[NZP]陶瓷零膨胀性能的设计

研究了「ＮＺＰ」材料的零膨胀性能，并尝试对零膨胀的「ＮＺＰ」陶瓷作了设计，从晶体结构、原子复合、各向异性、显微结构和复合材料等方面提出了设计思路。     

扣式锂离子可充电池的开发

扣式锂离子可充电池的开发ＹｏｓｈｉａｋｉＡｓａｍｉ（日）１概述近年来，可充锂电池的开发获得了很大进展。一种以五氧化二矾［１］、锂氧化钴［２］及锂二氧化锰［３］为阳极材料，锂铝合金［４］及碳［５］为阴极材料的新型锂电池已在商业上应用。这些电池主要有柱式...     

p型Cu/Q(Q=S,Se,Te)透明导体的设计、制备及性能研究

利用结构功能区思想的导电功能区和透光功能区,提出了层状p型Cu/Q透明导体的设计模型. LaCuOTe和Sr₃Cu₂Sc₂O₅S₂因结构层［Cu₂Te₂］和［Cu₂S₂］对应导电功能区、［La₂O₂］和［Sr₃Sc₂O₅］对应透光功能区,符合模型设计思想,是兼具高导电性和高透光性的透明导体,光谱和电导等验证了模型设计p型透明导体的可行性和正确性. 从功能区角度,改变LaCuOS中导电功能层(［Cu₂S₂］→［Cu₂Te₂］)可显著提高材料导电性(10^-3S/cm→10⁰S/cm）;替换LaCuOTe中透光功能层(［La₂O₂］→［Sr₃Sc₂O₅］)能可控改善材料透光性（2.3eV→3.1eV）.     

NZP陶瓷的热学性质及其应用研究

总结了ＮＺＰ族陶瓷的研究历程，制备方法，晶体化学，热膨胀等物理性质，首镒提出了ＮＺＰ族陶瓷的分类方法，提出近零膨胀陶瓷的主要设计原则。研究了ＮＺＰ族陶瓷的热膨胀，导热及热震法，并利用ＸＲＤ，ＳＥＭ和ＨＲＥＭ等检测手段进行了分析。     

NZP族陶瓷的组成与分类

首次提出根据晶体化学特性、轴膨胀特性及非化学计量性对ＮＺＰ簇陶瓷进行分类的方法，该分类法合成新型的ＮＺＰ族化合物具有一定的指导意义。     

镍钴离子浓度比对化学镀Co-Ni-P合金工艺的影响

讨论了［Ni2＋］／［Co2＋］的比值、镀液组成和操作条件对化学镀Co－Ni－P合金沉积速度的影响。［Ni2＋］／［Co2＋］的比值越大，沉积速度越快。［Ni2＋］／［Co2＋］的比值对镀液组成和沉积速度之间的关系有明显的影响。当镀液的温度和pH值较低时，［Ni2＋］／［Co2＋］的比值对沉积速度的影响也较小。     

各种碳质材料的电池特性

各种碳质材料的电池特性０概述可充锂离子电池的负极材料通常使用焦炭，该电池不含金属锂。由于锂离了在两极材料中穿梭，因此，在安全性方面具有十分显著的优点［１，２］。由于石墨较之焦炭具有较高的能量密度，因此，最近石墨被建议作为负极的替换材料［３─７］。但实...     

PbO－Bi_2O_3－B_2O_3－SiO_2系重金属氧化物玻璃的结构与光学性

通过密度、可见光光谱、红外吸收光谱、Ｃｏ－６０辐照损伤试验及荧光光谱的测试，研究了ＰｂＯ－Ｂｉ２Ｏ３－Ｂ２Ｏ３－ＳｉＯ２玻璃系的光学性能与结构．密度最高可达８．４６４ｇ／ｃｍ３其紫外吸收达截止波长随Ｐｂ２＋及Ｂｉ３＋含量升高而红移．玻璃熔化温度低达８５０℃．在ＰｂＯ－Ｂｉ２Ｏ３－Ｂ２Ｏ３系玻璃中加人ＳｉＯ２可使玻璃结构更致密．室温下该系统玻璃在３６０ｎｍ有一个宽的激发峰，能产生４１８ｕｍ及４３８ｕｍ两个弱的发射峰．该系统玻璃的结构是由［ＳｉＯ４］４－、［ＢＯ３］３－、［ＢＯ４］５－、［ＰｂＯ４］６－及［ＢｉＯ６］９－构成．其中部分Ｐｂ２＋及Ｂｉ３＋以网络外体进入玻璃．     

