三河闸钢闸门喷锌保护效果评析

三河闸闸门自１９６６年起采用了喷锌再加上封闭漆进行保护,文中将历年来有代表性的闸门作了检查,结果是喷锌上面再加氯化橡胶漆作封闭层基保护期达２５年,同时以喷铝作为比较,其效果不及喷锌好。     

Protection of carbon steel against hot corrosion using thermal spray Si- and Cr-base coatings

A Fe75Si thermal spray coating was applied on the surface of a plain carbon steel baffle plate. Beneath this coating, a Ni20Cr coating was applied to give better adherence to the silicon coating. The baffle was installed in the high-temperature, fireside, corrosion zone of a steam generator. At the same time, an uncoated 304 stainless steel baffle was installed nearby for comparison. For 13 months the boiler burned heavy fuel oil with high contents of vanadium. The samples were studied employing scanning electron microscopy, x-ray microanalysis, and x-ray diffraction techniques. After that, it was possible to inspect the structural state of the components, and it was found that the stainless steel baffle plates were destroyed almost completely by corrosion, whereas the carbon steel coated baffle plate did not suffer a significant attack, showing that the performance of the thermal spray coating was outstanding and that the coating was not attacked by vanadium salts of the molten slag.     

Laser glazing of plasma-sprayed zirconia coatings

A CO₂ laser with cylindrical focal lens has been used to glaze the surface layer of plasma-sprayed ZrO₂-20wt% Y₂O₃/MCrAlY coatings. Both a continuous-wave laser and a pulsed laser were used in this study. Different parameter settings for power, travel speed, and pulse frequency were used, and their effects on the melting width, melting depth, coupling efficiency, microstructure, surface roughness, and process defects have been evaluated. Results show that the melting width of the glazed track was slightly smaller than the diameter of the raw beam. The melting depth increased with increasing energy density for both a continuous-wave laser and a pulsed laser. The coupling efficiency as about 40 to 65% for a continuous-wave laser, which increased with increasing laser travel speed, but decreased with an increase in energy density. The power density has no significant effect on coupling efficiency. Defects, such as bubbles or depressions, occur easily with a continuous wave laser. A high-quality glazed layer is successfully produced using a pulsed laser. The surface roughness of the plasma-sprayed ceramic coatings was significantly improved by laser glazing. Surface roughness decreased slightly as the pulse frequency increased for the glazed surface. Based on this study, proper processing parameters have been suggested.     

Gas dynamic principles of cold spray

This paper presents an analytical model of the cold-spray process. By assuming a one-dimensional isentropic flow and constant gas properties, analytical equations are solved to predict the spray particle velocities. The solutions demonstrate the interaction between the numerous geometric and material properties. The analytical results allow determination of an optimal design for a cold-spray nozzle. The spray particle velocity is determined to be a strong function of the gas properties, particle material density, and size. It is also shown that the system performance is sensitive to the nozzle length, but not sensitive to the nozzle shape. Thus, it is often possible to use one nozzle design for a variety of operational conditions. Many of the results obtained in this article are also directly applicable to other thermal spray processes.     

喷雾热解法制备功能材料研究进展

综合评述了喷雾热解技术在超导陶瓷、介质材料、固体燃料电池电极、催化剂、磁性材料、人工骨材料以及气体传感器薄膜等领域的研究进展,并指出了进一步发展的方向。     

喷射成形镍基高温合金的研究进展

喷射成形是一种新型快速凝固技术,采用这项技术制备的镍基合金,具有细小,球状的晶粒和均一的组织,从而提高其性能,综述了喷射成形镍基高温合金的发展概况及组织,性能特点。     

催化裂化提升管反应器气液固3相流动反应的数值模拟 Ⅱ. 原料液雾流动气化过程的数值模拟

应用已建立的提升管反应器气液固３相流动反应模型,对两套工业馏分油催化裂化装置的提升管反应器内的流动、传热及裂化反应进行了系统的数值模拟,得到了原料油液雾流动与气化状况的实际图像。模拟结果表明,原料液雾相的流动是非常复杂的,在轴向、径向和圆周方向上都存在较大的梯度,且表现出与气固两相相似的流动形态。原料油液雾生存区,自下而上由小变大又变小;自轴线向边壁由大变小。随着气化过程的进行,液雾颗粒相的整个特性都在发生变化,正是这一复杂的气化过程,对其它两相的流动、传热及反应产生重要的影响     

汽车混流自动线侧喷漆机器人控制系统的开发和应用

本文介绍了多品种汽车混流机器人喷漆自动线上的北京侧喷漆机器人的组成,工作过程,详细阐述了PLC控制程序的设计,探讨了采用PLC控制设备运行的方法。通过实际运行表明：该侧喷漆机器人控制系统的设计和开发应用是成功的,提高了生产效率。     

HVAF-ARC喷涂Cr2C3活性功能涂层性能的研究

本文采用HYAF-ARC喷涂系统制造的NiCrFe-Cr2C3活性功能涂层。通过金相组织研究、SEM检测．X射线衍射以及涂层结合强度分析．证明其具有良好的组织形貌;同时HVAF-ARC所制备的Cr2C3合金除层的性能相对于普通电弧喷涂涂层的性能在同等试验条件下优于普通高速电弧喷涂。     

等离子熔射快速制模中机器人运动轨迹生成方法及实践

在机器人等离子熔射快速制模中,熔射轨迹对熔射皮膜的成形性有重要影响。本文提出了由CAM加工轨迹转化为机器人等离子熔射轨迹的方法,避免了以往通过STL文件生成机器人熔射轨迹的繁琐过程。文章重点介绍了如何将CAM加工轨迹转化为机器人熔射轨迹,并对其进行了仿真与实验验证,结果表明:该方法比原有的由STL文件生成机器人熔射轨迹的方法更简便、灵活,更适应机器人等离子熔射制模成形的要求。