Volume 33,Issue 7,2004 Table of Contents
2004, 33(7):673-678.
Abstract:
Current research activities on the fatigue of ferroelectric ceramics are reviewed. Research progress in the fatigue mechanism, factors which influence fatigue behavior, and experimental techniques employed in the study of the fatigue are summarized. Various mechanisms for electric fatigue and different models of the electric-field-induced fatigue process are compared and discussed. Problems that need to be solved and clarified in order to gain a deep insight of fatigue mechanism are suggested.
Current research activities on the fatigue of ferroelectric ceramics are reviewed. Research progress in the fatigue mechanism, factors which influence fatigue behavior, and experimental techniques employed in the study of the fatigue are summarized. Various mechanisms for electric fatigue and different models of the electric-field-induced fatigue process are compared and discussed. Problems that need to be solved and clarified in order to gain a deep insight of fatigue mechanism are suggested.
2004, 33(7):679-683.
Abstract:
The structural characteristics and electrochemical processing of LiFePO4 for lithium ion battery anodes are discussed. LiFePO4 is characterized by high specific capacity and good cycle performance, But its dielectric property and low diffusion coefficient being not sufficiently well known at present restict its application to small batteries at present. It is concluded that LiFePO4 powder with high electrochemical performance can be fabricated using proper fabrication and surface modification procedures. This powder: with its environmentally benign properties, low cost, and abundance, is a promising alternative for lithium ion battery anodes.
The structural characteristics and electrochemical processing of LiFePO4 for lithium ion battery anodes are discussed. LiFePO4 is characterized by high specific capacity and good cycle performance, But its dielectric property and low diffusion coefficient being not sufficiently well known at present restict its application to small batteries at present. It is concluded that LiFePO4 powder with high electrochemical performance can be fabricated using proper fabrication and surface modification procedures. This powder: with its environmentally benign properties, low cost, and abundance, is a promising alternative for lithium ion battery anodes.
2004, 33(7):684-686.
Abstract:
The research development and the main methods used in performance improvement of Mg2Ni-type hydrogen storage alloys are summarized. It is suggested that nanocrystallization or amorphization, composition adjustment and modification by compounding is the best ways to improve the performance indices of the alloys.
The research development and the main methods used in performance improvement of Mg2Ni-type hydrogen storage alloys are summarized. It is suggested that nanocrystallization or amorphization, composition adjustment and modification by compounding is the best ways to improve the performance indices of the alloys.
2004, 33(7):687-691.
Abstract:
报道了从水溶液中电沉积稀上含量高于30％的Ni-RE-P(RE=Ce，Nd)合金，其中Ni-P，Ni-Ce-P及Ni-Nd-P合金镀层均为非晶态结构，玻璃化温度约为385℃；用DTA测定了3种合金的晶化活化能分别为：523．3kJ／mol，574．4kJ／mol，558．9kJ／mol；利用二维Miedema坐标(△φ^*和△nws^-1.3)以及加入尺寸因素(△R/RA)构成的三维化学坐标分析了合金的非晶形成规律，探讨了实现稀土合金电沉积的途径，具体为：选择适当的络合剂、合适的电极材料及合适的共沉积元素。
报道了从水溶液中电沉积稀上含量高于30％的Ni-RE-P(RE=Ce，Nd)合金，其中Ni-P，Ni-Ce-P及Ni-Nd-P合金镀层均为非晶态结构，玻璃化温度约为385℃；用DTA测定了3种合金的晶化活化能分别为：523．3kJ／mol，574．4kJ／mol，558．9kJ／mol；利用二维Miedema坐标(△φ^*和△nws^-1.3)以及加入尺寸因素(△R/RA)构成的三维化学坐标分析了合金的非晶形成规律，探讨了实现稀土合金电沉积的途径，具体为：选择适当的络合剂、合适的电极材料及合适的共沉积元素。
2004, 33(7):692-695.