Cr2O3对掺锶亚锰酸镧非化学整比,晶体结构,电导率和热膨胀性能影响

讨论了掺杂Ｃｒ２Ｏ３（Ｃｒ部分取代Ｍｎ）对固体电解质燃料电池阴极材料（Ｌａ０．８５Ｓｒ０．１５）ＭｎＯ３的Ｍｎ＾４＋离子含量、氧非化学整比、晶体结构、电导率和热膨胀系数的影响。结果表明：［Ｍｎ＾４＋］／［Ｍｎ＋Ｃｒ］比率和氧的非化学整比δ随Ｃｒ取代Ｍｎ的摩尔比增加而减小，但［Ｍｎ＾４＋］／［Ｍｎ＾３＋］比率不变；晶体结构在室温到１０００℃间属菱形方晶系，且氧非化学整比（δ）保持稳定；导电激活能随Ｃ     

Sol—Gel法合成K（Ta,Nb）O3材料

以金属醇盐乙醇钾［Ｋ（ＯＣ２Ｈ５）］，乙醇铌［Ｎｂ（ＯＣ２Ｈ５）５］和乙醇钽［Ｔａ（ＯＣ２Ｈ５）５］为原料，用Ｓｏｌ－Ｇｅｌ法合成了Ｋ（Ｔａ，Ｎｂ）Ｏ３超细粉末和薄膜，研究了工艺参数如前驱体溶液浓度、热处理温度等因素对材料结构及物性的影响。粉料的粒径为２０￣４０ｎｍ，所需合成温度约为７００℃，比通过传统的固相反应制备同种材料的合成温度低近１００℃；以ＳｒＴｉＯ３（１００）单晶作基片，采用匀胶法获得     

NZP族磷酸盐材料研究进展

NZP族精细磷酸盐材料是一类具有相同晶体结构特征但化学组成各异的结晶化合物粉体及其陶瓷烧结体。综述了NZP族磷酸盐化合物的晶体结构特征、合成方法、NZP族陶瓷的快离子导电性、离子取代性、低热膨胀特性及其应用领域。介绍了NZP族磷酸盐材料作为抗热震催化剂载体和新型介孔分子筛催化剂的研究进展。     

Glass reactive sintering as an alternative route for the synthesis of NZP glass–ceramics

The NZP-type crystal structure allows a large number of ionic substitutions which leads to ceramics with adjustable thermal expansion properties or interesting ionic conductivity. However, NZP is difficult to fabricate into monoliths because it requires both high temperatures and long sintering times. An alternative low temperature route to obtain a tungsten (IV) and tin (IV) containing NZP crystalline phase uses a process of glass reactive sintering of a phosphate glass. Using a microwave oven, a glass with the appropriate composition in the NaPO3–Sn(II)O–W(VI)O3 ternary diagram is prepared by a conventional melting and casting technique. After crushing, the glass powder is pressed at room temperature. The green pellet is cured during various times at temperatures where glass reactive sintering takes place. From XRD and DTA experiments, we have shown that different parameters influence the achievement of NZP phase. Consequently, specific conditions, such as (i) initial glass composition, (ii) equimolar quantities of SnO and WO3, (iii) glass particle size lower than 100 μm, and (iv) curing conducted under air, are required to obtain a glass–ceramic with a single crystalline phase with the NZP-type crystal structure.     

Low thermal expansion of alkali-zirconium phosphates

The thermal expansion of all the alkali members of the [NZP] family has been studied using high-temperature x-ray measurements at the back diffraction angles and dilatometry. The discrepancy between the results obtained with both methods is discussed. Some of the phases studied showed very low thermal expansion coefficients (<1 E-06), including some negative values.     

Synthesis, microstructure and thermal expansion studies on Ca0·5+x/2Sr0·5+x/2Zr4P6−2x Si2x O24 system prepared by co-precipitation method

We report on the synthesis, microstructure and thermal expansion studies on Ca_0·5?+?x/2Sr_0·5?+?x/2Zr₄P_6???2x Si_2x O₂₄ (x = 0·00 to 1·00) system which belongs to NZP family of low thermal expansion ceramics. The ceramics synthesized by co-precipitation method at lower calcination and the sintering temperatures were in pure NZP phase up to x = 0·37. For x ≥ 0·5, in addition to NZP phase, ZrSiO₄ and Ca₂P₂O₇ form as secondary phases after sintering. The bulk thermal expansion behaviour of the members of this system was studied from 30 to 850 °C. The thermal expansion coefficient increases from a negative value to a positive value with the silicon substitution in place of phosphorous and a near zero thermal expansion was observed at x = 0·75. The amount of hysteresis between heating and cooling curves increases progressively from x = 0·00 to 0·37 and then decreases for x > 0·37. The results were analysed on the basis of formation of the silicon based glassy phase and increase in thermal expansion anisotropy with silicon substitution.     

