ZrSiO_4和TiO_2对铝硅系耐火材料抗热震性的影响

研究了ArSiO4（锆英石）、TiO2（铁白粉）加入物对铝硅系耐火材料抗热震性的影响及其作用机理。认为ZrSiO4、TiO2提高材料抗热震性的机理在于微裂纹增韧以及第二相（钛酸铝）降低了材料的热膨胀系数。     

“莫来凯特”物相分析及热膨胀机理研究

本文分析了“莫来凯特”的物相组成，根据复合物相的热膨胀系数的计算方法，从理论上计算了“莫来凯特”的热膨胀系数，并与熟矾土相比，论述了“莫来凯特”低热膨胀机理，从而阐明了“莫来凯特”的高抗热震性能。     

“莫来凯特”牺分析及热膨胀机理研究

本文分析了“莫来凯特”的物相组成，根据复合物相的热膨胀系数的计算方法，从理论上计算了“莫来凯特”的热膨胀系数，并与熟矾土相比，论述了“莫来凯特”低热膨胀机理，从而阐明了“莫来凯特”的高抗热震性能。     

低热膨胀系数堇青石材料的合成研究

以高岭土、烧滑石和氧化镁为原料合成堇青石,研究了烧成温度、镁铝硅含量及高岭土种类对合成堇青石热膨胀系数的影响。实验结果表明:合成堇青石的最佳配方1#高岭土82.4 wt%、滑石9.3 wt%、氧化镁8.4 wt%,试样热膨胀系数为1.24×10-6℃-1。适当的提高烧成温度可得到热膨胀系数低的堇青石材料,但合成温度过高则会因为形成过多的玻璃相而使其热膨胀系数增大。过多或过少的引入Si O2、Al2O3、Mg O均会由于形成高热膨胀系数的晶相而导致所合成堇青石的热膨胀系数增大。     

ZrSiO4颗粒/Ca0.6Mg0.4Zr4P6O24基复相陶瓷的烧结行为及力学性能

本文对ZrSiO4颗粒/Ca0.6Mg0.4Zr4P6O24基复相陶瓷的烧结行为及力学性能进行了研究.发现引入ZrSiO4相,可促进Ca0.6Mg0.4Zr4P6O24基陶瓷的烧结,并抑制主晶相的晶粒长大.在Ca0.6Mg0.4Zr4P6O24中引入10vol%ZrSiO4,可获得一种具有较高抗弯强度(197MPa)和较低热膨胀系数(1.54×10-6/℃)的NZP基复相陶瓷材料.     

R_2O_3(R=Al,B)对含磷硅酸盐乳浊玻璃显微结构和热膨胀行为的影响

采用传统的熔融法制得了含P_2O_5的硅酸盐乳浊玻璃,利用XRD、SEM和EDS等手段研究了玻璃乳浊机理和微观结构,并且讨论了Al_2O_3和B_2O_3相对含量对显微结构和热膨胀系数的影响.结果表明:采用P_2O_5为乳浊剂,可以得到乳浊效果明显的硅酸盐系统乳浊玻璃,玻璃的乳浊是由亚稳分相的不稳分解造成的;用3wt% B_2O_3取代Al_2O_3后,玻璃试样析出少量晶体,第二相颗粒的尺寸变得不均匀,热膨胀系数变大.     

莫来石-磷酸锆复相陶瓷材料性能的研究

本文研究了在莫来石中添加低膨胀第二相磷酸锫的莫来石-磷酸锆复相陶瓷的性能,找到了在保证强度的同时,获得较低热膨胀系数的莫来石-磷酸锆复相陶瓷的制备方法.实验表明：莫来石-磷酸锆复相陶瓷能通过将莫来石粉料与磷酸锆粉料或莫来石粉料与磷酸锆生料粉按不同质量比混合烧结制备;加入1wt％的MgO作为烧结助剂,在1350℃烧成的样品具有最低的热膨胀系数和较小的吸水率.     

陶瓷纤维增强堇青石质陶瓷材料的研究

为了制得热膨胀系数小、力学性能好的优质堇青石质陶瓷材料,以粒径≤0.074 mm的黏土、d_(50)=1μm的SiO_2微粉和≤0.074 mm的轻烧MgO为原料,按照堇青石的理论组成进行配料,外加质量分数10%的硅酸铝陶瓷纤维或多晶莫来石纤维,采用挤出方式成型,分别于1 250、1 300和1 350℃保温3 h制得堇青石质陶瓷材料。采用国标检测了试样的常温物理性能和热膨胀系数,采用X射线衍射仪和扫描电镜对试样的物相组成和显微结构进行了分析。结果表明:1 350℃保温3 h制得的堇青石质陶瓷材料的热膨胀系数较低,力学性能较好;试样以堇青石相为主晶相,堇青石相在引入的硅酸铝陶瓷纤维表面生成且基本呈定向分布。     