Abstract:
The thermodynamic requirements of internal oxidation of Cu-Al alloy were systematically analyzed, and a zone chart of internal oxidation thermodynamics was drawn. The results indicate that the preferential oxidation zone is quite large in the zone chart, and is determined by the maximum and minimum partial pressure of oxygen, where=(max)O2lgP(17 611/T)+12.91,=(min)O2lgP (55 830/T)(4/3)lg[%Al]+19.95. In fact the practical internal oxidation zone is a small part of the preferential oxidation zone near the maximum partial pressure of oxygen. The volume concentration product Ksp and concentration of residual aluminum are so low that the internal oxidation can procede completely. The temperature and partial pressure of oxygen should be adjusted synchronously during the control of internal oxidation. The optimum conditions for internal oxidation are heat treatment at a high temperature of about 1 223 K, and a high oxygen partial pressure approaching or even equal to the upper limit. Rapid cooling with hydrogen is used to prevent oxidation of the copper.
The thermodynamic requirements of internal oxidation of Cu-Al alloy were systematically analyzed, and a zone chart of internal oxidation thermodynamics was drawn. The results indicate that the preferential oxidation zone is quite large in the zone chart, and is determined by the maximum and minimum partial pressure of oxygen, where=(max)O2lgP(17 611/T)+12.91,=(min)O2lgP (55 830/T)(4/3)lg[%Al]+19.95. In fact the practical internal oxidation zone is a small part of the preferential oxidation zone near the maximum partial pressure of oxygen. The volume concentration product Ksp and concentration of residual aluminum are so low that the internal oxidation can procede completely. The temperature and partial pressure of oxygen should be adjusted synchronously during the control of internal oxidation. The optimum conditions for internal oxidation are heat treatment at a high temperature of about 1 223 K, and a high oxygen partial pressure approaching or even equal to the upper limit. Rapid cooling with hydrogen is used to prevent oxidation of the copper.
2004, 33(7):696-700.
Abstract:
The effects of the Ce content on the structure, thermodynamics, electrochemical properties and kinetic performance of the AB5-type hydrogen storage alloys La0.8(1-x)Ce0.8x(PrNd)0.2B5 have been systematically studied. The results show that, the Ce content dependence of the alloy structure is negligible, though the cell parameters a, c and the cell volume change linearly with Ce content. With the increase of the Ce content, the equilibrium pressure for hydrogen absorbing-desorbing of the alloys increases, the hysteresis gets smaller, and the thermodynamic stability of alloy hydride becomes poorer. The Ce content has a little effect on the electrochemical activation property of the alloys, its increase could raise the charge-discharge voltage plateau of the alloys, could improve the high-rate discharge ability and power characteristics of the alloys, while the discharge capacity at low discharge current is decreased. The increase of the Ce content is beneficial to improving kinetic performance of the alloys, it could decrease charge transfer resistance of the electrode reaction and make it more reversible. Hydrogen in the alloys diffuses faster with the increase of the Ce content.
The effects of the Ce content on the structure, thermodynamics, electrochemical properties and kinetic performance of the AB5-type hydrogen storage alloys La0.8(1-x)Ce0.8x(PrNd)0.2B5 have been systematically studied. The results show that, the Ce content dependence of the alloy structure is negligible, though the cell parameters a, c and the cell volume change linearly with Ce content. With the increase of the Ce content, the equilibrium pressure for hydrogen absorbing-desorbing of the alloys increases, the hysteresis gets smaller, and the thermodynamic stability of alloy hydride becomes poorer. The Ce content has a little effect on the electrochemical activation property of the alloys, its increase could raise the charge-discharge voltage plateau of the alloys, could improve the high-rate discharge ability and power characteristics of the alloys, while the discharge capacity at low discharge current is decreased. The increase of the Ce content is beneficial to improving kinetic performance of the alloys, it could decrease charge transfer resistance of the electrode reaction and make it more reversible. Hydrogen in the alloys diffuses faster with the increase of the Ce content.
2004, 33(7):706-709.
