Characterization of microstructure of Nano-TiO2 coating deposited by vacuum cold spraying

Control of the microstructure of TiO₂ coatings through preparation methods significantly influences the coating performance. In this study, a vacuum cold-spray process, as a new coating technology, is used to deposit nanocrystalline TiO₂ coatings on conducting glass and stainless steel substrates. TiO₂ deposits were formed using two types of nanocrystalline TiO₂ powders with mean particle diameters of 200 and 25 nm. Coating microstructures were characterized by scanning electron microscopy and x-ray diffraction analysis. Results demonstrate that a thick nanocrystalline TiO₂ coating can be deposited by the vacuum cold-spray process. The coating was found to consist of particles stacked as agglomerates that build up to several hundred nanometers. The coating also presents a mesoporous microstructure that could be effective in such applications as photocatalytic degradation and dye-sensitized solar cells. This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials Park, OH, 2006.     

铜磷非晶箔带钎料的制备及性能研究

利用液态单辊急冷法和传统铸造技术分别制备出成分相同的Cu68.5Ni15.7P6.5Sn9.3非晶箔带钎料和普通钎料,制得的非晶铜磷钎料箔带成型性良好,对折180°不断.将两种钎料在四种钎焊温度(660、670、680和690℃)和三种保温时间(5、10和15 min)下与紫铜进行真空钎焊,借助DTA、XRD进行分析.结果表明,制备的非晶箔带钎料与相同成分的普通钎料相比,前者熔点低于后者;在同一钎焊条件下,前者润湿性优于后者.     

Effect of surface modification of metal hydride electrode on performance of MH/Ni batteries

A novel method was applied to the surface modification of the metal hydride(MH)electrode of MH/Ni batteries.Both sides of the electrode were plated with a thin silver film about 0.1μm thick using vacuum evaporation plating technology,and the effect of the electrode on the performance of MH/Ni batteries was examined.It is found that the surface modification can enhance the electrode conductivity and decrease the battery ohimic resistance.After surface modification,the discharge capacity at 5C(7.5A)is increased by 212 mA.h and the discharge voltage is increased by 0.11 V,the resistance of the batteries is also decreased by 32%.The batteries with modified electrode exhibit satisfactory durability.The remaining capacity of the modified batteries is 89%of the initial capacity even after 500 cycles.The inner pressure of the batteries during overcharging is lowered and the charging efficiency of the batteries is improved.     

焊后真空热处理对BT20钛合金激光焊接接头性能的影响

研究了焊后真空热处理对BT20合金CO2激光和YAG激光焊接接头性能的影响。研究结果表明：真空热处理前，BT20钛合金激光焊接接头的抗拉强度和延伸率基本与母材相当，而接头各区域的显微硬度高于母材。焊后真空热处理能显著降低激光焊接接头中的残余应力并改善其分布状态，同时对焊接接头的性能影响不大。焊后真空热处理对YAG激光焊接接头性能的影响较CO2激光焊接接头敏感，其原因在于焊后真空热处理对YAG激光焊缝中的α'针状马氏体的影响较显著。     

The Integration of Vacuum Brazing into Heat Treatment - A Progressive Combined Process

The continuous constructive challenge to improve the functionality and efficiency of components always results in higher demands on production engineering, against the background of the generally increasing cost pressure. In many cases, you will just succeed in producing competitive and innovative products by combining and coupling of different procedures to an independent (hybrid) technology. The use of hybrid procedures for metal joining and heat treatment of metallic materials finds more and more industrial fields of application. Modern vacuum lines with integrated pressurized gas quenching are considered high-performance and flexible means of production for brazing and heat treatment tasks as well in the turbine industry as in the mould making and tool manufacturing industry. In doing so, the heat treatment is coupled with the brazing cycle in a combined process so that the brazing temperatures and soak times are adapted to the necessary temperatures and times for solution heat treatment and austeniting. This user-oriented article describes on the one hand examples of brazing of turbine components, but above all the practical experience from the plastics processing industry, where the requirement for a high-efficient cooling of injection moulding dies gains more and more importance.The combined procedure “Vacuum Brazing and Hardening” offers plenty of possibilities to produce mould inserts with an efficient tempering system in an economic way.     

