ZrO2-Al2O3-TiC纳微米复合陶瓷模具材料的研究

以钇稳定四方氧化锆(Y-TZP)、Al2O3、纳米级的TiC为主要原料,采用真空热压烧结工艺,制备了ZrO2-Al2O3-TiC纳微米复合陶瓷模具材料.研究了该材料的力学性能和微观结构.研究结果表明:当TiC含量为20vol%,Y2O3含量为3mol%时,制备的ZrO2-Al2O3-TiC复合陶瓷模具材料具有良好的力学性能.抗弯强度、断裂韧性和硬度分别达到824 MPa、10.7 MPa·m1/2和11.67 GPa.晶粒细化、穿晶断裂、颗粒桥联、裂纹偏转和相变增韧是主要的增韧补强机理.     

低温烧结法制备4Y—ZrO2增韧高铝瓷

研究了添加4Y－ZrO2对烧结法制备高铝瓷力学性能的影响,发现通过添加适量的4Y－ZrO2,可以最大限度地使基质中的氧化锆以亚稳四方相形式存在,通过四方到单斜的相变同时使韧性和强度得到提高。     

ZrO2-A12O3纳米复合陶瓷条梁的研究

以工业氢氧化铝微粉为原料,添加ZrO2纳米粉、粘土等。研究了利用ZrO2相变和纳米微粉的效应,对氧化铝复合陶瓷增强、增韧和力学特征进行了探讨。     

ZrO2增韧陶瓷的研究进展

综述了ZrO2陶瓷及添加氧化物稳定剂对四方相氧化锆的稳定性影响，以及ZrO2陶瓷材料的种类，增韧机理及其主要应用领域，并展望了氧化锆增韧陶瓷的研究发展趋势。     

纳米ZrO2对Al2O3陶瓷性能的影响

以纳米ZrO2,微米Al2O3为原料,采用无压烧结方式制备了ZTA复相陶瓷.结果表明:纳米ZrO2的加入有利于制备细晶ZTA复相陶瓷.此外,nano-ZrO2的加入对Al2O3陶瓷的显微结构也产生影响,ZrO2颗粒以"晶内型"和晶界型2种形式存在.合理的配方组成及制备工艺有利于ZrO2以四方亚稳相存在.ZrO2质量分数为30%时,其四方相质量分数可达69%,有利于应力诱导相变增韧,该ZTA复相陶瓷的抗弯强度、断裂韧性分别达到604MPa,6.87MPa·m1/2.     

ZrO2-Al2O3复相陶瓷的研究

采用工业ZrO2,Al2O3为原料,通过适当的工艺制备出ZrO2-Al2O3复相陶瓷.研究结果表明:添加Al2O3可有效地抑制ZrO2晶粒的生长,有利于使ZrO2晶粒以亚稳四方相存在,从而提高材料的强度与断裂韧性.Al2O3质量分数为20%时,复相陶瓷的抗弯强度、断裂韧性分别为676.7MPa,10MPa*m1/2.相变增韧与颗粒弥散增韧作用相互叠加提高了复相陶瓷材料的力学性能.     

ZrO_2—Al_2O_3纳米复合陶瓷条梁的研究

以工业氢氧化铝微粉为原料,添加ZrO2纳米粉、粘土等。研究了利用ZrO2相变和纳米微粉的效应,对氧化铝复合陶瓷增强、增韧和力学特征进行了探讨。     

ZrO2—CeO2—HfO2系陶瓷的特性

1．简介部分稳定的四方多晶ZrO2陶瓷（TZP）的常用稳定剂有Y2O3和CeO2，它们能够降低马氏相变温度MS而稳定四方相，但提高添加量将会导致室温下临里相变应力的增大及韧性的降低。HfO2和ZrO2完全固溶，并能提高ZrO2的Ms温度（＋650℃／O～100mol％），因而可用于ZrO2以提高其高温相变增韧性能。对于Zro。一Hfo。体系而言，冷至室温时对于单斜相的转化很敏感，然而深加降低MS稳定四方相的y。0。或．Ceo。氧化物便可使这一问题得到解决。为了能够获得再现性强、在特定温度范围内具有最佳增韧效果的动O。系列陶瓷，作为稳定剂的固溶…     

