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富镧稀土在水稻上的应用技术和效果研究 总被引:9,自引:0,他引:9
通过二年三季水稻的小区试验,一次大田对比和盆栽试验,研究不同镧、铈配比的硝酸稀土的应用技术和效果。结果表明:水稻分蘖始期喷施50mg/kg,抽穗始期喷施200mg/kg的氧化镧相对含量为82.0%的富镧硝酸稀土,平均增产稻谷348kg/ha增产率6.5%,t测试达极显著水平。富镧稀土的增产效果优于“常乐”富铈稀土。 相似文献
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镧铁合金、铈铁合金和镧铈铁合金主要用作钕铁硼永磁材料或钢铁材料的稀土添加剂,而快速准确测定镧铁合金、铈铁合金和镧铈铁合金中主量稀土含量对产品的质量控制具有重要意义。采用盐酸-过氧化氢溶解样品,选择La 492.098 nm、Ce 447.124 nm为分析谱线,建立了电感耦合等离子体原子发射光谱法(ICP-AES)测定镧铁合金、铈铁合金和镧铈铁合金中主量稀土的分析方法。讨论了基体浓度、共存元素干扰等对测定的影响。结果表明,当铁质量浓度不大于0.2 mg/mL和镧(铈)质量浓度不大于20μg/mL时,基体效应可以忽略。样品中共存稀土元素和钙、镁、铝、锰、镍、硅、硫、磷等非稀土元素对稀土测定的影响可以忽略。镧、铈质量浓度在1.00~20.00μg/mL范围内与其对应的发射强度呈线性关系,校准曲线线性相关系数均为0.999 9。按照实验方法测定镧铁合金样品中镧,铈铁合金样品中铈,镧铈铁合金样品中镧、铈,结果的相对标准偏差为(RSD,n=11)均小于3%。按照实验方法测定镧铁合金、铈铁合金和镧铈铁合金内控样品的主量稀土含量,结果与草酸盐重量法测定结果一致。 相似文献
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氟碳铈镧矿稀土萃取分离流程研究 总被引:3,自引:0,他引:3
根据以轻稀土为主的氯化稀土原料的组成特点,针对氟碳铈镧矿,应用串级萃取理论原理进行优化设计,得到氟碳铈镧矿分离稀土的优化工艺流程。 相似文献
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采用HRL-1型热裂纹试验机测试焊缝临界变形速度的方法,研究了常用稀土金属镧、铈、镨、钇及钕在纯镍铸铁焊条冷焊时。对焊缝临界变形速度VBL、焊缝微观组织以及热裂敏感性的影响规律。试验结果表明:焊缝中加入适量的稀土镧、铈、钇和镨。有脱硫、脱磷、去除晶界杂质的作用,每种稀土金属,偏离该最佳值都会使焊缝抗热裂性降低。纯镍铸铁焊条中加入稀土钕会增加焊缝热裂敏感性。稀土镧、铈、钇和镨能在一定范围内显著提高焊缝临界变形速度VBL,改善纯镍铸铁焊缝抗热裂性能。 相似文献
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样品经硝酸-过氧化氢分解后,采用电感耦合等离子体原子发射光谱法(ICP-OES)测定镧、铈以及其他13种稀土杂质的含量。以基体匹配法消除主量镧、铈元素对稀土杂质的干扰。通过实验确定了各稀土元素的分析谱线,并实验了酸度、功率、共存离子对测定结果的影响。本方法测定范围:镧20.00%~40.00%,铈60.00%~80.00%,镨、钕、钐0.0040%~0.50%,其他稀土杂质0.0020%~0.50%。与X荧光光谱法及ICP-MS法对比结果基本一致,准确度较好,RSD≤4.3%。本方法可满足镧铈金属及其化合物中稀土含量分析检测的要求。 相似文献
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铥镱镥富集物的镧铈热还原研究 总被引:1,自引:0,他引:1
计算了镧、铈热还原铥镱镥富集物制取金属镱的基本热力学条件;并成功地进行了有关热还原试验.试验结果表明,在适宜技术条件下,可以获得纯度高于98%的金属镱,其金属直收率为85%~90%。文内探讨了原料中各主要稀土成分及其他非稀土杂质在还原时的行为走向,同时对镧、铈热还原的实用性作了简要的比较。 相似文献
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The alteration of the strength, hardness and impact ductility of 5CrNiMo steel using three different additions of RE La element is studied in this paper. The mechanical properties of 5CrNiMo steel with RE La additions are be compared with that of the 5CrNiMo steel on the same heat-treatment condition without RE La element addition. The results show that the strength. hardness and impact ductility of 5CrNiMo steel will be improved obviously when the content of RE La element is proper, and as the content of RE La element is 0.033% (mass fraction), the 5CrNiMo steel has the best mechanical properties. 相似文献
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利用光学显微镜、X射线衍射和扫描电镜等分析研究含铈镁合金AZ91D(0.25%Ce、0.7%Ce、0.95%Ce)的显微组织,并对其力学性能进行了测试,同时与不含铈镁合金AZ91D进行了比较。结果表明,加入一定量Ce后的镁合金AZ91D形成杆状化合物Al4Ce,被推移到生长界面,阻碍枝晶的自由生长,从而细化合金显微组织;Ce能提高镁合金AZ91D抗拉强度和硬度,而对其屈服强度和延伸率影响不大;加入0.7%Ce的AZ91D镁合金晶粒细化效果和综合力学性能比较理想。 相似文献
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CuZnAl Shape Memory Alloy Refined with Composite Rare Earths La Ce 总被引:15,自引:0,他引:15
司乃潮 《中国稀土学报(英文版)》1999,(4)
TheCu-basedshapememoryalloys(SMA)havelowc0standrichresourcesandmayhavewidepracticalapplications,0wingtotheirbettershapememoryeffect(SME)thanNi-TiSMA.However,someseri0usproblemssuchasinter-granularfractureduetolargegrainsizeandsta-bilizati0nofmartensitemusthes0lvedbeforetheyareputinuse,Thewell-knownmethodforreducinggrainsizeistheadditionoflesssolub1e.l....t.[l'2j.Ithasbeenreportedthattherareearthelementshavedramaticeffectsinreducinggrainsizeandimprovingthemechanicalproper-tiessuchasbetterf… 相似文献
