含La_2O_3的 B_2O_3-PbO系玻璃相对部分色散研究

本文研究了在B_2O_3-PbO玻璃中加入La_2O_3后,TF类光学玻璃的相对部分色散,论证了含La_2O_3的TF类玻璃化学组成、结构和玻璃性质关系。TF类玻璃在0.5升铂坩埚中熔制。     

TF3特殊相对部分色散光学玻璃

本文研究了在B_2O_3-PbO玻璃中引入La_2O_3、Sb_2O_3、SiO_2后,TF_3光学玻璃化学稳定性及特殊相对部分色散。论证了TF_3光学玻璃性质,化学组成和结构关系。TF_3光学玻璃在3.5立升铂坩埚中熔制。     

重火石光学玻璃化学稳定性的研究

本工作为提高重火石系列光学玻璃化学稳定性,进行了一系列规律性探讨。研究并讨论了以TiO_2取代PbO,以Al_2O_3取代SiO_2,外加二价金属氧化物及混合碱效应对该系列玻璃化学稳定性的影响,取得了一定的效果。     

Li_2O-La_2O_3-B_2O_3系玻璃的X射线衍射研究

用径向分布函数法研究了Li_2O-La_2O_3-B_2O_3系玻璃的结构,在RDF曲线上r=2.58A处有一峰,利用由二硼酸盐基团组成网络的2B_2O_3·Li_2O晶体的准晶态模型,对该峰进行了拟合,得出La~(3 )离子第一近邻(La—O)配位数为9,平均键长为2.58A;O~(2-)离子(O—O)平均配位数为5.1,平均间距为2.4A;B离子(B—B)平均配位数为3.5,平均间距为2.46A。最后根据样品的化学组成对上述准晶态模型作了进一步的改进,得到较为满意的结果。     

R_2O-CaO-Al_2O_3-B_2O_3-SiO_2-P_2O_5玻璃的制备及性能

采用高温熔融的方法制备R_2O-CaO-Al_2O_3-B_2O_3-SiO_2-P_2O_5多元系统乳浊玻璃,运用FT-IR、SEM和XRD对玻璃的结构和分相进行了分析,测试了玻璃的热膨胀曲线、耐水性、显微硬度和釉烧性能。研究了以MgO-CaO取代Na_2O对玻璃乳浊程度以及其结构与性能的影响。结果表明,随着Na_2O含量的降低和MgO-CaO含量的增加,玻璃的乳浊程度逐渐降低最后趋于透明,热膨胀系数表现出递减的趋势,而转变温度和软化温度呈逐渐升高的趋势;化学稳定性优异且逐渐增强,玻璃水解等级均为一级。     

Bi_2O_3-P_2O_5二元系统玻璃性能

采用高温熔融的方法制备xBi_2O_3-(100-x)P_2O_5二元系统玻璃,研究了Bi_2O_3含量变化对该体系玻璃的结构、热膨胀系数、密度和化学稳定性等的影响。在二元系统中随着Bi_2O_3含量的增加,熔融温度不断升高。当Bi_2O_3摩尔分数达到30%,在1 200℃下熔制且保温2h的玻璃液均化程度高、成玻性能良好,化学稳定性达到最好。随着Bi_2O_3含量的增加,热膨胀系数呈先减小后增大的趋势,在Bi_2O_3摩尔分数为25%出现最小值。     

无硫无铬一氧化碳中温变换催化剂的开发——Fe_2O_3—PbO催化剂

利用共沉淀法使铁和铅的硝酸盐在NH_4OH作用下生成氢氧化物沉淀,经过过滤、干燥和煅烧得到了Fe_2O_3—PbO无硫无铬一氧化碳中温变换催化剂。通过对不同含铅量催化剂样品的活性测定,得到该催化剂最佳铅含量为12％(重量百分比),并且其活性高于某厂定型生产的无硫LHB—103型Fe_2O_3—Cr_2O_3催化剂。     

TiO_2对Bi_2O_3-SiO_2-ZnO-B_2O_3玻璃性能影响

TiO2掺杂的铋锌硼玻璃作为封接玻璃和特种光学玻璃材料,其光学特性和化学稳定性研究是至关重要的。主要研究了掺加2%、4%、6%和8%TiO2的Bi2O3-SiO2-ZnO-B2O3体系玻璃的光学和化学稳定性,研究结果表明:玻璃表面没有条纹和缺陷,从可见光透过率可知,玻璃为半透明,透过率在20%~50%之间。玻璃的耐水性能受玻璃中离子含量的影响较大,Ti离子的含量越高,结构越稳定,耐水性能越好;玻璃的耐酸性能与结构中阳离子的极化能力有关,极化能力越大,耐酸性能越好,而且玻璃的侵蚀是渐缓的;玻璃在碱性介质中的侵蚀机理是铋锌硼长链末节的金属离子被水化,导致Bi-O-Bi断键,耐碱性能变差,加入TiO2后,改善其耐碱性能。     

