CaZr4(PO4)6陶瓷力学及介电性能研究

CaZr4（PO4）6（简称CZP）属于NZP族材料。本文用共沉淀法合成了CZP粉体。粉料添加3％的Zn0作为助烧剂在100MPa压力下单面加压成型，坯体在1100℃下无压烧结2h制成CZP陶瓷。讨论了CZP陶瓷的抗弯强度及介电性能（包括介电常数和介质损耗）与工艺参数间的影响关系，并用扫描电镜对陶瓷断面进行观察。实验测得CZP陶瓷的抗弯强度为59．45MPa，介电常数为3．85，属于低介电材料。     

低温烧结微波介质陶瓷（1－x）Ba3（VO4）2-xLi2 MoO4的微波性能研究

采用固相反应制备了（1－x）Ba3（VO4）2-xLi2MoO4微波介质陶瓷,研究了掺入不同质量比的Li2MoO4对Ba3（VO4）2的微观结构和微波介质性能影响,X线衍射（XRD）测试结果表明,Ba3（VO4）2和Li2MoO4二者兼容性良好,无第二相产生。添加具有低熔点及相反（负）频率温度系数的Li2 MoO4能有效降低Ba3（ VO4）2的烧结温度,并随着添加剂Li2 MoO4的增加,此复合陶瓷的相对体密度、介电常数εr 和品质因数Q ×f呈现出先增加随后又降低的趋势,而谐振频率里面温度系数τf逐渐降低。当烧结温度为660℃且添加量30wt％Li2 MoO4的复合微波介质陶瓷获得了最佳的微波介电性能：εr ＝11．99, Q ×f＝39700 GHz,τf ＝－24 ppm／℃。     

直接共沉淀法制备CaZr4(PO4)6粉体

以硝酸钙、氯氧化锆、磷酸二氢铵为原料，用直接共沉淀法制备了CaZr4（PO4）6（简称CZP）粉末。控制反应过程中溶液的pH．并用低分子有机溶剂分散处理共沉淀物，防止反应过程及固液分离过程中团聚体的形成。用TG—DTA、XRD、SEM、激光粒度分析仪对CZP粉末进行了表征。CZP粉末的结晶状况和颗粒大小及团聚情况取决于热处理温度的高低，粉体中添加3％（质量分数）氧化锌作为助烧剂及3％（质量分数）二氧化硅作为晶粒抑制剂，在1150℃下烧结2h制成CZP陶瓷。结果表明：经860℃热处理之后的粉体制成的CZP陶瓷具有较好的综合性能，弯曲强度为74．96MPa，相对密度为96．6％。     

添加石墨烯或碳纳米管对Si3N4结合SiC陶瓷强度的影响

以Si3N4结合SiC材料为基础,通过添加不同形态的碳纳米材料来改善其力学性能.采用Si和SiC为主要原料,添加不同含量（1wt％和3wt％）的石墨烯（GPL）和碳纳米管（CNT）,氮气气氛下,在1600℃烧结制备Si3N4结合SiC复合陶瓷材料.对试样的气孔率、体积密度和耐压强度等基本烧结性能进行了测试.借助XRD和SEM等方法对试样的物相组成和显微结构进行了表征.实验结果表明,当石墨烯含量为1wt％时,Si3N4/SiC的耐压强度为207MPa,试样的体积密度及显气孔率较好.当碳纳米管含量为3wt％时,力学性能增强,耐压强度达到了247MPa.     

