Volume 34,Issue 5,2005 Table of Contents
2005, 34(5).
Abstract:
Low Co AB5-type Mm(NiCoMnAl)5Bx (x=0~0.2) hydrogen storage alloys were prepared by casting and rapidly quenching. The microstructures and electrochemical characteristics of the alloys were analyzed and measured. The effects of boron content and rapidly quenched technique on the lattice constants, thermodynamic parameters, microstructures and electrochemical properties of the alloys were investigated in detail. The obtained results show that the lattice constants, cell volume and standard enthalpy increased with the increase of boron content. When quenching rate is in a specifically range, the rapidly quenched treatment could enhance the discharge capacity of the alloys. When quenching rate is more than a certain critical value, The discharge capacity of the as-quenched alloy is less than that of the as-cast alloys. The cycle life of the alloys monotonously increased with the increase of quenching rate.
Low Co AB5-type Mm(NiCoMnAl)5Bx (x=0~0.2) hydrogen storage alloys were prepared by casting and rapidly quenching. The microstructures and electrochemical characteristics of the alloys were analyzed and measured. The effects of boron content and rapidly quenched technique on the lattice constants, thermodynamic parameters, microstructures and electrochemical properties of the alloys were investigated in detail. The obtained results show that the lattice constants, cell volume and standard enthalpy increased with the increase of boron content. When quenching rate is in a specifically range, the rapidly quenched treatment could enhance the discharge capacity of the alloys. When quenching rate is more than a certain critical value, The discharge capacity of the as-quenched alloy is less than that of the as-cast alloys. The cycle life of the alloys monotonously increased with the increase of quenching rate.
2005, 34(5):673-675.
Abstract:
The paper commented to the following content synthetically: (1) current study of Mn-Znferrite system; (2) magnetic thin film in Fe-Al system; (3) preparation and application of magnetic liquid; (4) improvement of the magnetic property of Fe-Si system; (5) development of magnetic microwave devices.
The paper commented to the following content synthetically: (1) current study of Mn-Znferrite system; (2) magnetic thin film in Fe-Al system; (3) preparation and application of magnetic liquid; (4) improvement of the magnetic property of Fe-Si system; (5) development of magnetic microwave devices.
2005, 34(5):676-679.
Abstract:
PuNi3型RM3(R=稀土元素，Mg，Ca及第3，4族元素；M=Ni，Co，Fe，Cu，Zn等)被认为是替代LaNi5基贮氢合金的最重要候选电极材料之一，本文将介绍RM3合金的结构特点、氢化物的结构、氢化行为以及合金电极电化学性能的研究现状，并分析了PuNi3型RM3贮氢合金的发展应用仍需解决的问题。
PuNi3型RM3(R=稀土元素，Mg，Ca及第3，4族元素；M=Ni，Co，Fe，Cu，Zn等)被认为是替代LaNi5基贮氢合金的最重要候选电极材料之一，本文将介绍RM3合金的结构特点、氢化物的结构、氢化行为以及合金电极电化学性能的研究现状，并分析了PuNi3型RM3贮氢合金的发展应用仍需解决的问题。
2005, 34(5):680-683.
Abstract:
The basic concept of quantum properties of gold nanowire was presented in this paper. The research background and the present situation is introduced, and the mechanics of conductance by theory is analyzed. The research of the nanocontact of gold wire by STM and MCBJ is also introduced. The conductance of nanocontact of gold wire is quantum, and the quantum properties is under the influence of the electrical field, magnetic field and temperatures, et, al. On the base of experiment results, the unsolved scientific problems are pointed out and the future development direction of this field is predicted.
The basic concept of quantum properties of gold nanowire was presented in this paper. The research background and the present situation is introduced, and the mechanics of conductance by theory is analyzed. The research of the nanocontact of gold wire by STM and MCBJ is also introduced. The conductance of nanocontact of gold wire is quantum, and the quantum properties is under the influence of the electrical field, magnetic field and temperatures, et, al. On the base of experiment results, the unsolved scientific problems are pointed out and the future development direction of this field is predicted.
2005, 34(5):684-687.
Abstract:
采用热压工艺研究了不同工艺制度和原料中不同的Si含量对Ti3AlC2合成的影响.研究表明在1 300℃～1 500℃,30MPa压力和Ar气氛中热压摩尔比为n(TiC)n(Ti)n(Al)n(Si)=2110.2的混合粉末,可以得到纯度达98%(质量分数)以上的致密块体Ti3AlC2材料;添加的Si均匀分布在基体中,形成固溶体,当添加Si的摩尔比为0.2时,固溶体的化学式为Ti2 76Al0 78Si0.22C2.烧结试样的晶体为层片状结构,1 300℃和1 400℃时,烧结试样的晶粒尺寸分别为10μm～15μm和20μm～30μm.材料的维氏硬度为3.3 GPa～5.0 GPa,弹性模量为289 GPa,抗压强度为785 MPa,抗弯强度为375 MPa,断裂韧性为7.0 MPa·m1/2;25℃时,电导率为3.1×106 S·m-1,热容为125.4 J/mol·K,热导率为27.5 W/m·K;热膨胀系数为8.8×10-6 K-1.
采用热压工艺研究了不同工艺制度和原料中不同的Si含量对Ti3AlC2合成的影响.研究表明在1 300℃～1 500℃,30MPa压力和Ar气氛中热压摩尔比为n(TiC)n(Ti)n(Al)n(Si)=2110.2的混合粉末,可以得到纯度达98%(质量分数)以上的致密块体Ti3AlC2材料;添加的Si均匀分布在基体中,形成固溶体,当添加Si的摩尔比为0.2时,固溶体的化学式为Ti2 76Al0 78Si0.22C2.烧结试样的晶体为层片状结构,1 300℃和1 400℃时,烧结试样的晶粒尺寸分别为10μm～15μm和20μm～30μm.材料的维氏硬度为3.3 GPa～5.0 GPa,弹性模量为289 GPa,抗压强度为785 MPa,抗弯强度为375 MPa,断裂韧性为7.0 MPa·m1/2;25℃时,电导率为3.1×106 S·m-1,热容为125.4 J/mol·K,热导率为27.5 W/m·K;热膨胀系数为8.8×10-6 K-1.
