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1.
在700℃与850℃的高温下,Fe3Al金属间化合物表面形成了Al2O3保护膜,使其抗氧化性能远优于不锈钢,2%Cr(原子百分比)加入Fe3Al会导致氧化过程初期氧化速率的增高,在熔融的硫酸盐和高压锅炉的烟气中,Fe3Al的耐热腐蚀性能优于高温合金GH132。 相似文献
2.
用循环氧化法研究了Fe-28Al-5Cr-0.1Zr(at%)和Fe-28Al-5Cr-0.5Nb(at%)金属间化合物的高温氧化行为.结果表明,含Zr的Fe3(Al,Cr)金属间化合物在800℃、1000℃、500h循环氧化后形成一个独特的晶须状氧化物层,微量Zr能增加氧化物层与基体金属的粘附性,从而提高了该合金的高温抗氧化性能.而含Nb的Fe3(Al,Cr)金属间化合物在1000℃、350h循环氧化后形成多孔的卷绕状形貌,对Fe3(Al,Cr)金属间化合物的高温抗氧化性没有改善. 相似文献
3.
研究了Fe3Al/TiC复合材料在高浓度SO2和SiO2细颗粒气流中的耐高温冲蚀磨损性能,并与Fe3Al基合金和钴基高温合金在同等实验条件下进行比较,结果表明:Fe3Al/TiC复合材料的高温抗冲蚀性优于2种对比材料。SEM分析显示:Fe3Al/TiC复合材料的冲蚀表面形貌以薄片屑形成机制为主。 相似文献
4.
一氧化碳氧化的钯催化剂研究Ⅰ.钯催化剂性能和反应条件对催化活性的影响 总被引:2,自引:0,他引:2
用浸渍法制备了不同担载量的Pd/Al_2O_3和Pt/Al_2O_3催化剂,在固定床微反中测定了它们催化CO氧化为CO_2的活性。结果表明,催化剂金属含量低于7×10 ̄(-5)时,Pd/Al_2O_3的活性优于Pt/Al_2O_3。催化剂经高温(800℃)水蒸汽预处理活性下降。稀释用的载体和GHSV在750~1500h ̄(-1)范围内对催化活性没有明显影响。 相似文献
5.
采用喷射共沉积法制备了Al-Fe2O3及Al-CuO复合体,Fe和Cu的质量分数分别为9.60%和5.50%.在热处理过程中,随着温度由600℃升高到800℃和1000℃,Fe3O4按Fe3O4FeOFe顺序被还原,得到Al-Fe/Al2O3复合材料,其中Fe以Al13Fe4相及AlFe相形式存在.Al2O3粒度为2~4μm均匀分布在基体中.Al/CuO复合体在900℃处理后,形成Al-Cu/Al2O3复合材料.文中对显微结构形成、反应进行的过程作了分析. 相似文献
6.
用循环氧化法研究了Fe-28Al-5Cr-0.1Zr(at%)和Fer-28Al-5Cr-0.5Nb(at%)金属间化合物的高温氧化行为。结果表明,含Zr的Fe3(Al,Cr)金属间化合物在800℃、1000℃、500h循环氧化后形成一个独特的晶须状氧化物层,微量Zr能增加氧化物层与基体金属的粘附性,从而提高了该合金的高温抗氧化性能。而含Nb的Fe3(Al,Cr)金属间化合物在1000℃、350h 相似文献
7.
施国洪 《江苏大学学报(自然科学版)》1994,(6)
在酸性氯化物电解液中进行Al_2O_3微粒与铁、镍的共沉积试验,对所得Fe-Ni-Al_2O_3复合镀层的摩擦磨损性能进行研究,结果表明,铁镍合金镀层中弥散分布8.51%重量的Al_2O_3微粒后,其摩擦系数和磨损率显著降低,镀层的摩擦磨损性能得到改善。 相似文献
8.
通过添加碱性氧化物MgO来调节γ-AL_2O_3表面的酸性,考察了不同镁含量对γ-AL_2O_3的表面酸性及积炭性能的影响,同时考察了以镁改性的γ-Al_2O_3为活性基体的FCC模式催化剂的活性及积炭性能,结果表明,加镁不改变γ-Al_2O_3表面的酸中心类型,只是减少了强Lewis酸中心,有利于抑制γ-Al_2O_3上的积炭反应,适量的镁对FCC模式催化剂的活性有所提高。 相似文献
9.
Fe基-Al_2O_3复合材料的界面研究 总被引:1,自引:0,他引:1
将工业还原铁粉、Al2O3颗粒、炭粉及某种适量粘结剂,通过粉末冶金方法在高温下进行烧结,制备了Al2O3颗粒增强Fe基复合材料。用STEM,TEM及SEM对界面结合机制进行了分析与研究。结果表明,烧结过程中在Al2O3颗粒与Fe基界面生成了中间相,使Al2O3与铁基有良好的结合强度,所制备的Fe基-Al2O3复合材料的硬度、耐磨性已超过相同含碳量的碳钢材料 相似文献
10.
高能量密度等离子体表面微晶化对Fe_3Al高温氧化的影响 总被引:1,自引:0,他引:1
应用高能量密度等离子体对Fe3Al进行微晶化处理,在合金表面获得了晶粒尺寸介于10~100nm的微晶层。对比研究了铸态Fe3Al微晶处理前后在空气中1000℃高温氧化的行为和规律,发现微晶化处理后,合金表面在氧化过程中形成了微晶氧化膜,极大地改善了氧化膜的塑性和粘附性,氧化速率显著降低,氧化动力学服从4次方规律。 相似文献
11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness. 相似文献
12.
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly. 相似文献
13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。 相似文献
14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death. 相似文献
15.
Miao Maosheng 《华南师范大学学报(自然科学版)》2014,(6)
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula- 相似文献
16.
Yang Weitao 《华南师范大学学报(自然科学版)》2014,46(6):137-138
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re- 相似文献
17.
Bernard Kirtman 《华南师范大学学报(自然科学版)》2014,(6)
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that 相似文献
18.
《上海师范大学学报(自然科学版)》2014,(5):550
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with 相似文献
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20.
《吉林大学学报(理学版)》2014,(5):1105
<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has 相似文献