Volume 0,Issue 11,2003 Table of Contents
2003(11):869-874.
Abstract:
对室温磁致冷材料的最新进展作了综合报道,主要包括Gd、Gd-Si-Ge、La-Fe-(Si、Al)、Mn-As-Sb、Mn-Fe-P-As几个化合物系列。Gd,居里温度294K,其磁热性能在所有纯金属中最好;Gd5Si2Ge2,居里温度274K,在此温度处具有巨磁热效应;在La-Fe-Co-Si、La-Fe-Co-Al化合物中,改变Co的含量可以使化合物的居里温度得到调整,其磁热性能可以与Gd比拟甚至超过Gd;MnFeP0.45As0.55,居里温度308K,具有巨磁热效应,磁热性能远远超过Gd。在MnAs1-xSbx化合物中,随Sb(0
对室温磁致冷材料的最新进展作了综合报道,主要包括Gd、Gd-Si-Ge、La-Fe-(Si、Al)、Mn-As-Sb、Mn-Fe-P-As几个化合物系列。Gd,居里温度294K,其磁热性能在所有纯金属中最好;Gd5Si2Ge2,居里温度274K,在此温度处具有巨磁热效应;在La-Fe-Co-Si、La-Fe-Co-Al化合物中,改变Co的含量可以使化合物的居里温度得到调整,其磁热性能可以与Gd比拟甚至超过Gd;MnFeP0.45As0.55,居里温度308K,具有巨磁热效应,磁热性能远远超过Gd。在MnAs1-xSbx化合物中,随Sb(0
2003(11):875-879.
Abstract:
Driving by the lower cost and better properties, the development of new positive electrode materials of Li ion battery has been paid more attention by the researchers. It is not occasional for most of positive electrode materials to have a layer type or tunnel structure. In this paper, a brief presentation on the situation of positive electrode materials was done, based on which the fundamentals to improve the positive electrode properties and to find new type materials were proposed. The necessary requirement is to have layer type structure and/or tunnel structure.
Driving by the lower cost and better properties, the development of new positive electrode materials of Li ion battery has been paid more attention by the researchers. It is not occasional for most of positive electrode materials to have a layer type or tunnel structure. In this paper, a brief presentation on the situation of positive electrode materials was done, based on which the fundamentals to improve the positive electrode properties and to find new type materials were proposed. The necessary requirement is to have layer type structure and/or tunnel structure.
2003(11):880-884.
Abstract:
利用旋转铜辊急冷法和铜模铸造法制备非晶合金薄带或圆棒，并采用X衍射仪(XRD)、差示扫描量热仪(DSC)和差示热分析仪(DTA)研究了Ta，Nb和Mo对Ti50Ni20Cu25Sn5非晶合金玻璃形成能力(GFA)的影响。结果表明，Ta的添加提高了Ti50Ni20Cu25Sn5合金的GFA，Mo的添加降低了该合金的GFA，Nb的添加剂对该合金的GFA没有明显的影响；含Ta合金具有超过60K的宽过冷液态区(△Tx)，且其约化玻璃转变温度因子(Tg／Tm)大于含Nb合金和含Mo合金；采用常规铜模铸造法制备出了直径为lmm的(Ti0.5Ni0.2Cu0.25Sn0.05)98Ta2和(Ti0.5Ni0.2Cu0.5Sn0.05)96Ta4块状非晶圆棒；(Ti0.5Ni0.2Cu0.25Sn0.05)98Ta2块状非晶圆棒的Tg，△Tx和Tg／Tm分别为678K，84K和0．60，而(Ti0.5Ni0.2Cu0.25Sn0.05)96Ta4块状非晶圆棒的Tg，△Tx和Tg／Tm分别为680K，70K和0．60。
利用旋转铜辊急冷法和铜模铸造法制备非晶合金薄带或圆棒，并采用X衍射仪(XRD)、差示扫描量热仪(DSC)和差示热分析仪(DTA)研究了Ta，Nb和Mo对Ti50Ni20Cu25Sn5非晶合金玻璃形成能力(GFA)的影响。结果表明，Ta的添加提高了Ti50Ni20Cu25Sn5合金的GFA，Mo的添加降低了该合金的GFA，Nb的添加剂对该合金的GFA没有明显的影响；含Ta合金具有超过60K的宽过冷液态区(△Tx)，且其约化玻璃转变温度因子(Tg／Tm)大于含Nb合金和含Mo合金；采用常规铜模铸造法制备出了直径为lmm的(Ti0.5Ni0.2Cu0.25Sn0.05)98Ta2和(Ti0.5Ni0.2Cu0.5Sn0.05)96Ta4块状非晶圆棒；(Ti0.5Ni0.2Cu0.25Sn0.05)98Ta2块状非晶圆棒的Tg，△Tx和Tg／Tm分别为678K，84K和0．60，而(Ti0.5Ni0.2Cu0.25Sn0.05)96Ta4块状非晶圆棒的Tg，△Tx和Tg／Tm分别为680K，70K和0．60。
2003(11):885-888.
