Thermodynamic Assessment of the ZrO2—CeO2 and ZrO2—CeO1.5 Binary System

An optimal set of thermodynamic parameters of the ZrO2-CeO1.5 system has been obtained using phase diagram data by modern CALPHAD (CAL culation of PHAse Diagrams) technique.The liquid and other solid solution phases were regarded as substitutional solution.The ordered ZrCe2O7 phase was treated as a stoichiometric compound.The ZrO2-CeO2 system has been re-optimized with new reference state.A comparison between the ZrO2-CeO2 system and ZrO2-CeO1.5 system has been made through calculation.With the calculation, the experimental information is well reproduced and a good agreement is obtained.     

ZrO2及ZrO2陶瓷的应用

５０多年前，ＺｒＯ２在工业上的应用远远没有开发出来，７０年代以来，世界范围内都致力于ＺｒＯ２陶瓷的研究，原因是它在工程应用上显示出了比现代金属刚性件更优异的性能。可以预言，若干年后，ＺｒＯ２在各种工程陶瓷、电子陶瓷、高级耐火材料、喷气式飞机的某些零部件等方面的应用将得到更大的发展。     

Mechanical properties and microstructure of ZrO2–SiO2 composite

ZrO2–SiO2 composite powder has been prepared by a wet chemical route using zirconyl chloride and fumed silica as starting materials and subsequently sintered by the hot-pressing method to obtain a ZrO2–SiO2 ceramic. The mechanical properties of the silica matrix have been much increased by the addition of 20 vol% zirconia. The microstructural features of the composite are observed by transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM). The stabilibity of tetragonal zirconia in the matrix is attributed to the particle-size effect, and to the constraint effect of the silica matrix and that of the interphasic reaction layer. The increase in mechanical properties is discussed in relation to the residual stress and the enhanced elastic modulus caused by the incorporated ZrO2 particles.     

ZrO2–TiO2Materials

The magnetic, electrical, catalytic, and photocatalytic properties of ZrO₂–TiO₂materials were studied. The ZrO₂–TiO₂system was shown to contain ZrO₂-, TiO₂, and ZrTiO₄-based solid solutions. Procedures for the preparation of high-activity ZrO₂–TiO₂photocatalysts and photostable pigments were developed.     

Fractal Surfaces of ZrO2 , WO3 , and CeO2 Powders

The surface fractal properties of ZrO₂, WO₃, and CeO₂ powders prepared by the thermal decomposition of ZrO(NO₃)₂, (NH₄)₄W₅O₁₇, and (NH₄)₂Ce(NO₃)₆, respectively, were studied by mercury porosimetry. The results demonstrate that these oxides may, in principle, have fractal surfaces owing to topochemical processes of the type A(s) B(s) + C(g). The surface fractal dimension of individual crystallites and their aggregates are determined.     

ZrO2及ZrO2:CdS薄膜的制备和表征

利用ｓｏｌ－ｇｅｌ方法合成了ＺｒＯ_２薄膜,并通过在ＺｒＯ_２薄膜中复合ＣｄＳ纳米粒子成功地制备了ＺｒＯ_２：ＣｄＳ薄膜．制得的ＺｒＯ_２薄膜透明并具有较好的光透射性,而ＺｒＯ_２的含量及膜厚是影响其光透射性的主要因素．分散在ＺｒＯ_２：ＣｄＳ薄膜中的ＣｄＳ纳米粒子为六方相结构,并具有较好的分散性,其平均尺寸为４～６ｎｍ．实验结果表明：ＺｒＯ_２颗粒的晶化会对薄膜的光学性能及表面形貌产生影响,但ＣｄＳ的形成可以抑制薄膜表面ＺｒＯ_２颗粒的晶化,从而得到较为平滑的薄膜．     

Phase relations in the systems ZrO2Y2O3Nd2O3 and ZrO2Y2O3CeO2

The phase relations of ZrO₂Y₂O₃Nd₂O₃ and ZrO₂Y₂O₃CeO₂ systems have been studied at 1100–1600°C. The single region of the fluorite phase was intensively examined using the relation between lattice parameter and composition. In the ZrO₂Y₂O₃Nd₂O₃ system, 37 mol% Nd₂O₃ is soluble in Y₂O₃-stabilized zirconia (fluorite phase) at 1100°C and 42 mol% Nd₂O₃ at 1600°C. In the ZrO₂Y₂O₃CeO₂ system, 40 mol% CeO₂ dissolves into the stabilized zirconia at 1600°C.     

ZrO2薄膜的表层结构

用射频溅射技术制备了ＺｒＯ２薄膜，用恒正电子束分析该谱膜，发现它的的表层存在一高正电子吸收区，它与钇的表面富集有关，提出了相应的模型。     

ZrO2和ZrO2:Dy3+纳米晶发光特性

采用液相沉淀法制备了不同掺杂浓度和尺寸的ZrO2和ZrO2:Dy纳米晶,研究了其发光特性.结果表明在纳米ZrO₂中,存在着宽带激发和发射,起源为电子在价带和导带之间的跃迁.在Dy³⁺掺杂的样品中,随着颗粒尺寸的长大,其发光增强.并且共掺杂Li⁺的样品发光强度被极大地提高.随着Dy³⁺浓度的变化,黄发射和蓝发射的强度比(Y/B)发生改变,且浓度猝灭是通过近邻激活剂间的交换作用进行的.     

