Study on Unified Understanding of Fundamental Coating Steps in Reactive Thermal Sprayings

反应热喷涂基本涂层步骤的统一理解研究

基本信息

批准号：
14350404
负责人：
TSUNEKAWA Yoshiki
金额：
$ 9.41万
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：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14350404/
关键词：
DC Plasma Spraying HVOF Spraying RF Plasma Spraying InProcess Reaction Wettability InSitu Composite Droplet Temperature Droplet Velocity 発熱反応プラズマ溶射

项目摘要

If composite powders consisted of multi-constituents are sprayed, it is worried about the decomposition of thermodynamically unstable species may occur in their spraying process. However, reactive spraying is quite effective to form in-situ composite coatings, because the required and thermodynamically stable compounds can be synthesized by the in process reaction. Following results are obtained in this study :(1) Cast iron coatings with solid lubricant of graphite were formed by DC plasma spraying for the surface modification of aluminum substrates. Specially designed cast iron powder, which were alloyed with high silicon and aluminum of strong graphitizer, were supplied as a spray material. In order to form cast iron coatings with graphite structure, (a) pre-annealing of cast iron powder, (b) post annealing of sprayed coatings and (c) mixing with additional solid lubricant of hBN. The cast iron coatings with graphite structure exhibits mood tribological properties.(2) Alloyed powder of Al-40wt%Si-10wt%Mg were sprayed by DC and RF plasma spraying, and also HVOF spraying. HVOF spraying gives the highest hardness among them due to refined microstructure and work hardening. The evaporation of magnesium occurs during the RF plasma spraying process, which causes less reinforced phase of Mg_2Si. It is expected that the in process reaction of SiO_2 reduction give us in situ composite coating in the case of Al-Si Mg powder mixed with SiO_2. The coatings with DC plasma spraying show the highest hardness, that is, the highly proceeded in process reaction, because it causes the high amount of MgAl_2O_4 due to the optimum droplet temperature.

如果喷涂由多种成分组成的复合粉末，人们担心在喷涂过程中可能会发生热力学不稳定物质的分解。然而，反应喷涂对于形成原位复合涂层非常有效，因为可以通过过程中的反应合成所需的热力学稳定的化合物。本研究取得了以下成果：(1)采用直流等离子喷涂技术形成石墨固体润滑剂铸铁涂层，用于铝基体的表面改性。特殊设计的铸铁粉末，与高硅和强石墨化铝合金化，作为喷涂材料提供。为了形成具有石墨结构的铸铁涂层，(a)铸铁粉末预退火，(b)喷涂涂层后退火，以及(c)与附加的六方氮化硼固体润滑剂混合。具有石墨结构的铸铁涂层表现出良好的摩擦学性能。(2)采用直流、射频等离子喷涂和超音速火焰喷涂Al-40wt%Si-10wt%Mg合金粉末。由于精细的微观结构和加工硬化，HVOF 喷涂具有其中最高的硬度。射频等离子喷涂过程中发生镁的蒸发，导致Mg_2Si强化相减少。在Al-Si Mg粉末与SiO_2混合的情况下，SiO_2的还原反应有望产生原位复合涂层。直流等离子喷涂涂层表现出最高的硬度，即过程反应高度进行，因为它因最佳熔滴温度而导致大量的MgAl_2O_4。