氧化铝代替锆英砂的研究

随着锆英砂原料的价格上涨,如何用低成本的原材料取而代之,是目前很多企业所关注的问题。本文以氧化铝在瓷砖砖坯和化妆土中代替锆英砂进行研究,从产品的性能角度分析其可能性。实践证明,ARZ或AFRZ氧化铝在配方中完全替代锆英砂是可行的。     

ZrSiO_4和Al_2O_3粒度对制动摩擦材料摩擦磨损性能的影响

采用热压成型法制备有机制动摩擦材料,对所制备的摩擦材料进行摩擦磨损测试。研究填料硅酸锆和氧化铝的粒度对多纤维增强树脂基制动摩擦材料摩擦磨损性能的影响。研究结果表明,硅酸锆和氧化铝的加入可起到良好的增摩效果,随着填料粒度的细化,摩擦系数减小,但稳定性在粒度居中时最好,同时对磨损率也有一定影响。通过观察试样磨损后表面形貌探讨摩擦磨损机理。     

氧化铝-硅酸锆水成泥浆及流变性能

随着科学技术的发展，冶金铸造行业不仅要求材料具有耐高温性和抗磨损性，而且要求材料具有低膨胀性、高热震性和足够好的导热性等。具备这些性能的材料之一就是氧化铝－硅酸锆混合物。文中阐述了加入有机添加剂的氧化铝－硅酸锆水成泥浆（氧化铝：硅酸锆＝1：1）的pH值、粘度和流变性能。水成泥浆中氧化铝－锆英石混合物的流变性与泥浆浇注性能相关。文中还阐述了多孔模板浇注结果。     

微珠陶瓷材料的摩擦磨损性能

由高温摩擦磨损试验研究了复合莫来石(22.6%硅酸锆,75%莫来石,2.4%碳酸钙,质量分数)、硅酸锆和氧化铝3种陶瓷微珠材料在干摩擦和水润滑条件下的摩擦磨损性能,并对其磨损机理进行了分析.结果表明:3种材料的磨损均随着负荷的增加而加剧;在同等载荷下,水润滑条件相对于干摩擦,复合莫来石和硅酸锆的磨损都有所降低,氧化铝磨损反而加剧.在低载荷下,微珠磨损机理主要是塑性变形和微裂纹,在较高载荷下,主要磨损机理是脆性剥落和磨粒磨损.     

ZrSiO_4含量对Al_2O_3研磨球烧成及性能的影响

氧化铝陶瓷作为研磨介质时,具有强度高、耐磨、耐腐蚀等优点。研究者发现在氧化铝陶瓷中引入第二相氧化锆可进一步改善这些性能。本实验采用烧结法,在既有氧化铝研磨球配方的基础上加入硅酸锆引入第二相氧化锆,通过"粉体均匀混合球磨—生坯制备—烧成—性能测试分析"路线来研究第二相氧化锆的加入对研磨球的比重、磨耗的影响。结果表明在硅酸锆含量低的时候,适当的提高试样的烧结温度,有利于试样的烧结致密化。在硅酸锆含量大于10%时,硅酸锆的分解产物会与配方中的烧成助剂生成低共熔物,从而降低试样的烧成温度,有利于试样烧结致密化。     

建筑陶瓷放射性的原因分析、检测及对策

介绍了放射性的相关核物理知识和建筑陶瓷放射性对人体的危害,以及建筑材料放射性的检测原理、检测仪器和相关标准。通过分析建筑陶瓷产品放射性产生的原因,提出相应的对策:关键原料采购和使用的控制、对硅酸锆进行改性、用其他原料替代硅酸锆。     

硅酸锆粉体合成和涂层准备工艺分析

硅酸锆是一种形状为岛状结构的硅酸盐矿物,其具有高熔点、低热导率以及低膨胀系数等特点,而且还具有较好的化学稳定性,在高温结构陶瓷、耐火材料等制造领域有着重要的应用。对于自然环境下的硅酸锆粉体来说,其存在一定的缺陷和不足,在生产应用中一般都是使用合成硅酸锆粉体。硅酸锆粉体上的涂层具有较好的化学稳定性,较强的机械强度和抗微生物能力以及耐高温等特点,在腐蚀环境下对金属材料的表面具有很好的保护效果。笔者对硅酸锆粉体的合成工艺以及涂层的制备工艺进行了分析,并对相应的工艺和方法进行了研究。     

