Y.L.Cheng
,
J.F.Li
,
J.Q.Zhang
,
C.N.Cao
,
F.H.Cao
,
Z.Zhanq
金属学报(英文版)
The electrochemical features of commercial airframe material, Al alloy LY12, in 0.349mol/L neutral sodium chloride (NaCl) and sodium sulfate (Na2SO4) solutions were investigated by electrochemical impedance spectroscopy (EIS) and potentiody-namic polarization techniques. The microstructure of the as-tested samples was stud-ied by scanning electron microscopy. The results show that the Nyquist plots of LY12 at different immersion time displayed different features, indicating that the Cl^- ions elevate the corrosion rate and inhibit the repassivation of a metastable pit. It also shows that the corrosion product of LY12 formed in SO4^2- solution isn't easy to dis-solve, and it urill cover the surface of working electrode in the electrolyte. SEM images indicate that the corrosion apparent area and pit number of LY12 in NaCl solution are greater than that in Na2SO4 solution.
关键词:
LY12 aluminum alloy
,
null
,
null
马毅斌
,
李宁
,
黎德育
,
张密林
,
黄晓梅
腐蚀学报（英文）
用电化学方法研究了Mg-14Li-1Al-0.1Ce合金在卤素溶液(NaX, X=F, Cl,Br和I)中的腐蚀行为并用失重法测定其腐蚀速率, 用扫描电镜(SEM)观察腐蚀后的表面形貌, 利用XRD检定腐蚀产物的相组成.结果表明, 合金在卤素溶液中的腐蚀速率由低到高的顺序是:NaF<NaI<NaBr<NaCl. 经过48 h腐蚀后, 合金在NaCl、NaBr和NaI溶液中的腐蚀产物层的组分为Mg(OH)2,Li3Mg7和Li0.92Mg4.08,而在NaF溶液中的腐蚀产物层的组分为Li3Mg7和Li0.92Mg4.08. 此外, 合金在NaF溶液中的电化学活性非常低, 出现了钝化现象.电化学阻抗谱表明合金腐蚀产物层不能起到防止基体腐蚀的作用.
关键词:
镁锂合金
,
corrosion
,
sodium halide
,
EIS
,
XRD
马毅斌
,
李宁
,
黎德育
,
张密林
,
黄晓梅
腐蚀学报（英文）
用电化学方法研究了Mg-14Li-1Al-0．1Ce合金在卤素溶液（NaX，X=F，C1，Br和I）中的腐蚀行为并用失重法测定其腐蚀速率，用扫描电镜（SEM）观察腐蚀后的表面形貌，利用XRD检定腐蚀产物的相组成．结果表明，合金在卤素溶液中的腐蚀速率由低到高的顺序是：NaF〈NaI〈NaBr〈NaCl．经过48h腐蚀后，合金在NaCl、NaBr和NaI溶液中的腐蚀产物层的组分为Mg（OH）2，Li3Mg7和Li0.92Mg4.08，而在NaF溶液中的腐蚀产物层的组分为Li3Mg7和Li0．92Mg4．08．此外，合金在NaF溶液中的电化学活性非常低，出现了钝化现象．电化学阻抗谱表明合金腐蚀产物层不能起到防止基体腐蚀的作用．
关键词:
镁锂合金
,
腐蚀
,
卤化钠
,
EIS
,
XRD
胡安民
,
梁开明
,
顾守仁
无机材料学报
采用差热分析(DTA),X射线衍射分析(XRD),扫描电镜(SEM等分析手段研究了F-离子对Li2O-Al2O3-SiO2系微晶玻璃形核和晶化的影响.结果发现,引入F-离子使得玻璃的析晶峰值温度降低,玻璃的析晶活化能E降低,晶化指数n加大.引入F-离子后,一方面促进了玻璃析晶和晶化,LixAlxSi1-xO2固溶体析出以及LixAlxSi1-xO2固溶体向β-锂辉石固溶体转变加快,晶化后的晶粒尺寸加大,析晶活化能E,晶化指数n与扫描电镜(SEM)分析一致.表明F-离子促进了玻璃晶化和离子扩散.