Abstract:
Cu, Ag and the Ni films on stainless steel bases and Ni film on Ti substrates are prepared by using electroplating. The cantilever beam method and X ray diffraction are used to measure the internal stresses in the films. Internal stresses caused by interfacial electron transfer are also calculated using the modified TFD model. It is shown that the calculated results are comparable with those of the experiments, indicating that the main source of the internal stress in the films is the interfacial electron transfer.
Cu, Ag and the Ni films on stainless steel bases and Ni film on Ti substrates are prepared by using electroplating. The cantilever beam method and X ray diffraction are used to measure the internal stresses in the films. Internal stresses caused by interfacial electron transfer are also calculated using the modified TFD model. It is shown that the calculated results are comparable with those of the experiments, indicating that the main source of the internal stress in the films is the interfacial electron transfer.
2004, 33(7):710-713.
Abstract:
The Potential-pH diagrams of the Zr-H2O system at temperatures of 298 K, 333 K, 373 K and 423 K were be established through extensive study of thermodynamic data and thermodynamic calculation coupled with experimental results? The Potential-pH diagram at 298 K concides with that at the same temperature drawn by Professor M.Pourbaix. Comparing and analyzing potential-pH diagrams of Zr-H2O system at different temperatures, it is evident that with the temperature increasing there is no great change of the immunity area of zirconium, but remarkable reduction of the passivation area, which theoretically accounts for the high temperature limitation of zirconium.
The Potential-pH diagrams of the Zr-H2O system at temperatures of 298 K, 333 K, 373 K and 423 K were be established through extensive study of thermodynamic data and thermodynamic calculation coupled with experimental results? The Potential-pH diagram at 298 K concides with that at the same temperature drawn by Professor M.Pourbaix. Comparing and analyzing potential-pH diagrams of Zr-H2O system at different temperatures, it is evident that with the temperature increasing there is no great change of the immunity area of zirconium, but remarkable reduction of the passivation area, which theoretically accounts for the high temperature limitation of zirconium.
2004, 33(7):714-717.
Abstract:
The tribological properties of Ni-Cr-CaF2 as well as Ni-Cr-PbO/Si3N4 tribo-couples were investigated. The transferring behavior of solid lubricants at the interface of Ni-Cr alloy/Si3N4 tribo-couples were analyzed by scanning electron microscopy. The results showed a significant presence of CaF2 on the Si3N4 surface, while a completely transferred Pb film was not found on the Si3N4 surface due to its poor wetting capability on Si3N4.
The tribological properties of Ni-Cr-CaF2 as well as Ni-Cr-PbO/Si3N4 tribo-couples were investigated. The transferring behavior of solid lubricants at the interface of Ni-Cr alloy/Si3N4 tribo-couples were analyzed by scanning electron microscopy. The results showed a significant presence of CaF2 on the Si3N4 surface, while a completely transferred Pb film was not found on the Si3N4 surface due to its poor wetting capability on Si3N4.
2004, 33(7):718-722.
Abstract:
研究了回归温度(180℃，200℃，220℃)及预时效时间(12h，18h，24h)对含Ag的7055铝合金回归再时效后的强度和微观组织的影响。结果表明，由于微量Ag的添加，120℃，l8h预时效处理后180℃回归再时效的强度稳定性较高，而随着回归温度的提高，再时效强度下降较快，这种现象归因于Ag的添加提高了GP区和η′相的稳定性，使得GP区溶解温度升高，因而180℃回归时只发生GP区和η′相的缓慢粗化，而200℃和220℃回归时发生GP区的溶解并促进，η′相快速粗化形成η相；实验结果显示，预时效时间对回归再时效后的强度也有较大的影响：预时效时间较长或较短时(12h，24h)，再时效强度随回归时间的变化较大，而经18h预时效，再时效强度稳定性较高。这种差别是由于预时效后析出相的种类和体积分数不同所致。
研究了回归温度(180℃，200℃，220℃)及预时效时间(12h，18h，24h)对含Ag的7055铝合金回归再时效后的强度和微观组织的影响。结果表明，由于微量Ag的添加，120℃，l8h预时效处理后180℃回归再时效的强度稳定性较高，而随着回归温度的提高，再时效强度下降较快，这种现象归因于Ag的添加提高了GP区和η′相的稳定性，使得GP区溶解温度升高，因而180℃回归时只发生GP区和η′相的缓慢粗化，而200℃和220℃回归时发生GP区的溶解并促进，η′相快速粗化形成η相；实验结果显示，预时效时间对回归再时效后的强度也有较大的影响：预时效时间较长或较短时(12h，24h)，再时效强度随回归时间的变化较大，而经18h预时效，再时效强度稳定性较高。这种差别是由于预时效后析出相的种类和体积分数不同所致。
2004, 33(7):723-727.
