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稀土钼合金力学和热发射性能的研究 总被引:3,自引:1,他引:2
稀土氧化物 (La2 O3 、Y2 O3 )在强化钼的同时 ,对钼具有显著的韧化作用 ,即具有综合强韧化作用。稀土钼材作为高温结构材料正逐步取代Al Si K掺杂钼 (ASK)和TZM钼合金 ;通过成分设计和加工工艺优化 ,稀土钼还是一种工作温度低、无放射性污染的新型阴极材料 ,由稀土钼作为阴极的电子管 ,发射性能与寿命均达到或超过同类型W ThO2 阴极电子管 ,达到实用化水平。因此 ,稀土钼作为一种集结构与功能于一身的新型材料 ,有广泛的应用前景 相似文献
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利用双层辉光等离子渗金属技术,在20号钢表面进行钨-钼-钇和钨-钼共渗,并获得合金渗层。利用扫描电镜(SEM)和能谱仪(EDS)进行微观组织分析和成分分布检测,用X射线衍射仪(XRD)进行结构分析,用Fick第二扩散定律分别计算上述二元共渗和三元共渗渗层的钨、钼扩散系数以及扩散激活能。研究表明:钨-钼-钇和钨-钼共渗渗层组织均为柱状晶,渗层与基体之间有一条分界线。稀土钇的加入细化了渗层的组织;钨-钼-钇共渗层物相主要为:Fe(W,Mo,Y),Fe3Mo,Fe17Y2,W,Y等;钨-钼共渗渗层物相主要为:Fe(W,Mo);钇的加入使渗层中钼在距表面12~15,24~25,35~36μm处的扩散系数分别提高了1.72,1.85,2.10倍,平均增大1.89倍。而钨原子的扩散系数在加入稀土元素后减小了0.92,0.99,0.76,平均降低了0.89倍;稀土钇的加入降低了钼原子的扩散激活能,说明了稀土钇对钼具有催渗作用,但对钨没有催渗作用。 相似文献
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《中国钨业》2015,(3)
钼粉的费氏粒度和K含量是钼粉的两个重要物化指标。文章研究了在不同工艺条件下,不同粒度、不同K含量的Mo O3原料对还原产品Mo O2、Mo粉粒度及K含量之间的影响,采用平均粒度测定仪测定了Mo O2、Mo粉粒度,采用偏振塞曼原子吸收分光光度计测定了K含量。结果表明,粒度较大的Mo O3对应Mo粉的粒度也相对较大;纯Mo O3原料中K含量越高,经相同工艺还原所得Mo粉的粒度越大;随着一段还原温度的升高,对应Mo O2、Mo粉中K含量都呈现出先降低、后增长的规律;提高一段还原氢气露点,中间Mo O2、Mo粉粒度、K含量都呈增长趋势;增加一段还原的料层厚度,对应Mo O2、Mo粉中K含量呈降低趋势。 相似文献
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《稀有金属》2016,(1)
通过试验研究了钼精矿在真空分解过程中的物相和形貌演变规律。结果表明钼精矿料球在分解过程中由外及内逐层分解,分解过程中料球出现了Mo,Mo_2S_3,Mo S_23层,且获得的钼产品呈疏松多孔海绵状。Mo S_2的分解遵循逐步分解的原则,即Mo S_2先分解为Mo_2S_3,然后Mo_2S_3再分解为Mo。升高温度,有利于钼精矿的分解。在压力为10~20 Pa时,钼精矿在1423 K已经开始分解;在1523 K时料球外层有明显Mo_2S_3生成;在1573 K时已有金属Mo生成;至1773 K下分解2 h,分解反应已完毕,得到了海绵态的金属钼和硫磺产品。所得到的金属钼产品钼含量达到93.69%,杂质元素含量很低,主要杂质为Si O_2和Ca O。进一步控制分解过程条件,所得到的金属钼产品中的钼含量可达到97%以上。分解过程中硫磺可采用冷凝或者液化的方式回收,回收率达到98.20%,得到的硫磺质量较高,硫含量达到98.60%,接近工业硫磺标准。 相似文献
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稀土钼合田力学和热发射性能的研究 总被引:6,自引:4,他引:2
稀土氧化物(La2O3,Y2O3)在强化钼的同时,对钼具有显著的韧化作用,即具有综合强韧化作用,稀土钼材作为高温国结构材料正逐步取代Al-Si-K掺杂钼(ASK)和TZM钼合金;通过成分设计和加工工艺优化,稀土钼还是一种工作温度低,无放射性污染的新型阴极材料,由稀土钼作为阴极的电子管,发射性能与寿命均达到或超过同类型W-ThO2表极电子管,达到实用化水平,因此,稀土钼作为一种集结构功能于一身的新型材料,有广泛的应用前景。 相似文献
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金属液中定硫传感器的稳定性 总被引:2,自引:0,他引:2
采用高温化学电池固体电解质的方法来测定碳饱和铁液中的硫含量。用ZrO2(Y2O3)作为定硫传感器的固体电解质,将Y2O3+Y2O2S作为其辅助电极组成A型定硫传感器;或用ZrO2(Y2O3)+Y2O2S直接作为固体电解质组成B型定硫传感器。其电池形式分别为:Mo,Cr2O3+Cr|ZrO2(Y2O3)|Y2O3 Y2O2S|[S]Fe,Mo,Mo;Mo,Cr2O3 Cr|ZrO2(Y2O3) Y2O2S|[S]Fe,Mo。定硫实验结果表明,该定硫传感器所测电动势信号稳定,响应快,重现性好,持续时间长,准确度较高,是一种比较成功的定硫传感器。此外,还得到了在1583K下电动势与铁液中硫含量的关系。 相似文献
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对在酸性条件下Cu还原Mo O42-的行为及还原产物的特性进行了研究。考察了还原体p H值、还原时间、反应温度等因素对钼还原率的影响。结果表明,还原反应要在酸度比较高的条件下才能进行,提高酸度有利于钼的还原;还原速率随温度的升高而增大,符合经典的Arrhenius温度对反应速率的影响规则。同时,采用X-衍射、X荧光分析、拉曼光谱以及扫描电镜对还原产物的特性进行了表征,确定了还原产物的组成与形态,即还原产物中主要的元素有Na、Mo、O,比例是0.2∶4.96∶1,产物组成可定性为Na0.91O19.2H7Mo5.33。产物晶系为六棱型结构,产物中Mo呈现出+5.72价的混合价态。碱分解机理分析得,Cu还原Mo O42-的产物易被氧化,生成Mo O42-。 相似文献
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采用粉末冶金方法制备含Y2O3的稀土钼合金,利用金相显微镜、扫描电子显微镜(SEM)、X射线衍射(XRD)、能谱分析(EDS)等手段对钼合金的断裂特征和组织结构进行对比分析,研究稀土氧化物Y2O3含量对钼合金组织和性能的影响.研究表明:添加Y2O3能细化晶粒、改善钼合金的晶粒均匀性和致密度、提高钼合金的性能:拉伸强度和屈服强度随Y2O3含量的增加呈现先增高后降低的趋势,在Y2O3含量为1%时,抗拉强度达511.43MPa,屈服强度456.99MPa,分别是纯钼材料的1.31倍和1.57倍,综合力学性能最佳;在烧结坯中,Y2O3颗粒分布均匀,主要以球形和等轴状形式存在于晶界上. 相似文献
