水热法制造氧化锆系超微粒子

日本新技术开发事业团选定水热法制造氧化锆系超微粒子研究课题,并委托秩父水泥公司。这次开发的新技术是使用氧氯化锆为原料,用氯化钇、尿素为沉淀剂,混合溶液在160～220℃、50～70大气压的高温、高压下进行水热反应,制得超微细二氧化锆微粒。通过控制原料混合比,水热反应条件     

水热法制备球形二氧化锆粉体的研究

以氯氧锫为前躯体通过水热法制备出了粒径在5μm左右,粒度分布均匀的球形二氧化锆粉体.研究结果表明水热温度、水热时间以及醇水比例对产物的微观结构均有影响.140℃水热处理24h获得产物为无定型态的氢氧化锆粉体,而200℃水热处理24h可获得单斜和四方混相的二氧化锆粉体.随水热时间的延长,产物相结构经历了由无定型氢氧化锆向单斜与四方混相的二氧化锆转变,相转变机制则经历了由均匀饱和析出机制到溶解沉淀为主、原位结晶为辅机制再到原位结晶为主、溶解沉淀为辅机制的变化过程.     

二氧化锆制备技术进展及发展趋势

本文在介绍锆英石分解制二氧化锆的工业生产方法及进展后，认为生产作为结构材料使用的二氧化锆之传统工艺，应设法降低成本，其中等离子体法和电熔法最具发展潜力；同时指出，为适应功能材料的发展需要，应加快开发制备高纯、超细、稳定二氧化锆的工艺方法。     

乙胺-水体系中水热法制备纳米二氧化锆

利用乙胺对二氧化锆胶粒表面的修饰作用 ,降低胶粒的表面张力 ,避免胶粒的团聚 ,在乙胺 -水体系中用水热法制备出比表面积达到 4 5 9m2 ·g-1的二氧化锆 ,产物在水热反应温度达到 180℃时晶化为四方型二氧化锆 ,产物粒径 5 0～ 70nm ,粒径分布窄。由于乙胺对二氧化锆表面的修饰作用 ,水热反应温度不显著影响产物的比表面积和粒度分布。     

陶瓷和耐火材料用的含锆材料的制取

以不同质量二氧化锆为原料生产各种陶瓷制品和耐火制品，并制定出生产工艺。这种二氧化锆系利用柯夫多尔斯克矿业公司精选斜锆石时的尾矿制取，其质量符合国家标准FOCT 21907-76的要求。     

纳米二氧化锆悬浮液分散稳定性研究

纳米二氧化锆悬浮液分散稳定性是一个十分重要的问题。通过测定纳米二氧化锆悬浮液的ξ电位和吸光度，探讨了不同pH、不同表面活性剂种类和浓度对纳米氧化锆水相体系分散性的影响，并分析其作用机理。发现在阴离子和非离子复配表面活性剂中分散稳定性最好，体系ξ电位绝对值较高。氧化锆水相体系的等电点（IEP）在pH=6附近，在pH为2-3附近具有较大的正电位，在pH为9-11附近具有较大的负电位。     

以锆英砂制取镨黄颜料

江苏省陶瓷研究所研制了以锆英砂代替二氧化锆制取镨黄颜料获得成功。已通过技术鉴定。国内生产陶瓷用无机颜料镨黄一直采用价格昂贵的二氧化锆等原料来制取,存在原料供应紧张、成本高及半成品损耗大等问题。现以廉价的锆英砂代替二氧化锆生产镨黄颜料。其工艺简单、烧成温度低,节     

用锆英石制氧氯化锆

1 前言氧氯化锆的分子式为 ZrOCl_2·8H_2O,它是生产二氧化锆的中间产品,用于耐火材料、陶瓷和釉的处理、纤维处理,还用于催化剂、固色剂、助染剂、防水剂、橡胶添加剂、涂料干燥剂等。近几年,由于新型材料精细陶瓷的兴起,许多国家都竞相开发二氧化锆的生产和应用,尤其是超纯、超细的半稳定氧化锆(PSZ)。目前日本、美国、澳大利亚、英国等国家所开发二氧化锆的生产方法几乎都是以氧氯化锆为中间产品。这样使氧氯化锆的市场需求量增大。     