Abstract:
采用电化学测试技术研究了Ce对新研制的口腔用Ti-Fe-Mo-Mn-Nb-Zr合金在人工体液中耐腐蚀性能影响，采用浸泡试验探讨了Ce对Ti-Fe-Mo-Mn-Nb-Zr合金在不同pH值乳酸中耐腐蚀性能的影响。研究表明，含Ce与不含Ce的合金在Hank’s人工模拟体液浸泡的自腐蚀电位均高于0．42V，且随Ce加入量的增加合金的自腐蚀电位先降低再升高然后再降低；Ce的加入没有改变合会的阳极化曲线类型，均为典型的钝化类型阳极化；Ce的加入使合金在乳酸中的腐蚀由点蚀转变为点蚀和晶界腐蚀；原子发射光谱(ICP)分析表明随乳酸酸性增强，含Ce与不含Ce合金的耐腐蚀性能差异增大；Ce的加入不利于提高该材料在人工体液和乳酸中的耐腐蚀性能。如果为了提高合金力学性能，Ce的最佳加入量为0．1％(按质量）。
采用电化学测试技术研究了Ce对新研制的口腔用Ti-Fe-Mo-Mn-Nb-Zr合金在人工体液中耐腐蚀性能影响，采用浸泡试验探讨了Ce对Ti-Fe-Mo-Mn-Nb-Zr合金在不同pH值乳酸中耐腐蚀性能的影响。研究表明，含Ce与不含Ce的合金在Hank’s人工模拟体液浸泡的自腐蚀电位均高于0．42V，且随Ce加入量的增加合金的自腐蚀电位先降低再升高然后再降低；Ce的加入没有改变合会的阳极化曲线类型，均为典型的钝化类型阳极化；Ce的加入使合金在乳酸中的腐蚀由点蚀转变为点蚀和晶界腐蚀；原子发射光谱(ICP)分析表明随乳酸酸性增强，含Ce与不含Ce合金的耐腐蚀性能差异增大；Ce的加入不利于提高该材料在人工体液和乳酸中的耐腐蚀性能。如果为了提高合金力学性能，Ce的最佳加入量为0．1％(按质量）。
2004, 33(7):728-730.
Abstract:
将Zr-4合金样品分别放在盛有350℃，0．1mol／L的LiOH和KOH水溶液的高压釜中进行腐蚀，当2种样品的氧化膜厚度相同时，用二次离子质谱仪(SIMS)测量Li^ ,K^ 和OH^-在氧化膜剖面上的浓度分布，发现进入氧化膜的Li^ 比K^ 深而且记数强度高，同时在LiOH水溶液中腐蚀的样品，其氧化膜中OH^-的强度也比在KOH水溶液中腐蚀的样品高，这表明OH^-在氧化膜中的分布和扩散与其对应的阳离子有关。根据以上结果讨论了Zr-4合金在LiOH水溶液中耐腐蚀性能降低的原因。
将Zr-4合金样品分别放在盛有350℃，0．1mol／L的LiOH和KOH水溶液的高压釜中进行腐蚀，当2种样品的氧化膜厚度相同时，用二次离子质谱仪(SIMS)测量Li^ ,K^ 和OH^-在氧化膜剖面上的浓度分布，发现进入氧化膜的Li^ 比K^ 深而且记数强度高，同时在LiOH水溶液中腐蚀的样品，其氧化膜中OH^-的强度也比在KOH水溶液中腐蚀的样品高，这表明OH^-在氧化膜中的分布和扩散与其对应的阳离子有关。根据以上结果讨论了Zr-4合金在LiOH水溶液中耐腐蚀性能降低的原因。
2004, 33(7):731-735.
