ZrO2对CaO-Al2O3-SiO2系统微晶玻璃烧结过程的影响研究

CaO-Al2O3-SiO2系统微晶玻璃作为微晶玻璃中的一个新品种,具有非常鲜明的特点.本文讨论了在CaO-Al2O3-SiO2系统微晶玻璃中加入ZrO2,研究了ZrO2对CaO-Al2O3-SiO2系统微晶玻璃烧结的影响.随着ZrO2加入量的增加,玻璃颗粒的烧结收缩率下降,说明ZrO2的加入对玻璃颗粒的烧结收缩有一定的阻碍作用.ZrO2的加入对CaO-Al2O3-SiO2系统微晶玻璃中的主晶相(β-硅灰石晶体)的析出没有大的影响.     

PbO-Fe2O3-V2O5-P2O5玻璃结构与性能研究

钒、铁磷酸盐玻璃作为一种半导体材料受到许多研究者的关注.选择了PbO-V2O5-P2O5、PbO-Fe2O3-P2O5和PbO-Fe2O3-V2O5-P2O5三组玻璃系统,研究了V2O5和Fe2O3对磷酸盐玻璃结构和性能的影响.通过红外光谱(IR)和差热分析(DTA)发现,V2O5和Fe2O3对磷酸盐玻璃结构的影响不同,Fe2O3不但会降低[PO4]基团的桥氧数,还会打断P=O双键,以[FeO4]形式参加网络结构,使玻璃结构趋于稳定.     

硫酸根离子对CaO-Al2O3-P2O5-SiO2体系耐水性的影响

研究了硫酸根离子对CaO-Al2O3-P2O5-SiO2体系耐水性的影响,通过XRD、SEM及孔结构分析手段对其耐水性机理进行分析。结果表明:在CaO-Al2O3-P2O5-SiO2体系中掺入适量的硫酸根离子,不会改变其主要水化产物的组成。浸水180d后,掺石膏的试件211S的耐水性指数较未掺石膏的试件211提高10.2%,劈裂强度提高6.7%,Ca2 、[AlO4]5-离子溶出浓度分别下降11.59%、7.2%,211S具有优异的孔结构。掺入硫酸根离子可以明显的提高该体系的后期强度和耐水性。     

PbO—Fe2O3-V2O5-P2O5玻璃结构与性能研究

钒、铁磷酸盐玻璃作为一种半导体材料受到许多研究者的关注。选择了PbO-V2O5-P2O5、PbO-Fe2O3-P2O5和PbO-Fe2O3-V2O5-P2O5三组玻璃系统,研究了V2O5和Fe2O3对磷酸盐玻璃结构和性能的影响。通过红外光谱(IR)和差热分析(DTA)发现,V2O5和Fe2O3对磷酸盐玻璃结构的影响不同,Fe2O3不但会降低[PO4]基团的桥氧数,还会打断P=O双键,以[FeO4]形式参加网络结构,使玻璃结构趋于稳定。     

ZnO-B2O3-P2O5系封接玻璃的研究

采用熔融法制备了ZnO-B2O3-P2O5系无铅磷酸盐封接玻璃,研究了组成对玻璃结构、特征温度、热膨胀和化学稳定性的影响.结果表明:B2O3和P2O5为玻璃网络形成体,ZnO含量较低时可以参与到玻璃网络结构中,提高玻璃的稳定性;玻璃转变点Tg、熔制温度Tm、封接温度Ts、软化点Td都随P2O5/B2O3减小而增加;B2O3/ZnO是影响玻璃熔制温度的主要因素;ZnO含量对玻璃密度和热膨胀系数影响较大.ZnO-B2O3-P2O5系玻璃在中性环境下的化学稳定性较好.     

Y2O3掺杂对Al2O3-SiO2-P2O5系统玻璃结构和析晶性能的影响

采用高温熔融冷淬法制备了Al2O3-SiO2-P2O5（ASP）系统玻璃,用原位晶化法获得了磷酸盐微晶玻璃;用IR、DSC、XRD、SEM等测试方法表征了玻璃结构及析晶性能,讨论了稀土Y2O3掺杂对ASP玻璃结构和析晶性能的影响。结果表明：Y2O3处于ASP的玻璃结构空隙中,起网络修饰体的作用,并未改变玻璃的基本结构,但Y^3＋离子会加强玻璃中P-O^-键的伸缩振动。当Y2O3的掺杂量少于1．5wt％时,随着Y2O3含量的增加,玻璃的稳定性增强,析晶活化能升高;引入量为1．5wt％时,玻璃的稳定性最好,析晶活化能最大,玻璃不易析晶;掺杂量多于1．5wt％时,稳定性开始下降,析晶活化能降低。少量Y2O3掺杂并未改变玻璃析出的晶相种类,析出的主晶相仍为AlPO4,次晶相为Mg3（CO4）2,但玻璃中加入适量的Y2O3会减少次晶相Mg3（PO4）2的析出量。     