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The substrate molybdenum doped with La2O3, Y2O3 cathode material was made by the powder metallurgy method. The secondary emission coefficients of the materials were tested. The experimental results show that Mo cathodes doped with La2O3, Y2O3 have good secondary emission properties. When the cathodes are activated, the maximal secondary emission coefficients of these cathodes are higher than 2.0 and can meet the practical requirement. The distribution of the rare earth in the interior and at surface of this kind of cathode material before and after emission was studied using Scanning Electronic Microscopic (SEM) and X-Ray Photoelectron Spectrum(XPS). The analysis results show that the rare earth is easy to gather at grain boundaries and the relevant concentration of rare earth on the surface after emission is obviously greater than that before emission. 相似文献
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Tadaaki Amano 《中国稀土学报(英文版)》2010,(Z1):12-21
High-temperature oxidation resistance of Al2O3-and Cr2O3-forming heat-resisting alloys with rare earths(yttrium-implanted FeCrAl,-added FeCrAl,-added FeCrAlPt alloys,Y2O3-or CeO2-coated NiCrSi,yttrium-or lutetium-added NiCr and NiCrSi) was studied in oxygen at high temperatures,by mass gain measurements,mass change measurements,amount of spalled oxide,observation of surface appearance,X-ray diffraction(XRD),scanning electron microscopy(SEM),electron probe X-ray microanalysis(EPMA) and transmission electron microscopy(TEM).After oxidation at 1573 K for 18 ks in oxygen,oxide scale on FeCrAl alloy spalled from the entire surface,however,yttrium-implanted FeCrAl alloys showed good oxide adherence.After oxidation at 1473 K for 18 ks in oxygen,mass gain of FeCrAlY alloys decreased with increasing yttrium of up to 0.1 wt.% follwed by an increase with the yttrium content,and the mass gain of FeCrAl0.005Pt0.05Y alloy with appropriate additions of platinum and yttrium was lower than that of FeCrAl0.1Y alloy.Yttrium-added FeCrAl alloys showed good oxide adherence.TEM analysis revealed that the alumina/alloy interface of FeCrAl0.005Pt0.05Y alloy showed good coherency.The scale surface of FeCrAl alloy was rough,however,those of FeCrAlY and FeCrAlPtY alloys were smooth.Cyclic oxidation of NiCrSi,Y2O3-or CeO2-coated NiCrSi alloys was studied up to 10 cycles(1 cycle:300 s) at 1523 K in oxygen.Mass change of NiCrSi alloy increased up to 3 cycles and then decreased up to 10 cycles because of oxide spallation during cooling.On the other hand,mass change of Y2O3-or CeO2-coated NiCrSi alloy increased up to 10 cycles,and these alloys showed good oxide adherence.Granular Cr2O3 particles on Y2O3-coated NiCrSi alloy were in size smaller than these on CeO2-coated NiCrSi alloy.This result suggested that oxidation rate of Y2O3-coated NiCrSi alloy was lower than that of CeO2-coated NiCrSi alloy.After oxidation at 1473 and 1573 K for 18 ks in oxygen,mass gain of yttrium-or lutetium-added NiCr and NiCrSi alloys decreased.Oxide scales on NiCrS 相似文献
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The chemical reaction between lanthanum oxide and molybdenum carbide was studied by thermodynamic calcu-lation, thermal analysis and in-situ X-ray Photoelectron Spectroscopy. The theoretical results show that at the environment allowing for the evaporation of lanthanum, such as in high vacuum, La2O3 in the La2O3-Mo materials can be reduced to metallic lanthanum by molybdenum carbide (Mo2C). To confirm the conclusion, many analysis methods such as XRD, SPS, and TG-DTA were taken. The experimental results show that the chemical state of lanthanum changes during heat-ing. It was proved, for the first time, that reacted metallic lanthanum appears at the surface of this kind of material at high temperature. 相似文献
