰喷淬法制备了不含网络形成体的BaTi2O5(BTO)和35La2O3-65Nb2O5 (LNO)玻璃微球。结果表明,所有BTO为透明的、表面光滑、无结晶痕迹的玻璃微球,粒径分布集中在8~40μm,且具有较低的非晶形成能力;而大部分的LNO为透明的、具有光滑表面的玻璃微球,粒径分布集中在10~40μm,少量粒径较大的LNO微球表面粗糙,存在微米级LaNbO4和LaNb3O9晶粒。计算结果显示,BTO和LNO玻璃微球均具有高折射率,分别为2.20和2.23,是非常有应用前景的窗口、镜头以及反光标志膜材料。     

PbF2-TeO2-B2O3-Eu2O3玻璃介电性能和弛豫动力学

在频率范围为1 Hz~10 MHz和温度范围为313~773 K条件下,采用熔炼?淬火技术制备20PbF2?20TeO2?(60?x)B2O3?xEu2O3(x=0~2.5,摩尔分数,%)玻璃,并研究频率和温度对介电性能的影响。通过介电模量行为分析材料的介电弛豫动力学。在313~523 K温度范围内,介电损失可以忽略不计,表明玻璃具有良好的热稳定性。所制备的Eu2O3掺杂氧氟硼玻璃在高频低温下介电损失低,是良好的非线性光学材料。     

Fe-15Ce合金在H2-CO2、H2-H2S及H2-H2S-CO2气氛下的腐蚀

研究了600℃时Fe-15Ce合金在H2-CO2、H2-H2S及H2-H2S-CO2 3种气氛中的腐蚀行为，Fe-15Ce合金腐蚀后发生了Ce的内氧化或形成了复杂的腐蚀产物膜，而未出现Ce的选择性氧化或硫化，这主要是合金中存在着两相及Ce在Fe中极低的溶解度的结果。Fe-15Ce合金在本实验条件下的氧化-硫化腐蚀速度低于相同温度、压力下的纯硫化。     

用氢-氧取代氧-乙炔作焊接切割的必要性及可行性

阐述了用氢代乙炔的必要性．通过时HGQU2000／315火焰电孤焊割机的考察和试用证实了用氢代乙炔的可行性，比较了两种气体的性质并提出了使用特性差异和注意事项．提出了进一步探索的问题。     

Thermodynamics and phase diagrams in the binary systems Na2O-SiO2, Na2O-GeO2, Na2O-B2O3, Li2O-B2O3, CaO-B2O3, SrO-B2O3, and BaO-B2O3

We applied our model to the enthalpy of mixing data of the binary systems Na₂O-SiO₂, Na₂O-GeO₂, Na₂O-B₂O₃, Li₂O-B₂O₃, CaO-B₂O₃, SrO-B₂O₃, and BaO-B₂O₃. The most stable composition in the liquid, that is where the enthalpy of mixing is most negative, is with a metal-oxygen ratio of 4 to 3, for monovalent metals (Na and Li) and 3 to 4 for divalent metals (Ba and Ca) in liquid silicates or borates. The same applies to the CaO-SiO₂, CaO-Al₂O₃, PbO-B₂O₃, PbO-SiO₂, ZnO-B₂O₃, and ZnO-SiO₂ systems. The oxygen to metal ratio, its constant value in various types of systems, reflects and describes the structure of the liquid. Using the analyzed enthalpies of mixing data and the available phase diagrams, we calculated the enthalpies of formation of the various binary compounds. The results are in excellent agreement with data in the literature that were obtained from direct solid-solid calorimetry.     

IrO2-MnO2中间层Ti/RuO2-TiO2-SnO2电极制备及性能

通过热分解法制备了含IrO2-MnO2中间层Ti/RuO2-TiO2-SnO2电极,采用SEM、EDX、XRD、CV等检测方法对中间层进行表征,同时采用强化加速寿命试验对电极电化学稳定性进行表征。结果表明:450℃时前躯体完全氧化并形成固溶体,制备的中间层晶粒细小,表面结构致密,电化学孔隙率小。添加中间层使Ti/RuO2-TiO2-SnO2电极强化寿命由未加中间层的7.5h提高到995.8h,远高于国家标准20h。     

ACTIVITY OF La_2O_3 IN LIQUID La_2O_3-CaF_2 AND La_2O_3-CaF_2-CaO-SiO_2 SLAGS

用石墨为还原剂,将渣中La_2O_3还原入液态Sn,以测定1500℃下La_2O_3-CaF_2和La_2O_3-CaF_2-CaO-SiO_2渣中La_2O_3的活度.对La_2O_3-CaF_2系,并用Gibbs-Duhem积分法求得CaF_2的活度. 根据液态渣的离子结构模型,对上述二渣系中La_2O_3的活度数据进行了简单的讨论.     