添加剂对堇青石合成温度及热膨胀系数的影响

采用煤系高岭土、滑石、镁砂为原料合成堇青石,主要探讨了添加剂对合成堇青石的性能影响。通过X-Ray衍射(XRD)分析,用K值法求算合成堇青石矿物相含量,在保证矿物相含量的前提下,探讨添加剂对热膨胀系数的影响。研究结果表明:添加剂的使用均能降低合成堇青石的热膨胀系数,不加添加剂的热膨胀系数为2.04×10-6/℃(20～1100℃);加入碳酸钡热膨胀系数为α=1.84×10-6/℃(20～1100℃);加入碳酸锂热膨胀系数为α=1.86×10-6/℃(20～1100℃)。     

TiO2对堇青石多孔陶瓷性能的影响

目前,在堇青石多孔陶瓷的研究中,如何进一步降低其热膨胀系数仍是国内外研究的重点。热膨胀系数的降低途径很多,引入添加剂是其中一种非常有效的方法。常用的添加剂有钛酸铝(直接引入或者外加TiO2和Al2O3合成)、锂辉石及氧化锆等,而关于TiO2影响热膨胀系数的文献则极少。本工作     

Thermal-Expansion Anisotropy of Oxide Solid Solutions

The effect of solid-solution atoms on the thermal-expansion anisotropy of some oxides has been studied as part of a program directed toward the prediction of the thermal-expansion coefficients of single crystals and single-phase and polyphase ceramic bodies. The importance of solid-solution atoms in determining the thermal-expansion anisotropy of rutile, SnO₂, corundum, and Cr₂O₃ solid solutions has been demonstrated. Vanadium additions to rutile are particularly effective in reducing thermal-expansion anisotropy. The thermal-expansion anisotropy was determined by X-ray diffraction techniques in the temperature range room temperature to 1000°C. Information relating to the extent of solid solution of vanadium in rutile is presented. Research in this area may be important because reduction of thermal-expansion anisotropy can prevent the formation of microcracks in ceramic bodies, thus leading to stronger bodies.     

Slag Resistance Mechanism of Lightweight Microporous Corundum Aggregate

The microstructures of the reaction interfaces between slag and corundum aggregates, microporous corundum produced in the laboratory and tabular corundum were observed after slag resistance experiments, and their associated slag resistance mechanisms were investigated. A continuous isolation layer was observed around the microporous corundum, which showed a significantly better slag resistance than tabular corundum. The formation of columnar crystals of CaAl₁₂O₁₉ (CA₆) and CaAl₄O₇ (CA₂) in the isolation layer was the main reason for the difference in slag resistance. With respect to the nucleation and growth of second phase, the slag resistance mechanism of lightweight microporous corundum was explored by thermodynamic and kinetic analysis. Due to its smaller pore size, the second phase is more likely to achieve supersaturation, and large quantities of crystal nuclei are generated for microporous corundum. The critical dissolved depths of the microporous and tabular corundum in saturated slag were calculated to be 0.14 and 0.27 μm, respectively. Additionally, the small pore sizes lead to an increase in the Ostwald ripening rate of the second phase, and the Ostwald ripening rate of microporous corundum was 12 times that of the tabular corundum based on Ardell's theory.     

第三相的加入对气液传质过程的影响

系统地介绍了气液传质过程中,固体小颗粒或第二分散液相(有机相)所形成的第三相的加入对传质过程的影响.分别论述了在不同的气-液接触器(搅拌釜、鼓泡塔)中,固体小颗粒和第二分散液相的加入对体系的传质系数、传质速率及界面面积等的影响,叙述并讨论了传质机理及模型的最新进展.     

SHS转炉补炉料的物相组成及显微结构特征

利用自蔓延高温合成(SHS)原理,选择工业铝粉作为发热剂,菱镁矿为供氧剂,通过铝热反应,研制出了一种以镁砂为骨料,以镁铝尖晶石和炭质材料作为结合相的新型SHS转炉补炉料.对不同环境温度下补炉料的物相组成及显微结构进行了研究,并对合成尖晶石的固相反应原理及SHS产物相的烧结机制进行了探讨.结果表明补炉料中颗粒状的骨料方镁石与SHS反应产物尖晶石、非晶质碳、少量刚玉相和硅酸盐玻璃相共同构成含有气孔的交织结构,形成尖晶石、碳桥和陶瓷相与方镁石骨料的多重结合;SHS反应过程分碳酸盐矿物的分解反应、铝热氧化还原反应(即SHS反应)和合成尖晶石的固相烧结反应三步进行,其烧结受扩散机理控制.     