二氧化锆:一种多用途的高性能新材料

二氧化锆作为结构材料和功能材料具有许多优良的性能,例如高硬度、高熔点、高介电常数等物理性能以及出色的化学和热稳定性,因此被广泛应用于结构陶瓷、功能陶瓷、核技术以及生物医学等领域,形成如切削及抛光工具、氧传感器、固体氧化物燃料电池、高温加热元件、牙齿等诸多新材料。氧化锆的多种结构、多种制备工艺技术使得其性能及应用多样化,本文综述了二氧化锆的晶型结构特征、锆资源现状、锆精矿生产二氧化锆的方法、二氧化锆材料主要应用等,具体包括:总结了以锆英砂为原料制备二氧化锆粉体的碱熔制备法、氯化法、电熔法、等离子法等几种常见方法;介绍了氧化锆在合成宝石、陶瓷、耐火材料、催化材料、膜材料、核级锆及锆合金等领域的应用。作为一种高性能的多用途新材料,进一步深入研究二氧化锆及相关材料的微观结构和性能特征,开发环保无污染、成本低廉、质量优良且利于大规模生产二氧化锆的工艺技术,为二氧化锆相关新材料在更广阔的领域上的开辟应用新天地,仍将是今后研究 的重点。     

锆化合物的生产,应用及发展

主要介绍了锆化合物氯氧化锆、二氧化锆的生产、应用及发展方向,并结合材料科学的发展论述了我国开发高纯超细二氧化锆粉体的重要性。     

Hydrothermal Zirconia Powders: A Bibliography

This paper provides references for zirconia powder processing, especially hydrothermal processing and for the properties of hydrothermal zirconia.     

水热法制备ZrO2及其复合粉体的研究进展

随着电子和新材料工业的发展,纳米氧化锆及其复合粉体的应用越来越广泛.与纳米ZrO2传统湿化学制备方法相比,显示了水热法制备的优点.水热法包括水热晶化、水热沉淀、水热氧化和微波水热等.论述了水热法制备纳米ZrO2及其复合粉体的各种方法及研究进展,指出了水热法发展方向及所需解决的问题.     

The preparation and surface characterization of zirconia polymorphs

Zirconium hydroxides were obtained by precipitation of zirconium chloride with aqueous ammonia at constant pH followed by hydrothermal treatment The effect of thermal activation of the zirconium hydroxide on physical properties, and the effect of crystalline phase on the surface properties of zirconia were studied. The pressure during the hydrothermal treatment of zirconium hydroxide affected the surface area, particle growth, and phase transformation of the zirconia product. Hydrothermally treated zirconia under atmospheric pressure (LP) shows higher surface area than that under high pressure (HP) and untreated (UT). HP zirconia shows a mixture of tetragonal and monoclinic phase after hydrothermal treatment due to the higher solubility and reprecipitation rate, whereas LP sample shows a tetragonal crystal structure from 600 to 1,050 ℴC. Monoclinic phase zirconia shows greater CO₂ and NH₃ surface adsorption than amorphous and tetragonal phase zirconia. This suggests that the crystal structure of zirconia strongly affects the amount and strength of the surface adsorption site.     

氧化锆的水热合成及其应用研究进展

介绍了水热合成氧化锆的发展历程以及水热法制备氧化锆的特点和发展趋势。水热合成是一种合成氧化锆的重要方法,自发明以来就是该领域的研究热点。同时,介绍了氧化锆在陶瓷增韧、催化剂及载体、离子导电和生物等方面的应用。由于氧化锆的优异性质,其应用范围将越来越广阔。     

Ageing-resistant zirconia/graphene-based nanostructures composites for use as biomaterials

This work explores the incorporation of graphene-based two-dimensional nanostructures as moisture barriers to delay hydrothermal ageing of yttria-stabilized zirconia and strengthen its use in biomedical applications. Two sets of highly dense zirconia composites incorporating multilayered graphene with very different lateral dimensions, few layer graphene and exfoliated graphene nanoplatelets, were prepared. The effect of the addition of graphene nanostructures on zirconia ageing was investigated by conducting accelerated hydrothermal degradation experiments in an autoclave. An improved resistance to low-temperature degradation and a high tolerance to damage were achieved in the composites compared to those of monolithic zirconia. The incorporation of 1 vol% multilayered graphene was very effective in restricting the hydrothermal degradation. In particular, the composite incorporating exfoliated graphene nanosheets exhibited outstanding resistance to ageing because of their fine dispersion throughout the matrix, which effectively seemed to restrict grain growth and slow the propagation of the transformation front to the ceramic bulk.     