2005, 34(5):688-690.
Abstract:
研究了磁流体表观密度与外磁场间的变化规律。采用流体静力称衡法对自行研制的煤油基磁流体进行测量，得到了如下结论：在磁流体中非磁性物体的质量与外磁场成反比，表观密度与外加磁场成正比。
研究了磁流体表观密度与外磁场间的变化规律。采用流体静力称衡法对自行研制的煤油基磁流体进行测量，得到了如下结论：在磁流体中非磁性物体的质量与外磁场成反比，表观密度与外加磁场成正比。
2005, 34(5):691-695.
Abstract:
提出了电磁无模成形无量纲数的概念，并从电磁无模成形的基本原理出发推导建立了该无量纲数的数学模型，为判断不同金属实现电磁铸造无模电磁成形的难易程度以及估算金属实现无模电磁成形所必需的电磁参数提供了有用的数学工具。
提出了电磁无模成形无量纲数的概念，并从电磁无模成形的基本原理出发推导建立了该无量纲数的数学模型，为判断不同金属实现电磁铸造无模电磁成形的难易程度以及估算金属实现无模电磁成形所必需的电磁参数提供了有用的数学工具。
2005, 34(5):701-704.
Abstract:
将NiCrBSi合金粉末预涂于6061Al合金表面，采用高功率连续波2kWNd-YAG激光器进行激光表面熔覆处理。试验结果表明，铝合金对于波长1．06gm的激光具有很高的吸收率，选用合适的激光加工工艺参数和Ar气保护，可在铝合金表面获得致密的Ni—Al合金激光表面改性层，熔覆层的组织以Ni-Al金属间化合物为主，改性层的硬度Hv高达9000MPa以上，且与基体呈现良好的冶金结合。在3．5％NaCl水溶液中的阳极极化曲线测定及摩擦磨损试验结果表明，Ni基合金改性层明显改善了6061Al合金的电化学腐蚀及摩擦磨损性能。
将NiCrBSi合金粉末预涂于6061Al合金表面，采用高功率连续波2kWNd-YAG激光器进行激光表面熔覆处理。试验结果表明，铝合金对于波长1．06gm的激光具有很高的吸收率，选用合适的激光加工工艺参数和Ar气保护，可在铝合金表面获得致密的Ni—Al合金激光表面改性层，熔覆层的组织以Ni-Al金属间化合物为主，改性层的硬度Hv高达9000MPa以上，且与基体呈现良好的冶金结合。在3．5％NaCl水溶液中的阳极极化曲线测定及摩擦磨损试验结果表明，Ni基合金改性层明显改善了6061Al合金的电化学腐蚀及摩擦磨损性能。
2005, 34(5):705-708.
Abstract:
系统研究了TiV1．35Cr1．35-x．Mnx（x=0，0．15，0．25，0.35，0．45)合金的相结构及储氢性能。XRD分析表明，所有合金均为体心立方(b.c.c．)结构的单一固溶体相，其晶胞常数随Mn含量的增加而逐渐减小。储氢性能测试表明，用Mn部分取代Cr后，合金的活化性能变差，25℃最大吸氢量有所下降，但合金的吸放氢压力滞后减小，放氢压力平台变得平坦，100℃有效放氢量和放氢率也随着Mn含量的增加先升后降，并在x=0.35时达到最大值。
系统研究了TiV1．35Cr1．35-x．Mnx（x=0，0．15，0．25，0.35，0．45)合金的相结构及储氢性能。XRD分析表明，所有合金均为体心立方(b.c.c．)结构的单一固溶体相，其晶胞常数随Mn含量的增加而逐渐减小。储氢性能测试表明，用Mn部分取代Cr后，合金的活化性能变差，25℃最大吸氢量有所下降，但合金的吸放氢压力滞后减小，放氢压力平台变得平坦，100℃有效放氢量和放氢率也随着Mn含量的增加先升后降，并在x=0.35时达到最大值。
2005, 34(5):709-712.
Abstract:
利用溶胶．凝胶技术制备了TiO2氧敏薄膜，通过氧化物掺杂和贵金属的表面修饰，在空气气氛下烧结氧敏薄膜a结果表明：600℃～800℃下处理的薄膜是以金红石为主晶相及少量锐钛矿的混合晶型，随着温度升高锐钛矿减少，900℃时锐钛矿相的峰基本消失：800℃下处理的薄膜灵敏度明显高于600℃和900℃下处理的薄膜灵敏度。W，Ce氧化物掺杂促进TiO2薄膜微量氧化还原，增加催化反应活性，使薄膜的氧气灵敏度有明显提高：以Pd对W-TiO2薄膜进行表面修饰，使薄膜的阻温特性得到了明显提高。
利用溶胶．凝胶技术制备了TiO2氧敏薄膜，通过氧化物掺杂和贵金属的表面修饰，在空气气氛下烧结氧敏薄膜a结果表明：600℃～800℃下处理的薄膜是以金红石为主晶相及少量锐钛矿的混合晶型，随着温度升高锐钛矿减少，900℃时锐钛矿相的峰基本消失：800℃下处理的薄膜灵敏度明显高于600℃和900℃下处理的薄膜灵敏度。W，Ce氧化物掺杂促进TiO2薄膜微量氧化还原，增加催化反应活性，使薄膜的氧气灵敏度有明显提高：以Pd对W-TiO2薄膜进行表面修饰，使薄膜的阻温特性得到了明显提高。
2005, 34(5):713-716.
