(MgO)0.1-x(CaO)x(ZrO2)0.9陶瓷的相组成、力学与抗热震性能研究

首先以电熔ZrO2为主原料,以碱式碳酸镁和CaCO3为稳定剂,经混合、成型和预烧(1550℃3h)后,制成(MgO)0.1-x(CaO)x(ZrO2)0.9系列陶瓷粉体(x值分别取0、0.01、0.02、0.03、0.04、0.05、0.1);然后将预烧后试样破碎、筛分成0.1~0.074mm的粗粒级颗粒和<0.055mm的细粒级颗粒,分别按单一细颗粒和粗颗粒与细颗粒混合(粗、细颗粒质量比为11)两种方案进行坯体配料,经1550℃5h烧成后制成(MgO)0.1-x(CaO)x(ZrO2)0.9系列陶瓷试样,研究了稳定剂组成的相对变化对试样的相组成、体积密度、力学性能与抗热震性能的影响。结果表明(1)在稳定剂MgO、CaO总量10%(摩尔分数)不变的情况下,试样中立方相含量随着CaO量(即x值)增加而增加;当x=0.01时,陶瓷中单斜相与立方相含量之比为21,此时陶瓷具有较高的常温抗折强度和较为理想的抗热震性(1100℃水急冷5次后未出现裂纹),而且其抗热震性受陶瓷材料致密度的影响程度较小。(2)在陶瓷粉体中增加粗粒级配料,可有效降低ZrO2陶瓷试样的致密度,提高试样的抗热震性能,但其抗折强度也随之下降。     

ZrO2(CaO)纳米粉体的性能与CaO含量的关系

采用凝胶-超临界流体干燥技术合成不同CaO含量的稳定化ZrO2超微粉体,对粉体的织构性能和烧结性能进行研究.实验表明:粉体中CaO的浓度会显著影响其粒度、相组成及烧结性能,而且这种影响作用与传统粉体的不同.     

ZrO2粒度对ZrO2-C质耐火材料耐蚀性的影响

利用不同粒度的ZrO2改变耐火材料和保护渣的接触面积，研究其对耐蚀性的影响。     

耐火材料热膨胀试验方法解析

叙述了顶杆法热膨胀试验的测试方法及设备,校验方法及标准样,并通过对部分耐火材料的热膨胀值的测试对其精度进行了验证。结果表明:该方法及设备具有良好的测试精度,能用于测试耐火材料的膨胀性能。     

Development of ZrO2—CaO—BN Composite

The weaknesses of submerged nozzles being used now were analyzed and ZrO2-CaO-BN composite was proposed to develop to overcome them.The feasibility to prepare ZrO2-CaO-BN compostie was made by thermodynamic method and the omposite was prepared in hot-press.The phase components of the composite were identified by X-ray diffraction method(XRD) and the microstructure of the composite was observed with SEM. Th results were consistent with thermodynamic calculation.     

水泥回转窑用含ZrO2耐火材料

含ZrO2耐火材料在水泥窑上的应用不断增加,水泥窑用含ZrO2耐火材料包括含锆白云石砖、含锆镁砖、含锆镁尖晶石砖、含锆高铝砖等.本文从材料的抗化学侵蚀性、热震稳定性、导热性和力学性能等方面讨论了ZrO2的引入对耐火材料使用性能的影响.     

不定形耐火材料中的原位反应与相组成设计

阐明了原位耐火材料的定义 ,根据反应特征及其生成物进行了分类 ,同时分析了原位反应在不定形耐火材料中的应用原理 ,并且举例说明了在不定形耐火材料中的实际应用 ,说明利用原位反应原理可以指导不定形耐火材料的相组成设计。     

