. . . .TBC coating cost reduction by optimization of the Atmospheric Plasma Spray process 优化大气等离子喷涂工艺，降低TBC（热障涂层）生产成本S. Mihm, T. Duda, Birr / CH, G. Thomas, H. Gruner, Mgenwil / CH and B. Dzur, Ilmenau / DThe global economic growth has triggered a dramatic increase in the demand for resources over the last few years, resulting in steady price increases for energy and raw materials. In the gas turbine manufacturing sector, process optimizations of cost-intensive production steps involve a heightened savings potential and form the basis for securing future competitive advantages in the market economy.全球经济增长在过去的几年中引发了对资源需求急剧增加，导致能源和原材料价格稳步上涨。在燃气轮机制造业，对成本密集的生产工艺优化具有成本节约的潜力并能为企业在将来市场经济的竞争中打下坚实的基础。In this context, the atmospheric plasma spraying (APS) process for thermal barrier coatings (TBC) has been optimized. A constraint for the APS coating process optimization is the use of the existing coating equipment.在这样的大背景下，热障涂层（TBC）的大气等离子喷涂（APS）工艺得以改进优化。而APS制备涂层工艺优化的一个限制条件在于现有涂层设备的使用。Furthermore, the current coating quality and characteristics are not allowed to change in order to avoid new qualification and testing.此外，为了避免重新申请资质以及进行额外测试，还不能改变当前的涂层质量和性能。Using experience in atmospheric plasma spraying and empirically gained data, the process optimization plan included the variation of e.g. the plasma gas composition and flow rate, the electrical power, the arrangement and angle of the powder injectors to the plasma jet, the grain size distribution of the spray powder and the plasma torch movement procedure like spray distance, offset and iteration. In particular, plasma properties (enthalpy, velocity, temperature), powder injection conditions (injection point, injection speed, grain size distribution,) as well as the coating lamination (coating pattern, spraying distance) are examined. The optimized process and resulting coating was compared to the current situation by several diagnostics methods.在以往大气等离子喷涂经验和日常获取的宝贵数据基础上，我们的工艺优化计划包括一系列的改变，如等离子气体组成，流量；用电，布局及粉末注入等离子流的角度，粉末的粒径分布、等离子枪的移动（如喷距、偏差以及重复性等）。特别是等离子性能（焓值、速度以及温度），注粉条件（注粉点、注粉速度、粒径分布），以及还有涂层（涂层形式，喷涂距离）等方面做了重点研究。我们将优化后的工艺及其所制备的涂层与当前普遍使用的几种工艺采用不同的分析方法进行了对比。The improved process provides significantly lower costs by achieving the requirement of comparable coating quality. Furthermore, a contribution was made to a better comprehension of the atmospheric plasma spraying of ceramics and a method for future process developments was defined.在同等涂层质量的前提下，优化后的工艺能很大程度的降低生产成本。此外，我们对大气等离子陶瓷粉末喷涂过程做了一些详细描述，使其更加通俗易懂，同时，我们还了未来工艺的研发方法。1 Introduction 引言Plasma coated thermal barrier coatings (TBC) are successfully established in the gas turbine manufacturing business since the seventies 1. In the hot gas section of gas turbines TBCs fulfill the functions of thermal insulation, therefore lowering the temperature of the metallic portion of the part. Firing temperatures in the combustion chamber above 1300C and limited long term operation temperatures of approx. 950C for the metallic materials resulting in high requirements to coating systems on blades, vanes and combuster parts.从上世纪七十年代起，采用等离子技术制备的热障涂层（TBC）成功应用到燃气轮机制造业。在燃气轮机的热燃气领域，热障涂层满足了隔热的要求，从而降低了工件金属部分的温度。燃烧室的烧结温度超过1300摄氏度，而大部分金属材料的长期工作温度在950摄氏度左右，这样一来，就势必导致旋片，小叶片以及燃烧室部件在喷涂时的高要求。Typical thermal barrier coatings are multi-layer systems based on a duplex structure, a dense metallic bond coat layer (material: MCrAlY, M-Ni and/or Co) and a porous ceramic top coat layer (material: YSZ, yttrium-stabilized zirconia), shown in Fig. 1.典型的热障涂层是一个以复式结构为基础的多层系统，包括致密金属结合涂层（材料如：MCrAlY, M-Ni和/或Co），以及上层多孔陶瓷涂层（材料如：YSZ, 钇稳定氧化锆），如图1所示。Fig. 1. plasma coated TBC-coating system on turbine blade图1：轮机叶片上的热障涂层系统（等离子制备）The dense MCrAlY coating protects the base material against corrosion/oxidation and provides the connection for the ceramic top coat. The porous ceramic top coat functions in connection with the external and internal component cooling as a thermal barrier. Contrary to the dense MCrAlY coating a defined porosity of the YSZ coating is necessary to compensate strain difference and to reduce thermal conductivity. These specific requirements pose a challenge to the technology for producing such coating systems. MCrAlY致密涂层对母材起到了抗氧化防腐蚀作用，并同时实现了与表面陶瓷涂层的连接。表面多孔陶瓷涂层一来用于与里面的涂层相连，也为其所覆盖的内部部件形成了一个热障碍层，起到了冷却的作用。相对于MCrAlY致密涂层而言，固定孔隙率的YSZ涂层对拉力差异补偿及降低导热率来说是非常必要的。而这些特殊要求就对当今涂层生产技术提出了新的挑战。In addition to ensure coating quality, the manufacturing costs are more and more in focus of current developments.除涂层质量外，制造成本也越来越成为了当前发展的焦点问题。The production of porous YSZ coatings is done by Atmospheric plasma spraying (APS). Using this technology the plasma torch construction is one limiting factor for process improvements. For example voltage and power fluctuations influence the particle properties negatively 2, 3, 4. The use of cylindrical nozzle design limits the po