Abstract:
采用Gleeble-1500热模拟试验机研究了Ti14阻燃钛合金在990℃以上半固态条件下的氧化和变形行为，利用金相显微镜观察变形前后及氧化的微观组织形貌，采用X射线衍射(XRD)仪分析氧化层的组成，利用线扫描分析氧化层中元素分布。结果表明，半固态氧化温度升高，氧化增重急剧增加，表面氧化层中只存在Ti的氧化物，不存在Cu的氧化物，表面形成5层氧化层结构，熔融的晶界是氧向基体内扩散的优先通道；Ti14合金半固态变形中，晶界、晶内的Ti2Cu相熔融长大，形成宽化的晶界和网格状结构。
采用Gleeble-1500热模拟试验机研究了Ti14阻燃钛合金在990℃以上半固态条件下的氧化和变形行为，利用金相显微镜观察变形前后及氧化的微观组织形貌，采用X射线衍射(XRD)仪分析氧化层的组成，利用线扫描分析氧化层中元素分布。结果表明，半固态氧化温度升高，氧化增重急剧增加，表面氧化层中只存在Ti的氧化物，不存在Cu的氧化物，表面形成5层氧化层结构，熔融的晶界是氧向基体内扩散的优先通道；Ti14合金半固态变形中，晶界、晶内的Ti2Cu相熔融长大，形成宽化的晶界和网格状结构。
2003(11):889-892.
Abstract:
利用Miedema参数△φ*和△nws^-1/3构成坐标系统，探讨了准晶合金形成规律。对已有实验结果的31个二元、48个三元准晶合金进行了系统的分析，同时与利用化学镀及电镀方法制备的二元合金系中的47个非晶、32个晶态；三元合金系的54个非晶J2个晶态合金进行了比较。结果表明：在给定的准晶合金形成区内，区分二元准晶、非晶以及晶态合金形成的准确率分别为93．5％、87．2％和72．7％；区分三元合金形成的准确率分别为97．9％、87．0％和75．0％。该判据对于定性地研究及寻找新型准晶合金开辟了一条新的途径，在材料研究领域具有一定的理论指导意义。
利用Miedema参数△φ*和△nws^-1/3构成坐标系统，探讨了准晶合金形成规律。对已有实验结果的31个二元、48个三元准晶合金进行了系统的分析，同时与利用化学镀及电镀方法制备的二元合金系中的47个非晶、32个晶态；三元合金系的54个非晶J2个晶态合金进行了比较。结果表明：在给定的准晶合金形成区内，区分二元准晶、非晶以及晶态合金形成的准确率分别为93．5％、87．2％和72．7％；区分三元合金形成的准确率分别为97．9％、87．0％和75．0％。该判据对于定性地研究及寻找新型准晶合金开辟了一条新的途径，在材料研究领域具有一定的理论指导意义。
2003(11):893-897.
Abstract:
A simulation study on the formation properties of nano clusters in a large scale liquid Al system consisting of 400,000 atoms has been performed by a molecular dynamics method. And a cluster type index method (CTIM) has been also used to describe the structural configurations of various clusters. The results demonstrate that the icosahedron clusters (12 0 12 0) and their combines play the most important role in the microstructure transition; the nano clusters (containing up to 150 atoms) are formed by combining of some middle clusters which also are formed by combining smaller clusters; the structures of these nano clusters are very different from that of those nano clusters obtained by evaporation, ionic spray methods, and so on, the latter is formed by the multi shell crystals accumulated with an atom as the center and the surrounding atoms arranged according to octahedron configuration. These results just can be used to explain the essential distinction between the cluster configurations of Al formed by different ways.