Ti-6Al-4V合金在真空中的干滑动磨损行为

在真空(10^-^5Pa)条件下对Ti-6Al-4V合金进行了系统的磨损性能测试，研究了载荷和滑动速度对Ti-6Al-4V合金磨损率的影响．对Ti-6Al-4V合金的磨损表面进行了显微组织分析．实验结果表明，Ti-6Al-4V合金的磨损率随载荷和滑动速度的升高而增加．磨损表面具有层状结构的舌状形貌特征，分析表明这是Ti-6Al-4V合金表面通过接触点处材料的被推挤和碾压过程形成了特殊的变形堆砌层的结果．显微组织分析显示，这种变形堆砌层具有50—100nm尺寸的细小显微组织结构和50mm以上的厚度．     

汽车轮毂钢板的真空退火

采用ＲＪＺ型微机控制组合式真空多用炉对小汽车１６Ｍｎ钢轮毂钢板进行真空退火，介绍了退火工艺参数的制定及实际生产应用效果。     

Structure and properties of cathodic vacuum arc deposited NbN and NbN-based multi-component and multi-layer coatings

Binary Nb-N coatings, ternary Ti-Nb-N and Zr-Nb-N, and multi-layer TiN/NbN coatings consisting of up to 100 alternating TiN and NbN layers, were deposited onto WC-Co substrates, using two different vacuum arc deposition (VAD) systems: with and without magnetic guiding of the metal plasma flow. Binary Nb-N coatings were fabricated by deposition of metal plasma produced by a Nb cathode in a background of reactive nitrogen gas at different pressures, P. Ternary coatings were fabricated at co-deposition of plasmas originating from two different cathode materials. Multilayer coatings were fabricated by alternatively depositing plasmas of Ti and Nb in reactive nitrogen gas. The crystalline coating structure, phase composition, hardness and critical load for coating failure were studied.For binary Nb-N coatings fabricated using both deposition systems, the phase composition, the Vickers hardness, HV, and the critical load strongly depended on the deposition pressure. Using VAD with magnetic plasma guiding, the highest HV of ∼ 42 GPa was measured for coatings deposited at low nitrogen pressure. These coatings contained a hexagonal β-Nb₂N phase and had a relatively low critical load. The highest critical load and HV ∼ 38 GPa were obtained for coatings consisted of a single phase NaCl-type cubic δ-NbN structure, deposited at a higher nitrogen pressure. The structure and properties of Nb-N coatings deposited using VAD without magnetic plasma guiding had a similar correlation with the deposition pressure, however, their hardness values were lower.Ternary Ti-Nb-N and Zr-Nb-N coatings fabricated by both deposition processes had a single phase cubic NaCl-type structure and the hardness higher than that of the binary nitrides TiN, ZrN and NbN. The hardest coatings, HV ∼ 51.5 Pa, deposited with magnetic plasma guiding had a single-phase cubic δ-(Ti,Nb)N structure and a Ti:Nb ratio of ∼ 50:50 (at.%).Multilayer coatings TiN/NbN consisting of 20-40 alternating TiN and NbN layers with total thickness of 4-5 μm increased the life time of cemented carbide cutting inserts at turning tough Ni-base alloys by 2-7 times relative to uncoated cutting tools, while conventional vacuum arc deposited TiN coatings were not effective in machining of these alloys.     

真空离子液-气相渗硼的研究

介绍了用自制的无毒无腐蚀的有机渗硼剂——硼酸三甲酯对排气阀热嵌模进行真空离子液-气相渗硼，经检测，整个化合物层和扩散层中含有B和Fe2B，并呈高度弥散分布状态，起到了抗重载热冲击、抗热磨损、抗反复低周循环热疲劳的良好作用，能大大提高热镦模的使用寿命。     

汽轮机组真空度过低原因探析与解决措施

重点讨论了凝汽系统和真空系统两方面的内容,说明了可能导致汽轮机真空度降低的原因,并给出了有针对性的解决措施,很好地解决了这个问题。