火花塞陶瓷绝缘体高温分流电阻的研究

火花塞陶瓷绝缘体的高温分流电阻会影响火花塞的使用性能和寿命,笔者研究了氧化铝中Na2O含量、配方组成和烧结温度对火花塞陶瓷绝缘体高温分流电阻的影响。结果表明:随着氧化铝原材料中Na2O含量的增加,试样的高温分流电阻逐渐降低;在配方组成中,当CaO的含量由33%增加至40%,氧化铝原材料中Na2O含量为0.1%时,试样在500℃时的分流电阻由517MΩ提升至1 192MΩ;烧结温度低于1 580℃时,试样的高温分流电阻较低。     

钠基膨润土胶质价测试方法的改进

以两种人工钠化膨润土为研究对象,探讨了文献胶质价测试方法的不合理性、取土量和MgO量这两个关键因素。实验结果表明:用常规100 mL量筒测胶质价时,取土量和MgO量影响较大,有必要针对具体试样做条件试验,最佳条件是1#钠土为取3.00 g土、0.2 g MgO,2#钠土为取5.00 g土、0.33 g MgO。     

Cathode properties of metal trifluorides in Li and Na secondary batteries

Fluorine compounds have high discharge voltage due to its highly ionic metal-ligand bonds. In them, perovskite-type metal trifluorides with corner sharing matrix have large bottlenecks of diffusion pathways for intercalants. Iron trifluoride composites (FeF₃-C) prepared by planetary ball milling with carbon showed reversible charge/discharge behavior not only for Li, but also for Na anodes. X-ray diffraction and ⁵⁷Fe Mössbauer spectroscopy were applied to characterize the electrochemical properties of FeF₃ vs. Li and Na anodes. The cathode performances of the other commercially available transition metal trifluorides such as MF₃ (M = Ti, V, Mn, Co) have been also investigated.     

Influence of Zn2+ doping on the morphotropic phase boundary in lead-free piezoelectric (1 – x)Na1/2Bi1/2TiO3-xBaTiO3

A series of morphotropic phase boundary (MPB) compositions of (1–x)Na_1/2Bi_1/2TiO₃-xBaTiO₃ (x = 0.05, 0.055, 0.06, 0.065, 0.07), with and without 0.5 mol% Zn-doping was synthesized using the solid-state route. The samples were characterized using X-ray diffraction, dielectric analysis, and electromechanical measurements (piezoelectric d₃₃ coefficient, coupling factor k_p, mechanical quality factor Q_m, and internal bias field E_bias). The increase in the ferroelectric-relaxor transition temperature upon Zn-doping was accompanied by a shift of the MPB toward the Na_1/2Bi_1/2TiO₃-rich side of the phase diagram. Higher tetragonal phase fraction and increased tetragonal distortion were noted for Zn-doped (1 – x)Na_1/2Bi_1/2TiO₃-xBaTiO₃. In addition, ferroelectric hardening and the presence of an internal bias field (E_bias) were observed for all doped compositions. The piezoelectric constant d₃₃ and the coupling coefficient k_p decreased by up to ∼30%, while a 4- to 6-fold increase in Q_m was observed for the doped compositions. Apart from establishing a structure–property correlation, these results highlight the chemically induced shift of the phase diagram upon doping, which is a crucial factor in material selection for optimal performance and commercialization.     

CO2传感器的制作及特性

采用高温固相反应法制备了Na超离子导体（NASICON）的固体电解质材料，用IR技术分析了不同合成温度下制备的NASICON材料的基本性质。用所制得的NASICON材料制作了具有较高灵敏度和选择性的CO2气体传感器。     

Comparison of Superconductivity and Structure for YBa2Cu3Oy with Potassium and Sodium Doping

The nominal composition of YBa_2–x M _x Cu₃O _y (M = K, Na) cuprates with x 0.30 were synthesized by the standard solid-state reaction technique. X-ray diffraction (XRD) and the resistivity measurements were used to characterize the structure and the superconductivity of the doped cuprates. There was no impurity phase detected within the whole doping range. The structure of the main phase (123) has the orthorhombic with P _mmm symmetry. With increasing the content of dopants, the lattice constants and some other structural parameters are almost unchanged for M = K, whereas they changed for M = Na. The refined contents of dopants are consistent with that of the nominal ones. The zero resistance temperature T _c0 decreases sharply with the increase of the content of potassium in potassium-doped samples as x 0.20. For sodium-doped YBa_2–z Na _x Cu₃O _y cuprates, T _c0 varies very little. The difference in superconductivity depression may result from the shift oxygen, which transfers conducting carriers from Cu-O chains to Cu-O₂ sheets or the structural stress effect.     