Abstract:
The segregation of Ti-2.5Cu, Ti-3Fe and Ti-3Cr, in Ti-alloy ingots has been studied. It was found that in equiaxed grains, segregation of Cu and Fe is obvious and segregation of Cr is slight. In columnar grains, segregation of Cu, Fe, and Cr is slight. In both cases the contents of Cu, Fe, and Cr increase along the directions of grain growing. It is rich in Cu and Fe in grains; but it is rich in Cr at grain boundaries. In the bulk it is rich in Cu, Fe and Cr on the top and radial zone of the ingots.
The segregation of Ti-2.5Cu, Ti-3Fe and Ti-3Cr, in Ti-alloy ingots has been studied. It was found that in equiaxed grains, segregation of Cu and Fe is obvious and segregation of Cr is slight. In columnar grains, segregation of Cu, Fe, and Cr is slight. In both cases the contents of Cu, Fe, and Cr increase along the directions of grain growing. It is rich in Cu and Fe in grains; but it is rich in Cr at grain boundaries. In the bulk it is rich in Cu, Fe and Cr on the top and radial zone of the ingots.
2004, 33(7):736-739.
Abstract:
采用固定床化学气相法存800℃碳化纳米α-W粉体制备成功晶粒尺寸为15nm左右的纳米WC粉体。用XRD分析测量了不同退火温度下纳米WC的晶粒尺寸。结果表明，随着退火温度升高，纳米WC粉体的晶粒尺寸随之增大，从原始晶粒尺寸15nm长大到1500℃时的47nm。同时在不同升温速率下测量纳米WC粉体的DSC曲线，并由Kissinger方程求得其晶粒长大激活能为3．494eV。
采用固定床化学气相法存800℃碳化纳米α-W粉体制备成功晶粒尺寸为15nm左右的纳米WC粉体。用XRD分析测量了不同退火温度下纳米WC的晶粒尺寸。结果表明，随着退火温度升高，纳米WC粉体的晶粒尺寸随之增大，从原始晶粒尺寸15nm长大到1500℃时的47nm。同时在不同升温速率下测量纳米WC粉体的DSC曲线，并由Kissinger方程求得其晶粒长大激活能为3．494eV。
2004, 33(7):740-743.
Abstract:
用工业型脉冲等离子体增强化学气相沉积设备，在550℃的高速钢基材表面沉积由纳米晶TiN，纳米非晶Si3N4以及纳米或非晶TiSi2组成的复相薄膜。通过改变氯化物混合比例调节薄膜的成分。薄膜中的Si含量在0at％～35at％范围内变化。结果表明，当加入少量Si元素后，由于非晶相的产生，TiN薄膜的耐腐蚀性能显著提高，并在一定Si含量的薄膜中发生了负腐蚀现象。但由T-Si的低导电性能，致使高硅含量薄膜颗粒粗大，因此更高Si含量薄膜的耐腐蚀性能又有所下降。
用工业型脉冲等离子体增强化学气相沉积设备，在550℃的高速钢基材表面沉积由纳米晶TiN，纳米非晶Si3N4以及纳米或非晶TiSi2组成的复相薄膜。通过改变氯化物混合比例调节薄膜的成分。薄膜中的Si含量在0at％～35at％范围内变化。结果表明，当加入少量Si元素后，由于非晶相的产生，TiN薄膜的耐腐蚀性能显著提高，并在一定Si含量的薄膜中发生了负腐蚀现象。但由T-Si的低导电性能，致使高硅含量薄膜颗粒粗大，因此更高Si含量薄膜的耐腐蚀性能又有所下降。
2004, 33(7):744-747.