球形四方相氧化锆的水热法合成与表征

以氧氯化锆为原料，尿素为矿化剂，氧化钇为稳定剂，水和乙醇为反应溶剂，结合一步水热的方法，在不添加表面活性剂以及不经过煅烧的前提下，通过改变水热温度、水热时间、醇水比以及氧化钇添加量等条件探究了球形四方相氧化锆的形成机理，制备了结晶性好、粒度分布均匀以及球形度高的四方相氧化锆粉体。     

Effect of the properties of hydrous zirconia prepared under various hydrothermal conditions on the isomerization activity of Pt/WO3-ZrO2

A series of hydrous zirconia samples were prepared by hydrothermal method and the effects of the properties of hydrous zirconia on the catalytic activity of Pt/WO₃-ZrO₂ in the hexane isomerization were investigated. The catalysts were characterized by X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and differential thermal analysis (TDA), H₂-temperature programmed reduction (H₂-TPR) and NH₃-temperature programmed desorption (NH₃-TPD). The results showed that the hydrothermal treatment under different times and pH values led to remarkable changes in the properties (such as hydroxyl group, ordering degree and thermal stability) of hydrous zirconia. Moreover, the isomerization activity of Pt/WO₃-ZrO₂ varied distinctly with the hydrothermal treatment condition of hydrous zirconia. The correlation between the properties of hydrous zirconia and the isomerization activity of the catalyst was primarily established. It was proposed that the isomerization activity was strongly dependent on the stability and ordering degree of hydrous zirconia, while it was irrelevant to the amount of hydroxyl groups in hydrous zirconia.     

Modified hydrothermal treatment route for high-yield preparation of nanosized ZrO2

Nanosized ZrO₂ particles are applied in high-performance thermal barrier coatings and catalyst carriers. To synthesize nanosized zirconia, precipitation from aqueous solutions followed by hydrothermal treatment is widely conducted. In this work, a modified hydrothermal treatment route is described for high-yield fabrication of well-dispersible nanosized t–ZrO₂. Zirconium oxychloride and sodium hydroxide were used as the precursor and precipitant, respectively. N, N-bis(2-hydroxyethyl) glycine (bicine) was used as surface stabilizer to inhibit the early agglomeration of nuclei, and ultrasonication was used to enhance the dispersion of ZrO₂ nanocrystals. The hydrothermal treatment was optimized for reaction temperature, time, fill fraction, and solid content. The synthesized zirconia was characterized using X-ray diffraction, dynamic light scattering, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The yield of zirconia increased to 134 g/L after hydrothermal. Tetragonal ZrO₂ obtained with hydrothermal treatment at 200 °C for 8 h at a fill fraction of 80% has a good dispersibility, with an average particle size of 20 nm and a narrow size distribution.     

Formation of Ultrafine Tetragonal ZrO2 Powder Under Hydrothermal Conditions

Ultrafine tetragonal ZrO₂ powder was prepared by hydrothermal treatment at 100 MPa of amorphous hydrous zirconia with distilled water and LiCl and KBr solutions. The resulting powder consisted of well-crystallized particles; at 200°C, the particle size was 16 nm and at 500°C, 30 nm. Under hydrothermal conditions tetragonal ZrO₂ appears to crystallize topotactically on nuclei in the amorphous hydrous zirconia.     

Effect of hydrothermal aging on dental multilayered zirconia for monolithic restorations: An in vitro study

The aim of this in vitro study was to investigate the changes in mechanical, optical, and surface properties of multilayered zirconia during hydrothermal aging.One conventional block (Katana Zirconia HT) and three multilayered blocks (Katana Zirconia ML, STML, and UTML) of monolithic zirconia were examined. Bar-shaped specimens were autoclaved at 134°C and 0.2MPa for 0, 5, and 10 h. The Young's modulus, three-point flexural strength, and nanoindentation hardness were measured to evaluate the mechanical properties. The surface roughness, phase distribution, surface microstructure, and elemental composition were measured to analyze the surface properties. The contrast ratio and total transmittance were measured via spectrophotometry to evaluate the optical properties. Statistical differences were analyzed using appropriate ANOVA, Tukey HSD post hoc tests, and independent and paired sample t-tests (α = .05).The monoclinic phase increased gradually after hydrothermal aging. The yttrium and zirconium concentrations decreased, and the oxygen concentration and the surface roughness increased in all specimens (P<.05) after the aging process. All specimens showed significant grain push-out and microcracks. The total transmittance increased, and the contrast ratio and Young's modulus decreased in all specimens (P<.05) after the aging process. The nanoindentation hardness and three-point flexural strength exhibited a decreasing tendency after the aging process. However, there were no statistical differences (P>.05) between the materials. Significant interactions between material grades and hydrothermal aging were found for all the properties studied (P<.001).Microstructural alterations and significant phase transformations were detected on the surface of the multilayered zirconia after hydrothermal aging. The hydrothermal aging led to increased surface roughness, opaqueness, and elasticity of multilayered zirconia. The optical, mechanical, and surface properties of multilayered zirconia were influenced by the grade of the material after hydrothermal aging. Careful consideration of the grade of materials is necessary for the appropriate selection of multilayered zirconia ceramics for monolithic restorations.