NZP族磷酸盐材料CaZr_4（PO_4）_6对金属离子的吸附性能

采用共沉淀法合成了化学组成为CaZr4（PO4）6（简称CZP）的NZP族磷酸盐结晶化合物粉体,分别用XRD和N2吸附BET法表征物相和孔结构,研究了CaZr4（PO4）6对Fe3＋和Mg2＋的吸附性能。吸附动力学研究表明：CZP对Fe3＋的吸附平衡时间为8 h,对Mg2＋则为3 h;室温下模拟原液中Fe3＋含量处于10～100 mg/L时,CZP对Fe3＋的平衡吸附容量为0.336～1.332 mg Fe3＋/g CZP;CZP在60℃时对Fe3＋的平衡吸附容量要小于20℃时的平衡吸附容量。CZP用量为5 g时,对Fe3＋的吸附率为55.22%,合适的吸附剂用量为2 g。     

烧结工艺对CaZr4P6O24陶瓷性能的影响

本文研究了升温速度、保温时间对CaZr4P6O24（简称CZP）陶瓷的力学性能和介电性能（包括介电常数和介质损耗）的影响关系。实验结果表明：当升温速度为5℃／min、保温时间为2h时陶瓷的综合性能最好。     

4，4’-（4，4’-砜基二苯氧基）二苯甲酰氯（SODBC）的合成

以对甲基苯酚、4,4’-二氯二苯砜为原料，通过亲核取代反应合成了4，4’-二（4-甲基苯氧基）二苯砜，用高锰酸钾将甲基氧化得到4，4’-（4，4’-砜基二苯氧基）二苯甲酸（SoDBA），后者在二氯亚砜和路易斯碱的催化下合成了4，4’-（4，4’-砜基二苯氧基）二苯甲酰氯（SoDBC）白色固体。用FT-IR、H—NMR、3C—NMR、DSC等对其进行了表征，实验证明该化合物具有预期的结构和较高的纯度。     

MgO添加量对CaZr_4(PO_4)_6陶瓷力学及介电性能影响研究

CaZr4(PO4)6(简称CZP)属于NZP族材料。用直接共沉淀法合成了CZP粉体,粉料添加2%到10%五种不同质量分数的MgO作为助烧剂在100MPa压力下单面加压成型,坯体在1300℃下无压烧结制成CZP陶瓷。对五种CZP陶瓷的抗弯强度及介电性能(包括介电常数和介质损耗)进行分析,并用扫描电镜对陶瓷断面进行观察,测试结果表明MgO添加量4%质量分数时,CZP陶瓷的综合性能最好。     

4-（6-氨基己氧基）-4’-氰基联苯的合成

以4-羟基-4’-氰基联苯（Ⅰ）为原料，在碳酸钾（水和乙醇作溶剂）溶液中与1，6-二溴己烷反应得到4-（6-溴己氧基）4’-氰基联苯（Ⅱ），然后经过Gabriel反应、肼解反应制得4-（6-氨基己氧基）-4’-氰基联苯（Ⅳ）。与国外相似结构的合成工作相比，简化了反应步骤，且总收率由文献[2]的27．8％提高到55．2％。用IR、^1HNMR和元素分析确证了目标产物的化学结构；经DSC测试，其液晶相转变温度为：Tm（熔点）83℃，Ti（清亮点）104℃。为了应用和贮存将其转变为相应的盐酸盐。     

N-（4-氯苯基）-N’-（3，4-二氯苯基）脲的合成研究

以3，4-二氯苯胺和对氯苯异氰酸酯反应制备N-（4-氯苯基）-N’-（3，4-二氯苯基）脲，以甲苯为溶剂，在回流状态下反应2小时，反应完毕，冷却到0—5℃，过滤，洗涤，重结晶得白色针状结晶，收率可达95．0％以上。     

Excellent mechanical property of fast hot pressure sintering CaZr4(PO4)6 low thermal expansion ceramics

The low mechanical property of the CaZr₄(PO₄)₆ (CZP) ceramics restrict its application prospects in area of high anti-thermal shock applications. Herein, the fast hot pressure sintering (FHP) was adopted to modify the microstructure and optimize the mechanical property of CZP ceramics for the first time. The as-fabricated CZP ceramics exhibited smaller grain size and lower stomatal rates than that of the normal-pressure sintering ceramics owing to the lower processing temperature and shorter insulation time. Consequently, the CZP ceramics prepared with FHP method demonstrated an unprecedented bending strength of 94.5 MPa, with the thermal expansion coefficient of the CZP ceramics remaining at a low level. This study is important for promoting the application of CZP ceramics in flood anti-thermal shock applications, the fast hot pressure sintering would trigger a new direction of improvement methods of sodium zirconium phosphate ceramics.     