钴蓝影响硅酸锆发色的实验研究

针对钴蓝在不同添加量和不同细度对硅酸锆发色的影响进行实验,确定了添加量、细度与硅酸锆发色的关系。结果表明:钴蓝能显著改变硅酸锆的色调,使黄白色硅酸锆呈青白色,但却不能增加其白度,添加量过多反而会使亮度下降,影响白度;钴蓝细度的变化对硅酸锆发色无明显影响。添加微量的钴蓝可改变其色调,可拓宽硅酸锆的应用范围。     

不同制备条件对硅酸锆超细粉体水热法合成影响的研究

以正硅酸乙酯(TEOS)和氧氯化锆(ZrOCl_2·8H_2O)为原料,氟化锂为矿化剂,去离子水为溶剂,采用水热法制备硅酸锆粉体。研究了制备工艺中前驱体的Zr/Si摩尔比,前驱体溶液的pH值等因素对硅酸锆粉体合成的影响。并借助X射线衍射(XRD)、扫描电子显微镜(SEM)等测试手段对粉体进行表征。研究结果表明:前驱体中Zr/Si摩尔比影响着硅酸锆粉体的合成率,其最佳摩尔比为1.2∶1。前驱体溶液的pH值对硅酸锆粉体的合成有着重要的影响,pH值为9时最有利于合成硅酸锆粉体,此条件下所得粉体平均粒度大小在500~600 nm。     

硅酸锆和铬铁矿添加物对MgO-镁铝尖晶石耐火材料性能的影响

用于钢铁和水泥行业的六种合成镁铝尖晶石基的耐火材料合成物,它们以纯氧化镁和氧化铝近似1：1的比例为基础,分别添加0．5％、1．0％和2．0％硅酸锆和2．0％、3．0％和5．0％铬铁矿,采用两段烧结工艺于1760℃下进行烧结。分别研究这些合成物组分对密度、化学和矿物相组成方面的影响。研究结果显示：伴随镁铝尖晶石的生成游离方镁石在所有试样中均有出现。在加入硅酸锆试样的样品中,有高熔点相CaZrO3形成,以提高其密度和耐火性能,但要限制铝酸钙和硅酸钙相的形成。在所有试样中,添加硅酸锆均使体积密度增加。在含有铬铁矿添加物的试样中,Cr^3＋和Fe^3＋进入尖晶石晶格中替代A^3＋离子,不仅加速尖晶石的形成,同时还增加晶体的密度和晶体间直接结合。随着铬铁矿加入量的增多,试样体积密度隧之增大。     

Using polyfurfuryl alcohol to improve the hydrothermal stability of mesoporous oxides for reactions in the aqueous phase

Hydrodeoxygenation (HDO) of bio-oils derived from the pyrolysis of woody biomass is required to improve the stability and heating value of the liquid hydrocarbon products. Since pyrolysis produces bio-oils having up to 30 vol% water, HDO catalysts must not only be active and selective, but also stable under hydrothermal conditions associated with HDO upgrading. We investigated the effect of carbon coatings on a variety of silica, mixed zirconia-silica oxides and alumina. Surface area and porosity changes from exposure to controlled steaming conditions were used to evaluate the effectiveness of carbon coating on support stability. Systematic studies of the effects of the composition and structure of the carbon precursor, the inclusion of a zirconium modifier, the carbon loading and carbonization conditions led to the development of highly stable carbon modified zirconium silicate and mesoporous alumina supports that substantially maintain pore size distribution and surface area after steaming at 493 K with 23 bar of steam pressure.     

Hardening in Creep of Alumina by Zirconium Segregation at the Grain Boundary

The effect of zirconium segregation on hardening in the creep of fine-grained alumina was studied by using the tensile creep test. To avoid the effect of zirconia particle dispersion on creep, 100-ppm-zirconium-doped alumina and 1000-ppm-zirconium-doped alumina were fabricated by using a zirconium-containing precursor. The scanning transmission electron microscopy/energy-dispersive X-ray spectroscopy study revealed that the zirconium was segregated at the alumina grain boundary. Doping even as little as 100 ppm of zirconium caused the hardening effect. The creep rate was further reduced by increasing the amount of zirconium dopant. Although the stress exponent of 2 was not affected by zirconium segregation, the apparent activation energy of the creep was found to be increased, from 520 kJ/mol for undoped alumina to 670 kJ/mol for 100-ppm-zirconium-doped alumina and 760 kJ/mol for 1000-ppm-zirconium-doped alumina. It was suggested that grain-boundary sliding was accommodated by impurity-drag-controlled diffusional creep.     