Abstract:
研究了低温燃烧合成前驱物制备纳米级AlN粉末的低温烧结行为,利用XRD,SEM等手段对陶瓷粉末及烧结体进行了表征。结果表明:由于该粉末的粒径小(约为100nm),比表面积大(17.4m2/g),具有很好的烧结活性,在未使用烧结助剂时,在常压下1700℃获得了致密的陶瓷材料;添加5%Y2O3烧结助剂后,AlN的烧结致密化温度又降低为1600℃,比通常采用的比表面积低于5m2/g的AlN粉末的烧结致密化温度降低了200℃。分析了该种粉末促进烧结的机理,并在1650℃时制备出热导率为132.4W·m-1·K-1的AlN陶瓷。
研究了低温燃烧合成前驱物制备纳米级AlN粉末的低温烧结行为,利用XRD,SEM等手段对陶瓷粉末及烧结体进行了表征。结果表明:由于该粉末的粒径小(约为100nm),比表面积大(17.4m2/g),具有很好的烧结活性,在未使用烧结助剂时,在常压下1700℃获得了致密的陶瓷材料;添加5%Y2O3烧结助剂后,AlN的烧结致密化温度又降低为1600℃,比通常采用的比表面积低于5m2/g的AlN粉末的烧结致密化温度降低了200℃。分析了该种粉末促进烧结的机理,并在1650℃时制备出热导率为132.4W·m-1·K-1的AlN陶瓷。
2005, 34(5):717-720.
Abstract:
研究了添加Zr元素对快淬(Nd,Pr)10.5Fe81.5-xZrxCo2B6(x=0,0.5,1.0,1.5,2.0,2.5)合金显微组织结构和磁性能的影响,用AFM观察了合金条带自由表面的显微结构.结果表明添加Zr元素能显著细化合金的晶粒,从(Nd,Pr)10 5Fe81 5Co2B6合金的～150 nm减小到(Nd,Pr)10.5Fe80Zr1.5Co2B6合金的～50 nm;1%是Zr最佳添加量,低于1%晶粒不够细化,合金的各项磁性能指标均很低,超过1%,富集在晶界处的富Zr晶间相加厚,晶粒间的交换作用和剩磁增强效应减弱,磁体的剩磁Br和最大磁能积(BH)m降低.(Nd,Pr)10.5Fe80.5Zr1Co2B6粘结磁体磁性能最佳Br=0.675 T,Hci=616 kA·m-1,(BH)m=77 kJ·m-3.
研究了添加Zr元素对快淬(Nd,Pr)10.5Fe81.5-xZrxCo2B6(x=0,0.5,1.0,1.5,2.0,2.5)合金显微组织结构和磁性能的影响,用AFM观察了合金条带自由表面的显微结构.结果表明添加Zr元素能显著细化合金的晶粒,从(Nd,Pr)10 5Fe81 5Co2B6合金的～150 nm减小到(Nd,Pr)10.5Fe80Zr1.5Co2B6合金的～50 nm;1%是Zr最佳添加量,低于1%晶粒不够细化,合金的各项磁性能指标均很低,超过1%,富集在晶界处的富Zr晶间相加厚,晶粒间的交换作用和剩磁增强效应减弱,磁体的剩磁Br和最大磁能积(BH)m降低.(Nd,Pr)10.5Fe80.5Zr1Co2B6粘结磁体磁性能最佳Br=0.675 T,Hci=616 kA·m-1,(BH)m=77 kJ·m-3.
2005, 34(5):721-725.
Abstract:
采用扫描电镜、透射电镜、X射线衍射及硬度测试等手段研究了添加2at％Cu的AlZn对称成分合金在冷轧后重新加热过程中的组织结构变化。结果发现：该合金不连续析出组织在冷变形后重新加热时发生了再结晶，以连续粗化与不连续粗化2种机制进行，再结晶温度约为100℃：而且相组成物由Al相、Zn相和细小的ε相转变为Al相、Zn相和粗大的T'相。AlZn-2Cu合金不连续析出组织在冷变形后重新加热时，硬度的变化是由再结晶软化、T’相粗化以及Zn原子的固溶强化共同影响的结果。
采用扫描电镜、透射电镜、X射线衍射及硬度测试等手段研究了添加2at％Cu的AlZn对称成分合金在冷轧后重新加热过程中的组织结构变化。结果发现：该合金不连续析出组织在冷变形后重新加热时发生了再结晶，以连续粗化与不连续粗化2种机制进行，再结晶温度约为100℃：而且相组成物由Al相、Zn相和细小的ε相转变为Al相、Zn相和粗大的T'相。AlZn-2Cu合金不连续析出组织在冷变形后重新加热时，硬度的变化是由再结晶软化、T’相粗化以及Zn原子的固溶强化共同影响的结果。
2005, 34(5):726-730.
Abstract:
通过对实验Al—Zn—Mg—Cu—Zr-Ag合金不同温度下(90℃～150℃)时效得到的硬度和导电率数据进行了神经网络建模，发现在目标函数为0．3，隐层节点数为5，学习率为0．15时，系统误差较小。利用所建立的网络模型预测不同时效状态下材料的硬度和导电率值，发现预测数据与实验数据吻合良好(总误差3．5％)，为铝合金时效性能预测和控制提供了1条新途径。
通过对实验Al—Zn—Mg—Cu—Zr-Ag合金不同温度下(90℃～150℃)时效得到的硬度和导电率数据进行了神经网络建模，发现在目标函数为0．3，隐层节点数为5，学习率为0．15时，系统误差较小。利用所建立的网络模型预测不同时效状态下材料的硬度和导电率值，发现预测数据与实验数据吻合良好(总误差3．5％)，为铝合金时效性能预测和控制提供了1条新途径。
2005, 34(5):731-733.
Abstract:
Anatase phase TiO2 and WO3-doped TiO2 thin films were prepared on microscope glass slides by self-assembly method. The films were characterized by atomic force microscope (AFM) and UV-VIS spectrophotometer. The photocatalytic activities of the films were tested on the degradation of rhodamine B dye. The results indicate that when the atom ratio of W/Ti is 2at%, the photocatalytic activity of the TiO2 is improved.
Anatase phase TiO2 and WO3-doped TiO2 thin films were prepared on microscope glass slides by self-assembly method. The films were characterized by atomic force microscope (AFM) and UV-VIS spectrophotometer. The photocatalytic activities of the films were tested on the degradation of rhodamine B dye. The results indicate that when the atom ratio of W/Ti is 2at%, the photocatalytic activity of the TiO2 is improved.
