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

基于熔滴压平、凝固和反应步骤控制的射频等离子喷涂涂层的合成

基本信息

批准号：
09450280
负责人：
TSUNEKAWA Yoshiki
金额：
$ 8.7万
依托单位：
Toyota Technological Institute
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

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

已经进行了这项研究，以了解通过反应性RF等离子体对金属和金属和金属间基质复合涂料的合成的基本现象，这是基于与气体的液滴变平，固化和反应的液滴变平，固化和反应。如果提供的钛粉末尺寸变得更细或氮部分压，则包含较小平坦比率的突出覆盖率（TIN）的碎片与普通的磁盘类型一起出现。铝制碎片也分为两类：具有不规则外围外围和半结节型的磁盘类型。氧存在于Splat表面上，在其上存在与AIN相对应的氮浓度区域。因此，氮化物的形成在飞行过程中以及基板上进行钛和铝液滴进行。 If The substrate temperature in … More higher than 873 K just before spraying with premixed titanium and aluminum powder, the formation of TiAl and Tii 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通过过程检查了TIC的形成。分解的碳在熔融钛液滴中的苦难发生在血浆火焰中的飞行过程中，因此在喷雾的钛颗粒中识别出高体积的沉淀，而混合甲烷的体积增加。撞击底物上的碎片的讨人喜欢之比随预混合甲烷的增加而降低。钛基质涂层中的TIC沉淀量大约是喷雾颗粒在飞行过程中的五倍，而不论其预混合甲烷如何。因此，在SPLAT沉积步骤中，TIC的形成占主导地位，因为甲烷混合等离子体火焰暴露的时间比液滴的飞行时间更长。涂料中抽动沉淀的最大体积分数约为30 vol％。较少的