ZrO2陶瓷膜结构研究

以氧氯化锆为起始原料，通过溶胶－凝胶技术制备了无支撑体ＺｒＯ２陶瓷膜，ＤＴＡ－ＴＧ、ＸＲＤ、ＢＥＴ、ＳＥ等分析测试手段对陶瓷膜结构及其孔性能进行了表征，结果表明，ＺｒＯ２陶瘊膜具有高度的择优取向特征，膜烧结过程存在关ＺｒＯ２昌相转变，ＺｒＯ２陶瓷膜孔径〈５０ｎｍ，且呈双值分布，本言语亦基于实验分析对陶瓷膜的结构模型进行了初步探讨。     

Microstructure,mechanical and wear properties of Cu–ZrO2 nanocomposites

Cu–ZrO₂ nanocomposites were produced by the thermochemical process followed by powder metallurgy technique. Microstructure development during fabrication process was investigated by X-ray diffraction, field emission scanning electron microscope and transmission electron microscope. The results show an improved distribution of zirconium dioxide (ZrO₂) nanoparticles (45?nm) in the copper matrix, which resulted in the improvement of mechanical properties of Cu–ZrO₂ composites. The nanocomposite with 9 wt-% ZrO₂ possesses the highest hardness (136.5 HV) and the superior compressive strength (413.5?MPa), resulting in an overall increase by 52 and 25%, respectively. The wear rate of the nanocomposites increased with increasing applied loads or sliding velocity.     

Dielectric property and electrical conduction mechanism of ZrO2–TiO2 composite thin films

ZrO₂–TiO₂ composite films were fabricated by radio frequency magnetron sputtering and post annealing in O₂. It was found the films remained amorphous below the annealing temperature of 500 °C. The as-deposited ZrO₂–TiO₂ film has a high dielectric constant of 22, and which increases to 34 after annealing at 400 °C. At low electric field, the dominant conduction mechanisms are Schottky emission for both the as-deposited and the annealed thin films. At high electric field, the conduction mechanism changes to space-charge-limited current and then changes to Poole–Frenkel (PF) emission after annealing at 400 °C.     

Sol-Gel Synthesis and Thermal Evaluation of Cordierite–Zirconia Composites (Ce–ZrO2, Y–Ce–ZrO2)

Cordierite and cordierite–zirconia composites (ceria- and yttria–ceria-stabilized zirconia) were prepared by sol-gel processing for different compositions. The precursor powders of these composites were studied using analytical techniques such as thermogravimetric analysis, differential thermal analysis, X-ray diffraction, and infrared spectroscopy for different temperatures to investigate the crystallization behavior of the material. It was observed that the cordierite–zirconia composite powders are crystallized as -cordierite and tetragonal zirconia when sintered at a temperature above 1200°C in the presence of zircon in the cordierite matrix. Powder morphologies of cordierite–zirconia composites have also been investigated.     

ZrO2薄膜的XPS分析

用射频溅射制备了氧化锆薄膜，用Ｘ光电子能谱技术分析了ＹＳＺ膜的结构，发现低能轰击会引起膜中钇的反优再溅射，造成钇的分布不均匀导致单斜相的出现。     

超细ZrO2粒子的制备

使二氯氧锆水溶液与环氧氯丙烷相互作用可制得ZrO(OH)2凝胶.将凝胶干燥、灼烧即得二氧化锆超细粉.ZrO2超细粉为单斜晶,平均粒径为9.6nm,比表面积为95.3m2/g.用该法还可制得部分稳定化的ZrO2.     

大功率CO2激光熔凝稳定ZrO2

利用大功率ＣＯ２激光熔凝稳定ＺｒＯ２高温快离子导体获得成功．报导了激光熔凝的原理、工艺过程及熔凝后样品的微观分析等研究结果．激光熔凝的ＣＳＺ和ＭＳＺ快离子导体样品在温度为１０００℃时的电导率达到２×１０－２Ω－１ｃｍ－１量级．     

硬脂酸法制备纳米ZrO2

以氧氯化锆为原料，采用硬脂酸溶胶工艺制备出了纯氧化锆及钇稳定的氧化锆（YSZ）纳米晶。用傅立叶变换红外光谱（FT－IR）和热重（TG）、差热（DTA）分析仪对反应历程进行了分析，X射线衍射仪（XRD）进行物相分析及粒径计算，透射电镜（TEM）观察粒子形貌。结果表明，该工艺方法简单且制备的纳米晶颗粒均匀，分散性较好。     

The mechanical and electrical properties of ZrO2-Naβ″-Al2O3 composites

ZrO₂-Na-Al₂O₃ composites were prepared by a conventional method using two different powder routes and different milling liquids. The retained tetragonal-phase ZrO₂ was 85 to 90% for composites with 2.4 to 15 vol% ZrO₂. The fracture toughness (K _lc) and strength increased with increasing ZrO₂ content. At 20 vol % ZrO₂,K _lc and bend strength were 4.35 M Pa m^1/2 and 390 MPa, respectively. Stress-induced transformation toughening is the predominant toughening mechanism. Dispersion toughening also contributes to the increase ofK _lc. Surface strengthening was found to be an effective strengthening method for low ZrO₂ levels. The critical tetragonal ZrO₂ grain size was found to increase from 0.86 to 1.02gmm as the ZrO₂ content increased from 2.5 to 15 vol %. A detailed study of the ionic conductivity of the 15 vol % ZrO₂ dispersed sample was conducted by an a.c. technique between –124° C and 300° C. The bulk and total conductivities were calculated via complex-plane analysis. The total (grain and grain-boundary) ionic specific resistivity was 9 cm at 300° C. The activation enthalpies of the bulk and total conductivity processes were 0.30 and 0.32 eV, respectively.