Synthesis of RF Plasma-sprayed Coatings Based on the Controls of Droplet Flattening, Solidification and Reaction Step

本研究已对金属和金属基质复合物涂层合成中的基本现象进行了初步分析，该合成是由反应式RF等离子体喷射与优质元素粉末混合的，它是基于滴状闪烁、固体化和与气体反应的。在基底上撞击钛滴的典型形态学是一种带有外边缘边缘的磁盘类型。如果供应的钛粉大小变得更好或更好的硝基部分压力，则碎片含有一个较小的平坦比率与普通磁盘类型相似。铝片也分为两类：一种不规则外Periphery和一种半节点类型的磁盘类型。氧在splat表面上存在，在那里有一个硝基集中区，与AIN相对应。从某种意义上说，钛和铝滴在飞行期间如良好的基础上进行了硝酸盐的形成过程。如果在地下温度下 ... More 高于873 K仅在用优质钛和铝粉喷洒前，在基底上形成了TiAl和Ti-D22-D2 SIN程序。原位复合涂层含有钛碳化物（TiC）的预先填充物通过反应性RF等离子体喷洒与元素钛粉混合，在甲基集中的影响中，预先混合进入了等离子体气体在TiC形成上通过测试过程。在等离子体火焰中吸收分解的碳进入熔化的钛滴，当它们在等离子体火焰中飞行时，因此，精细的TiC浓度会增加与混合的甲基在sprayed钛颗粒中被识别的体积。在一个基底退化的基础上，碎片的平坦比率受到了增加的预先混合的甲烷的影响。钛基质涂层中的TiC精确度的数量大约要比它们在预混合甲烷中散布的颗粒中飞行无管制的情况高出五次。汉斯，TiC形成是在splat沉积的步骤中主导的，因为甲基化等离子体火焰暴露的时间比水滴的飞行时间长得多。TiC准物的最大体积部分在涂层中接近30%。Less（低）

This research has been performed to understand the fundamental phenomenon in the synthesis of metal and intermetallic matrix composite coatings by reactive RF plasma spraying with premixed elemental powder, which is based on the droplet flattening, solidification and reaction with gases.Typical splat morphology of impinged titanium droplets on a substrate is a disk-type with an outer peripheral fringe. If the supplied titanium powder size becomes finer or the nitrogen partial pressure, splats containing prominent asperities (TiN) with a smaller flattening ratio appear along with the plain disk-type. Aluminum splats are also classified into two categories : a disk-type with an irregular outer periphery and a semi-nodular-type. Oxygen exists on the splat surfaces, on which there are nitrogen concentrated areas corresponding to AIN. Consequently, the nitride formation proceeds on titanium and aluminum droplets during the flight as well as on the substrate. If the substrate temperature in … More higher than 873 K just before spraying with premixed titanium and aluminum powder, the formation of TiAl and TiィイD22ィエD2SIN proceeds on the substrate.In situ composite coatings containing titanium carbide (TiC) precipitates were synthesized by reactive RF plasma spraying with elemental titanium powder, in which the effect of methane concentration premixed into the plasma gas on the TiC formation was examined through the process. The absorption of decomposed carbon into molten titanium droplets occurs during their flight in the plasma flame, so that fine TiC precipitates which increase in volume with mixed methane are recognized in the sprayed titanium particles. The flattering ratio of splats impinged on a substrate decreases with increasing premixed methane. The amount of TiC precipitates in titanium matrix coatings is approximately five times higher than that in sprayed particles during their flight regardless of premixed methane. Hence, the TiC formation is dominated at the splat depositing step, because the time exposed by the methane mixed plasma flame is much longer than the flight time of droplets. The maximum volume fraction of TiC precipitates is approximately 30 vol% in the coatings. Less