四方相氧化锆粉体制备工艺研究

以ZrOCl2·8H2O和Y2O3为主要原料,采用醇-水溶液加热结合共沉淀法制备出Y2O3稳定的纳米ZrO2复合粉体.利用X射线衍射(XRD)分析和扫描电子显微镜(SEM)研究了复合粉体的物相组成和晶粒大小.结果显示,当Y2O3含量为2mol%时,复合粉体由单斜相ZrO2和少量四方相ZrO2组成;当Y2O3含量为3mol%、4mol%时,粉体全部由四方相ZrO2,组成.750℃～900℃煅烧时,复合粉体的物相组成变化不大,但四方相ZrO2,的晶粒尺寸随煅烧温度升高而增大.     

ZrO2-Al2TiO5复相材料的抗热冲击性能

以不同粒径的部分稳定ZrO2 (partially stabilized zirconia,PSZ)粉体为原料,采用共沉淀法包覆Al2TiO5纳米颗粒层,经高温烧结制备了高强度低膨胀的ZrO2-Al2TiO5复相材料.研究了原料粒径、Al2TiO5含量、烧成温度对复相材料的烧结性能、相组成、显微结构以及抗热冲击性能的影响.结果表明:随烧成温度的提高,PSZ各粒径样品的显气孔率呈逐步减小的规律,抗折强度呈逐步增大的趋势.随样品中纳米Al2TiO5含量的增加,单斜氧化锆到四方氧化锆的相变温度不断降低.在1 500℃烧结的、Al2TiO5含量为5%(质量分数,下同)、ZrO2(平均粒径为0.8μm)的样品,其显气孔率最小,为6.29%;抗折强度最大,为53.14MPa;室温到1100℃急冷急热冲击20次后,样品仍保持完整,仅在表面出现轻微剥落,抗热震性能明显高于其他样品.     

ZrO2粉体及陶瓷的制备

叙述了ZrO2的基本性能和应用，介绍了ZrO2微粉和超细粉的制备方法及目前ZrO2结构陶瓷生产常用的成型方法，比较了几种成型方法的优缺点，指出了成型和烧成是较关键的两道工序。同时详细分析了干压成型中分层和烧成过程中开裂出现的原因，并提出了解决的办法。     

Fabrication of lightweight ZrO2 fiberboards using hollow ZrO2 fibers

ZrO₂ fiberboards with ultra-low densities (0.34–0.40 g/cm³) were fabricated using biomorphic ZrO₂ hollow fibers, which have a lower density and better thermal insulation than traditional ZrO₂ solid fibers. The effects of sol binder content, sintering temperature, and proportion of solid fibers on the density, microstructure, compressive strength, linear shrinkage, and thermal conductivity of lightweight ZrO₂ fiberboards were investigated. The results showed that the hollow features of biomorphic ZrO₂ fibers were successfully maintained after they were made into ZrO₂ fiberboards, which made them less dense and thermally conductive. The best conditions were found to be a sol binder content of 30 vol%, sintering temperature of 1400 °C, and 20 wt% sintered solid fibers to balance thermal insulation and compressive strength. The results show that the density and thermal conductivity of lightweight ZrO₂ fiberboard gives it obvious advantages as a heat-insulating ceramic. Specifically, when the sintering temperature was 1400 °C, the sample had an ultra-low density of 0.34–0.40 g/cm³, a thermal conductivity of 0.101–0.116 W/(m·K) (at 500 °C), a compressive strength of 0.05–0.24 MPa, and a linear shrinkage of 9.4–13%.     

Effect of hydrogen treatments on ZrO2 and Pt/ZrO2 catalysts

ZrO₂ and Pt/ZrO₂ catalysts have been investigated by TPR, hydrogen chemisorption, TPDH and in the conversion ofn-hexane. At high temperature, ZrO₂ takes up hydrogen. High temperature hydrogen treatment is a precondition of the catalytic activity in then-hexane conversion. Possibly, catalytically active acid sites are formed by this hydrogen treatment. The high temperature hydrogen treatment induces a strong Pt-ZrO₂ interaction.     