关键词:
差热分析
,
glass-ceramics
,
nucleation
,
crystallization
胡安民
,
梁开明
,
顾守仁
无机材料学报
doi:10.3321/j.issn:1000-324X.2003.06.003
采用差热分析(DTA),X射线衍射分析(XRD),扫描电镜(SEM)等分析手段研究了F-离子对Li2O-Al2O3-SiO2系微晶玻璃形核和晶化的影响.结果发现,引入F-离子使得玻璃的析晶峰值温度降低,玻璃的析晶活化能E降低,晶化指数n加大.引入F-离子后,一方面促进了玻璃析晶和晶化,LixAlxSi1-xO2固溶体析出以及LixAlxSi1-xO2固溶体向β-锂辉石固溶体转变加快,晶化后的晶粒尺寸加大,析晶活化能E,晶化指数n与扫描电镜(SEM)分析一致.表明F-离子促进了玻璃晶化和离子扩散.
关键词:
差热分析
,
Li2O-Al2O3-SiO2系微晶玻璃
,
形核
,
晶化
SHAO Jun Shanghai University of Science and Technology
,
Shanghai
,
ChinaXU Hua CHEN Nianyi Shanghai Institute of Metallurgy
,
Academia Sinica
,
Shanghai
,
China SHAO Jun Associate Professor
,
Dept.of Chemistry
,
Shanghai University of Science and Technology
,
Shanghai 201800
,
China
金属学报(英文版)
The structure and properties of molten salt solution o J Li,KF,Cl system have been investigedby computerized simulation of molecular dynamic method.The partial RDF,the partial molarenergy of mixing and the diffusion coeffients of Li~+,K~+,F~- and Cl~- have been calculated.The results are in agreement with the experimental values.The regularities of the distributionof ions and mieroscopic holes are discussed based on the results of computerized simulation.
关键词:
alkali halide
,
null
,
null
,
null
刘才
,
温兆银
,
芮琨
无机材料学报
doi:10.15541/jim20150163
通过传统固相反应法合成一种新型的F掺杂Li7La3Zr2O12 (LLZO)石榴石结构固体电解质.添加适量LiF和CaF2等氟化物经过两步煅烧在室温下获得纯立方相的LLZO陶瓷粉体,验证氟离子掺杂具有稳定石榴石结构立方相和增强陶瓷烧结活性的作用.制备的1wt％ LiF-LLZO电解质总电导率达5×10-4 S/cm,接近立方相LLZO的体电导率,电导活化能仅为0.26 eV,低于其他阳离子掺杂的LLZO.(321)、(400)、(642)和(800)晶面衍射峰由于晶粒的生长取向而显著增强,陶瓷内部晶界消失,形成由闭气孔构成的独特显微结构,导致该新型电解质的晶界阻抗的消失和总电导率的提升.
关键词:
固体电解质
,
石榴石结构
,
氟离子掺杂
,
显微结构
Physical Review B
The Hamiltonian for a four-sublattice Heisenberg ferrimagnet or ferromagnet with different exchange constants (J(ab) = J(cd) not equal J(bc) = J(da)) was established. An extended Bogoliubov transformation was developed by solving an equation group, consisting of 20 equations and 20 unknowns. The procedure for solving the equation group was carried out by introducing a simple way of reducing the numbers of the equations and the unknowns. The spin-wave spectra in the present system have been determined by performing the standard Holstein-Primakoff transformation and the Bogoliubov one. It has been found that the spin-wave spectra of the present system depend on the exchange constants and that the degeneracy of the spin-wave spectra remains. The results for a special case (J(ab) = J(bc)) i.e., an antiferromagnet are discussed briefly. The spin-wave spectra of the four-sublattice Heisenberg antiferromagnet are found to be degenerative also and they are linear in k for small k.
关键词:
model