NZP族磷酸盐材料CaZr4（PO4）6对金属离子的吸附性能

采用共沉淀法合成了化学组成为CaZr4(PO4)6(简称CZP)的NZP族磷酸盐结晶化合物粉体,分别用XRD和N2吸附BET法表征物相和孔结构,研究了CaZr4(PO4)6对Fe3+和Mg2+的吸附性能。吸附动力学研究表明:CZP对Fe3+的吸附平衡时间为8 h,对Mg2+则为3 h;室温下模拟原液中Fe3+含量处于10～100 mg/L时,CZP对Fe3+的平衡吸附容量为0.336～1.332 mg Fe3+/g CZP;CZP在60℃时对Fe3+的平衡吸附容量要小于20℃时的平衡吸附容量。CZP用量为5 g时,对Fe3+的吸附率为55.22%,合适的吸附剂用量为2 g。     

In situ preparation of CoFe2O4–Pb(ZrTi)O3 multiferroic composites by gel-combustion technique

Diphase magnetoelectric composites of CoFe₂O₄–Pb(ZrTi)O₃ were prepared by citrate–nitrate combustion technique by using Pb(Zr,Ti)O₃ template powders obtained by the mixed oxide method. Pure diphase powder composites with a good crystallinity were obtained after calcination. The composition and purity were maintained after sintering at temperature of 1100 °C/2 h, which ensured limited reactions at interfaces, while by sintering at 1250 °C/2 h, some small amounts of secondary phases identified as nonstoichiometric ZrO_2?x resulted. The method allowed to produce diphase ceramics with homogeneous microstructures and a very good mixing of the two phases. The dielectric and magnetic investigation at room temperature confirmed the formation of composite ceramics with both dielectric and magnetic properties at room temperature, with permittivity and magnetization resulted as sum properties from the parent Pb(Zr,Ti)O₃ and ferrite phases.     

蜂窝堇青石陶瓷负载的CaZr_4P_6O_(24)涂层的制备及表征

采用溶胶-凝胶法制备了化学组成为CaZr4P6O24(CZP)的溶胶态前驱物,用其涂覆薄壁蜂窝堇青石陶瓷,经过700℃焙烧2h转化为具有低热膨胀特性的结晶态CZP涂层。用X射线衍射和BET(Brunauer-Emmett-Teller)氮吸附法表征了涂层的物相和孔结构,用扫描电镜观察了涂层表面及涂层与基体的界面结合处的形貌,用能量色散光谱仪分析了涂层中的元素分布及含量。结果表明:在蜂窝堇青石陶瓷基体上形成的涂层组成为CZP;表面沉积了19.5%(质量分数)CZP的蜂窝堇青石陶瓷的BET比表面积、孔体积和平均孔径分别为16.4m2/g,0.0225mL/g和2.74nm。CZP涂层与蜂窝堇青石基体的界面结合良好。发动机台架性能试验结果表明:"CZP-蜂窝堇青石"复合载体负载的单钯催化剂表现出与"γ-Al2O3-蜂窝堇青石"负载的单钯催化剂相近的三效转化活性。     

CaZr4—xTix（PO4）6（CZTP）的热膨胀

探讨了ＣａＺｒ４－ｘＴｉｘ（ＰＯ４）６（ＣＺＴＰ）离子置换与热膨胀的关系，随着Ｘ的增加，晶格参数ａ和ｃ减小，热膨胀系数αａ由负值变为正值，其平均的晶格膨胀系数大大增加，因而明显增大了ＣＺＴＰ系更的热膨胀系数。     