ZrO2-C质耐火材料中碳对氧化锆的稳定作用

分别以粒度均<0.045 mm的氧化钙部分稳定氧化锆、氧化镁部分稳定氧化锆和氧化钇部分稳定氧化锆为原料,酚醛树脂作为结合剂和碳源,按部分稳定氧化锆与酚醛树脂质量比为9 1配料,研究了在埋焦炭条件下于1 600℃渗碳处理后3种部分稳定氧化锆的相组成变化,以及保护渣对渗碳处理后氧化锆稳定性的影响。结果表明:1)高温下树脂碳对氧化锆存在渗碳过程,并对氧化锆有稳定作用,促进了部分稳定氧化锆中单斜相向四方相的转化;但也发现渗碳过程对部分稳定氧化锆中的氧化钙和氧化镁稳定剂存在还原作用并引起其挥发。2)由于渗碳处理过程中部分氧化钙和氧化镁稳定剂被还原挥发,高温下空气气氛中部分稳定氧化锆随着氧化锆晶格中碳的氧化而迅速失稳;而在埋炭条件下部分稳定氧化锆晶格中碳的存在减缓了部分稳定氧化锆的失稳过程。     

Al2 TiO5-ZrO2复相材料中ZrO2的相变特性

以α-Al2O3、TiO2、ZrO2为主要原料,以MgO-SiO2或MgO-Fe2O3为Al2TiO5的稳定剂,经1500℃2 h烧成制得Al2TiO5-ZrO2复相材料,研究了Al2TiO5对ZrO2相变及复相材料热膨胀性的影响.试验发现以MgO-SiO2稳定的Al2TiO5对ZrO2相变的影响显著,随复相材料中Al2TiO5含量增加,m-ZrO2相变为t-ZrO2的温度不断降低,Al2TiO5含量为58.8%的复相材料,ZrO2的相变开始温度由原1150℃降至500℃,相变结束温度为700℃.Al2TiO5-ZrO2复相材料具有低膨胀特性,其室温～1300℃的热膨胀系数仅为1.57×10-6℃-1,适于用作冶金浇钢系统的高抗热震性材料.     

Phase structure and thermal conductivities of Er2O3 stabilized ZrO2 toughened Gd2Zr2O7 ceramics for thermal barrier coatings

3.5 mol% Er₂O₃ stabilized ZrO₂ (ErSZ) and Gd₂Zr₂O₇ powders were produced by a chemical co-precipitation and calcination method, and ErSZ was used to toughen Gd₂Zr₂O₇. The phase structure, toughness and thermal conductivities of ErSZ toughened Gd₂Zr₂O₇ ceramics were investigated. When the ErSZ content was below 15 mol%, the compound consisted of pyrochlore phase, the ordering degree of which decreased with the increase of the ErSZ content. High ErSZ doping led to the formation of metastable tetragonal (t′) phase in the compound. The addition of ErSZ in Gd₂Zr₂O₇ benefited its toughness, mainly attributable to the presence of t′ phase in the compound. With the increase of the ErSZ content in the compound, the thermal conductivity first decreased and then showed an upward tendency, and 10 mol% ErSZ toughened Gd₂Zr₂O₇ exhibited the lowest thermal conductivity.     

Synthesis and thermal expansion of ZrO2/ZrW2O8 composites

In this work, a ceramic composite of ZrW₂O₈ and ZrO₂ was synthesized, in order to investigate the possibility of compensating the positive thermal expansion of ZrO₂ with the negative thermal expansion (NTE) compound ZrW₂O₈, tailoring the thermal expansion of these composites. The NTE material was mixed with varying amounts of ZrO₂. The thermal expansion coefficients of this series of composites decrease with increasing amounts of ZrW₂O₈. Nevertheless, a negative deviation from the values expected by the rule of mixtures was found to be most pronounced in the middle of the compositional region.     