2005, 34(5):734-737.
Abstract:
TiO2 films doped with SnO2 were prepared on quartz substrate by electrostatic self-assembly method in this paper. Atom force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and UV-Vis-NIR spectrophotometer were employed to characterize the microstructure and performance of the samples. Results of the optical absorption spectra and the measurement of photo-catalytic activity show that the photo-absorbency of the samples is greatly increased and the photo-catalytic activity of the films is well improved by SnO2-doping.
TiO2 films doped with SnO2 were prepared on quartz substrate by electrostatic self-assembly method in this paper. Atom force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and UV-Vis-NIR spectrophotometer were employed to characterize the microstructure and performance of the samples. Results of the optical absorption spectra and the measurement of photo-catalytic activity show that the photo-absorbency of the samples is greatly increased and the photo-catalytic activity of the films is well improved by SnO2-doping.
2005, 34(5):738-741.
Abstract:
Ti-Si-N thin films prepared by pulsed-d.c. PCVD on the surface of HSS substrates, which were bolted with one end of deep holes to simulate the condition of complex-shaped inter-surface of various moulds and dies, were investigated. The micrographs show that the surface morphologies of the films become smoother with the increase of the depths of the holes. The thickness and hardness of the films decrease with the increase of the depth of the hole, which may result from the change of the composition of the films, while the adhesion between the films and substrates show an increase.
Ti-Si-N thin films prepared by pulsed-d.c. PCVD on the surface of HSS substrates, which were bolted with one end of deep holes to simulate the condition of complex-shaped inter-surface of various moulds and dies, were investigated. The micrographs show that the surface morphologies of the films become smoother with the increase of the depths of the holes. The thickness and hardness of the films decrease with the increase of the depth of the hole, which may result from the change of the composition of the films, while the adhesion between the films and substrates show an increase.
2005, 34(5):742-745.
Abstract:
Under constrained condition, severe plastic deformation at high speed can be carried out at extreme low temperature without annealing. Homogeneously Ultrafine-Grained (UFG) 7075 aluminum alloy (e.g. Al-Zn-Mg alloy) with size about 200 nm was fabricated. Evolution of microstructure was studied by transmission electron microcopy (TEM). Different deformations were observed. Factors such as low temperature and dynamic recrystallization contributing to microstructural evolution were discussed.
Under constrained condition, severe plastic deformation at high speed can be carried out at extreme low temperature without annealing. Homogeneously Ultrafine-Grained (UFG) 7075 aluminum alloy (e.g. Al-Zn-Mg alloy) with size about 200 nm was fabricated. Evolution of microstructure was studied by transmission electron microcopy (TEM). Different deformations were observed. Factors such as low temperature and dynamic recrystallization contributing to microstructural evolution were discussed.
2005, 34(5):746-749.
Abstract:
研究了Ga2O3／Al2O3膜反应自组装制备GaN薄膜。首先利用磁控溅射法在硅衬底上制备Ga2O3／Al2O3膜，再将Ga2O3／Al2O3膜在高纯氨气气氛中氨化反应得到GaN薄膜。用傅里叶红外谱仪(FTIR)，X射线衍射(XRD)和扫描电镜(SEM)对试样进行结构、组分和形貌分析。通过分析薄膜各方面的性质，得出了用此方法制备氮化镓薄膜的Al2O3缓冲层最佳的厚度为15nm左右，最佳氨化条件是在900℃下氨化15min。
研究了Ga2O3／Al2O3膜反应自组装制备GaN薄膜。首先利用磁控溅射法在硅衬底上制备Ga2O3／Al2O3膜，再将Ga2O3／Al2O3膜在高纯氨气气氛中氨化反应得到GaN薄膜。用傅里叶红外谱仪(FTIR)，X射线衍射(XRD)和扫描电镜(SEM)对试样进行结构、组分和形貌分析。通过分析薄膜各方面的性质，得出了用此方法制备氮化镓薄膜的Al2O3缓冲层最佳的厚度为15nm左右，最佳氨化条件是在900℃下氨化15min。
2005, 34(5):750-753.
Abstract:
通过在3．0．MPa氢气气氛下球磨Mg-30％LaNi2(质量分数)的混合粉末，制得镁基复合储氢材料。X射线衍射分析表明，球磨80h后的物相组成为MgH2，Mg2NiH4和LaH3，表明球磨过程中发生固态反应；SEM及EDS分析表明，复合体系中成分分布均匀：该复合储氢材料具有较高的活性和储氢量，在3．0MPa氢气压力和473K～553K之间的条件下，可以在1min之内完成饱和吸氢量的80％以上；在553K时储氢量达到5．419％(质量分数)。
通过在3．0．MPa氢气气氛下球磨Mg-30％LaNi2(质量分数)的混合粉末，制得镁基复合储氢材料。X射线衍射分析表明，球磨80h后的物相组成为MgH2，Mg2NiH4和LaH3，表明球磨过程中发生固态反应；SEM及EDS分析表明，复合体系中成分分布均匀：该复合储氢材料具有较高的活性和储氢量，在3．0MPa氢气压力和473K～553K之间的条件下，可以在1min之内完成饱和吸氢量的80％以上；在553K时储氢量达到5．419％(质量分数)。
2005, 34(5):754-757.
Abstract:
以CaHPO4为初始粉料，采用等离子喷涂一水热合成复合技术在Ti-6Al-4V基体上制备了羟基磷灰石(HA)涂层。用SEM，EDX和XRD分析涂层的形貌和组成，用电子拉伸机测定涂层的结合强度。并与等离子喷涂HA涂层做对比，研究了涂层的微观结构和结合强度及其在生理盐水中浸泡后的变化。结果表明：喷涂CaHPO4涂层由β-Ca2P2O7和α-Ca3(PO4)2组成，经水热合成，转化为高纯度和高结晶度的HA涂层；在生理盐水中浸泡1周～4周后，该HA涂层的溶解性和结合强度退化程度均低于等离子喷涂HA涂层，呈现较高的组织和力学稳定性。
以CaHPO4为初始粉料，采用等离子喷涂一水热合成复合技术在Ti-6Al-4V基体上制备了羟基磷灰石(HA)涂层。用SEM，EDX和XRD分析涂层的形貌和组成，用电子拉伸机测定涂层的结合强度。并与等离子喷涂HA涂层做对比，研究了涂层的微观结构和结合强度及其在生理盐水中浸泡后的变化。结果表明：喷涂CaHPO4涂层由β-Ca2P2O7和α-Ca3(PO4)2组成，经水热合成，转化为高纯度和高结晶度的HA涂层；在生理盐水中浸泡1周～4周后，该HA涂层的溶解性和结合强度退化程度均低于等离子喷涂HA涂层，呈现较高的组织和力学稳定性。
2005, 34(5):758-760.