A simulation study on the formation properties of nano clusters in a large scale liquid Al system consisting of 400,000 atoms has been performed by a molecular dynamics method. And a cluster type index method (CTIM) has been also used to describe the structural configurations of various clusters. The results demonstrate that the icosahedron clusters (12 0 12 0) and their combines play the most important role in the microstructure transition; the nano clusters (containing up to 150 atoms) are formed by combining of some middle clusters which also are formed by combining smaller clusters; the structures of these nano clusters are very different from that of those nano clusters obtained by evaporation, ionic spray methods, and so on, the latter is formed by the multi shell crystals accumulated with an atom as the center and the surrounding atoms arranged according to octahedron configuration. These results just can be used to explain the essential distinction between the cluster configurations of Al formed by different ways.
2003(11):898-901.
Abstract:
The valence electron structures of Ti 48Al 2X(X=Nb,Cr,V,Mn,W) (at%) intermetallics were investigated by empirical electron theory of solid and molecules(EET). The results provide a theoretical reference for the study of macroscopic properties of TiAl based alloys.
The valence electron structures of Ti 48Al 2X(X=Nb,Cr,V,Mn,W) (at%) intermetallics were investigated by empirical electron theory of solid and molecules(EET). The results provide a theoretical reference for the study of macroscopic properties of TiAl based alloys.
2003(11):907-910.
Abstract:
采用铜模铸造方法研究了Nd70-x Fe20Al10Y，(x=0，5，10，15)合金的非晶形成能力。Nd70Fe20A10和Nd60Fe20Al10Y10具有较大的非晶形成能力，在普通铜模铸造条件下，至少可以制备出直径为3mm的块状非晶。随合金元素Y的增加，合金的热稳定性提高，在x=15％(原子分数，下同)时，合金Nd55Fe20Al10Y15表现出明显的玻璃转变现象，玻璃转变温度瓦、晶化温度Tx和过冷液相区△Tx分别为777K，830K和53K。Y的加入对Nd70-xFe20Al10Yx块状非晶合金的硬磁性能影响很大，矫顽力(Hc)随Y的加入单调减少，在Y=15％时表现为软磁特征。还讨论了影响非晶形成能力和磁性等因素。
采用铜模铸造方法研究了Nd70-x Fe20Al10Y，(x=0，5，10，15)合金的非晶形成能力。Nd70Fe20A10和Nd60Fe20Al10Y10具有较大的非晶形成能力，在普通铜模铸造条件下，至少可以制备出直径为3mm的块状非晶。随合金元素Y的增加，合金的热稳定性提高，在x=15％(原子分数，下同)时，合金Nd55Fe20Al10Y15表现出明显的玻璃转变现象，玻璃转变温度瓦、晶化温度Tx和过冷液相区△Tx分别为777K，830K和53K。Y的加入对Nd70-xFe20Al10Yx块状非晶合金的硬磁性能影响很大，矫顽力(Hc)随Y的加入单调减少，在Y=15％时表现为软磁特征。还讨论了影响非晶形成能力和磁性等因素。
2003(11):911-914.
Abstract:
利用高温液态金属X射线衍射仪研究了In-5％Cu合金熔体的结构。结果表明：随温度由400℃升高到900℃，In-5％Cu合金熔体的平均最近邻原子间距ri总体上呈现出减小的趋势，原子配位数Ns的变化比较复杂，R1和Ns都在600℃左右出现转折，原子团簇出现热收缩现象，其结构在600℃附近出现异常变化。利用回转振动粘度仪对In-5％Cu合金在液相线以上不同温度进行粘度测量的结果表明：随温度升高，In-5％Cu合金熔体的粘度值减小，总体上呈现指数变化规律，在600℃左右发生突变.粘度突变温度与结构突变温度一致。
利用高温液态金属X射线衍射仪研究了In-5％Cu合金熔体的结构。结果表明：随温度由400℃升高到900℃，In-5％Cu合金熔体的平均最近邻原子间距ri总体上呈现出减小的趋势，原子配位数Ns的变化比较复杂，R1和Ns都在600℃左右出现转折，原子团簇出现热收缩现象，其结构在600℃附近出现异常变化。利用回转振动粘度仪对In-5％Cu合金在液相线以上不同温度进行粘度测量的结果表明：随温度升高，In-5％Cu合金熔体的粘度值减小，总体上呈现指数变化规律，在600℃左右发生突变.粘度突变温度与结构突变温度一致。
2003(11):915-918.