Phase stability and thermal conductivity of RE2O3 (RE=La,Nd, Gd,Yb) and Yb2O3 co-doped Y2O3 stabilized ZrO2 ceramics

Y₂O₃ stabilized ZrO₂ (YSZ) has been considered as the material of choice for thermal barrier coatings (TBCs), but it becomes unstable at high temperatures and its thermal conductivity needs to be further reduced. In this study, 1 mol% RE₂O₃ (RE=La, Nd, Gd, Yb) and 1 mol% Yb₂O₃ co-doped YSZ (1RE1Yb–YSZ) were fabricated to obtain improved phase stability and reduced thermal conductivity. For 1RE1Yb–YSZ ceramics, the phase stability of metastable tetragonal (t′) phase increased with decreasing RE³⁺ size, mainly attributable to the reduced driving force for t′ phase partitioning. The thermal conductivity of 1RE1Yb–YSZ was lower than that of YSZ, with the value decreasing with the increase of the RE³⁺ size mainly due to the increased elastic field in the lattice, but 1La1Yb–YSZ exhibited undesirably high thermal conductivity. By considering the comprehensive properties, 1Gd1Yb–YSZ ceramic could be a good potential material for TBC applications.     

稀土镧添加氧化锆的合成与物相分析研究

以硝酸锆、硝酸镧和柠檬酸为原料,原位合成了稀土镧（La）掺杂氧化锆（ZrO₂）和锆酸镧/氧化锆（La₂Zr₂O₇/ZrO₂）复合材料。采用X射线衍射（XRD）和拉曼光谱（Raman）作为分析和表征手段,研究了稀土La掺杂ZrO₂和La₂Zr₂O₇/ZrO₂复合材料的物相组成以及La₂Zr₂O₇/ZrO₂复合材料的高温热稳定性。研究结果表明：稀土La很难进入ZrO₂晶格形成固溶体,当稀土La掺杂量较少时,生成以m-ZrO₂为主相的m-ZrO₂和La₂Zr₂O₇的复合材料;当稀土La掺杂量较大时,生成以La₂Zr₂O₇为主相的t-ZrO₂和La₂Zr₂O₇的复合材料。在1 400 ℃煅烧6 h条件下,LZZ11（按La₂Zr₂O₇与ZrO₂物质的量比为1∶[KG-*2]1称取原料制备的样品）中的t-ZrO₂转变为m-ZrO₂相,此时La₂Zr₂O₇失去了对ZrO₂的稳定作用。     

On the Modification of Hydration Resistance of CaO with ZrO2 Additive

Various ZrO₂/CaO samples were fabricated by cold isostatic pressing and sintered at 1750°C for 4 h. It was observed that the sample with 12% ZrO₂ additive possessed the good hydration resistance and had the lowest apparent porosity of about 0.75%; its weight additive stored after 56 days was less than 0.6 wt%, and it contributed to the occurrence of CaZrO₃ on the surface of CaO. The CaO crucible with 12 mol% ZrO₂ additive did not react with titanium melt during melting TiNi alloy. This provides a support for searching a new refractory with the good hydration resistance for induction melting titanium alloys.     

Synthesis and thermal expansion of chalcogenide MAX phase Hf2SeC

Thermal expansion of MAX phases along different directions tends to be different because of the anisotropy of hexagonal crystals. Herein, a new Hf₂SeC phase was synthesized and confirmed to be relatively isotropic, and the coefficients of thermal expansion (CTEs) along a and c directions were determined to be 9.73 μK^?1 and 10.18 μK^?1, respectively. The strong MS bond endowed Hf₂SC and Zr₂SC lower CTEs than those of Hf₂SeC and Zr₂SeC. The relationship between the thermal expansion anisotropy and the ratio of elastic stiffness constant c₁₁ and c₃₃ was established. This straightforward approximation can be used to roughly predict the thermal expansion anisotropy of MAX phases.     

ZrO2陶瓷产品的开发应用研究

利用ZrO2材料优良的方法性能及物理性能，开发各种氧化锆制品，已广泛引起人们的注意。通过对ZrO2凡尔球阀及阀座制备过程的研究，综合分析了影响ZrO2凡尔球阀及阀座性能的各工艺环节，并对重要的影响因素进行了分析。