Abstract:
The 873 K isothermal section of La-Ni-Cr ternary system phase diagram was investigated by X-ray powder diffraction, differential thermal analysis and electron microscopy techniques. It is composed of 10 single-phase regions, 17 two-phase regions and 8 three-phase regions. At 873 K, the existence of ternary compounds has not observed in the isothermal section. The maximum solid solubility of Ni in Cr is about 3 at%Ni, and that of Cr in Ni, LaNi5, La2Ni7, LaNi3, La2Ni3, LaNi, La7Ni3 is about 35, 20, 15, 8, 9, 9 and 6 at% Cr, respectively. The solid solubility of Cr in the La7Ni16 phase is nearly zero.
The 873 K isothermal section of La-Ni-Cr ternary system phase diagram was investigated by X-ray powder diffraction, differential thermal analysis and electron microscopy techniques. It is composed of 10 single-phase regions, 17 two-phase regions and 8 three-phase regions. At 873 K, the existence of ternary compounds has not observed in the isothermal section. The maximum solid solubility of Ni in Cr is about 3 at%Ni, and that of Cr in Ni, LaNi5, La2Ni7, LaNi3, La2Ni3, LaNi, La7Ni3 is about 35, 20, 15, 8, 9, 9 and 6 at% Cr, respectively. The solid solubility of Cr in the La7Ni16 phase is nearly zero.
Dong Xiangting
,
Feng Xiuli
,
Wang Jinxian
,
Yan Jinghui
,
Wang Ying
,
Liu Zhongxin
,
Hong Guangyan .College of Materials
,
Chemical Engineering
,
Changchun University of Science
,
Technology
,
Ch
2005, 34(5):761-763.
Abstract:
AgI hydrosol was prepared by the precipitation method and the effect factors on hydrosol were discussed systematically. TEM photos show that the AgI nanoparticles are spherical in shape , the size of which is less than 50nm.The particle size distribution: in a anarrow range, and no agglomerate has been observed. ED images indicate that the AgI nanoparticles are polycrystalline structure, and some are well-grown monocrystalline particles.
AgI hydrosol was prepared by the precipitation method and the effect factors on hydrosol were discussed systematically. TEM photos show that the AgI nanoparticles are spherical in shape , the size of which is less than 50nm.The particle size distribution: in a anarrow range, and no agglomerate has been observed. ED images indicate that the AgI nanoparticles are polycrystalline structure, and some are well-grown monocrystalline particles.
2005, 34(5):764-767.
Abstract:
利用先驱体NiNb2O6与MnNb2O6掺杂法改性BaTiO3系统。由于2种先驱体可以有效地起到展宽与移峰效应,使系统居里峰在室温附近取得最大值,在1290℃烧结时介电常数达到5000以上,容量变化率ΔC/C≤±15%;在系统中加入适量助熔剂可以实现中温烧结(1150℃),介电常数大于3600,容量变化率ΔC/C≤±12%,满足X7R特性要求,可用于厚膜EMI滤波介质瓷料的制备。
利用先驱体NiNb2O6与MnNb2O6掺杂法改性BaTiO3系统。由于2种先驱体可以有效地起到展宽与移峰效应,使系统居里峰在室温附近取得最大值,在1290℃烧结时介电常数达到5000以上,容量变化率ΔC/C≤±15%;在系统中加入适量助熔剂可以实现中温烧结(1150℃),介电常数大于3600,容量变化率ΔC/C≤±12%,满足X7R特性要求,可用于厚膜EMI滤波介质瓷料的制备。
Su Yanqing
,
Liu Chang
,
Bi Weisheng
,
Ding Hongsheng
,
Li Bangsheng
,
Guan Xingju
,
Guo Jingjie
,
Jia Jun
,
Fu Hengzhi
2005, 34(5):768-772.
Abstract:
采用区域重熔定向凝固技术制备了Ti-45Al合金定向凝固试样,研究了不同参数下的凝固组织。结果表明,该合金在定向凝固过程中一次凝固可以以胞晶形式实现定向生长,胞晶内α2/γ片层方向与生长方向成45°或90°。凝固过程中稳定相β及亚稳相α同时存在,并以胞状生长,存在竞争而引起的交替现象。降速生长时定向组织比较理想。淬火实验表明,在大过冷度下亚稳α相作为领先相析出。
采用区域重熔定向凝固技术制备了Ti-45Al合金定向凝固试样,研究了不同参数下的凝固组织。结果表明,该合金在定向凝固过程中一次凝固可以以胞晶形式实现定向生长,胞晶内α2/γ片层方向与生长方向成45°或90°。凝固过程中稳定相β及亚稳相α同时存在,并以胞状生长,存在竞争而引起的交替现象。降速生长时定向组织比较理想。淬火实验表明,在大过冷度下亚稳α相作为领先相析出。
2005, 34(5):773-776.
Abstract:
Active template process was successfully used to prepare nano nickel powder. The influences of different technology conditions on the properties of the nano nickel particles were investigated. Laser Granularity Instrument, XRD and TEM were used to analyze the properties of the samples respectively. The action mechanism of active template was also discussed. The results show that active template not only has micro-reactor action and steric stabilization function, but also acts as reducer during reaction. The nano nickel powder via active template process take on regular sphericity-chain morphology without obvious agglomeration and has fine particle size(45.7 nm) and narrow distribution(16.0 nm~59.1 nm).