CaO—CaF_2—Fe_tO熔剂对高碳铁液脱磷时Al_2O_3和Fe_tO的影响

使用Al_2O_3坩埚,在1400℃下实验测定了CaO—CaF_2—Fe_2O渣系和高碳铁液间的磷分配。得到了如下结果:(1)磷分配比(L_p)随熔剂中CaO/Fe_2O_3(重量)比值按3/6,7/2,6/3,5/4,4/5的顺序依次升高;(2)Al_2O_3饱和的CaO—CaF_2·Fe_2O—P_2O_5渣系,其磷容量lgC_(po_4~(3-))=21.2～22.9;(3)渣中CaO对Al_2O_3含量的影响关系为:(%Al_2O_3)=-12.89+0.69(%CaO)     

Al_2O_3—Zr O_2—MgO—长石系统高硬陶瓷材料的研究

本文对 Al_2O_3—Zr O_2—Mgo—长石系统的高硬陶瓷材料的初步研究,在 Al_2 O_3含量低于90%的高铝陶瓷材料中引入高弹性 Zr O_2、稳定剂 Mgo 和少量熔剂长石,用正交试验法进行了系列试验。优选出了最佳高铝陶材料配方,在1580℃～1590℃温度下烧结,获得了吸水率小于0.5%HRc 硬度为72～94的高硬陶瓷材料。     

在V_2O_5、Sb_2O_3、Bi_2O_3、Fe_2O_3、K_2O/Al_2O_3催化剂上邻二甲苯的氨氧化

本文论述了邻二甲苯氨氧化合成邻苯二甲腈的最佳工艺条件,载在高温热处理的三氧化二铝上的 V_2O_s、Sb_2O_3、Bi_2O_3、Fe_2O_3、K_2O 催化剂,对生成邻苯二甲腈表现出良好的活性及选择性,其选择率>95%。催化剂的酸度是一个关键因素.     

Cr_2O_3、Al_2O_3掺杂V_2O_3系PTC陶瓷的制备与特性

本文在还原性气氛（Ｈ２）中制备出Ｃｒ２Ｏ３、Ａｌ２Ｏ３掺杂的Ｖ２Ｏ３系ＰＴＣ陶瓷。测量了材料的电阻率、采用ＸＲＤ、ＳＥＭ分析了材料的结构。并初步讨论了液氮淬冷对Ｖ２Ｏ３系ＰＴＣ陶瓷的结构及ＰＴＣ性能的影响。     

Fe_2O_3-Mn_2O_3-SiO_2系统涂层的研究

本文概述了用溶胶-凝胶法制备 Fe_2O_3-Mn_2O_3-SiO_2系统涂层的工艺,并且运用红外吸收光谱、综合热分析和透射电镜等分析手段,研究了该涂层由凝胶向玻璃态的转化过程、涂层的显微结构特点和着色机理。结果表明,凝胶经加热排除多余溶剂和缩聚反应,逐渐转变为固态。涂层中含有 Fe_2O_2和 Mn_2O_3的胶粒,因此出现光散射和光吸收着色。     

Structure of Bi_2O_3-ZnO-B_2O_3 system low-melting sealing glass

Bi2O3-ZnO-B2O3 system glass is a kind of lead-free low melting sealing glasses.The structure of Bi2O3-ZnO-B2O3 system low-melting sealing glass was investigated by DSC,FT-IR,XRD and SEM.The results show that with the increase of B2O3 content,the transition temperature Tg and softening temperature Tf of Bi2O3-ZnO-B2O3 system low-melting sealing glasses increase,which leads to the liquid phase precipitation temperature increasing and promotes the structure stability in the glass.With increasing the heat treatment temperature,a large number of liquid phases appear in samples and the sinter efficiency of the samples increases.The FT-IR spectra of the glasses show the presence of some bands that are assigned to vibrations of Bi-O bond from [BO3] pyramidal and [BiO6] octahedral units and B-O from [BO3] and [BO4] units.With the decrease of B2O3 content,the crystallization tendency of the glass increases.In glass samples B1 and B2,crystallization starts at 460℃ and 540℃,respectively.Both of them precipitate Bi24B2O39 phases.     