Abstract:
探索了用机械合金化制备得到的金属锑与石墨复合材料(Sbx-C1-x,x=0．1—0．4)作为锂离子电池负极材料的电化学吸放锂特性，发现球磨得到的Sbx-C1-x是由微米级Sb颗粒和C所组成的复合物。Sb0.2-C0.8的吸放锂过程实际上是由石墨和金属锑的吸放锂反应组成，首次吸锂容量达705mAh／g，首次不可逆容量约130mAh／g。对Sb含量与Sbx-C1-x(x=0．1-0．4)电化学吸放锂性能的关系表明Sb0.2-C0.8具有最高的首次充放电容量，而碳含量对循环稳定性有较大的影响。
探索了用机械合金化制备得到的金属锑与石墨复合材料(Sbx-C1-x,x=0．1—0．4)作为锂离子电池负极材料的电化学吸放锂特性，发现球磨得到的Sbx-C1-x是由微米级Sb颗粒和C所组成的复合物。Sb0.2-C0.8的吸放锂过程实际上是由石墨和金属锑的吸放锂反应组成，首次吸锂容量达705mAh／g，首次不可逆容量约130mAh／g。对Sb含量与Sbx-C1-x(x=0．1-0．4)电化学吸放锂性能的关系表明Sb0.2-C0.8具有最高的首次充放电容量，而碳含量对循环稳定性有较大的影响。
2003(11):923-926.
Abstract:
Sonoelectrodeposition technique has been used to prepare bioactive brushite coatings on carbon/carbon composites. The effects of current density on the structures and morphology of the bioactive brushite coatings were also investigated. It is found that the coatings with plate like (021), granular like (111), and flower like(220)morphology can be fabricated by using different current densities respectively. The results show that the sizes of as deposited particles decrease with increasing current density. In addition, the mechanism of the variation of their microstructures was also discussed.
Sonoelectrodeposition technique has been used to prepare bioactive brushite coatings on carbon/carbon composites. The effects of current density on the structures and morphology of the bioactive brushite coatings were also investigated. It is found that the coatings with plate like (021), granular like (111), and flower like(220)morphology can be fabricated by using different current densities respectively. The results show that the sizes of as deposited particles decrease with increasing current density. In addition, the mechanism of the variation of their microstructures was also discussed.
2003(11):927-929.
Abstract:
配制了5种不同Nb，C含量的Fel4Mn5Si9Cr5Ni形状记忆合金，测量了不同温度和不同时间条件下固溶-时效处理的合金记忆性能，采用透射电镜和原子力显微镜观察了合金的显微组织。结果表明NbC的析出对合金的形状记忆性能有明显影响，经1200℃，10h固溶处理后的Fel4Mn5Si9Cr5Ni0．5Nb合金，经800℃，6h时效获得了最好的形状记忆性能，且优于无铌Fel4Mn5Si9Cr5M合金经热机械循环训练的记忆性能指标。显微观察表明经过高温固溶．中温时效处理后的该合金中NbC粒子在合金基体时效析出，有利于合金应力诱发细小马氏体核心的形成。
配制了5种不同Nb，C含量的Fel4Mn5Si9Cr5Ni形状记忆合金，测量了不同温度和不同时间条件下固溶-时效处理的合金记忆性能，采用透射电镜和原子力显微镜观察了合金的显微组织。结果表明NbC的析出对合金的形状记忆性能有明显影响，经1200℃，10h固溶处理后的Fel4Mn5Si9Cr5Ni0．5Nb合金，经800℃，6h时效获得了最好的形状记忆性能，且优于无铌Fel4Mn5Si9Cr5M合金经热机械循环训练的记忆性能指标。显微观察表明经过高温固溶．中温时效处理后的该合金中NbC粒子在合金基体时效析出，有利于合金应力诱发细小马氏体核心的形成。
2003(11):930-933.