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莫哈梅德·H·K采用升华急冷法制出表面50 m2/g的纳米三氧化钼.用这种三氧化钼在哈珀转管炉中制出新型超细钼粉.用超细钼粉与一氧化碳反应制出纳米碳化钼(Mo2C·MoC).又用超细钼粉与氨反应制出纳米氮化钼.这些纳米材料用作催化剂、高强涂层和具有纳米粒子结构的超硬合金钢等. 相似文献
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A Study on La_2O_3-Y_2O_3-Mo Secondary Emission Material 总被引:1,自引:0,他引:1
Thephenomena ,mechanismandtheapplicationofsecondaryemissionofmanykindsofmaterialshavebeenstudiedsincethesecondaryemissionphenomenawasdiscoveredbyCompellin 1899.Withthedevel opmentofelectronictechnologythephenomenaofsec ondaryemissionhavebeenincreasinglyappliedinmanyfields[1,2 ] ,especiallyinhighpowermagnetrontube .Nowadays ,thecathodesofhighpowermag netrontubeusedinthefieldsofbroadcast,correspon denceandnationaldefensearemainlyBa Wcath odes[3] andsomeTh Wcathodes .However ,Ba Wcathodeishard… 相似文献
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Masahiro Kitajima Masatoshi Okada Ryoji Watanabe 《Metallurgical and Materials Transactions A》1980,11(10):1645-1655
Secondary ion analysis was applied to the study of the carburization behavior of a superalloy by using the ion microprobe
mass analyzer (IMMA). The corrosion test of Inconel 617 was carried out for 1000 h under an environment of methane-doped impure
helium gas at 1000 °C. 20 KeV O
2
+
and N
2
+
were used as primary ions. IMMA showed that C, O, Al, Si, Ti and Mo were enriched near the surface. The chemical states of
the scale and the precipitates were determined from chemical shifts of X-ray emission spectra. It was confirmed that silicon
carbide and molybdenum carbide were coprecipitated in the same areas: in the scale, in the matrix at a depth of 10 μm to about
40 μm below the scale, and at grain boundaries. Aluminum and titanium were found to exist as oxides near the surface. It was
shown that carburization was limited near the surface, and the grain boundary precipitation of carbides in the bulk was due
to aging at high temperatures. The concentration profiles of silicon and molybdenum in (Si,Mo)-carbide were obtained by using
standard carbide samples assuming that the concentration of implanted oxygen atoms of the specimen was equal to that of the
standard sample. The ratio, (Si)/(Mo), was increased from about 0.1 in bulk to 2.4 ∼ 3.8 near the surface. This result indicates
that silicon is carburized much more preferentially than molybdenum. 相似文献
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TheMo La2 O3cathode ,whichpossessesthead vantagesofhighstrengthandgoodambientductility ,excellentelectronemissionability ,lowoperatingtem peratureandradioactive freepollution ,isapromisingcathodeforreplacingW ThO2 cathodeinavarietyofvacuumelectrondevices[1~4 ] .However ,itisfoundthattheemissioncurrentofMo La2 O3cathodeelectrontubesattenuatedwithlifetimerapidly .Inordertoob tainstableemissionofMo La2 O3tubes ,muchefforthasbeendoneonthematerialcomposition ,thecar bonizingprocessandemissionm… 相似文献