首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
采用球磨方法制备了 Mg-50%(ZrFe1.4Cr0.6)(质量分数)复合材料,并对其热力学、动力学、抗氧化能力及循环性能进行了研究该复合材料在保持高储氢容量(达3.4%,质量分数)的同时,具备优异的氢化动力学性能,即使在较低温度仍具有一定的吸氢速率.采用 SEM, TEM, EDS和 X射线衍射对吸、放氢前后的物相变化及微观形貌进行了分析和研究均匀分布于Mg颗粒表面和内部的 ZTFe1.4Cr0.6微粒及颗粒内部大量的相界、微观缺陷的存在是材料具备优异氢化性能的主要原因  相似文献   

2.
结合核动力堆用燃料包壳对锆合金耐蚀性能的要求,大范围考察了Nb含量为0.5%,1.0%,2.6%(wt%)的Zr—Nb二元合金及含Cr、Mo、Sn、Bi、Fe、Ce和Si的Zr-1Nb及多元合金,共17种成分的Zr-Nb系合金在400℃,10.3MPa水蒸汽中的长期腐蚀规律(达182天)。在腐蚀转折前,Zr-Nb系合金的腐蚀动力学曲线均近似于抛物线规律,而在转折之后存在与线性规律偏离现象。长期腐蚀增重的分析说明:通过合理的多元合金化,即增加或降低Nb含量,并主加Fe、Bi、Sn和Ni而辅加少量的Cr、Mo  相似文献   

3.
结合核动力堆用燃料包壳对锆合金耐蚀性能的要求,大范围考察了Nb含量为0.5%,1.0%,2.6%(wt%)的Zr—Nb二元合金及含Cr、Mo、Sn、Bi、Fe、Ce和Si的Zr-1Nb及多元合金,共17种成分的Zr-Nb系合金在400℃,10.3MPa水蒸汽中的长期腐蚀规律(达182天)。在腐蚀转折前,Zr-Nb系合金的腐蚀动力学曲线均近似于抛物线规律,而在转折之后存在与线性规律偏离现象。长期腐蚀增重的分析说明:通过合理的多元合金化,即增加或降低Nb含量,并主加Fe、Bi、Sn和Ni而辅加少量的Cr、Mo、Te和Si,Zr-1Nb合金的耐蚀性大有潜力可挖。  相似文献   

4.
合金元素对Zr-Sn-Fe-Cr-Nb合金性能的影响   总被引:1,自引:0,他引:1  
介绍了几种新锆合金400℃,10.3MPa静态高压釜试验结果和室温及高温(375℃)的拉伸试验结果,分析了新合金中合金元素Nb.Sn.Fe.Cr对抗伸强度及耐蚀性能的影响。结果表明:通过控制合金元素的含量,在经历与Zr-4相同的生产工艺条件下、可以得到强度和耐蚀性能更为优异的新铝合金。试验表明:这种新型的Zr-Sn-Fe-Cr-Nb中加入Nb量应在0.1wt%-0.3wt%之间;在含1wt%Nb的新合金中,Sn的含量不应低于0.5wt%:在新合金研制时,适当提高Fe+Cr的含量是有益的,但Fe/Cr比不应太高。  相似文献   

5.
介绍了几种新锆合金400℃,10.3MPa静态高压釜试验结果和室温及高温(375℃)的拉伸试验结果,分析了新合金中合金元素Nb.Sn.Fe.Cr对抗伸强度及耐蚀性能的影响。结果表明:通过控制合金元素的含量,在经历与Zr-4相同的生产工艺条件下、可以得到强度和耐蚀性能更为优异的新铝合金。试验表明:这种新型的Zr-Sn-Fe-Cr-Nb中加入Nb量应在0.1wt%-0.3wt%之间;在含1wt%Nb的新合金中,Sn的含量不应低于0.5wt%:在新合金研制时,适当提高Fe+Cr的含量是有益的,但Fe/Cr比不应  相似文献   

