Cold spray is a solid-state process in which solid particles are subjected to severe plastic deformation to form a coating. The effect of naturally occurring oxides on bonding in the cold spray was investigated in this work. Deposition characteristics of copper powder with different surface oxide thicknesses on steel substrate were examined using a local pull-off test. This enables the investigation of individual particle/substrate interfaces. X-ray photoelectron spectroscopy was used to study thoroughly the powder surface chemistry and the oxide thickness as a function of exposure time. This study revealed that the oxide film thickness grew from 6 nm for the as-received powder to 11.6 nm after 2 months of exposure to atmospheric conditions. Scanning electron microscopy and x-ray energy dispersive spectroscopy were used to characterize the particle/substrate interfacial bonding. Adhesion test results show that the bond strength is highly influenced by the surface oxide thickness. Different bonding behaviors and a drop in coating deposition efficiency were observed as the oxide thickness increased. Finite element simulations supplemented our understanding of the particle adhesion dynamics as the oxide film thickness increases. They were also used to study the surface oxide cleanup and bonding mechanism for particles with different oxide film thicknesses.

中文翻译：

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冷喷涂中的粘合机制：粉末储存过程中表面氧化的影响

冷喷涂是一种固态工艺，其中固体颗粒经受剧烈的塑性变形以形成涂层。在这项工作中研究了天然存在的氧化物对冷喷涂中结合的影响。使用局部拉脱试验检查了具有不同表面氧化物厚度的铜粉在钢基材上的沉积特性。这使得能够研究单个颗粒/基材界面。X 射线光电子能谱用于彻底研究粉末表面化学和氧化物厚度作为曝光时间的函数。该研究表明，暴露于大气条件 2 个月后，氧化膜厚度从原样的 6 nm 增加到 11.6 nm。使用扫描电子显微镜和 X 射线能量色散光谱来表征颗粒/基材的界面结合。附着力测试结果表明，结合强度受表面氧化物厚度的影响很大。随着氧化物厚度的增加，观察到不同的结合行为和涂层沉积效率的下降。随着氧化膜厚度的增加，有限元模拟补充了我们对颗粒粘附动力学的理解。它们还用于研究具有不同氧化膜厚度的颗粒的表面氧化物清理和结合机制。随着氧化物厚度的增加，观察到不同的结合行为和涂层沉积效率的下降。随着氧化膜厚度的增加，有限元模拟补充了我们对颗粒粘附动力学的理解。它们还用于研究具有不同氧化膜厚度的颗粒的表面氧化物清理和结合机制。随着氧化物厚度的增加，观察到不同的结合行为和涂层沉积效率的下降。随着氧化膜厚度的增加，有限元模拟补充了我们对颗粒粘附动力学的理解。它们还用于研究具有不同氧化膜厚度的颗粒的表面氧化物清理和结合机制。