整体法制备CaO—Al2O3-SiO2系统微晶玻璃晶核剂的选择

措助X射线衍射仪、扫描电镜等现代分析测试手段．分析研究在基础玻璃中加入不同的晶核剂,对整体析晶法制备CaO-Al2O3-SiO2。系统微晶玻璃晶化行为的影响。研究表明．CaF2能有效促进CaO-Al2O3-SiO2系统玻璃的整体析晶．形成以β-硅灰石为主晶相的微晶玻璃．晶核剂质量浓度不同对玻璃析晶的影响不同。     

P2O5含量对Al2O3-SiO2-P2O5系统玻璃结构和析晶性能的影响

采用高温熔融冷淬法制备Al2O3-SiO2-P2O(5ASP)系统玻璃,用原位晶化法获得了磷酸盐微晶玻璃;用IR、DSC、XRD、SEM等测试方法表征了玻璃结构及析晶性能,讨论了P2O5含量对ASP玻璃结构和析晶性能的影响。结果表明:P2O5含量在35～50%能形成稳定的ASP玻璃。在磷含量较低时,玻璃结构中的P5 主要以不含P=O双键的[PO4]四面体形式存在,P2O5含量较高时,结构中的P-O-键削弱,P=O双键加强,P5 部分以含P=O双键的[PO4]四面体形式存在。随着P2O5含量的增加,玻璃稳定性变差,析晶趋势增强;晶化后的玻璃以AlPO4为主晶相,同时含有少量的Al(PO)3晶相,当晶化温度由650℃升高到800℃时,晶相含量增加并出现YPO4晶相。     

CaO-Al2O3-SiO2系统微晶玻璃的冲蚀磨损研究

CaO-Al2O3-SiO2系统微晶玻璃装饰板材是一种新型建筑装饰材料。本文利用冲蚀磨损实验研究了影响CaO-Al2O3-SiO2系统烧结法微晶玻璃装饰板材磨蚀行为。讨论了微晶玻璃组成、结构、磨粒粒径、冲蚀角、冲蚀时间对CaO-Al2O3-SiO2系统微晶玻璃的冲蚀性的影响。结果表明:随着微晶玻璃中晶相含量的增加,磨料对其表面的冲蚀磨损量明显下降。微晶玻璃的冲蚀量随冲蚀角的增大、冲蚀时间的增长、磨粒粒度的增大而增加。     

CaO对CaO-Al2O3-SiO2微晶玻璃晶化过程活化能的影响

CaO对CaO-Al2O3-SiO2系统微晶玻璃的烧结及析晶性能有较大影响,从而影响了微晶玻璃的结构及性能.本文运用DTA、烧结收缩率分别测定了CaO-A12O3-SiO2系统微晶玻璃的烧结活化能及析晶活化能,研究了这两者的变化趋势.     

R2O对ZnO-Sb2O3-P2O5低熔玻璃性能的影响

借助IR、DTA等研究了碱金属氧化物R2O(R=Li,Na,K)对ZnO-Sb2O3-P2O5低熔玻璃结构及性能的影响。结果表明:不同种类碱金属氧化物的加入对玻璃的磷酸盐网络结构无明显影响,但K2O的引入提高了玻璃的转变温度(Tg)、软化温度(Ts)、析晶倾向和耐水性。R2O取代ZnO后破坏了玻璃的网络结构,导致玻璃的Tg及Ts温度和耐水性的降低,增加了玻璃的析晶倾向。在总碱量不变的条件下,借助混合碱效应,调节Li2O/(Li2O Na2O)摩尔比能够获得Tg及Ts温度更低的玻璃,同时耐水性也有所提高。对玻璃膨胀系数(α)的影响依次为K2O>Na2O>Li2O,且随R2O含量的增加而增加。此外混合碱效应对α的变化无明显影响。     

Oxide/oxide composites in the system Cr2O3-Y2O3-Al2O3

Ceramic compacts in the systems Al₂O₃–Y₂O₃, Cr₂O₃–Y₂O₃ and Y₃(Cr_yAl_1-y)₅O₁₂ (Cr-doped YAG) were prepared by solid state reaction in calcined co-precipitated powder mixtures of appropriate compositions. Various solid-solution phases were formed, e.g. Y₃(Al_1-xCr_x)₅O₁₂, YAl_yCr_1-yO₃ and Al_2-xCr_xO₃. Composite materials in the pseudo-binary or ternary systems Al₂O₃–Y₃Al₅O₁₂, Cr₂O₃–Y₂O₃ and Y₃(Al_1–xCr_x)₅O₁₂–YAl_yCr_1–yO₃–(Al_zCr_1−z)₂O₃ were obtained by hot-pressing appropriate powder precursors at 1600–1650°C for 1 h. The microstructure of the prepared materials was studied in a scanning electron microscope with element analysis facilities. X-ray diffraction was used to reveal the phases present and their lattice parameters. The chemical compatibility of these phases was investigated. The results are discussed with a special emphasis on the solubility of Cr in the YAG structure, and on the compatibility relationship between Cr-doped YAG and its neighbouring phases. A gel-coating process for preparing Al₂O₃–YAG composites with tailored microstructures is also described.     

