包覆型ZrO2（3Y）粉体研制

用微波法制备单分散、纳米水合二氧化锆，利用异相成核工艺在水合二氧化锆粒子表面均匀包覆一层Y（OH）3，制备出包覆型ZrO2（3Y）粉体先驱体．最后对煅烧ZrO2（3Y）粉体进行相结构分析，发现在室温下包覆型ZrO2（3Y）粉体中无m－ZrO2存在．结果表明；利用包覆的方法能将Y2O3均匀地加入到ZrO2中，提高ZrO2（3Y）粉体中亚稳定t－ZrO2的含量．     

高分散、均混合Al2O3-SiC-ZrO2(3Y)水悬浮液

用微波法制备主水合二氧化锆,通过包覆工艺,将Ｙ（ＯＨ）３均匀地包覆在水合二氧化锆粒子表面,制备出ＺＯ２（３Ｙ）的先驱体。然后用聚甲基丙烯酸铵（ＰＭＡＡ－ＮＨ４）对α－Ａｌ２Ｏ３、纳米ＳｉＣ及包覆水合二氧化锆表面的改性。     

高分散、均混合 Al2O3-SiC-ZrO2(3Y)水悬浮液

用微波法制备纳米水合二氧化锆, 通过包覆工艺, 将Y(OH)     

包覆型ZrO2(3Y)粉体研制

用微波法制备单分散、纳米水合二氧化锆，利用异相成核工艺在水合二氧化锆粒子表面均匀包覆一层Y（OH）₃，制备出包覆型ZrO₂（3Y）粉体先驱体．最后对煅烧ZrO₂（3Y）粉体进行相结构分析，发现在室温下包覆型ZrO₂（3Y）粉体中无m－ZrO₂存在．结果表明；利用包覆的方法能将Y₂O₃均匀地加入到ZrO₂中，提高ZrO₂（3Y）粉体中亚稳定t－ZrO₂的含量．     

Al2O3和Y2O3包覆的SiC复合粒子制备

本文利用非均匀成核法,将Al（OH）3和Y（OH）3均匀地包匿在SiC粒子表面,制备出被覆Al2O3和Y2O3的SiC复合粒子．包覆Al（OH）3的SiC粒子,其等电点IEP的pH=3．4移至pH=7.3,再用Y（OH）3包覆表面被覆Al（OH）3的SiC复合粒子后,其等电点IEP又从pH=73移至pH=8.6左右．并且表面包覆的SiC粒子,其水悬浮液流变性质发生了变化．经盐酸滴定表明,涂层物质的包覆率可达95％以上．     

硬脂酸包覆对纳米Y2O3:Eu发光性质的影响

采用熔融包覆法制备出表面包有硬脂酸的纳米级 Y2O3 ∶Eu发光粉体。运用粒度测试仪、X射线衍射(XRD)、荧光光谱(FP)、红外光谱(IR)、紫外光谱(UV)对其进行了一系列表征。结果表明硬脂酸表面包覆改性后的 Y2O3 ∶Eu 发光强度明显提高,这是由于硬脂酸包覆后减少了纳米Y2O3∶Eu表面的羟基以及不饱和键的数目,从而提高了发光材料的发光强度。     

纳米ZrO_2、Al_2O_3单相及混合粉体的分散稳定性研究

以蒸馏水和无水乙醇作为分散介质,研究了六偏磷酸钠(NaPO3)6、聚乙二醇和聚丙烯酸对纳米Al2O3、纳米ZrO2单相及其混合粉体悬浮液分散稳定性的影响。结果表明:纳米Al2O3、ZrO2单相粉体在乙醇中的分散性较好,两者的混合粉体在水或乙醇中的分散性差别不大,主要取决于分散剂的种类,当pH=6～8时悬浮液最稳定,其中以聚丙烯酸为分散剂时分散效果最佳,六偏磷酸钠次之,聚乙二醇最差。     

聚合物分散剂对纳米TiO_2水悬浮液分散稳定性的影响

纳米TiO2复合乳胶漆的制备一般要求预先分散纳米TiO2并制成水悬浮液。为了制备稳定分散的纳米TiO2水悬浮液,研究了乳胶漆中常用的分散剂SN5040和PEG对纳米TiO2在水溶液中分散稳定性的影响,并分析了分散剂的作用机理。实验结果表明:SN5040能有效分散纳米TiO2,按照先SN5040后PEG的方式添加一定比例的混合分散剂,PEG能在SN5040吸附层上嵌入式吸附,显著提高了纳米TiO2的Zeta电位值,更有利于纳米TiO2水悬浮液的分散稳定性。红外光谱分析(FT-IR)表明:SN5040主要是通过与表面裸露的Ti4+形成配位键而吸附到纳米TiO2粒子表面上的。     