6.
发展高性能核燃料组件是提高核电经济性的必由之路,改善核燃料元件包壳锆合金的性能是其中关键问题之一。本文概述了我们近几年研究改善锆合金耐腐蚀性能的结果:控制Zr4合金成材时的热加工制度,可以明显改善它的耐腐蚀性能,尤其是耐疖状腐蚀性能。其主要原因是αZr中Fe+Cr的固溶含量变化,而不是析出相微粒的大小。由于Zr4合金中析出相Zr(Fe,Cr)2微粒的氧化比αZr基体慢,并与成分中的Fe/Cr比有关,当嵌镶在氧化膜中的Zr(Fe,Cr)2微粒继续氧化形成单斜结构ZrO2和立方结构(Fe,Cr)3O4后,由于体积膨胀会造成氧化膜中的局部张应力。从这一角度出发,热处理对析出相细化、均匀分布以及Fe/Cr比的变化等也是应考虑的问题。发展ZrSnNb(Fe+Cr)新合金,对改善锆合金的耐腐蚀性能有更大的潜力,成分(%,质量分数,下同)的选择应为Sn1~12,Nb~1,Fe+Cr可保持或略高于Zr4的水平。  相似文献   

7.
Fe0.85Mn0.15Ti0.9M0.1(M=Zr,V,Ca)合金的贮氢性能   总被引:2,自引:0,他引:2  
系统地研究了Fe0.85Mn0.15Ti0.9M0.1(M=Zr,V,Ca)合金的贮氢性能。研究结果表明:Fe0.85Mn0.15Ti0.9Zr0.1合金在室温下经几分钟的孕育期就可吸氢,但合金在氢化过程中形成了氢含量很高的α相,导致合金的贮氢量降低,同时还使p-c-T曲线的平台特性变差;Fe0.85Mn015Ti0.9V0.1合金的活化性能进上步得到改善,在室温下几乎不需要孕育期就可以吸氢,但同  相似文献   

8.
含钒FeNiCr合金在0.4%H2SH27%CO2和1%H2SH27%CO2气氛中于600℃下的腐蚀产物包括外层疏松多孔、呈粉状的(Ni,Fe)S,其下致密的FeCr2S4和里层的Cr3S4。1%H2S气体中腐蚀,FeCr2S4的上部还有(Fe,Ni)S块的形成。钒与镍富集于FeCr2S4/Cr3S4交界处。  相似文献   

9.
安白  马莒生  唐祥云 《金属学报》1995,31(16):173-178
用TEM、X射线衍射、SEM等技术研究了Ni42Cr6Fe玻封合金在高温湿氢中的氧化膜生长过程。氧化初期,Cr_(2)O_3和尖晶石氧化物同时形核长大,前者在晶界处形核长大,后者在晶内处形核长大。随后由于Cr的选择氧化,氧化膜主要以Cr2O3生长为主.当氧化进行到一定程度后,由于表面层Cr的贫化,氧化膜生长转化以(Fe,Mn)Cr2O4尖晶石氧化物生长为主.最后形成表层以粗大晶粒(Fe,Mn)Cr2O4为主,底部以较小晶粒Cr2O3为主,中部由大晶粒(Fe,Mn)Cr2O4围绕小晶粒Cr2O3的稳态氧化膜组成  相似文献   

10.
测定了Fe-15Cr-4Al合金在500℃的时效脆化动力学,利用内耗,TEM,EPMA和SEM等手段研究了合金在时效后的组织变化和断裂行为。结果表明,时效脆化第一阶段(0-100h)主要是碳化物在α相晶界析出的作用,它损害界面结合,降低断裂应力,使塑性在时效0.25h后消失;第二阶段(100-1000h)主要是富Cr-α'相均匀析出的作用,它通过强化基体引起二次脆化。含0.2和0.4%的Fe-15  相似文献   