Mechanoluminescence in BaSi2O2N2:Eu

Mechanoluminescence (ML), a general term for the phenomenon in which light emission occurs during any mechanical action on a solid, can be divided roughly into two classes: destructive ML and non-destructive ML. For practical use in high-end applications (e.g. pressure sensors), materials with non-destructive ML properties are preferred. This paper reports on the strong non-destructive ML in BaSi₂O₂N₂:Eu. When irradiated in advance with ultraviolet or blue light, this phosphor shows intense blue-green light emission upon mechanical stimulation such as friction or pressure. The ML has an emission band peaking at 498 nm, which is ～4 nm red-shifted compared to the steady-state photoluminescence. The origin of the ML is discussed and related to the persistent luminescence of BaSi₂O₂N₂:Eu. The same traps are responsible for both phenomena. Based on the occurrence of ML in this phosphor, we were able to show that the predominant crystallographic structure of BaSi₂O₂N₂:Eu belongs to space group Cmc2₁.     

氢分子在贮氢材料Li2MgN2H2表面的吸附与解离

采用第一性原理计算方法研究了Li-Mg-N-H体系贮氢材料的放氢产物Li2MgN2H2的吸氢反应过程中的过渡态、表面电子态密度和表面能。结果表明:氢分子在Li2MgN2H2低指数表面中最低能量(100)表面的Mg-Mg-Li穴位吸附位置能够形成最稳定的吸附结构并发生解离,氢分子吸附能为-0.1898eV,解离能约为0.84eV(81kJ/mol),表明该反应所需的反应活化能仍较高,吸氢反应速度缓慢。     

Thermodynamic evaluation of phase equilibria in the CaCl2-MgCl2-CaF2-MgF2 system

The phase diagram of the CaCl₂-CaF₂-MgCl₂-MgF₂ reciprocal ternary system was calculated thermodynamically from available data on the common-ion binary subsystems and from available data on the CaCl₂-MgF₂ join. This join is very nearly quasibinary and divides the system into two quasiternary systems: the CaCl₂-MgF₂-CaF₂ system with a ternary eutectic calculated at 724 +-5 °C and the CaC₂-MgF₂-MgCl₂ system with a ternary eutectic calculated at 561 +-5 °C.     

High temperature corrosion of Fe-Cr-Mn-alloys in H2-H2S and H2-H2O-H2S gas mixtures

The sulfidation of Fe-20% Cr-30% Mn, Fe-25%Cr-20%Mn and Fe-25% Cr was studied at 700°C in H₂-H₂S and the oxidation and sulfidation in H₂-H₂O-H₂S after preoxidation in H₂-H₂O. The sulfidation rate is strongly increased for the Mn-containing alloys, layers of (Mn,Cr)S and (Mn,Fe)Cr₂S₄ are formed. Also the oxidation rate is enhanced compared to Fe-25% Cr by formation of MnCr₂O₄ instead of Cr₂O₃. The sulfidation after preoxidation leads to internal and external sulfidation of the Mn-containing alloys. With increasing oxygen pressure p(O₂) = 10^?26…10^?22 atm. of the H₂-H₂O-H₂S mixtures the sulfidation is suppressed, for the higher oxygen pressure 10^?23 and 10^?22 atm. fast oxidation prevails under formation of MnCr₂O₄. Manganese cannot increase the sulfidation resistance of alloys, in spite of the stability and low degree of disorder of its sulfide, since the mixed sulfide (Mn,Cr)S is formed which has a high degree of disorder, high diffusivities and high growth rate according to the doping effect of trivalent Cr³⁺.     

The Quasi-Ternary System Cu2Se-Ga2Se3-GeSe2

The quasi-ternary system Cu₂Se-Ga₂Se₃-GeSe₂ was investigated using the methods of differential thermal and x-ray analysis. An isothermal section at 770 K and a liquidus surface projection of the phase diagram were constructed. The existence of the quaternary phase CuGaGeSe₄, the boundaries of solid solutions ranges of the system compounds were established.