Abstract:
采用Si3N4和SiC作为Al2O3／BN可加工陶瓷的添加剂，考察了添加剂种类和含量对材料力学性能及可加工性能的影响。研究表明，2种添加剂均对调节体系中由于热膨胀失配所引起的人的内应力起到积极的作用。材料的抗弯曲强度随添加剂含量的增加而提高，同时可加工性能略有降低。尤其是Si3N4的加入使体系在热压烧结过程中原位反应生成液相x-Sialon，显著降低了烧结温度，促进材料的致密化。
采用Si3N4和SiC作为Al2O3／BN可加工陶瓷的添加剂，考察了添加剂种类和含量对材料力学性能及可加工性能的影响。研究表明，2种添加剂均对调节体系中由于热膨胀失配所引起的人的内应力起到积极的作用。材料的抗弯曲强度随添加剂含量的增加而提高，同时可加工性能略有降低。尤其是Si3N4的加入使体系在热压烧结过程中原位反应生成液相x-Sialon，显著降低了烧结温度，促进材料的致密化。
2004, 33(7):748-751.
Abstract:
通过对样品压敏性能和介电性能的测定，研究了CeO2对Nb-TiO2电容-压敏电阻器的影响。研究发现，晶界处硅钛酸铈相的生成使Ce02对Nb-TiO2电容-压敏电阻的性能有显著的影响。在1350℃烧结条件下，掺杂量为0．4m01％CeO2的样品表现出优良的综合电性能，其压敏电压为15．84V／mm，非线性系数α为4．62，并具有很高的相对介电常数(εγ=158600)，较低的介电损耗(tgδ=0．32)，是1种具有较好潜力的新型电容-压敏电阻器。
通过对样品压敏性能和介电性能的测定，研究了CeO2对Nb-TiO2电容-压敏电阻器的影响。研究发现，晶界处硅钛酸铈相的生成使Ce02对Nb-TiO2电容-压敏电阻的性能有显著的影响。在1350℃烧结条件下，掺杂量为0．4m01％CeO2的样品表现出优良的综合电性能，其压敏电压为15．84V／mm，非线性系数α为4．62，并具有很高的相对介电常数(εγ=158600)，较低的介电损耗(tgδ=0．32)，是1种具有较好潜力的新型电容-压敏电阻器。
2004, 33(7):752-754.
Abstract:
TiO2 thin films were prepared on microscope glass slides by radiofrequency magnetron sputtering method under different flow ratios of Ar and O2 gases. The films were characterized by X-ray diffraction (XRD), atomic force microscope (AFM), Raman spectroscopy and UV-VIS spectrophotometer. The results indicated that the film prepared under the flow ratio of ArO2=20 sccm5 sccm has a higher photocatalytic activity.
TiO2 thin films were prepared on microscope glass slides by radiofrequency magnetron sputtering method under different flow ratios of Ar and O2 gases. The films were characterized by X-ray diffraction (XRD), atomic force microscope (AFM), Raman spectroscopy and UV-VIS spectrophotometer. The results indicated that the film prepared under the flow ratio of ArO2=20 sccm5 sccm has a higher photocatalytic activity.
2004, 33(7):755-758.
Abstract:
In order to prevent the agglomeration and improve the dispersion of ultrafine ceramic powders in liquid paraffin system etc. organic media, different kinds of polymer films were coated on the surface of ultrafine ZrO2 and SiC particles by low temperature plasma polymerization. The encapsulated powders were analyzed by TEM, TGA, and DRIFT. The results show that, the dispersion of plasma treated ZrO2 powders in the organic medium was better than that of untreated ZrO2 powders. The viscosity of liquid paraffin with same solid loading showed a significant difference between plasma treated and untreated ceramic powders.
In order to prevent the agglomeration and improve the dispersion of ultrafine ceramic powders in liquid paraffin system etc. organic media, different kinds of polymer films were coated on the surface of ultrafine ZrO2 and SiC particles by low temperature plasma polymerization. The encapsulated powders were analyzed by TEM, TGA, and DRIFT. The results show that, the dispersion of plasma treated ZrO2 powders in the organic medium was better than that of untreated ZrO2 powders. The viscosity of liquid paraffin with same solid loading showed a significant difference between plasma treated and untreated ceramic powders.