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通过电导率测试、拉伸试验、SEM、EDS、金相显微镜观察等手段,研究稀土元素铈、镧的添加量对Al-B电工圆杆组织和性能的影响。结果表明,当稀土元素铈、镧的添加含量分别为0.05%~0.30%、0.10%~0.35%时,Al-B电工圆杆具有良好的综合性能。 相似文献
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The effect of rare earth element Ce on microstructure, electrical conductivity and mechanical properties was studied.Using optical microscope, scanning electron microscope, transmission electron microscope and X-ray diffractometer, the microstructure and phase composition of aluminum rod for electrical purpose were measured and analyzed.The results indicate that rare earth element Ce can considerably refine grain size of aluminum rod for electrical purpose,improve the regular distribution pattern of the impurity, such as silicon and iron which present in the aluminum matrix,form stable metal compound with pernicious impurity.This metal compound precipitates on the crystal boundary.As a result, the solid solubility of impurity in aluminum reduce, and the electrical conductivity of aluminum rod for electrical purpose is improved.It is found that the mechanical properties of aluminum rod for electrical purpose are improved by rare earth element in certain range of RE addition. 相似文献
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Pb-Ag-Ca-Sr四元合金具有较好的力学性能、导电性能和耐腐蚀性能,但合金元素分布不均、性能不稳定、稀贵金属损耗大、制作成本高,制约其在湿法炼锌电积阳极的广泛应用。通过熔炼工艺向Pb-Ag-Ca-Sr四元合金中添加稀土Ce,然后进行轧制,分别考察稀土Ce对Pb-Ag-Ca-Sr四元合金显微组织、力学性能、导电性和耐腐蚀性能的影响。结果表明,添加质量分数为0.04%的稀土Ce后,Pb-Ag-Ca-Sr四元合金的晶粒明显得到细化,抗拉强度、屈服强度和电导率分别提高9%、23%和1.75%,耐腐蚀性能也得到明显提高,稀土Ce对Pb-Ag-Ca-Sr四元合金阳极材料综合性能提升作用强于轧制工艺。 相似文献
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Luo Alan A. Wu Wenyun Mishra Raj K. Jin Li Sachdev Anil K. Ding Wenjiang 《Metallurgical and Materials Transactions A》2010,41(10):2662-2674
Current commercial magnesium extrusion alloys do not offer desirable combinations of strength, ductility, and extrusion speed
for automotive structural applications. The effect of small additions of cerium (Ce) to pure magnesium (Mg) and Mg-3 pct Al
alloy extruded tubes has been studied. The results suggest that 0.2 pct Ce addition can significantly improve the extrudability
and mechanical properties of the Mg extrusions. The improvement in mechanical properties is due to grain refinement and dispersion
strengthening provided by the Mg12Ce particles and the beneficial texture obtained. Higher Ce contents further increase strength, but significantly reduce ductility
and cause excessive surface oxidation during extrusion. The beneficial effect of 0.2 pct Ce on mechanical properties of pure
Mg is not observed when it is added to Mg-3 pct Al alloy, due to the higher affinity of Ce to Al to form the Al11Ce3 phase in the Mg-Al-Ce ternary alloys. The Mg-0.2 pct Ce alloy is a promising base alloy for further development in automotive
applications; however, Al should be avoided in Mg-Ce–based extrusion alloys. 相似文献
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E. Aguirre-De la Torre R. Pérez-Bustamante J. Camarillo-Cisneros C.D. Gómez-Esparza H.M. Medrano-Prieto R. Martínez-Sánchez 《中国稀土学报(英文版)》2013,31(8):811-816