Active template process was successfully used to prepare nano nickel powder. The influences of different technology conditions on the properties of the nano nickel particles were investigated. Laser Granularity Instrument, XRD and TEM were used to analyze the properties of the samples respectively. The action mechanism of active template was also discussed. The results show that active template not only has micro-reactor action and steric stabilization function, but also acts as reducer during reaction. The nano nickel powder via active template process take on regular sphericity-chain morphology without obvious agglomeration and has fine particle size(45.7 nm) and narrow distribution(16.0 nm~59.1 nm).
2005, 34(5):777-780.
Abstract:
采用热压法制备出二层锆钛酸铅(PZT)／聚偏氟乙烯(PVDF)与1层Tb0.28Dy0.72Fe2(Terfenol-D)／PVDF叠层结构的三元复合磁电材料，研究了不同PVDF含量，以及不同层厚比tp／L对样品的介电常数、介电损耗、电阻率、谐振频率以及磁电转换系数αE33，αE31的影响规律，结果显示PVDF的含量和层厚比都存在最佳值(最佳值出现在产0．5，tp／L=2／7)，并且在这个最佳值处，磁电转换系数达到最大。
采用热压法制备出二层锆钛酸铅(PZT)／聚偏氟乙烯(PVDF)与1层Tb0.28Dy0.72Fe2(Terfenol-D)／PVDF叠层结构的三元复合磁电材料，研究了不同PVDF含量，以及不同层厚比tp／L对样品的介电常数、介电损耗、电阻率、谐振频率以及磁电转换系数αE33，αE31的影响规律，结果显示PVDF的含量和层厚比都存在最佳值(最佳值出现在产0．5，tp／L=2／7)，并且在这个最佳值处，磁电转换系数达到最大。
2005, 34(5):781-785.
Abstract:
以叶片中的一类重要叶片——钛合金单榫头叶片为研究对象，利用自主开发的并经实验验证的叶片精锻三维有限元变形．传热一微观组织演变耦合模拟系统对其精锻过程进行了模拟，研究了不同工艺参数下叶身典型截面锻后微观组织的分布规律。结果表明：随着变形温度的升高，晶粒尺寸和β相体积分数增大；随着变形速度的增大，晶粒尺寸和β相体积分数相应增大；随着模具温度的升高，晶粒尺寸分布的均匀性提高：而摩擦条件对晶粒尺寸和β相体积分数的影响不显著。
以叶片中的一类重要叶片——钛合金单榫头叶片为研究对象，利用自主开发的并经实验验证的叶片精锻三维有限元变形．传热一微观组织演变耦合模拟系统对其精锻过程进行了模拟，研究了不同工艺参数下叶身典型截面锻后微观组织的分布规律。结果表明：随着变形温度的升高，晶粒尺寸和β相体积分数增大；随着变形速度的增大，晶粒尺寸和β相体积分数相应增大；随着模具温度的升高，晶粒尺寸分布的均匀性提高：而摩擦条件对晶粒尺寸和β相体积分数的影响不显著。
2005, 34(5):786-789.
Abstract:
利用硅烷偶联剂KH550对Sm2Fe17Nx永磁粉末进行了表面包覆处理，研究了不同包覆状态的磁粉在300℃以下的氧化行为及其磁性能的变化规律。采用红外光谱(FT-IR)、俄歇电子能谱(AES)分析了磁粉表面有机物的成分、结构及其与磁粉的结合机制。测试了不同温度下磁粉的氧化增重及磁特性参数。结果表明，偶联剂以化学键的方式吸附在磁粉表面，形成了1层网状薄膜，有效地阻止了磁粉与环境中氧的接触，从而提高了磁粉在高温下的抗氧化能力。
利用硅烷偶联剂KH550对Sm2Fe17Nx永磁粉末进行了表面包覆处理，研究了不同包覆状态的磁粉在300℃以下的氧化行为及其磁性能的变化规律。采用红外光谱(FT-IR)、俄歇电子能谱(AES)分析了磁粉表面有机物的成分、结构及其与磁粉的结合机制。测试了不同温度下磁粉的氧化增重及磁特性参数。结果表明，偶联剂以化学键的方式吸附在磁粉表面，形成了1层网状薄膜，有效地阻止了磁粉与环境中氧的接触，从而提高了磁粉在高温下的抗氧化能力。
2005, 34(5):795-798.
Abstract:
The influence of different contents of RE on microstructure of Mg-5Al-1Si alloys was studied. Also, the extracting phases were identified and the extracting process and its influence on the mechanical property of alloy were investigated. The results show that addition of small amount of RE to Mg-5Al-1Si alloys resulted in refinement of microstructure. The morphology of the Mg2Si phase changed form coarse Chinese script shape to the fine polygonal shape. Owing to the improvement of microstructure, the mechanical properties of Mg-5Al-1Si alloys at both ambient and elevated temperatures were increased . The high temperature creep resistant properties of Mg-5Al-1Si-xRE raises with the increase of RE content and higher than that of AE42.
The influence of different contents of RE on microstructure of Mg-5Al-1Si alloys was studied. Also, the extracting phases were identified and the extracting process and its influence on the mechanical property of alloy were investigated. The results show that addition of small amount of RE to Mg-5Al-1Si alloys resulted in refinement of microstructure. The morphology of the Mg2Si phase changed form coarse Chinese script shape to the fine polygonal shape. Owing to the improvement of microstructure, the mechanical properties of Mg-5Al-1Si alloys at both ambient and elevated temperatures were increased . The high temperature creep resistant properties of Mg-5Al-1Si-xRE raises with the increase of RE content and higher than that of AE42.
2005, 34(5):799-802.
Abstract:
In this paper, plate-like nano-particles of strontium hydrogen phosphate (SrHPO4) with a thickness of 30 nm~80 nm and a width of 140 nm~200 nm were synthesized by chemical wet method. The influence of processing parameters including aging time, temperature, pH and concentration of solution, on composition, size and morphology of nano-particle was investigated by XRD and TEM. Results show that pH of reaction solution places a critical role on the composition of the final products. Both reaction time and temperature affect greatly morphology but little particle size.