Abstract:
Graded carbonate containing apatite coatings were formed on the surface of porous titanium alkali treated or alkali and heat treated by soaking in simulated body fluid. The results indicated that a porous network structure composed of sodium titanate and titanium oxide was formed on the surfaces after the porous titanium was treated by NaOH aqueous solution. Apatite nucleation on the surface of alkali and heat treated porous titanium at early stage was homogeneous. The contents of Ca, P and O decreased while that of Ti increased with the increasing of depth and a graded structure was formed near the surface of porous titanium. The porous titanium coating with the graded apatite is expected to be applied in clinical orthopedics to enhance bone implant bonding strength.
Graded carbonate containing apatite coatings were formed on the surface of porous titanium alkali treated or alkali and heat treated by soaking in simulated body fluid. The results indicated that a porous network structure composed of sodium titanate and titanium oxide was formed on the surfaces after the porous titanium was treated by NaOH aqueous solution. Apatite nucleation on the surface of alkali and heat treated porous titanium at early stage was homogeneous. The contents of Ca, P and O decreased while that of Ti increased with the increasing of depth and a graded structure was formed near the surface of porous titanium. The porous titanium coating with the graded apatite is expected to be applied in clinical orthopedics to enhance bone implant bonding strength.
2003(11):934-938.
Abstract:
以YT5硬质合金为对象，以正庚烷作为溶剂，系统研究了以多组元聚合物为粘结剂的注射坯样的溶剂脱脂行为。考查了粘结剂体系组成、脱脂温度、脱脂时间、样品厚度、样品形状对坯样脱脂率的影响及其原因。结果表明：在3组粘结剂体系中，改进型蜡基粘结剂溶剂脱脂速度最快，脱脂效果最好，40℃，3h条件下该粘结剂体系中能被溶剂溶解的组元的脱除率达到98％；随脱脂温度的升高，脱脂时间的延长，粘结剂脱除率增大；溶剂脱脂初期为扩散控制，后期为溶解控制；粘结剂平均脱除速率与生坯表面积成正比，与生坯厚度成反比；脱脂完成后，脱脂坯边缘和中心组织均匀一致。
以YT5硬质合金为对象，以正庚烷作为溶剂，系统研究了以多组元聚合物为粘结剂的注射坯样的溶剂脱脂行为。考查了粘结剂体系组成、脱脂温度、脱脂时间、样品厚度、样品形状对坯样脱脂率的影响及其原因。结果表明：在3组粘结剂体系中，改进型蜡基粘结剂溶剂脱脂速度最快，脱脂效果最好，40℃，3h条件下该粘结剂体系中能被溶剂溶解的组元的脱除率达到98％；随脱脂温度的升高，脱脂时间的延长，粘结剂脱除率增大；溶剂脱脂初期为扩散控制，后期为溶解控制；粘结剂平均脱除速率与生坯表面积成正比，与生坯厚度成反比；脱脂完成后，脱脂坯边缘和中心组织均匀一致。
2003(11):939-941.
Abstract:
采用机械合金化制备出Mg-50％Mm(NiCoMnAl)5(质量分数，下同)复合材料，对其吸氢过程热力学、动力学研究发现：该复合材料退火后不需要活化，在250℃、0．16MPa时的吸氢量为3．53％，α-β相区退火前后的反应速度分别为3．13％／min，5．83％／min，具备良好的动力学性能。采用XRD衍射测试和分析机械合金化后产物的物相结构，实验证明：物相组成为Mm2Mg17和Mm(NiCoMnAl)5，混合粉末经过机械合金化后，晶粒细化，增加了固态扩散能力，有利于固相反应的进行，从而改善材料的氢化性能。
采用机械合金化制备出Mg-50％Mm(NiCoMnAl)5(质量分数，下同)复合材料，对其吸氢过程热力学、动力学研究发现：该复合材料退火后不需要活化，在250℃、0．16MPa时的吸氢量为3．53％，α-β相区退火前后的反应速度分别为3．13％／min，5．83％／min，具备良好的动力学性能。采用XRD衍射测试和分析机械合金化后产物的物相结构，实验证明：物相组成为Mm2Mg17和Mm(NiCoMnAl)5，混合粉末经过机械合金化后，晶粒细化，增加了固态扩散能力，有利于固相反应的进行，从而改善材料的氢化性能。
2003(11):942-945.