The research of rare earths for the synthesis of materials with improved mechanical performance is of great interest when they are considered for potential applications in the automotive industry. In this regard, the effect on the mechanical properties and microstructure of the automotive A356 aluminum alloy reinforced with 0.2 (wt.%) Al-6Ce-3La (ACL) was investigated. The ACL was added to the melted A356 alloy in the as-received condition and processed by mechanical milling. In the second route, the effect of the ACL processed by mechanical milling and powder metallurgy techniques was investigated, and compared with the results obtained from the A356 alloy strengthened with ACL in the as-received condition. Microstructural properties were evaluated by means of X-ray diffraction in order to observe the solubility of Ce/La in the Al matrix. In addition, electron microscopy was employed in order to investigate the effect of milling time on the size and morphology of La/Ce phase under milling process. Mechanical properties of the A356 alloy modified with ACL were measured by hardness and tensile test. For comparison unmodified specimens of the A356 were characterized according to the previous procedure. The microstructural and mechanical characterization was carried out in specimens after solution and artificial aging. Observations in scanning electron microscopy indicated a homogeneous dispersion of La/Ce phases by using both routes; however, mechanical results, in the modified A356 alloy with the ACL in the as-received condition, showed an improvement in the mechanical performance of the A356 alloy over that reinforced with the ACL mechanically milled. 相似文献
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Two kinds of Cu-Al_2O_3 composites(with and without La) were prepared via mechanical alloying-spark plasma sintering(MA-SPS) method. Microstructure, mechanical properties and electrical resistivity were investigated systematically using metallography, scanning electron microscopy, transmission electron microscopy, mechanical and electrical properties testing. The results indicate that an appropriate amount of La can homogenize the distribution of Al_2O_3. As such, yield strength, ultimate tensile strength and elongation of Cu-Al_2O_3-La are greatly increased. Some semi-coherent interface between Cu and Al_2O_3 is found, which means a low interface energy. The grain shape of Cu changes to irregular band with the addition of La. This change results in a density decrease of grain boundary and reduces electrical resistance. Lanthanum may exist in the form of La_2O_3. 相似文献
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The effects of Ce, Y and Gd additions on the as-cast microstructure and mechanical properties of Mg-3Sn-1Mn alloy were investigated and compared by using optical and electron microscopies, X-ray diffraction analysis, and tensile and creep tests. The results indicated that the microstructure of the Mg-3Sn-1Mn alloy with the addition of 0.87 wt.%Ce was refined while the microstructures of the alloys with the additions of 0.79 wt.%Y or 0.84 wt.%Gd were coarsened. Furthermore, adding 0.87 wt.%Ce to the Mg-3Sn-1... 相似文献