Preparation and electrochemical properties of LiMn1.95M0.05O4 （M=Cr, Ni）

The preparation process and electrochemical properties of LiMn2O4 and LiMnl.95M0.05O4 （M = Cr, Ni） were studied. The results show that the decomposition temperature range of xerogel prepared with lithium acetate and manganese acetate as raw rnaterials is large and the decomposition speed is slow. Oxygen consumed is apt to get a prompt supplement during the preparation of LiMn2O4, and carbonization of the organic matter can be reduced or avoided, which is favorable to the combination of lithium and manganese. Using lithium acetate, manganese acetate, chromium nitrate, and nickel nitrate as raw materials and adopting the citric acid complexing method, it has been found that the prepared powders have high purity, high quality stability, and even doping characters. With the increase of sintering temperature, the particle size and crystal lattice constant of LiMn1.95M0.05O4 （M = Cr, Ni） enhance. However, the purity of the product is relatively high and has no obvious change, which is advantageous to the control of the quality of LiMn1.95M0.0504 （M = Cr, Ni）. Doping with a small amount of Cr3. and Ni^2＋ can stabilize the spinel structure of LiMn2O4, suppress the Jahn-Teller effect, and improve the cycling properties but reduce the initial capacity.     

微米SiCp/Cu基复合材料的组织与性能

以微米级(14／μm)SiCp和微米级(10μm)铜粉为原料，采用冷压烧结方法成功制备出了SiCp／Cu基复合材料，并进行了热挤压加工，研究了组织、导电性能、硬度、拉伸性能和耐磨性能。结果表明：SiCp分布均匀；在SiCp含量为1％vol～10％vol时，SiCp／Cu基复合材料的导电率为95．9％～82．2％IACS．硬度为84．5～89．2HV0.2，抗拉强度为243．3～166．6 MPa，伸长率为50．6％～23．0％；5vo1％SiCp／Cu基复合材料具有良好的耐磨性能，其磨损失重分别是QSn 6．5-0．4的1／18．3和T3纯Cu的1／24.7。     

铸造金属耐磨材料研究的进展

详细介绍了耐磨材料奥氏体锰钢、低合金钢和白口铸铁的成分、组织、性能及其应用进展,还对耐磨钢结材料和耐磨铸造复合材料以及新开发的高硼铸造耐磨合金进行了评述,期待为科学选择耐磨材料提供参考。     

ANALYSIS OF DISSIPATIVE STRUCTURE IN MATERIAL COMMINUTION

ＡＮＡＬＹＳＩＳＯＦＤＩＳＳＩＰＡＴＩＶＥＳＴＲＵＣＴＵＲＥＩＮＭＡＴＥＲＩＡＬ　ＣＯＭＭＩＮＵＴＩＯＮＺｈａｎｇ；Ｚｈｉｔｉｅ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，ＣｅｎｔｒａｌＳｏｕｔｈＵｎｉｖｅｒｓｉｔｙｏｆＴｅ...     

复合材料电磁传播特性及应用分析

分析了复合材料微波检测中电磁参量、电磁波频率和介质薄片厚度的计算方法。基于复合材料媒质间的电磁传播特性，提出了微波无损检测技术应用于复合材料检测时的局限性和不足。给出了由于脱粘空气层引入后，透射波振幅减小和相位延迟的解决方法。推导了层间脱粘将会改变总的传输系数的结果，对今后复合材料微波检测工作的方向进行了探讨。     

Relationship between yield ratio and the material constants of the Swift equation

The relationship between the yield ratio and the material constants,b andN, of the Swift equation for hotrolled low carbon steels has been established. The yield ratio calculated by using the Swift equation agrees well with an experimentally obtained yield ratio. It was found that the yield ratio decreases with an increasing value ofN or with a decreasing value ofb. It was also found, however, that high yield strength is associated with small values of bothb andN. Therefore, to obtain both high yield strength and low yield ratio, a detailed microstructural control is needed to determine the optimum values ofb andN.     

Fe76.5Cu1Si13.5B9非晶合金晶化过程的X射线衍射研究

Fe_(76.5)Cu_1Si_(13.5)B_9非晶合金在晶化过程中析山的α-Fe固溶体(α相)的X射线衍射峰存在不对称性并随退火温度而变化,对α相衍射峰进行分峰拟合证实,Cu原子可以促进α相形核并固溶其中,合金晶化与原始态中残存晶核无关,α相晶粒中Cu含量的不同导致衍射峰的不对称性,键合能准化学近似计算结果表明,Cu原子降低了周围原子的迁移势垒,导致合金的晶化首先在含Cu量较高的区域开始,使晶化温度降低。     

重型机械企业信息化中的物料编码解决方案

制造企业实施信息化是以现代信息技术改造传统工业的有效手段。企业信息的集成是实施信息化的基础。本文作者在西安冶金机械有限公司实施ERP系统的实践中,在设计和工艺阶段有机整合现有的CAD和CAPP功能,通过解决物料编码的添加的问题,为重型机械制造企业实施ERP系统提供了有益的借鉴和指导。     

Electrochemical behaviour of commercially pure titanium and Co—Cr alloy in Ringer‘s solution

The electrochemical behaviors of commercially pure titanium(CP Ti) and Co-Cr alloy in Ringer‘s solution have been investigated.The results indicate that the electric potential of passive region for CP Ti is up to 3000mV,and its passive current density is 3.078 μA/cm^2,The excellent corrosion resistance of CP Ti can be attributed to the formation of TiO2 oxide film.The passive region of Co-Cr alloy is 770mV,which is narrower than that of CP Ti.However,no hystersis loops are found in the reverse scanning curves of Cu-Cr alloy.A complex oxide film of Co3O4,Co2O3,and Cr2O3 formed on the surface provides Co-Cr alloy with a stable electrochemistry property.The corrosion rates of the crevice samples increase with the pH value of medium decreasing.The electron probe microanalyzer(EPMA) analysis indicates that Ti in CP Ti and Co,Cr in Co-Cr alloy dissolve in crevice area due to the Sealed-Cell effect.     

运用复合剂制备WC颗粒增强钢基表面复合材料

以ZG310-570为基体、WC颗粒为增强相,在普通水玻璃石英砂干型、无负压条件下,运用自制的复合剂,制备出WC颗粒增强钢基表面复合材料.抗磨料磨损性能是含20%Cr高铬铸铁的3.30倍.硬度可达60HRC以上.铸件表面平整光洁,尺寸精度大为提高.合金层厚度均匀,可达8mm,且与基体之间结合良好.