A careful substrate preparation and the physical properties of the coating particles are decisive for the quality and envisaged properties of the deposited layer. Temperature, size, rate and velocity represent the classical quantities, which can be measured in situ using various diagnostics. Nonetheless, another quality-determining parameter is the degree of oxidation which could not be measured in situ (up to now) by established diagnostics and must therefore be qualitatively derived from the above-mentioned quantities or subsequently be measured by means of destructive methods. Within this work, a diagnostic approach to determine in-flight particle oxidation has been outlined and tested. The presented measurement method detects the entire particle plume from different directions using a 2D two-color pyrometry and allows for the calculation of spatially resolved 3D temperature and intensity distributions based on a tomographic evaluation method. By additionally using measurements of the particle velocities and particle sizes, the surface emissivity of the particles along the spraying direction can be calculated, which in turn allows quantitative conclusions on the degree of particle oxidation. Investigations on the wire arc spraying process have shown that particle oxidation degrees could be determined and tend to correlate well with oxide contents in finished coatings.

中文翻译：

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一种确定热喷涂工艺中飞行中颗粒氧化的新方法

仔细的基材准备和涂层颗粒的物理特性对于沉积层的质量和预期特性是决定性的。温度、大小、速率和速度代表经典量，可以使用各种诊断方法进行原位测量。尽管如此，另一个决定质量的参数是氧化程度，它无法通过已建立的诊断进行原位（到目前为止）测量，因此必须从上述数量中定性地推导出来，或者随后通过破坏性方法进行测量。在这项工作中，概述并测试了一种确定飞行中颗粒氧化的诊断方法。所提出的测量方法使用 2D 双色高温计检测来自不同方向的整个粒子羽流，并允许基于断层扫描评估方法计算空间分辨的 3D 温度和强度分布。通过额外使用粒子速度和粒子尺寸的测量，可以计算粒子沿喷射方向的表面发射率，这反过来又允许对粒子氧化程度的定量结论。对电弧喷涂工艺的研究表明，可以确定颗粒氧化程度，并且往往与成品涂层中的氧化物含量密切相关。通过额外使用粒子速度和粒子尺寸的测量，可以计算粒子沿喷射方向的表面发射率，这反过来又允许对粒子氧化程度的定量结论。对电弧喷涂工艺的研究表明，可以确定颗粒氧化程度，并且往往与成品涂层中的氧化物含量密切相关。通过额外使用粒子速度和粒子尺寸的测量，可以计算粒子沿喷射方向的表面发射率，这反过来又允许对粒子氧化程度的定量结论。对电弧喷涂工艺的研究表明，可以确定颗粒氧化程度，并且往往与成品涂层中的氧化物含量密切相关。