Abstract:
The effects of heat treatment on the electrochemical properties and structure of La0.7Mg0.3Ni2.8Co0.5 hydrogen storage alloy were studied. It is found, by electrochemical studies, that the discharge capacity, cycle stability, high rate dischargeability (HRD), exchange current density I0 and the limiting current density IL of the alloy electrodes increase after annealing treatment. The discharge capacity of the alloy annealed at 1 123 K and the cycle life of the alloy annealed at 1 223 K are the highest and the best, respectively. In addition, the exchange current density I0 and the limiting current density IL of the alloy electrode increase with annealing at 1 123 K and then decrease with increasing annealing temperature. Meanwhile, the improvement of the high rate dischargeability (HRD) of the annealing samples is consistent with the variation of the exchange current density I0 and the limiting current density IL. Furthermore, it is found, by XRD analysis, that the peak positions and peak intensities change with increasing annealing temperature, which can be ascribed to the structural change and more homogeneous composition after annealing treatment.
The effects of heat treatment on the electrochemical properties and structure of La0.7Mg0.3Ni2.8Co0.5 hydrogen storage alloy were studied. It is found, by electrochemical studies, that the discharge capacity, cycle stability, high rate dischargeability (HRD), exchange current density I0 and the limiting current density IL of the alloy electrodes increase after annealing treatment. The discharge capacity of the alloy annealed at 1 123 K and the cycle life of the alloy annealed at 1 223 K are the highest and the best, respectively. In addition, the exchange current density I0 and the limiting current density IL of the alloy electrode increase with annealing at 1 123 K and then decrease with increasing annealing temperature. Meanwhile, the improvement of the high rate dischargeability (HRD) of the annealing samples is consistent with the variation of the exchange current density I0 and the limiting current density IL. Furthermore, it is found, by XRD analysis, that the peak positions and peak intensities change with increasing annealing temperature, which can be ascribed to the structural change and more homogeneous composition after annealing treatment.
2003(11):946-949.
Abstract:
Mechanical milling behavior of Mo Si Co powders has been investigated by using XRD, SEM and TEM techniques. The mixtures of elemental molybdenum, silicon and cobalt powders with a stoichiometry of Mo5 xCoxSi3 (x=0.5,1,2) were milled in a planetary mill up to 100 hours. It was found that three kinds of powder mixtures showed the same trend in the process of mechanical milling. First, Mo (Co, Si) supersaturated solid solution was formed (Moss). High energy milling led to a remarkable expansion of the solubility of Co, Si in molybdenum. The transformation of Moss to an amorphous phase was identified after a longer time milling. In the milling process, the grain size of Mo (Co, Si) decreased gradually and the internal stress increased sharply. After 40 hour milling, the grain size was reduced to about 8 nm. The SEM analysis of milled powders showed that the particle size increased initially with milling time. After 100 hours milling, particles exhibited a spherical morphology and the particle size was reduced to about 100nm.
Mechanical milling behavior of Mo Si Co powders has been investigated by using XRD, SEM and TEM techniques. The mixtures of elemental molybdenum, silicon and cobalt powders with a stoichiometry of Mo5 xCoxSi3 (x=0.5,1,2) were milled in a planetary mill up to 100 hours. It was found that three kinds of powder mixtures showed the same trend in the process of mechanical milling. First, Mo (Co, Si) supersaturated solid solution was formed (Moss). High energy milling led to a remarkable expansion of the solubility of Co, Si in molybdenum. The transformation of Moss to an amorphous phase was identified after a longer time milling. In the milling process, the grain size of Mo (Co, Si) decreased gradually and the internal stress increased sharply. After 40 hour milling, the grain size was reduced to about 8 nm. The SEM analysis of milled powders showed that the particle size increased initially with milling time. After 100 hours milling, particles exhibited a spherical morphology and the particle size was reduced to about 100nm.
2003(11):950-953.
Abstract:
研究了放电等离子体烧结(SPS)复合稀土氧化物的钼阴极材料的二次电子发射系数、致密化、组织、结构，对发射后的材料表面进行了微观组织观察，并与常规烧结(CIP-S)方法进行了比较。在低于常规烧结温度180℃-280℃，保温3min得到的复合稀土氧化物的钼阴极材料的晶粒明显细化，相对密度达95．6％-98．8％，因在激活发射过程中能快速在阴极表面形成高比例的稀土氧化物膜，使二次电子发射系数高于CIP—S烧结材料。但SPS烧结温度高于l600℃，晶粒将急剧长大，二次发射系数也显著下降.