In this paper, plate-like nano-particles of strontium hydrogen phosphate (SrHPO4) with a thickness of 30 nm~80 nm and a width of 140 nm~200 nm were synthesized by chemical wet method. The influence of processing parameters including aging time, temperature, pH and concentration of solution, on composition, size and morphology of nano-particle was investigated by XRD and TEM. Results show that pH of reaction solution places a critical role on the composition of the final products. Both reaction time and temperature affect greatly morphology but little particle size.
2005, 34(5):803-806.
Abstract:
将电化学噪音技术应用于AB5型贮氢合金的研究，初步探索了其放电深度与电化学噪音(EN)信号之间的关系。结果表明，贮氢合金M／Ni3.75Co0.65Mn0.4Al0．2在稳定状态的电化学噪音信号比充放电刚结束时要明显得多，而且在高温下的电化学噪音信号比室温下明显得多。虽然不同放电深度的该合金电极EN信号有明显的区别，但其功率密度谱(PSD)曲线均由低频区的白噪音和高频区的闪烁噪音组成。随着放电深度的增加，PSD曲线中闪烁噪音的斜率a和噪音功率P的变化规律正好相反，a先减小后增大，P先增大后减小。
将电化学噪音技术应用于AB5型贮氢合金的研究，初步探索了其放电深度与电化学噪音(EN)信号之间的关系。结果表明，贮氢合金M／Ni3.75Co0.65Mn0.4Al0．2在稳定状态的电化学噪音信号比充放电刚结束时要明显得多，而且在高温下的电化学噪音信号比室温下明显得多。虽然不同放电深度的该合金电极EN信号有明显的区别，但其功率密度谱(PSD)曲线均由低频区的白噪音和高频区的闪烁噪音组成。随着放电深度的增加，PSD曲线中闪烁噪音的斜率a和噪音功率P的变化规律正好相反，a先减小后增大，P先增大后减小。
2005, 34(5):807-810.
Abstract:
研究了铜碲合金的时效工艺，用扫描电镜(SEM)和能谱(EDS)分析了析出相的形貌与组成，进而研究了时效工艺对其电性能及力学性能的影响。研究表明：时效过程中Te以第二相形式析出(Cu2Te)；随时效温度的升高、时效时间的延长，时效态的铜碲合金位错密度降低，晶粒长大，第二相析出充分，因而电阻率单调下降；但由于时效析出与再结晶的交互作用，其抗拉强度出现波动，存在1个峰值；综合性能以420℃下时效6h较好。
研究了铜碲合金的时效工艺，用扫描电镜(SEM)和能谱(EDS)分析了析出相的形貌与组成，进而研究了时效工艺对其电性能及力学性能的影响。研究表明：时效过程中Te以第二相形式析出(Cu2Te)；随时效温度的升高、时效时间的延长，时效态的铜碲合金位错密度降低，晶粒长大，第二相析出充分，因而电阻率单调下降；但由于时效析出与再结晶的交互作用，其抗拉强度出现波动，存在1个峰值；综合性能以420℃下时效6h较好。
2005, 34(5):811-815.
Abstract:
In this work, the microstructure and electrochemical properties of Co-free MlNi4.0Al0.3Si0.1Fe0.6 hydrogen storage electrode alloys prepared by both conventional casting and melt-spinning processes at different solidification rate were studied comparatively. XRD analyses indicated that both as-cast and melt-spun alloys were of the CaCu5-type structure single phase, but the crystallizability and homogeneity of the melt-spun alloys were improved. The optical microscope and EDS analyses showed that the melt-spun alloys had a fine cellular structure and a more homogeneous composition than that of the as-cast alloy which had a coarse dendrite structure with noticeable composition segregation. The electrochemical tests indicated that the melt-spun alloys showed a good activation property and much better cycling stability, but lower discharge capacity and high-rate dischargeability. It is found that the decrease in both exchange current density I0 and the diffusion coefficient D of hydrogen in alloy bulk is the main reason for the degraded HRD of melt-spun alloys. The change of electrochemical properties of the alloy treated by rapid solidification process is related to the microstructure of the alloy.
In this work, the microstructure and electrochemical properties of Co-free MlNi4.0Al0.3Si0.1Fe0.6 hydrogen storage electrode alloys prepared by both conventional casting and melt-spinning processes at different solidification rate were studied comparatively. XRD analyses indicated that both as-cast and melt-spun alloys were of the CaCu5-type structure single phase, but the crystallizability and homogeneity of the melt-spun alloys were improved. The optical microscope and EDS analyses showed that the melt-spun alloys had a fine cellular structure and a more homogeneous composition than that of the as-cast alloy which had a coarse dendrite structure with noticeable composition segregation. The electrochemical tests indicated that the melt-spun alloys showed a good activation property and much better cycling stability, but lower discharge capacity and high-rate dischargeability. It is found that the decrease in both exchange current density I0 and the diffusion coefficient D of hydrogen in alloy bulk is the main reason for the degraded HRD of melt-spun alloys. The change of electrochemical properties of the alloy treated by rapid solidification process is related to the microstructure of the alloy.
2005, 34(5):821-825.
Abstract:
In order to analysis the effect of micro-arc oxidation time on the structure of the porous titania films prepared by a composite oxidation (that is pre-oxidation and micro-arc anodic oxidation), the SEM, EDS, XRD and micro-hardness testing methods were employed to investigate the phase constitutes, element compositions, morphologies and hardness of the modified films. The results show that micro-arc oxidation time is one of the major factors influencing the morphologies, structures, hardness and the ratio of Ca/P of the coatings treated by the two-step anodic oxidation treatment. With the micro-arc anodic oxidation time increasing, the diameter of the pores, roughness of the surface, hardness all increase, and the atomic ratios of Ca/P are changed at the same time. The rutile phase in the coatings become more and anatase become less when the time varied to a long period. So appropriate porous titania coatings can be gained by adjusting the micro-arc anodic oxidation time in the composite oxidation method.