Effect of ZnO-B_2O_3 Glass Addition on the Microwave Dielectric Properties of BaO-Nd_2O_3-TiO_2-Bi_2O_3 System

The effect of ZnO-B2O3(ZB) glass addition on the sintering behavior, microstructures and microwave dielectric properties of BaO-Nd2O3-TiO2-Bi2O3 (BNTB) system was investigated with the aid of X-ray diffraction, scanning electron microscopy and capacitance meter. It is found that the ZB glass addition, acting as a sintering aid, can effectively lower the sintering temperature of BNTB system to 850 ℃. The dielectric constant of BNTB-ZB ceramics increases with the increase of soaking time and the value of dielectric loss decreased with increasing soak time. The optical dielectric properties at 1 GHz of ε=74, tan δ=4×10-4, and TCC=25 ppm/℃ were obtained for the BNTB system doped with 25 wt% ZB glass sintered at 850 ℃ for 2 h, representing that the BNTB-ZB ceramics could be promising for multilayer low temperature co-fired ceramics applications.     

Reduction mechanism of Fe_2O_3-Cr_2O_3-NiO system by carbon

Isothermal experiments on the reduction of Fe_2O_3-Cr_2O_3-NiO(molar ratio of Fe-to-Cr-to-Ni is 3:2:2)by graphite were carried out at 1350–1550°C,and effects of various factors on reduction degree were studied.The results show that the reaction rate of the Fe_2O_3-Cr_2O_3-NiO system is fast during the initial period(reduction degree,α38%),and then the rate decreases until the end of the reduction.Factors such as temperature,carbon content,sample size have a more significant effect during the final stage(α38%).The metallic product formed at the initial stage(a Fe-Ni alloy)greatly promotes the reduction of Cr2O3 at the final stage.Further,during the reduction of Fe_2O_3-Cr_2O_3-NiO by carbon,interfacial reaction is the rate-controlling step and g(α)=1-(1-α)0.5 is the reaction mechanism for the initial stage,whereas two-dimensional diffusion is the rate-controlling step and f(α)=α+(1-α)ln(1-α)is the reaction mechanism for the final stage.The apparent activation energies are 55.43 k J/mol and 174.54 k J/mol for the initial and the final stages,respectively.     

无压烧结Si_3N_4－MgAl_2O_4－Al_2O_3系复合材料

本文对ｓｉ＿３Ｎ＿４－ＭｇＡｌ＿２Ｏ＿４－Ａｌ＿２Ｏ＿３系复合材料的无压烧结进行了研究。讨论了Ａ１＿２Ｏ＿３含量对材料性能的影响及烧结工艺对材料性能和显微结构的相互关系。实验表明：两段法烧结可以得到性能良好的Ｓｉ＿３Ｎ＿４－ＭｇＡｌ＿２Ｏ＿４－Ａｌ＿２Ｏ＿３复合材料     

组成对Li_2O-Bi_2O_3-WO_3-B_2O_3系统玻璃性能的影响

采用传统的熔融冷却法制备了Li2O-Bi2O3-WO3-B2O3系统玻璃,对玻璃的电导率、质量密度和硬度进行了研究。结果表明,在Li2O-Bi2O3-WO3-B2O3系统玻璃中,固定n（Bi）：n（B）=3：2,当Li2O摩尔分数保持不变时,随着WO3摩尔分数的增加,玻璃的质量密度增大,硬度减小;当WO3摩尔分数保持不变时,随着Li2O摩尔分数的增加,玻璃的质量密度和硬度先增大后减小,在Li2O摩尔分数为13％时达到最大值,出现了硼反常现象,质量密度最大值为6．6g／cm^3,硬度最大值为401．6HV。     

Oxidative Desulfurization of DBT with H_2O_2 over 3DOM H_3PW_(12)O_(40)/Al_2O_3 Catalyst

A series of heteropoly acid (HPA) based Al_2O_3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observed by scanning electron microscope (SEM) and transmission electron microscope (TEM).Mesopores could be detected by N_2 adsorption-desorption isotherms which further confirmed the 3DOM structural characteristics of catalyst.Moreover,Keggin-type HPW was highly dispersed in the Al_2O_3 framework,which suggested by powder X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) results.The oxidation desulfurization (ODS) performance of 3DOM H_3PW_(12)O_(40)/Al_2O_3 of refractory sulphur compounds was evaluated in the presence of hydrogen peroxide.It oxidized 98.5% of dibenzothiophene (DBT) into corresponding sulfone within 3 h,which exhibited superior ODS performance than corresponding mesoporous and microporous H_3PW_(12)O_(40)/Al_2O_3 catalyst.The enhancement of ODS efficiency is related to the improvement of mass transfer of DBT in the pore channel resulting from the interconnected 3DOM structure.Furthermore,the as-prepared catalyst still demonstrates outstanding cycle performance after 6 runs,which could be easily recovered from the model fuel.