研究了放电等离子体烧结(SPS)复合稀土氧化物的钼阴极材料的二次电子发射系数、致密化、组织、结构，对发射后的材料表面进行了微观组织观察，并与常规烧结(CIP-S)方法进行了比较。在低于常规烧结温度180℃-280℃，保温3min得到的复合稀土氧化物的钼阴极材料的晶粒明显细化，相对密度达95．6％-98．8％，因在激活发射过程中能快速在阴极表面形成高比例的稀土氧化物膜，使二次电子发射系数高于CIP—S烧结材料。但SPS烧结温度高于l600℃，晶粒将急剧长大，二次发射系数也显著下降.
2003(11):954-957.
Abstract:
The composition of machinable glass ceramics in the SiO2 Al2O3 MgO K2O B2O3 Li2O ZnO F system has been studied in order to decrease their melting temperature and to increase their strength at the same time. The results show that the melting temperature and the crystallizing temperature are decreased because of adding low melting point oxides Li2O and ZnO. ZnO can expande the forming area of glass and make the glass with higher content of Li2O transparent. At the optimizing composition of SiO2, Al2O3 and MgO, cordierite is formed among mica crystals contacted each other, and the glass phase is decreased. Thus the mean free path between crystals is decreased, which results in the high strength of the machinable glass ceramic.
The composition of machinable glass ceramics in the SiO2 Al2O3 MgO K2O B2O3 Li2O ZnO F system has been studied in order to decrease their melting temperature and to increase their strength at the same time. The results show that the melting temperature and the crystallizing temperature are decreased because of adding low melting point oxides Li2O and ZnO. ZnO can expande the forming area of glass and make the glass with higher content of Li2O transparent. At the optimizing composition of SiO2, Al2O3 and MgO, cordierite is formed among mica crystals contacted each other, and the glass phase is decreased. Thus the mean free path between crystals is decreased, which results in the high strength of the machinable glass ceramic.
2003(11):958-961.
Abstract:
The properties of Ba1-xSrxTiO3 and (V1-xCrx)2O3 double base PTC thermosensitive thick film material were studied. As (V1-xCrx)2O3 was used to replaced the expensive RuO2 and silver powders, the room temperature resistance was lowered, and non ohm contact was eliminated, not only the property of the thick film material was improved but also cost was greatly reduced. Two equations have been independently designed, according to which Ba1-xSrxTiO3 micro powders were prepared by using chemical coprecipitation. The results show that polyethylene glycol (PEG) and anhydrous ethanol can prevent granule agglomeration when making nano powders. As polyethylene glycol (PEG) with large formula weight is not poisonous and no harm to people's health, popularizing it is worth.
The properties of Ba1-xSrxTiO3 and (V1-xCrx)2O3 double base PTC thermosensitive thick film material were studied. As (V1-xCrx)2O3 was used to replaced the expensive RuO2 and silver powders, the room temperature resistance was lowered, and non ohm contact was eliminated, not only the property of the thick film material was improved but also cost was greatly reduced. Two equations have been independently designed, according to which Ba1-xSrxTiO3 micro powders were prepared by using chemical coprecipitation. The results show that polyethylene glycol (PEG) and anhydrous ethanol can prevent granule agglomeration when making nano powders. As polyethylene glycol (PEG) with large formula weight is not poisonous and no harm to people's health, popularizing it is worth.
2003(11):962-964.
Abstract:
采用国产钆制作Gd—Si—Ge合金，测量H-M曲线，计算磁熵变(-△Sm)判断其磁热效应。发现采用商业级钆配制合金时，由于杂质抑制了材料的一级相变，未发现巨磁热效应。经提纯后的钆尽管没有Ames实验室的纯度高，但配制的合金具有典型的一级相变，-△Sm值基本上达到Ames实验室报道的数据，而且居里点有所提高。
采用国产钆制作Gd—Si—Ge合金，测量H-M曲线，计算磁熵变(-△Sm)判断其磁热效应。发现采用商业级钆配制合金时，由于杂质抑制了材料的一级相变，未发现巨磁热效应。经提纯后的钆尽管没有Ames实验室的纯度高，但配制的合金具有典型的一级相变，-△Sm值基本上达到Ames实验室报道的数据，而且居里点有所提高。