硅酸锆放射性机理与改性的研究

初步分析了硅酸锆放射性的基本原理;探讨了硅酸锆的矿物形成、颗粒细度、百分含量、环境组成对放射性的影响;提出了复合乳浊法、溶胶-凝胶法、氧化剂吸收法、特种元素屏蔽法进行改性的技术途经;得出了通过控制硅酸锆细度、减少用量和改性处理,既可降低其放射性,并可被广泛应用的结论。     

Effects of zirconium silicate and chromite addition on the microstructure and bulk density of magnesia–magnesium aluminate spinel-based refractory materials

Six synthesized magnesium aluminate spinel-based refractory compositions used in steel and cement applications, were prepared using a two stage sintering process at 1760 °C, starting with approximately 1:1 wt% ratio of pure magnesia and alumina with additions of zirconium silicate (0.5, 1.0 and 2.0 wt%) and chromite (2.0, 3.0 and 5.0 wt%). These compositions were investigated for effects on densification, chemical and mineralogical phases formed.     

Increase in Phase Transition Temperature of Activated Alumina with Nano-Zirconia Synthesized by Pulsed Wire Discharge

Activated alumina powders have been synthesized by using a novel dry process of pulsed wire discharge. The temperature of phase transition from activated alumina to α-alumina and its variation caused by adding zirconia have been investigated. A mixture of activated alumina and zirconia was formed by mixing zirconium plasma with aluminum plasma and cooling together in an oxygen atmosphere. It was found that the transition temperature increased when the zirconia content ratio was increased. On the other hand, results of X-ray diffraction and X-ray photoelectron spectroscopy analysis indicated no substitution of zirconium in an alumina lattice. Thus, most of the zirconium atoms were located in zirconia particles on the surface and/or the grain boundary of alumina grains. Thus, it appears that the increase in the phase transition was caused by retardation of atomic diffusion at zirconia particles.     

硅酸锆的超细粉碎及其对釉料遮盖力的影响

本文阐述了硅酸锆在釉料中产生乳浊的机理．比较了国内外几种不同粒度分布的硅酸锆在釉层中的遮盖力，并探讨了使用国产设备粉碎硅酸锆的优缺点。     

Effect of the thermal treatment on the phase composition of the surface of coatings based on Si–B–ZrB<Subscript>2</Subscript> and modified with ZrO<Subscript>2</Subscript> fibers

Coatings on graphite that are stable to oxidation and based on the silicon–boron–zirconium boride composite containing from 5 to 50% of fibrous zirconium dioxide as a modifying dopant have been produced by the suspension–annealing method. A nonporous layer is formed at the zirconium dioxide content ranging from 5 to 15%, while a porous layer is formed at its 50% content. A glass-forming melt, as well as zirconium dioxide and silicate, is formed during thermal treatment as a result of the chemical reactions with the oxygen in air. The zirconium silicate content increases, along with the modifier’s concentration and temperature.     

Influence of heat-stable filler on the thermal shielding performance of water-based intumescent fire-resistive coating for structural steel applications

Intumescent coatings are the newest passive fireproofing materials which maintain structural integrity of high-rise buildings in fire events. The present work focuses on the influence of zirconium silicate as a heat-stable filler in intumescent coatings. Different coatings were formulated by varying the zirconium silicate concentration from 1, 3, 5, 8, and 10 on parts per hundred basis (phr). Fire performance of the coatings was then determined by fire test using a Bunsen burner fire flame at 950°C for 1 h. The degradation of coatings was examined by thermogravimetric analysis (TGA). The morphology of the intumescent chars was analyzed by environmental scanning electron microscopy. The char was also examined by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy. XRD confirmed the inertness of zirconium silicate with intumescent ingredients at high temperatures. TGA showed an increase in the weight residue of char at high temperature. The incorporation of zirconium silicate into intumescent coating forms a thermally stable char with better substrate adhesion. EDS analysis confirmed an increase in the antioxidation property of the char, and the fire test also confirmed an increase in char strength of coatings by the incorporation of zirconium silicate.     

陶瓷乳浊剂硅酸锆的研制

本文论述了陶瓷乳浊硅酸锆超细粉的质量指标,以及影响遮盖力的几个主要因素。比较了不同方法生产硅酸锆的优缺点。