等离子喷涂ZrO2／NiCoCrAlY梯度涂层中ZrO2组元的显微结构特征

Ｚｒｏ２／ＮｉＣｏＣｒＡｌＹ梯度涂层中的８％Ｙ２Ｏ３部分稳定ＺｒＯ２组元在等离子喷涂后的快速凝固和冷却过程，发生了ｃ→ｔ’非扩散型相变的ｃ→ｔ扩散型相变，以及少量的ｔ→ｍ相变。涂层中ＺｒＯ２主要由未转变的ｃ相及转变产物ｔ相和ｔ’相组成，并存在少量的ｍ相。     

Coating Titania Aerosol Particles with ZrO2, Al2O3/ZrO2 and SiO2/ZrO2 in a Gas-Phase Process

The formation of ZrO₂, Al₂O₃/ZrO₂, and SiO₂/ZrO₂ coatings on TiO₂ particles by a continuous gas-phase process was studied. Titania particles were formed by the reaction of TiCl₄ vapor with O₂ in a hot-wall tubular reactor at 1300°C and were mixed with ZrCl₄ and AlCl₃ or SiCl₄ vapors near the end of the reactor. The ZrCl₄/TiCl₄ molar ratio was varied from 6.7 x 10^-4 to 5 x 10^-3 while the AlCl₃/TiCl₄and SiCl₄/TiCl₄ molar ratios varied in the ranges 8 x 10^-3-8 x 10^-2 and 2 x 10^-2-8 x 10^-2, respectively. Discrete tetragonal ZrO₂ nanoparticles of average diameter 20 nm were formed on the surfaces of the titania particles at a surface concentration that increased with the ZrCl₄ gas-phase concentration. The sequential introduction of AlCl₃ and ZrCl₄ vapors resulted in composite coatings. These consisted of dense, coherent, amorphous, and smooth Al₂O₃ layers approximately 10 nm thick, on top of which ZrO₂ nanocrystalline particles were dispersed in a similar pattern as in the absence of Al₂O₃. Concentration depth profiles of these powders were obtained by Auger Electron Spectroscopy and supported the TEM observations. Particles coated by sequentially introducing SiCl₄ and ZrCl₄ vapors had amorphous rough SiO₂ coatings, 5-10 nm thick, and ZrO₂ particles sporadically dispersed on their surfaces. Increasing the SiCl₄/ZrCl₄ molar ratio from 5 to 19 increased the thickness and roughness of the silica layers and resulted in encapsulation of the ZrO₂particles inside the silica coatings. The different coating morphologies obtained were attributed to different coating formation mechanisms for the metal oxides used in this study.     

ZrO2复相陶瓷材料的研究

综合近几年来ZrO2复相陶瓷材料的研究情况,发现对ZrO2结构陶瓷的研究主要集中在力学性能的改善方面,本文总结了ZrO2复相陶瓷的研究情况和进展,作为后面对ZrO2复相陶瓷研究的基础和参考。     

Effect of ZrO2 nanocrystals on the stabilization of the amorphous state of alumina and silica in the ZrO2-Al2O3 and ZrO2-SiO2 systems

Structural and chemical transformations in the ZrO₂-Al₂O₃ and ZrO₂-SiO₂ systems containing ZrO₂ nanocrystals are examined. It is shown that the presence of zirconia nanoparticles in the oxide mixture retards the processes of crystallization and phase formation. The revealed effect is explained by the space blocking of nucleation in the systems under consideration.     

热处理温度对ZrO2纤维复合ZrO2-C材料性能的影响

浸入式水口是钢铁连铸工序中关键的功能耐火材料,其中以渣线部位的工作环境最为恶劣。目前,最适合的渣线材料是ZrO₂-C材料。为了提高浸入式水口的性能,本文以氧化锆与鳞片石墨为主要原料,添加增强材料氧化锆纤维及金属硅粉等,以酚醛树脂为结合剂制备ZrO₂-C复合材料。比较了1 000 ℃、1 200 ℃和1 500 ℃三种热处理温度对ZrO₂-C材料的性能及显微结构的影响,结果表明,在热处理温度高于1 200 ℃时,ZrO₂-C材料中的硅粉与石墨发生反应生成碳化硅,大量晶须状碳化硅与ZrO₂纤维交错在一起形成网络结构,提高了材料的力学性能和抗热震性。