Investigation on flattening behavior of thermal sprayed particle based on systematic data on 3-dimensional transition map

在第一年中，系统地观察了基体加热对热喷涂颗粒扁平化行为中的转变现象的影响。为此，在纳米范围内精确地分析了由于氧化而引起的基板表面性质，特别是粗糙度性质的变化。在此基础上，研究了粒子/基体界面润湿对热喷涂粒子扁平化的影响。更详细地，通过化学方式和物理方式来分析一旦在空气气氛中加热的衬底表面，即，通过俄歇分析来研究化学成分和氧化物层厚度的变化，并且通过原子力显微镜来研究纳米范围内的粗糙度变化。还精确地观察了一旦在空气气氛中加热的基板上的平坦化行为。根据氧化引起的基片表面变化的分析结果与平坦化过程中的过渡变化之间的关系， ...更多信息 讨论了颗粒在基体表面的分布。第二年，在几种喷涂金属材料上，系统地研究了环境压力对热喷涂颗粒转变行为的影响。研究了常压下临界转变压力与颗粒材料热喷涂的关系，得到了如下结论：1）由于氧化在基底表面上的化学变化非常少，2）由于氧化，通常认识到物理变化，特别是纳米范围内的粗糙度变化，3）纳米尺度的粗糙度变化对颗粒/基体界面的润湿状态有显著影响; 4）粗糙度变化引起的润湿状态变化可能主导热喷涂颗粒的相变行为; 5）降低环境压力也能发现相变现象。由于在衬底温度和环境压力的变化的转变行为总结在一个3-D的转变地图。利用该三维过渡图可以更有效地控制热喷涂过程。也就是说，所需的涂层的微观结构和性能，只需要选择一个适当的组合的基板温度和环境压力条件。结果表明，衬底表面温度场的变化与衬底表面环境压力的变化之间可能存在一定的等效性。因此，从本研究中获得的结果暗示，动态润湿可能是热喷涂颗粒的扁平化的可能的支配。少

In a first year, the effect of substrate heating on the transition phenomenon in the flattening behavior of thermal sprayed particle was systematically observed. To perform this, change in the substrate surface property, especially roughness property, due to the oxidation was precisely analyzed in nano meter range. Based oh the analyzed result, effect of wetting at particle/substrate interface on the flattening of thermal sprayed particle was investigated. In more detail, the substrate surface once heated in an air atmosphere was analyzed both by a chemical way and a physical way, that is, the chemical composition and oxide layer thickness change by Auger analysis and roughness change in nano meter range by atomic force microscope was investigated. The flattening behavior on the substrate once heated in an air atmosphere was observed precisely as well. From the relation between analyses results on the substrate surface change due to oxidation and transition change in the flattening beh … More avior of the particle on the substrate surface was discussed. In a second year, the effect of ambient pressure on the transition behavior of thermal sprayed particle was systematically investigated on several kinds of sprayed metal materials. The relation between critical transition pressure in ambient pressure and the particle material thermally sprayed was investigated.From the results obtained, followings were revealed in the present research : 1)chemical change on the substrate surface due to the oxidation was quite few, 2)physical change, especially roughness change in nano meter range, was typically recognized due to the oxidation, 3)the wetting condition at particle/substrate interface was effectively affected by the roughness change in nano meter range, 4)change in the wetting condition due to roughness change might dominate the transition behavior of thermal sprayed particle, 5)the transition phenomenon was recognized as well by just reducing the ambient pressure. The transition behavior due to the change both in the substrate temperature and ambient pressure was summarized in a 3-D transition map. Thermal spraying process can be controlled more effectively by using of this 3-D transition map. Namely, the desired coating microstructure and property are given by just selecting an appropriate combination of substrate temperature and ambient pressure conditions. The result implies that a certain equivalency may exist between the change in the temperature field of the substrate surface and the change in the ambient pressure on the substrate surface. Consequently, it was implied from the results obtained in the present research that the dynamic wetting could be the possible domination on the flattening of thermal sprayed particles. Less