11.
The Ba0.985Na0.015Ti0.985Nb0.015O3, Ba0.6Na0.4Ti0.6Nb0.4O3 and Ba0.3Na0.7Ti0.3Nb0.7O3 compositions of the (1 − x) BaTiO3xNaNbO3 (BTNNx) system have been studied by X-ray diffraction and by measurements of dielectric properties. The specimens with composition BTNN (x = 0.015, 0.40 and 0.70) have been refined by the JANA program from X-ray powder diffraction data. Ceramic samples with composition (1 − x) BaTiO3 + xNaNbO3 (where x = 0.015, 0.40 and 0.70) were prepared by calcinations from appropriate mixture of BaCO3, TiO2, Na2CO3 and Nb2O5. The calcined powder was sintered at temperature range 1200–1400 °C. As the composition x increased from 0.015 (and 0.70), the ferroelectric ceramics (x = 0.015, FE) with tetragonal phase changed to the ferroelectric relaxors (RFE, x = 0.40). RFE ceramics showed a peculiar diffuse phase transition and dielectric relaxation at the low temperature (down to 180 K) due to a frustration between RFE and FE state. These ceramics present the classical ferroelectric character when 0 ≤ x < 0.075 and 0.55 < x ≤ 1 and relaxor character when 0.075 ≤ x ≤ 0.55.  相似文献   

12.
Influence of 1 h annealing in vacuum on magnetic, electrical and plastic properties of Fe76Nb2Si13B9, Fe75Ag1Nb2Si13B9 and Fe75Cu1Nb2Si13B9 melt spun ribbons were carefully investigated. It was shown that in all cases soft magnetic properties can be significantly enhanced by applying 1-h annealing at characteristic temperatures Top. This optimization annealing causes that permeability increases more than 15-times and magnetic losses (tangent of loss angle) achieves a minimum in relation to the as quenched state. Using structural examinations (X-ray and HRTEM) it was shown that for the Fe75Cu1Nb2Si13B9 alloy the optimized microstructure corresponds to a nanocrystalline αFe(Si) phase whereas in other alloys to a relaxed amorphous phase free of iron nanograins. As a consequence of this fact the Fe76Nb2Si13B9 and Fe75Ag1Nb2Si13B9 alloys show higher plasticity in comparison to the nanocrystalline Fe75Cu1Nb2Si13B9 alloy. Temperatures of the first stage of crystallization, and related diffusion parameters were determined using measurements of resistivity versus temperature with different heating rates.  相似文献   

13.
针对草酸盐配位共沉淀热分解还原法制备超细铁镍合金粉过程中Fe2+-Ni2+-NH3-NH4+-C2O42--H2O体系的溶液平衡建立热力学分析模型,并根据模型进行相关计算,揭示反应体系中各物质随pH值、氨及草酸浓度的变化关系。结果表明:溶液中的Fe主要以[Fe(C2O4)n]2 2n络合物形式存在,而铁氨络合物含量很低。当氨含量较低时,溶液中的Ni主要以[Ni(C2O4)n]2 2n存在;氨含量较高时,在酸性条件下,溶液中的Ni主要以[Ni(C2O4)n]2 2n存在,在碱性条件下,则主要以[Ni(NH3)n]2+存在。低pH值下,Ni的沉淀率较Fe的高,而高pH值下,Ni的沉淀率则较Fe的低。  相似文献   

14.
We applied our model to the enthalpy of mixing data of the binary systems Na2O-SiO2, Na2O-GeO2, Na2O-B2O3, Li2O-B2O3, CaO-B2O3, SrO-B2O3, and BaO-B2O3. The most stable composition in the liquid, that is where the enthalpy of mixing is most negative, is with a metal-oxygen ratio of 4 to 3, for monovalent metals (Na and Li) and 3 to 4 for divalent metals (Ba and Ca) in liquid silicates or borates. The same applies to the CaO-SiO2, CaO-Al2O3, PbO-B2O3, PbO-SiO2, ZnO-B2O3, and ZnO-SiO2 systems. The oxygen to metal ratio, its constant value in various types of systems, reflects and describes the structure of the liquid. Using the analyzed enthalpies of mixing data and the available phase diagrams, we calculated the enthalpies of formation of the various binary compounds. The results are in excellent agreement with data in the literature that were obtained from direct solid-solid calorimetry.  相似文献   

15.
Results of a powder X-ray diffraction investigation of new ternary compounds are reported. The compounds Y6CoBi2 [a=0.8312(1) nm, c=0.4144(1) nm], Ho6CoBi2 [a=0.8246(2) nm, c=0.4095(1) nm], and Tm6CoBi2 [a=0.8155(2) nm, c=0.4066(1) nm] crystallize in the hexagonal Zr6CoAs2-type structure (space group P6b2m No. 189). The Zr6CoAs2-type structure is a superstructure of the Fe2P-type structure.  相似文献   