Separation of Phases by Spinodal Decomposition in the Systems Al2O3−Cr2O3 and Al2O3−Cr2O3−Fe2O3

Separation of phases was investigated in the hexagonal (rhombohedral) systems Al₂O₃−Cr₂O₃ and Al₂O₃−Cr₂O₃−Fe₂O₃. The binary system shows a miscibility gap with a T_c of 950°C; the miscibility gap for the ternary system was determined for a constant Cr₂O₃ content of 16.6 mol%. Dark field transmission electron microscopy of solid solutions annealed within the miscibility gap showed dark and light lamellas ∼50 to 200 Å thick. X-ray diffraction results for the solid solutions in the ternary system indicated that, in the early stages of annealing, broadening occurred only on (hkl) reflections where l≠0. There was no major change in the X-ray diffraction patterns of the annealed solid solutions in the binary system. Electron diffraction results indicated, however, that phase separation in both systems proceeded in the [001] direction. Solid solutions in the binary system separated very slowly; the separation could be enhanced hydrothermally. The mechanism of the separation of phases in both systems is spinodal and proceeds as follows: solid solution→intermediate modulated phase→equilibrium phases.     

La2O3的添加对P2O5-Al2O3-SiO2系微晶玻璃性能的影响

以ZrO2为晶核剂,根据DSC图谱制定合理的热处理制度,制备了磷扩散源P2O5-Al2O3-SiO2系微晶玻璃。采用XRD分析观察了P2O5-Al2O3-SiO2系微晶玻璃的析晶状况,热膨胀仪测试了该微晶玻璃的膨胀系数,分析La2O3的含量对P2O5-Al2O3-SiO2系微晶玻璃在高温下释放P2O5速率的影响。结果表明:随着La2O3含量增加,P2O5-Al2O3-SiO2系微晶玻璃中晶体含量增加,主晶相未发生改变,都为磷酸锆晶体;同时,该微晶玻璃的热膨胀系数相对降低,P2O5的释放速率也随之增加。     

Crystallization of glass of the system K2O(Na2O)Al2O3SiO2

In a whiteware composition, the glassy phase derives from the molten feldspar in which a portion of quartz, clay and other crystalline constituents are dissolved. This glass is the major and continuous phase in the whiteware body and is the potential source of the crystalline phase, viz. mullite. Synthetic glass has been prepared by melting mixtures of feldspar and quartz comparable to whiteware-glass in composition. Glasses were also synthesized by melting mixtures of feldspar, quartz and mineralizers. All of these glasses were heat-treated and their mullite contents were estimated by X-ray analysis supported by TEM & SEM study. Among thirtyone (31) different mineralizers tried, only thirteen (13) are found to be effective mullite is builders. The cation of the mineralizer helps replacement of the Al³⁺ ion from the glass which subsequently diffuses through the residual SiO₂ and mullite is formed. The replacement reaction and hence the degree of mullitization is dependent on factors, e.g. charge, radius, field strength of the cation as well as on the cation-oxygen bond strength. This last appears as the most predominant factor for mullitization.     

Effect of Li2O on the crystallization behavior of CaO-Al2O3-SiO2-Li2O-Ce2O3 mold slags

The effect of Li₂O on the crystallization properties of CaO-Al₂O₃-SiO₂-Li₂O-Ce₂O₃ slags was investigated. With increasing the Li₂O content, LiAlO₂ and CaCeAlO₄ were the main crystalline phases. LiAlO₂ formed for the charge compensating of Li⁺ ions to [AlO₄^5?]-tetrahedrons, and CaCeAlO₄ formed as a result of the charge balance of Ce³⁺ ions, Ca²⁺ ions, and [AlO₆^9?]-octahedrons. Increasing the content of Li₂O to 10%, the crystallization temperature was the highest, and the incubation time was the shortest. The crystallization ability was strong due to the three factors of strengthening the interaction between ions and ion groups, decreasing the polymerization degree, and increasing the melting temperature. Further increasing the content of Li₂O, the crystallization performance was obviously suppressed, because the melting temperature and the force between the cations and the anion groups decreased.     

Refractory articles based on the ZrO2-Y2O3(Nd2O3)-Cr2O3 systems

The nature of interactions in compositions of stabilized ZrO₂—rare-earth chromite at 1750°C and the technical properties of specimens of zirconia-chromite refractories are investigated. It is shown that the use of induction melting for stabilizing the cubic modification of ZrO₂ is very effective if the material is intended for the production of conducting ceramics with high thermomechanical characteristics.Translated from Ogneupory i Tekhnicheskaya Keramika, No. 8, pp. 8–12, August, 1996.