In order to analysis the effect of micro-arc oxidation time on the structure of the porous titania films prepared by a composite oxidation (that is pre-oxidation and micro-arc anodic oxidation), the SEM, EDS, XRD and micro-hardness testing methods were employed to investigate the phase constitutes, element compositions, morphologies and hardness of the modified films. The results show that micro-arc oxidation time is one of the major factors influencing the morphologies, structures, hardness and the ratio of Ca/P of the coatings treated by the two-step anodic oxidation treatment. With the micro-arc anodic oxidation time increasing, the diameter of the pores, roughness of the surface, hardness all increase, and the atomic ratios of Ca/P are changed at the same time. The rutile phase in the coatings become more and anatase become less when the time varied to a long period. So appropriate porous titania coatings can be gained by adjusting the micro-arc anodic oxidation time in the composite oxidation method.
2005, 34(5):826-829.
Abstract:
The pressure-composition (P-C) behavior of protium and deuterium in sponge Pd particle has been measured over a temperature range from 278 K to 323 K. Based on these data and combined with literature data, the effect of Pd crystal type and particle sizes on the thermodynamic properties in the Pd-H system was compared each other and discussed. The saturation solubility of hydrogen in solid solution region and the plateau pressure increase with decreasing Pd particle sizes at the ambient temperature. The effect of Pd morphology on above two parameters gets weaker at higher temperature and the difference of plateau pressure among several different Pd morphologies disappears. The absolute value of phase transformation enthalpy and entropy from solid solution to hydride decrease with decreasing particle sizes of Pd, but which are the smallest in single crystal Pd. The degree of hysteresis effect in Pd-H system depends on the background density in the sample, so it is the strongest in sponge Pd particle.
The pressure-composition (P-C) behavior of protium and deuterium in sponge Pd particle has been measured over a temperature range from 278 K to 323 K. Based on these data and combined with literature data, the effect of Pd crystal type and particle sizes on the thermodynamic properties in the Pd-H system was compared each other and discussed. The saturation solubility of hydrogen in solid solution region and the plateau pressure increase with decreasing Pd particle sizes at the ambient temperature. The effect of Pd morphology on above two parameters gets weaker at higher temperature and the difference of plateau pressure among several different Pd morphologies disappears. The absolute value of phase transformation enthalpy and entropy from solid solution to hydride decrease with decreasing particle sizes of Pd, but which are the smallest in single crystal Pd. The degree of hysteresis effect in Pd-H system depends on the background density in the sample, so it is the strongest in sponge Pd particle.
2005, 34(5):830-832.
Abstract:
CuCr25 alloy is prepared by vacuum induction melting and is rolled at low strain rate. The experimental results show that the electrical conductivity first increases, then it decreases gradually with the deformation. After deforming to certain degree, the conductivity increases again and Cr phases are deformed to ribbons or fibrous. The work hardening of the copper matrix leads to the hardness increase of the CuCr25 alloy. CuCr25 alloy has a superplasticity at room temperature.
CuCr25 alloy is prepared by vacuum induction melting and is rolled at low strain rate. The experimental results show that the electrical conductivity first increases, then it decreases gradually with the deformation. After deforming to certain degree, the conductivity increases again and Cr phases are deformed to ribbons or fibrous. The work hardening of the copper matrix leads to the hardness increase of the CuCr25 alloy. CuCr25 alloy has a superplasticity at room temperature.
2005, 34(5):833-836.
Abstract:
Microstructural evolution of the semisolid Al-4Cu-Mg alloy fabricated by strain induced melting activation (SIMA) at different deformation temperatures and strain rates during semisolid deforming were investigated. The experimental results show that the grain size increases with the increase of deformation temperature and decreases with the increase of height reduction. Fractal dimension decreases with the increase of deformation temperature and increases with the increase of height reduction after an early drop. Grain size decreases with the increase from 0.001 s-1 to 0.1 s-1 of strain rate, but increases slightly with the increase from 0.1 s-1 to 1 s-1 of strain rate. The lower the strain rate, the greater effect of strain rate on grain size. Fractal dimension increases with the increase of strain rate.
Microstructural evolution of the semisolid Al-4Cu-Mg alloy fabricated by strain induced melting activation (SIMA) at different deformation temperatures and strain rates during semisolid deforming were investigated. The experimental results show that the grain size increases with the increase of deformation temperature and decreases with the increase of height reduction. Fractal dimension decreases with the increase of deformation temperature and increases with the increase of height reduction after an early drop. Grain size decreases with the increase from 0.001 s-1 to 0.1 s-1 of strain rate, but increases slightly with the increase from 0.1 s-1 to 1 s-1 of strain rate. The lower the strain rate, the greater effect of strain rate on grain size. Fractal dimension increases with the increase of strain rate.
Dong Xiaodong
,
Dong Xiangting
,
Liu Junhua
,
Yan Jinghui
,
Hong Guangyan . College of Materials
,
Chemical Engineering
,
Changchun University of Science
,
Technology
,
Changchun
,
China)
2005, 34(5):837-840.
Abstract:
MoO3 organosol was obtained by using surface active agent CTAB to modify the nanoparticles in MoO3 hydrosol and n-pentanol to extract MoO3 nanoparticles modified by CTAB. The effect factors on organosol were discussed systematically. TEM photos showed that the MoO3 nanoparticles were spherical in shape, the size was about 40 nm, particle size distribution was in narrow range. ED images indicated that the MoO3 nanoparticles were polycrystalline structure. UV-VIS analysis showed that the MoO3 nanoparticles organosol had good photochromic effect.
MoO3 organosol was obtained by using surface active agent CTAB to modify the nanoparticles in MoO3 hydrosol and n-pentanol to extract MoO3 nanoparticles modified by CTAB. The effect factors on organosol were discussed systematically. TEM photos showed that the MoO3 nanoparticles were spherical in shape, the size was about 40 nm, particle size distribution was in narrow range. ED images indicated that the MoO3 nanoparticles were polycrystalline structure. UV-VIS analysis showed that the MoO3 nanoparticles organosol had good photochromic effect.