New [NZP] materials for protection coatings. Tailoring of thermal expansion

[NZP] (the NaZr₂P₃O₁₂-Family) materials can be selected for synthesizing new thermal shock resistant ceramic coatings with a thermal expansion that can be tailored to match that of the substrate, and to possess a low thermal expansion anisotropy. The tailoring technique will involve the selection of a suitable pair of compositions which, upon being mixed to form a crystalline solution, will possess the desired thermal expansion coefficient and will have negligible thermal expansion anisotropy. This can be done when the axial thermal expansion for one end member is larger in the a-direction than in the c-direction and vice versa for the other end member.     

NZP: A new family of low-thermal expansion materials

A new structural family of low-expansion materials known as NZP has been recently discovered and has generated great interest for wide-ranging applications such as fast ionic conductors, devices requiring good thermal shock resistance, hosts for nuclear wastes, catalyst supports in automobiles, etc. This family is derived from the prototype composition NaZr₂P₂O₁₂ in which various ionic substitutions can be made leading to numerous new compositions. The bulk thermal expansion of these materials varies from low negative to low positive values and can be controlled and tailored to suit the needs for specific applications. In general, most of the NZP members demonstrate an anisotropy in their lattice thermal expansions, which is the main cause of the low-thermal expansion behavior of these materials. In CaZr₄P₆O₂₄ and SrZr₄P₆O₂₄ an opposite anisotropy has been observed which has led to the development of near-zero expansion crystalline solution composition. On the basis of the coupled rotations of the polyhedral network formed by ZrO₆ octahedra and PO₄ tetrahedra, a crystal structure model to interpret and explain the thermal expansion behavior has been discussed.Paper presented at the Tenth International Thermal Expansion Symposium, June 6–7, 1989, Boulder, Colorado, U.S.A.     

Thermal expansion behaviour of M′Ti2P3O12 (M′=Li,Na, K,Cs) and M″Ti4P6O24 (M″=Mg,Ca, Sr,Ba) compounds

The [NZP] family has been attracting considerable attention because of its potential in thermal shock-resistant applications. The compounds MTi₂P₃O₁₂ (M=Li, Na, K, Cs) and MTi₄P₆O₂₄ (M=Mg, Ca, Sr, Ba) belong to this new family of low-expansion materials. The results of a systematic study undertaken to investigate the thermal expansion behaviour of these materials are reported. A correlation between the ionic size and lattice expansion was also attempted, and compounds possessing lowest bulk thermal and low anisotropy were identified.     

Strong anisotropic thermal expansion in oxides

The strong anisotropic thermal expansion behavior found for cordierite ((Mg₂Al₄Si₅O₁₅), β-eucryptite (LiAlSiO₄) and NZP (NaZr₂P₃O₁₂) is qualitatively rationalized using distance least squares (DLS) modeling. In this approach, the thermal expansion is driven by the ionic bonds of Mg²⁺, Li⁺ or Na⁺. Due to constraints imposed by shared polyhedra edges or faces, thermal expansion of the ionic bonds expands the lattice in only one or two dimensions. Due to the connectivity in these structures, this expansion in some directions causes contraction in the other directions. The thermal expansion of β-eucryptite was determined from powder neutron diffraction data over the temperature range 10–809 K. This revealed that the volume thermal expansion of β-eucryptite becomes substantially more negative below room temperature than it is above room temperature. The structure was refined by the Rietveld method from data collected at 12 different temperatures. DLS modeling studies suggest that Li–O bond expansion plus movement of Li from tetrahedral to octahedral sites can explain the thermal expansion behavior above room temperature. However, such an approach cannot explain the more pronounced low-temperature negative thermal expansion, which is most likely attributable to rocking motions of AlO₄ and SiO₄ tetrahedra.     

Crystal-Chemical Approach to Predicting the Thermal Expansion of Compounds in the NZP Family

The general structural aspects of phosphates with {[L₂(PO₄)₃] ^p–}₃ frameworks (L = octahedral cation) are considered, and the possible isomorphous substitutions in NaZr₂(PO₄)₃ (NZP) phosphates are analyzed. The available data on the thermal expansion of NZP materials in the range 293–1273 K, together with crystal-chemical data on their structure, are used to identify the processes underlying the thermal expansion of these materials. The results provide basic guidelines in designing NZP-based materials with controlled (ultralow) thermal expansion and near-zero expansion anisotropy.