超高分子量聚乙烯纤维表面处理的研究进展

详细介绍了超高分子量聚乙烯纤维的各种表面处理方法 ,如等离子体处理、电晕放电和化学氧化等 ,重点讨论了这些方法对纤维增强复合材料粘结性能和力学性能的影响 ,特别关注了近年来各种表面处理超高分子量聚乙烯纤维技术的进展。     

A process study of electron beam nano-lithography and deep etching with an ICP system

A systemic process study on an electron beam nanolithography system operating at 100 kV was present. The exposure conditions were optimized for resist ZEP520A. Grating structures with line/space of 50 nm/50 nm were obtained in a reasonably thick resist which is beneficial to the subsequent pattern transfer technique. The ICP etching process conditions was optimized. The role of etching parameters such as source power, gas pressure, and gas flow rate on the etching result was also discussed. A grating structure with line widths as small as 100 nm, duty cycles of 0.5, depth of 900 nm, and the side-wall scalloping as small as 5 nm on a silicon substrate was obtained. The silicon deep etching technique for structure sizes smaller than 100 nm is very important for the fabrication of nano-optical devices working in the visible regime. Supported by the National Basic Research Program of China (“973” Program) (Grant No. 2007CB935301)     

Effect of ZnO and TiO2 doping on the sintering behavior of Y2O3 ceramics

Full densification of Y₂O₃ is challenging and requires a very high sintering temperature (above 1700 °C). In this study, the effect of ZnO and TiO₂ dopants on its densification was investigated, showing that both dopants lowered the sintering temperature and improved the process. Moreover, ZnO promoted the grain growth, while TiO₂ inhibited it; hence, the ZnOTiO₂ co-doping and the change in the ZnO/TiO₂ ratio allowed the control of the sintered body microstructure while maintaining high densification. Since Y₂O₃ has a higher plasma erosion resistance than conventional Si-based materials, the plasma dry etching resistance of the sintered Y₂O₃ was also evaluated and found superior due to the improved densification and controlled grain size of the doped samples.     

Negative ion etching of Al−Si−Cu by employing a magnetic filter in halogen plasmas

Al etching was studied employing negative ions generated in downstream Cl₂ plasma. The Al etch rate by the alternate irradiation of positive and negative ions was two times higher than that by usual positive ions. In order to etch the Al film practically on an insulator covered electrode coupled with RF power, reduction of the negative self bias voltage (Vdc) was examined using a magnetic filter which traps electrons. The reason for the high etching reactivity is that the dominant negative ions F in SF₆ and Cl⁻ in Cl₂ plasmas are atomically very similar to the radicals. Addition of SF₆ and H₂ to a Cl₂/BCl₃ mixture reduced Vdc significantly. However, fluorine and hydrogen atoms inhibited Al etching in spite of sufficient ion energy.     

Effects of carbon content and solidification rate on thermal conductivity of grey cast iron

The thermal conductivity or diffusivity of pearlitic grey irons with various carbon contents is investigated by the laser flash method. The materials are cast in controlled thermal environments and produced in three dissimilar cooling rates. The cooling rate together with the carbon content largely influence the thermal conductivity of grey iron. Linear relationships exist between the thermal conductivity and the carbon content, the carbon equivalent and the fraction of former primary solidified austenite transformed into pearlite. The work shows that optimal thermal transport properties are obtained at medium cooling rates. Equations describing the thermal conductivity of pearlite,solidified as pre-eutectic austenite, and the eutectic of grey iron are derived. The thermal conductivity of pearlitic grey iron is modeled at both room temperature and elevated temperature with good accuracy.     

钒及钒基合金金相试样的制备方法

介绍了一种钒及钒基合金金相试样的常规制样方法,即试样的机械磨光,机械化学抛光,化学侵蚀等技术和经验。     

Metallographic sample prepared by ion beam etching

Ion beam etching technique was used to reveal the metallograhpic microstructure and interface morphology of electroplating chromium coating, in particular, whose substrate surface layer was treated in advance by laser quenching. Chemical etchings were also conducted for comparison. The reveal microstructures were observed and analyzed by scanning electron microscopy. The results show that ion beam etching can reveal well the whole microstructures of composite coating-substrate materials.     

固结磨料研磨单晶蓝宝石亚表面损伤的预测

目的 为了准确预测工件亚表面损伤，合理确定材料去除量，优化固结磨料研磨单晶蓝宝石的工艺参数。方法 针对固结磨料研磨特点和单晶蓝宝石特性，采用离散元模拟技术，建立单晶蓝宝石材料的离散元模型，仿真固结磨料对材料研磨的动态过程，分析载荷作用下材料单元颗粒间裂纹的产生和扩展规律，研究磨粒切入深度对亚表面损伤的影响，预测固结磨料研磨单晶蓝宝石亚表面裂纹的数量和深度，并借助化学腐蚀法验证预测结果。结果 采用粒度分别为W14、W28、W50、W65的金刚石固结磨料垫，其对应的研磨单晶蓝宝石亚表面损伤层深度预测值分别为3.75、5.28、7.62、10.92 μm，预测的裂纹数量分别为199、236、526、981条，对应的实验实测值分别为3.79、5.88、8.76、11.44 μm。固结磨料垫中的磨料粒径越大，单晶蓝宝石亚表面损伤层的深度越大，裂纹数量越密集。对比发现腐蚀实验的实测值和理论预测值基本一致，验证了预测结果模型的正确性。结论 采用离散元法可以快速有效地预测固结磨料研磨单晶蓝宝石亚表面损伤层的裂纹数量和深度，为研磨工艺参数的优化和后续抛光工艺参数的制定提供指导。     

Improvement in galvannealed coating of IF-HS steel strips by combined GDOES and colour-etching method

Galvannealed coating of high strength interstitial free (IF-HS) steel was characterised by Glow Discharge Optical Emission Spectroscopy (GDOES) and colour-etching techniques. Overalloyed galvannealed coatings with considerably high amount of Γ and Γ1 phases were detected in the first set of experiments. Necessary process modifications in galvannealing furnace were made to maximise the ä phase in the galvannealed coating, which was confirmed through GDOES and colour-etching techniques. As a result, an improvement in galvannealed product quality with a better powdering resistance property during forming has been achieved.