Zhiquan LIU
,
Douxing LI
,
Xiaolei XU
,
Liang WANG
,
Zukun HEI
材料科学技术（英文）
Two body centered tetragonal (bct) crystal structures of alpha"-Fe16N2 with x=0.25, z=0.3125 (Jack-1) and x=0.222, z=0.306 (Jack-2) respectively, were analyzed theoretically with EMS software package. The simulation of diffraction patterns indicates that both diffraction patterns of the same axis in these two structures obey bcc extinction rule. The conclusion is also obtained from the analyses of the diffracted waves. alpha"-Fe16N2 precipitates in the diffusion layer of ion-nitrided alpha-iron have been studied with transmission electron microscope (TEM). We have distinctly observed the electron diffraction patterns of alpha"-Fe16N2 in [100], [111], [110], [011], [210], [021], [311], [113], [331] and [133] zone axes with perfect symmetry, which indicate the parallel orientation relationship with alpha matrix: <001>(alpha")//<001>(alpha), {100}(alpha")// {100}(alpha). The analyses of diffraction patterns, which obey bcc extinction rule, verify the bet structure of alpha"-Fe16N2 discovered by X-ray diffraction.
关键词:
Materials and Corrosion-Werkstoffe Und Korrosion
CO(2) corrosion inhibition of N80 steel in liquid single-phase and liquid/particle two-phase flow by 2-undecyl-1-hydroxyethyl imidazoline (HEI-11) and 2-undecyl-1-hydroxyethyl-1-hydroxyethyl quaternary imidazoline (HQI-11) was investigated using weight loss, potentiodynamic polarization, EIS, and scanning electron microscope (SEM) techniques. The results show that the corrosion rate in the absence and presence of the imidazolines is strongly dependent on the flow condition and presence of entrained sand particles. The imidazolines function via a mixed-type corrosion inhibition mechanism. The inhibition efficiencies of the imidazolines followed the trend HQI-11 > HEI-11 in all the systems studied. inhibition mechanism has been discussed in relation to the polycentric adsorption sites on the imidazoline molecules.
关键词:
3-percent nacl solution;co2 corrosion;mild-steel;eis;performances;efficiency;pipelines;sand
Corrosion Engineering Science and Technology
Four kinds of imidazoline inhibitors with different hydrophilic group, i.e. carboxymertyl imidazoline (CMI-11), hydroxyethyl imidazoline (HEI-11), aminoethyl imidazoline (AEI-11) and imidazoline (IM-11) had been synthesised and characterised by infrared and ultraviolet spectra. The inhibition performance of these imidazoline inhibitors for CO(2) corrosion of N80 in 3%NaCl solution was investigated through linear polarisation resistance, polarisation curve and electrochemical impedance spectroscopy. In order to study the relationship between the molecular structure and inhibition properties of these imidazoline inhibitors, quantum chemical calculations have been also applied. The results showed that the presence of a hydrophilic group was beneficial to the corrosion inhibition properties of these imidazoline inhibitors, and the inhibition efficiency follows the order: CMI-11 > HEI-11 > AEI-11 > IM-11. The calculated quantum chemical parameters supported that the lower the lowest unoccupied and highest occupied molecular orbital energy gap, the higher the inhibition efficiency. The theoretical calculation was in good agreement with experimental results.
关键词:
carbon dioxide corrosion;corrosion inhibitor;imidazoline;hydrophilic;group;quantum chemical calculation;mild-steel;acidic media;impedance spectroscopy;molecular-structure;painted metals;eis;derivatives;efficiency
余勇
,
潘晓霞
,
戎咏华
金属学报
由于奥氏体不锈钢在核工业中的重要应用背景，本文对具有相同面心立方晶体结构的γ－Fe中的空位（V）、自间隙原子（SIA）、间隙氦原子（HeI）以及氦－空位（He－V）团簇的形成能进行了分子静力学计算。Fe－Fe、Fe－He和He－He原子间相互作用分别用修正嵌入原子法（MEAM）、Wilson-Johnson势和Beck势来描述。计算结果表明SIA<100>形成能远小于α－Fe中的SIA<110>形成能，HeI在γ－Fe中的四面体间隙位最稳定。团簇HenV0、HenV1、HenV2、HenV3中的He原子数分别达到2、5、9、11时即可以形成Frenkel对来实现自捕陷，实现自捕陷时的He/V不是定值，并随空位数的增加有逐渐下降趋势。
关键词:
形成能
,
point deffect
,
helium-vacancy cluster
,
self-trapping
余勇
,
潘晓霞
,
戎咏华
金属学报
doi:10.3321/j.issn:0412-1961.2007.01.001
利用分子静力学计算了γ-Fe中的空位(V)、自间隙原子(SIA)、间隙氦原子(HeI)和氦-空位(He-V)团簇的形成能.Fe-Fe,Fe-He和He-He原子间相互作用分别用修正嵌入原子法(MEAM)、Wilson-Johnson势和Beck势来描述.计算结果表明,SIA<100>形成能远小于α-Fe中的SIA<110>形成能,HeI在γ-Fe中的四面体间隙位最稳定.团簇HenV0,HenV1,HenV2和HenV3中的He原子数n分别达到2,5,9和11时即可形成Frenkel对来实现自捕陷,实现自捕陷时的He/V个数比不是定值,且随空位数的增加有逐渐下降趋势.
关键词:
γ-Fe
,
点缺陷
,
形成能
,
氦-空位团簇
,
自捕陷