16.
Single crystals of RbBa3Ca4Cu3V7O28 were prepared above the melting point of the reaction mixture. It crystallizes with hexagonal symmetry, space group C6V4-P63mc, a 11.1751, c 12.434 Å, Z = 2. RbBa3Ca4Cu3V7O28 is the second member of a new structure type of the copper-oxovanadates. Ba2+ shows an unusual 12-fold coordination. The two calcium positions are coordinated by trigonal prisms and octahedra respectively. The copper coordination is characterized by a stretched square pyramid. The Cu2+ ions are outside the centre nearly in plane of the pyramids.

Zusammenfassung

Einkristalle von RbBa3Ca4Cu3V7O28 wurden oberhalb des Schmelzpunktes der Reaktionsmischung erhalten. Die Verbindung kristallisiert hexagonal, Raumgruppe C6V4-P63mc, a 11.1751, c 12.434 Å, Z = 2. RbBa3Ca4Cu3V7O28 ist das zweite Beispiel für einen neuen Strukturtyp der Kupfer-Oxovanadate, mit 12-fach koordinierten Ba2+ -Ionen. Die zwei Calciumpositionen sind trigonal prismatisch bzw. oktaedrisch koordiniert. Die Koordination der Cu2+-Ionen ist durch eine gestreckte Pyramide charakterisiert. Cu2+ ist auβerhalb des Polyederzentrums nahezu in der quadratischen Fläche der Pyramide angeordnet.  相似文献   


17.
采用溶胶-凝胶法和低温燃烧技术制备Ce1-xSmxO2(x=0,0.1,0.2,0.3)和掺杂Sm和(2%-8%)Al2O3的二氧化铈;研究其合成、结构、致密化、导电性和热膨胀等性能,并利用XRD研究其结构和相组成。结果表明,于1300°C烧结球团,获得致密的陶瓷,于1250°C在Ce0.8Sm0.2O0.2中加入2%和4%的Al2O3以促进烧结。利用扫描电子显微镜观察烧结后球团的表面形貌,使用双探针交流阻抗谱研究总离子电导率。  相似文献   

18.
在Q235低碳钢板上利用电弧喷涂工艺进行喷涂,以制得Fe65Cr20Mo7B3.5SiMn1.5W3涂层。喷涂材料为自行配制的丝材,按照35%的填充率将配好的粉填充到U型不锈钢外皮中,经过多道拉拔、挤压工艺制成Φ2mm的粉芯丝材。采用X射线衍射仪、扫描电镜、能谱分析仪、透射电镜对涂层的物相和组织形貌及成分进行了表征;采用差示扫描量热仪、显微硬度仪等设备对涂层的热稳定性及显微硬度进行了检测和分析。试验结果表明:涂层组织形貌呈典型的层状组织结构,由变形良好的带状粒子相互搭接堆积而成。涂层含有50.63%的非晶相,同时含有纳米级的晶相。涂层组织均匀、结构致密、孔隙率低,并且涂层硬度高达1040.5HV0.3,属硬质涂层,具有良好的热稳定性。  相似文献   

19.
Spinel compound LiNi0.4Mn1.5Cr0.1O4 (LNMCO) and Li4Ti5O12 (LTO) were synthesized by the sol-gel method and the solid-state method, respectively. The particle sizes of the products LiNi0.4Mn1.5Cr0.1O4 and Li4Ti5O12 were 0.5 to 2 um and 0.5 to 0.8 um, respectively. All samples exhibited excellent electrochemical properties. A LiNi0.4Mn1.5Cr0.1O4/Li4Ti5O12 (LNMCO/LTO) cell was fabricated and was demonstrated to exhibit good electrochemical properties at the high current rate of 1 C. When the specific capacity was determined based on the mass of the LNMCO cathode, the LNMCO/LTO cell delivered 125 mAh g−1 at 1 C and 77 mAh g−1 at 5 C. The capacity retentions after 30 cycles were 94.4 % and 83.1 %, respectively.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号