材料期刊网

STRUCTURE FORMATION OF UNDERCOOLED Fe-30Ni ALLOY

J.F. Li , J.G. Li , X.P. Zhang and Y.H. Zhou (School of Materials Science and Engineering , Shanghai Jiao Tong University , Shanghai 200030 , China)

金属学报(英文版)

Bulk Fe-30Ni alloy melt was nudercooled up to 337K by combining the glass fluxing technique with superheating-cooling cycle. Grain refinement at low undercoolings was observed in the experiment in addition to that at high undercoolings. The current grain refinement mechanisms were examined, and it is concluded that the refined gains are all developed from dendrites, however the grain refinement at low undercoolings is due to chemical superheating, while that at high undercoolings due to rapid solidification contruction.

关键词: Fe-Ni alloy , null , null

SOLIDIFICATION MECHANISM OF UNDERCOOLED SINGLE PHASE ALLOYS

J.F. Li , G.C. Yang and Y.H. Zhou(State Key Laboratory of Solidification Processing , Northwestern Polytechnical University , Xi'an 710072 , China)

金属学报(英文版)

The solidification behavior of bulk undercooled Ni50Cu50 alloy was systematically investigated. Double recalescences were discovered for the first time in a single phase Ni-Cd alloy, in which there is no solid phase transition at elevated temperature. When the alloy melt was undercoolcd below the solidus temperature, the effect of nonequilibrium solidification could make the solid with the norminal composition C0 of the alloy nucleate and grow till tempemture approached To (the temperuture at which the free enengies of solid and liquid with C0 are equal). Following it, the nucleation and growth of the solid with more high melting point component were required, so the secondary recalescence took place. The concentration distribution in crystals was also analysed.

关键词: undercooled Ni-Cu alloy , null , null

Li,K|F,Cl互易系熔盐溶液的分子动力学计算机模拟研究

邵俊 , 徐桦 , 陈念贻

金属学报

用分子动力学方法对Li,K?F,Cl系熔盐溶液进行了计算机模拟研究。计算了径向分布函数、偏克分子混合能等热力学性质以及Li~+,K~+,F~-和Cl~-的扩散系数。计算值与实验值大体符合。根据计算结果,讨论了熔盐溶液中离子和空孔分布的规律。

关键词: 碱卤化物熔盐 , molecular dynamics , computerized simulation

Theoretical studies of g factors and defect structures for cubic, tetragonal, and orthorhombic Fe+ Centers in alkali halides MX (M = Li, Na; X = F, Cl)

Communications in Theoretical Physics

The EPR g factors for cubic, tetragonal and orthorhombic Fe+ centers in alkali halides MX (M = Li, Na; X = F, Cl) are calculated from second-order perturbation formulas of g factors based on cluster approach for 3d(7) ions in three symmetries. From calculations, the g factors of these Fe+ centers in MX crystals are reasonably explained and the defect structural data for the tetragonal and orthorhombic Fe+ centers are estimated. The results are discussed.

关键词: crystal;and ligand-field theory;electron paramagnetic resonance;defect structure;atomic screening constants;spin-orbit interaction;superposition model;resonance-spectra;epr parameters;crystal-field;scf functions;ions;co2+

Mg-14Li-1Al-0.1Ce合金在卤素溶液(NaX,X=F, Cl, Br和I)中腐蚀行为的研究

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Li_0.92Mg_4.08,而在NaF溶液中的腐蚀产物层的组分为Li₃Mg₇和Li_0.92Mg_4.08. 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

Mg-14Li-1Al-0．1Ce合金在卤素溶液（NaX，X=F，C1，Br和I）中腐蚀行为的研究

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

F^-离子对Li₂O-Al₂O₃-SiO₂系微晶玻璃晶化的影响

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,Li_xAl_xSi_1-xO₂固溶体析出以及Li_xAl_xSi_1-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

F-离子对Li2O-Al2O3-SiO2系微晶玻璃晶化的影响

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

COMPUTERIZED SIMULATION OF MOLTEN SALT SOLUTION OF Li,KF,Cl SYSTEM BY MOLECULAR DYNAMIC METHOD

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

高电导率F掺杂Li7La3Zr2O12石榴石结构固体电解质

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