包覆型纳米SiC-Al2O3水悬浮液流变特性研究

本文通过在纳米SiC颗粒表面包覆一层Al2O3,使包覆型SiC与Al2O3具有相似的表面化学性质,从而包覆型SiC-Al2O3混合粉悬浮液具有相似于单相Al2O3悬浮液的流变性质。研究了分散剂、颗粒匹配及温度对包覆型SiC-Al2O3混合粉悬浮液流变性质的影响。结果表明,对于亚微米粉,尤其纳米粉,高聚物电解质分散剂不能改善其流变性;合适的颗粒匹配及温度可以改善悬浮液的流动性。,The surface chemical property of SiC was similar to that of Al2O3 by coating SiC with Al2O3,so that the rheological behavior of coated SiC-Al2O3 suspension was like to that of single phase Al2O3 suspension.The effect of dispersant,size distribution and temperature on rheological behavior of coated SiC-Al2O3 suspension were studied.Results indicated that polyelectrolyte did not improve rheological behavior for fine powder suspension,especially for nanosized powder suspension,but proper size distribution and temperature could.     

H_2O_2处理碳包覆铁纳米颗粒的表面特性及分散行为

采用体积分数30%的H2O2处理碳包覆铁纳米粒子外层的非晶态类石墨碳层,并将其超声分散于水介质中,通过改变pH值分析测定碳包覆铁纳米粒子表面zeta电位和粒径。结果表明:碳包覆铁纳米粒子非晶碳层的特殊结构可通过双氧水化学处理使其表面产生羧基和羟基;在强碱性介质下,羟基和羧基可强化颗粒间的静电斥力,提高碳包覆铁纳米粒子在水介质中的分散性能。当pH值约为11.5时,碳包覆铁纳米粒子表面zeta电位为48 mV,水合粒子粒径可达到110 nm。     

Thermodynamic properties of seven gaseous halogenated hydrocarbons from acoustic measurements: CHClFCF3, CHF2 CF3, CF3 CH3, CHF2CH3, CF3CHFCHF2, CF3CH2CF3, and CHF2CF2CH2F

Measurements of the speed of sound in seven halogenated hydrocarbons are presented. The compounds in this study are 1-chloro-1,2,2,2-tetrafluoroethane (CHClFCF₃ or HCFC-124), pentafluoroethane (CHF₂ CF₃ or HFC-125), 1,1,1-trifluoroethane (CF₃CH₃ or HFC-143a), 1,1-difluoroethane (CHF₂CH₃ or HFC-152a), 1,1,1,2,3,3-hexafluoropropane (CF₃CHFCHF₂ or HFC-236ea), 1,1,1,3,3,3-hexafluoropropane (CF₃CH₂CF₃ or HFC-236fa), and 1,1,2,2,3-pentafluoropropane (CHF₂CF₂CH₂F or HFC-245ca). The measurements were performed with a cylindrical resonator at temperatures between 240 and 400 K and at pressures up to 1.0 MPa. Ideal-gas heat capacities and acoustic virial coefficients were directly deduced from the data. The ideal-gas heat capacity of HFC-125 from this work differs from spectroscopic calculations by less than 0.2% over the measurement range. The coefficients for virial equations of state were obtained from the acoustic data and hard-core square-well intermolecular potentials. Gas densities that were calculated from the virial equations of state for HCFC-124 and HFC-125 differ from independent density measurements by at most 0.15%, for the ranges of temperature and pressure over which both acoustic and Burnett data exist. The uncertainties in the derived properties for the other five compounds are comparable to those for HCFC-124 and HFC-125.     

Microstructure and Strength of Al2O3/Al2O3 Joints Bonded with ZnO-Al2O3-B2O3-SiO2 Glass-Ceramic

ZnO-Al2O3-B2O3-SiO2 （ZABS） glass powder was used as interlayer to join alumina ceramics. The effect of joining temperature on the microstructure and strength of joints was investigated. The results showed that the ZABS glass can react with alumina substrate to form a layer of ZnAl2O4 at Al2O3/glass interface. Bending test exhibited that low joining temperature （1150℃） led to low joint strength due to the formation of pores in the interlayer, originated by high viscosity of the glass. High joining temperature （1250 ℃） also resulted in low joint strength, because of large CTE （coefficient of thermal expansion） mismatch between amorphous interlayer and alumina substrate. Therefore, only when the joining temperature was appropriate （1200℃）, defect-free interface and high joint strength can be obtained. The optimum joint strength reached 285 MPa, which was the same as the base material strength.     