2004, 33(7):759-763.
Abstract:
研究了SmCo薄膜的复合及热处理对TbDyFe薄膜磁性及磁致伸缩性能的影响。XRD分析表明制备态的TbDyFe薄膜为非晶态，在450℃退火后，样品仍保持非晶态结构。退火处理减少了薄膜的垂直各向异性，并且退火热应力有利薄膜的易磁化轴转向膜面，从而提高了薄膜的磁导率和TbDyFe薄膜低场下的磁致伸缩值。磁控溅射的SmCo薄膜有良好的软磁性能，它的复合也能有效地增强TbDyFe薄膜的低场磁致伸缩性能。
研究了SmCo薄膜的复合及热处理对TbDyFe薄膜磁性及磁致伸缩性能的影响。XRD分析表明制备态的TbDyFe薄膜为非晶态，在450℃退火后，样品仍保持非晶态结构。退火处理减少了薄膜的垂直各向异性，并且退火热应力有利薄膜的易磁化轴转向膜面，从而提高了薄膜的磁导率和TbDyFe薄膜低场下的磁致伸缩值。磁控溅射的SmCo薄膜有良好的软磁性能，它的复合也能有效地增强TbDyFe薄膜的低场磁致伸缩性能。
2004, 33(7):764-767.
Abstract:
In this paper TiB2 coating was electrodeposited on the graphite by K2TiF6-KBF4-KF-KCl molten salts. The effects of pre-electrolysis conditions and electroactive component contents on the properties of coating were tested. The results showed that: pre-electrolysis conditions had important effect on the compositions of coating; as the mole ratio of K2TiF6 and KBF4is 1:2.5 with higher total content of K2TiF6-KBF4, the coating had better adhension to the substrate and the process had good repetition, but the crystal particle was large and the coating has less impurity; as the mole ratio of K2TiF6 and KBF4is 1:7.5 with lower total content of K2TiF6- KBF4, the coating had fine crystal particle and higher TiB2 content with metallic gloss, but the process had bad repetition. Further electrochemistry experiments need to be done to find the mechanism and stable conditions for electrodepositing of TiB2 coating.
In this paper TiB2 coating was electrodeposited on the graphite by K2TiF6-KBF4-KF-KCl molten salts. The effects of pre-electrolysis conditions and electroactive component contents on the properties of coating were tested. The results showed that: pre-electrolysis conditions had important effect on the compositions of coating; as the mole ratio of K2TiF6 and KBF4is 1:2.5 with higher total content of K2TiF6-KBF4, the coating had better adhension to the substrate and the process had good repetition, but the crystal particle was large and the coating has less impurity; as the mole ratio of K2TiF6 and KBF4is 1:7.5 with lower total content of K2TiF6- KBF4, the coating had fine crystal particle and higher TiB2 content with metallic gloss, but the process had bad repetition. Further electrochemistry experiments need to be done to find the mechanism and stable conditions for electrodepositing of TiB2 coating.
2004, 33(7):771-774.
Abstract:
Using a commercially available alloy such as BNi2 which contains the active elements Ti and Cr, and a self-made CuSnNiTi alloy as an active filler materials, a monolayer brazing diamond grinding wheel has been made in a vacuum furnace. Using thermal analysis (DSC) and EDX, it was shown that at appropriate an brazing temperature, duration and vacuum level, chemical bonding takes place among the diamond, brazing alloy and substrate, and that different bonding strengths and performance accompany the use of various brazing filler alloys. Since CuSnNiTi alloy wets the diamond surface, the brazing temperature can be reduced and the bond strength can be enhanced greatly. Grinding tests show that the matrix with this particular filler strongly retains the diamond, and that the cutting efficiency is increased at constant cutting life.