钢塑复合管的热补偿设计

从管道的热致伸缩和受力分析人手，理论分析了钢塑复合管道的复合弹性模量和复合膨胀系数，得出其与管材结构、几何尺寸和材料特性之间的函数关系，并以此为基础指导了钢塑复合管道工程应用中的热补偿设计。其方法和结论适用于各种结构和材料的复合管道。     

Preparation and Properties of a New Mediumdensity and High-strength Ceramic Proppant

Based on the needs of the market,a new 52 MPa medium-density and high-strength ceramic proppant was prepared by adopting third grade bauxite and clay as raw materials and using the solid phase sintering method,and the effect of the firing temperature on the microstructure,phase composition and mechanical properties of the ceramic proppant was studied. The broken resistance mechanism of this ceramic proppant was also discussed. The results show that the main phases of the prepared ceramic proppant are mullite and corundum; the broken rates are 3. 92% and 7. 21% under 52 MPa and69 MPa,respectively.     

Diffusion-thermal stability of gas filtration combustion waves in an inert porous medium

A mathematical model for the filtration gas combustion taking into account thermal conductivity, diffusion, and intense interfacial heat transfer is presented. The temperature dependence of the chemical reaction rate is approximated by a δ-function and the thermal-expansion coefficient of gases behind the combustion front is taken into account. Unsteady combustion regimes are analyzed using the method of small perturbations. The boundaries of the longitudinal and spatial stability for steady regimes of the filtration combustion wave are obtained. The dependence of the Lewis number on the thermal-expansion coefficient of the gas mixture along the boundary of stability is derived, along with other relations.     

攀钢高炉钛渣对出铁沟用耐火骨料侵蚀的相图热力学模拟分析

选取高炉出铁沟耐火材料常用的5种骨料(分别为棕刚玉、电熔刚玉、亚白刚玉、富铝尖晶石和特级矾土,粒度均为5～10 mm)和攀钢高炉钛渣(w(TiO2)=26%)作为研究对象,通过相图热力学计算和静态坩埚侵蚀试验对比研究,探讨了攀钢高炉钛渣条件下出铁沟耐火骨料的选择.热力学计算表明,电熔刚玉具有良好的抗钛渣侵蚀能力,而特级矾土骨料被侵蚀后形成的新渣相黏度高,有利于阻止渣对耐火材料的进一步渗透;而静态坩埚试验结果难以反映和判断材料高温下侵蚀的反应过程.因此,相图热力学计算技术可作为分析耐火材料侵蚀情况的可靠方法和手段.     

Determination of Residual Stresses in Titanium Carbide-Base Cermets by High-Temperature X-Ray Diffraction

The crystal structure and thermal expansion of titanium carbide, nickel, and two titanium carbide-base cermets were determined between room temperature and 1100°C. (2012°F.). No structural changes were observed. An abnormal rate of expansion was observed for pure nickel near the Curie temperature, 353°C. (665°F.), and for the nickel and carbide phases in the cermets at about 816°C. (1500°F.). The expansion coefficient of pure nickel and the nickel phase in the cermets was found to be approximately twice that of pure titanium carbide and the carbide phase in the cermets. The brittleness and poor impact strength of the cermets was attributed to the large residual stresses present in these materials as a result of this difference in thermal expansion. The stress-strain relations were interpreted on the basis of a mechanical interaction between the phases in the cermets. The carbide phase was found to be essentially under triaxial compression and the nickel phase under a triaxial tension of 158,000 lb. per sq. in. At elevated temperatures, increased solid solubility of carbide in the nickel phase and plastic deformation of this phase was believed to influence the stress-strain relations and the thermal-expansion behavior of the phases. It was concluded that replacement of the nickel phase in the cermets with a metal or alloy, such as a nickel-chromium-molybdenum alloy, which has a coefficient of thermal expansion similar to the carbide phase in the cermets, would improve the impact strength of these bodies. Equations were developed for the thermal expansion of titanium carbide and nickel. Values of the expansion coefficient were computed for each of the materials by differentiation of these equations.     

粉煤灰资源化合成莫来石材料及其性能研究

以天然铝矾土和工业废物粉煤灰为原料,运用反应烧结合成了低成本的莫来石陶瓷材料。结果证明,刚玉与方石英相在1200～1300℃间通过固态反应生成二次莫来石,在温度高于1300℃时,刚玉相熔于短暂玻璃相中。二次莫来石化及莫来石晶体生长所导致的样品体膨胀大于液相烧结所引起的收缩,导致样品出现膨胀现象。1600℃烧结样品的平均热膨胀系数为5.40×10-6℃-1,平均抗弯强度186.19 MPa。莫来石在强酸强碱热溶液中表现出两个阶段:快速阶段(0～5h)和低速阶段(5～20h),这分别对应于样品的表面腐蚀和体腐蚀过程。