Calculation of the Quasiternary Systems:Si_3N_4-Y_2O_3-SiO_2,Y_2O_3-SiO_2-BeO and Y_2O_3-Al_2O_3-BeO

Based on the thermodynamic model of Kaufman for the calculation of quasibinary and quasiternary system, numerical method for the calculation of stable equilibrium is developed and thermodynamic data of undefined phases are discussed in this work for several ceramic systems.The calculated isothermal sections in Si3N4-Y2O3-SiO2 system meet well with other previous calculated phase diagrams and experimental results. The diagrams in Y2O3-SiO2-BeO and Y2O3-Al2O3-BeO systems are calculated for the approach of prediction.     

Plasma spraying of Al2O3 and Al2O3Y2O3

A microstructural study has been carried out of plasma-sprayed Al₂O₃ and mixed and sintered Al₂O₃Y₂O₃. In order to ascertain the degree of metastability achieved by plasma spraying, these results are compared with a similar experiment utilizing a CO₂ laser for melting and the hammer-and-anvil technique for quenching of the same materials. X-ray diffraction methods were used to determine the obtained phases and crystal structures. In addition, transmission electron microscopy was used to confirm the phases present and to study their morpology. The porosity was studied with both mercury intrusion porosimetry and small angle neutron scattering. The addition of Y₂O₃ is shown to decrease the porosity from 15% to 7.5%. Adhesion is likewise related to the addition of Y₂O₃ and it is seen that adhesion of the mixture is measurably improved over that of pure Al₂O₃. The implication of these results is discussed.     

溶胶凝胶法制备Er3+-Yb3+共掺纳米SiO2粉

利用溶胶-凝胶法合成了Er2O3-Yb2O3-SiO2纳米二氧化硅(SiO2)粉。Er3 和Yb3 直接加入有机酸催化的TEOS反应溶液中,凝胶后经过700~900℃,得到Er3 -Yb3 共掺纳米SiO2粉。样品经过红外光谱、XRD、TEM等分析,结果表明,纳米粉的粒径受有机酸比例和处理温度的影响。在室温PL谱上,样品可观察到较强的1530nm荧光,同时镱的引入对掺铒SiO2纳米粉在1.54μm的荧光发射有增强作用。     

Si_2N_2O-Al_2O_3-La_2O_3和Si_2N_2O-Al_2O_3-CaO系统的亚固相关系

本文给出了 Si_2N_2O-Al_2O_3-La_2O_3和 Si_2N_2O-Al_2O_3-CaO 系统的亚固相图。实验结果表明:在 Si_2N_2O-Al_2O_3-CaO 系统中有一个未知结构的新化合物 CaO·Si_2N_2O,在3CaO·Si_2N_2O 和3CaO·Al_2O_3两化合物之间形成连续立方固溶体。而 Si_2N_2O-Al_2O_3-La_2O_3系统中则没有发现新化合物。在两个系统的富 Si_2N_2O区,过量的 Si_2N_2O 与 La_2O_3和 CaO 分别反应形成 Si_3N_4与 La_(10)[SiO_4]_(?)N_2(H-相)(和 CaSiO_3。所研究的这两个三元系统中,分别形成了如下几个四元相容性区。在 Si_2N_2O-Al_2O_3-La_2O_3系统内有:H-Si_3N_4-La_2O_3·Si_2N_2O-La_2O_3·Al_2O_3;H-Si_3N_4-La_2O_3·Al_2O_3-La_2O_3·11 Al_2O_3;H-Si_3N_4-La_2O_3·11 Al_2O_3-Al_2O_3;H-Si_3N_4-Al_2O_3-O′s.s;H-Si_3N_4-O′s.s-Si_2N_2O在 Si_2N_2O-Al_2O_3-CaO 系统内有:Si_3N_4-CaSiO_3-CaO·Si_2N_2O-3CaO·Al_2O_3;Si_3N_3-CaSiO_3-3CaO·Al_2O_3-2CaO·Al_2O_3·SiO_(?);Si_(?)N_(?)-CaSiO_3-2CaO·Al_2O_3·SiO_2-Al_2O_3;Si_3N_4-CaSiO_3-Al_2O_(?)-O′s.s;Si_3N_4-CaSiO_3-O′s.s-Si_(?)N_(?)O     

Subsolidus,high temperature phase relations in the systems Al2O3-Cr2O3-ZrO2, MgO-Cr2O3-ZrO2 and MgO-Al2O3-ZrO2

In the temperature range 1600 to 1900° C, the system A₂O₃-Cr₂O₃-ZrO₂ is characterized by the coexistence of ZrO₂ (unstablilized) and an (Al, Cr)₂O₃ solid solution series. In the systems MgO-Cr₂O₃-ZrO₂ and MgO-Al₂O₃-ZrO₂ a nearly stoichiometric spinel coexists with both stabilized and unstabilized ZrO₂. At temperatures above 1600°C a new ternary Mg-Al-Zr oxide becomes stable in the MgO-rich part of the MgO-Al₂O₃-ZrO₂ system.