STUDY OF POSITRON ANNIHILATION ONE DIMENSION ANGULAR-CORRELATION RADIATION ON POLYCRYSTAL Na~+ CONDUCTOR Na_5Y_(1-x)Cr_xSi_4O_(12)

With positron annihilation radiation onedimension angular-correlation device,it ismeasured that positron annihilation radiationone dimension angular-correlation curves ofpolycrystal sodium ion conductor Na_5Y_(1-x)Cr_xSi_4O_(12)(NYCS)system.After electronmomentum distribution curves arenormalized,linear parameters arecalculated.The parameters H,W and Sshow the change of Na~+ ion vacancyconcentration in NYCS series samples.Theresults show that parameters H,W and S ofone dimension angular-correlation curves ofthose samples vary greatly with Cr_2O_3contents.With Cr_2O_3 content increasing,Hand S parameters increase,but W decreases,and reaches extremes at x=0.05;then withCr_20_3 adding continually,parameters H andS decrease gradually,parameter W increasesgradually.This shows that,in addtion toCr_2O_3,the conductivity has close relation     

CaO—SiO2—Na2O三元渣系的挥发率

采用失重法对ＣａＯ－ＳｉＯ２－Ｎａ２Ｏ三元渣系在不同温度下的挥发率进行了测量。结果表明，在烧结温度下，低熔点渣的挥发率呈三段式变化，而高熔点渣无此特性；当修正碱度Ｒ′＞１、成分固定时，只有在温度超过其流动温度时才能显著提高挥发率；温度一定时，挥发率随着碱度Ｒ及Ｎａ２ＣＯ３含量的增加而提高；当Ｒ′＜１时，温度、碱度、Ｎａ２ＣＯ３含量对挥发率的影响都不大。     

离子交换分离-Na2EDTA滴定法测定含镍钴锌精矿中锌的改进

随着锌资源的日益枯竭,锌精矿的成分也越来越复杂化,准确测定锌精矿中锌含量具有重要意义。试验以盐酸-氟化铵-硝酸-硫酸-高氯酸溶解样品,在盐酸(1+5)的介质中,用大孔型强碱性阴离子树脂分离镍、钴、铁、锰、铝等,用氨水-氯化铵溶液洗脱Zn²⁺,在分离杂质后的溶液中加入少量氟化铵掩蔽残余的铁,硫代硫酸钠溶液掩蔽微量铜,用Na₂EDTA标准滴定溶液直接滴定锌、镉合量,扣除镉量即为锌量,建立了离子交换分离-Na₂EDTA滴定法测定含镍钴锌精矿中11%～62%锌的方法。研究了金属离子在3种典型强碱性阴离子树脂上,不同酸度下的分配系数K_d,最终选择了在D296型大孔型强碱性阴离子交换树脂上、盐酸(1+5)介质中进行离子交换分离。试验结果表明少量NH⁺₄的存在不影响Zn²⁺的吸附,离子交换柱柱高为30 cm时吸附损失率小于0.10%,样品溶液通过离子交换柱的流速为8～10 mL/min时工作效率较高,吸附损失率低。方法用于测定3个含镍钴锌精矿样品中锌,测定结果与使用氢氧化钠沉淀分离-EDTA滴定法及丁二酮肟沉淀分离-EDTA滴定法结果基本一致,结果的相对标准偏差(RSD,n=11)为1.6%～5.6%。     

用过硫酸钠氧化富集钴镍渣中的钴

研究了从湿法炼锌净化钴镍渣中回收有价金属。提出了处理钴镍渣的系统工艺，探讨了过硫酸钠浸出钴镍渣氧化沉钴的影响因素。在氧化温度80℃，过硫酸钠用量为理论量的8倍，氧化时间2h，溶液pH=5．0～5．2的最佳工艺条件下，钴富集达40倍。