The thermo-mechanical properties and ferroelastic phase transition of RENbO4 (RE = Y,La, Nd,Sm, Gd,Dy, Yb) ceramics

In this work, RENbO₄ (RE = Y, La, Nd, Sm, Gd, Dy, Yb) ceramics with low density, low Young's modulus, low thermal conductivity, and high thermal expansion have been systematically investigated, the excellent thermo-mechanical properties indicate that RENbO₄ ceramics possess the potential as the new generation of thermal barrier coatings (TBCs) materials. X-ray diffraction and Raman spectroscopy phase structure identification reveal that all dense bulk specimens obtained by high-temperature solid-state reaction belonged to the monoclinic (m) phase with C12/c1 space group. The ferroelastic domains are detected in the specimens, revealing the ferroelastic transformation between tetragonal (t) and monoclinic (m) phases of RENbO₄ ceramics. The Young's modulus and hardness of the RENbO₄ ceramics measured by the NanoBlitz 3D nanoindentation method are discussed in details, and the lower Young's modulus (60-170 GPa) and higher hardness (the maximum value reaches 11.48 GPa) indicating that higher resistance of RENbO₄ ceramics to failure and damage. Lower thermal conductivity (1.42-2.21 W [m k]⁻¹ at 500°C-900°C) and lower density (5.330-7.400 g/cm³) than other typical TBCs materials give RENbO₄ ceramics the unique advantage of being new TBCs materials. Meanwhile, the thermal expansion coefficients of RENbO₄ ceramics reach 9.8-11.6 × 10⁻⁶ k⁻¹ and are comparable or higher than other typical TBCs materials. According to the first-order derivative of the thermal expansion rate, the temperature of the ferroelastic transformation of RENbO₄ ceramics can be observed.     

Ca1-xSrxSn4(PO4)6粉料的制备及膨胀特性

介绍了NZP晶体化学结构、组成、粉料制备、应用等方面的研究进展 ,并指出目前存在的问题。根据NZP晶体化学近零膨胀的特性 ,设计出 2个新的组成———SSP ,CSP及 3种固溶体。采用水热法和共沉淀法合成物相 ,并对粉体进行粒度分析 ,X ray衍射物相鉴定 ,IR结构分析 ,SEM形貌观察 ,测量了CSP/SSP热膨胀系数及力学强度     

Sintering and Properties of Monazite-Type CePO4

Monazite-type CePO₄ powder (average grain size 0.3 μm) was dry-pressed to disks or bars. The green compacts began to sinter above 950°C. Relative density ≧ 99% and apparent porosity <1% were achieved when the specimens were sintered at 1500°C for 1 h in air. The linear thermal expansion coefficient and thermal conductivity of the CePO₄ ceramics were 9 × 10⁻⁶/°C to 11 × 10⁻⁶/°C (200° to 1300°C) and 1.81 W/(m · K) (500°C), respectively. Bending strength of the ceramics (average grain size 4 μm) was 174 ± 28 MPa (room temperature). The CePO₄ ceramics were cracked or decomposed by acidic or alkaline aqueous solutions at high temperatures.     

Thermal Expansion of Homogeneous and Gradient Solid Solutions in the System KZr2(PO4)3─KTi2(PO4)3

Low-thermal-expansion ceramics having arbitrary thermal expansion coefficients were synthesized from homogeneous solid solutions in the system KZr₂(PO₄)₃─KTi₂(PO₄)₃ (KZP–KTP). Dense and strong ceramics were fabricated by sintering at 1100° to 1200°C with 2 wt% MgO. The thermal expansion coefficient increased from 0 to +3 × 10⁻⁶/°C with increasing x in KZr_{2 − x}Ti_x (PO₄)₃ (KZTP). In addition, a functionally gradient material with respect to thermal expansion was prepared by forming a series of KZTP solid solutions in a single ceramic body. By heating a pile of KZP and KTP ceramics in contact with each other, KZP and KTP bonded together to form a KZTP gradient solid solution near the interface.