Using a commercially available alloy such as BNi2 which contains the active elements Ti and Cr, and a self-made CuSnNiTi alloy as an active filler materials, a monolayer brazing diamond grinding wheel has been made in a vacuum furnace. Using thermal analysis (DSC) and EDX, it was shown that at appropriate an brazing temperature, duration and vacuum level, chemical bonding takes place among the diamond, brazing alloy and substrate, and that different bonding strengths and performance accompany the use of various brazing filler alloys. Since CuSnNiTi alloy wets the diamond surface, the brazing temperature can be reduced and the bond strength can be enhanced greatly. Grinding tests show that the matrix with this particular filler strongly retains the diamond, and that the cutting efficiency is increased at constant cutting life.
2004, 33(7):775-777.
Abstract:
用轮番溅射工艺在多靶磁控溅射设备上制备了SmCo薄膜。通过改变Sm，Co纯金属靶的溅射时间间隔和溅射功率来调整薄膜的化学成分和均匀性。实验表明，可以通过调整溅射电流来优化薄膜的化学成分。沿垂直膜面俄歇电子(AES)逐层分析证明，优化溅射工艺制备的薄膜化学成分分布均匀。电子衍射表明薄膜溅射态为非晶结构，经过400℃退火处理，薄膜开始晶化。VSM分析表明溅射态的薄膜为软磁特征。晶化后的薄膜表现为硬磁特征，450℃退火时薄膜的矫顽力最大，达80320A／m。薄膜呈现一定的各向异性。
用轮番溅射工艺在多靶磁控溅射设备上制备了SmCo薄膜。通过改变Sm，Co纯金属靶的溅射时间间隔和溅射功率来调整薄膜的化学成分和均匀性。实验表明，可以通过调整溅射电流来优化薄膜的化学成分。沿垂直膜面俄歇电子(AES)逐层分析证明，优化溅射工艺制备的薄膜化学成分分布均匀。电子衍射表明薄膜溅射态为非晶结构，经过400℃退火处理，薄膜开始晶化。VSM分析表明溅射态的薄膜为软磁特征。晶化后的薄膜表现为硬磁特征，450℃退火时薄膜的矫顽力最大，达80320A／m。薄膜呈现一定的各向异性。
2004, 33(7):778-780.
Abstract:
A misch-metal hydrogen-storage alloy consisting of a homogenous CaCu5 phase with grain size less than 50 nm was prepared by rapid quenching between double rollers. The specific capacity of alloy reached 295 mAh/g during charge and discharge with 200 mA/g. The attenuation of capacity was 4.5% after 200 cycles. The charging capacity of a battery made from this alloy powder was up to 547.4 mAh/g after 2 cycles discharge with a Couloumb. The attenuation of capacity was 2.48% after 95 cycles.
A misch-metal hydrogen-storage alloy consisting of a homogenous CaCu5 phase with grain size less than 50 nm was prepared by rapid quenching between double rollers. The specific capacity of alloy reached 295 mAh/g during charge and discharge with 200 mA/g. The attenuation of capacity was 4.5% after 200 cycles. The charging capacity of a battery made from this alloy powder was up to 547.4 mAh/g after 2 cycles discharge with a Couloumb. The attenuation of capacity was 2.48% after 95 cycles.
25 Influence of Trace Amounts of Manganese and Aluminium on the Mechanical Properties of Silver Strip
2004, 33(7):781-784.
Abstract:
为解决银材自然时效软化的问题，存99．999％Ag中添加0.004％A1和0．003％Mn(按质量)制成纯度为99．99％的Ag材，实验表明，采用变形率为90．90％所制备的银材，在25℃温度下，自然时效365d，其强度σb=370MPa，硬度HV=1030MPa保持稳定不变，有效地抑制了纯银材自然时效80d，其力学性能便大幅度下降的问题。
为解决银材自然时效软化的问题，存99．999％Ag中添加0.004％A1和0．003％Mn(按质量)制成纯度为99．99％的Ag材，实验表明，采用变形率为90．90％所制备的银材，在25℃温度下，自然时效365d，其强度σb=370MPa，硬度HV=1030MPa保持稳定不变，有效地抑制了纯银材自然时效80d，其力学性能便大幅度下降的问题。
