Due to droplet‐based assembly, microstructure anisotropy is expected in atmospheric plasma‐sprayed coatings (APS), with lamellar separations and interfaces having critical effects on properties. Quantitative determination of these anisotropic properties is difficult due to geometric test constraints. This has been overcome in the literature through a variety of indirect, local, or modeled evaluation, however direct measurement on like‐dimensioned coatings is not available. In this work, 25‐mm thick ceramic coating variants, deposited at two different feed rates, were obtained from industry and macroscopic mechanical and thermal properties were evaluated in both in‐plane and out‐of‐plane orientations using identical specimen geometries. As expected, and confirming select past work, coating anisotropy has a direct influence on measured properties. The response of each property is microstructure‐dependent, highlighting the specific interaction: for instance, the fracture toughness is 120% higher in the through‐thickness orientation versus in‐plane after thermal aging, while the thermal conductivity was 24% lower in the through‐thickness. The former benefits from the lamellar interfaces that provide obstacles to crack propagation while the latter sees these interfaces as efficient phonon scatters. The results provide insights for design through robust property measurements and into operational mechanisms in this class of highly defected ceramics.

中文翻译：

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等离子喷涂陶瓷的取向相关的机械和热性能

由于基于液滴的组装，预计大气等离子喷涂涂料（APS）的微观结构各向异性，层状分离和界面对性能会产生关键影响。由于几何测试的限制，很难确定这些各向异性的性质。在文献中，通过各种间接，局部或模型评估已经克服了这一问题，但是无法对类似尺寸的涂层进行直接测量。在这项工作中，从行业获得了以两种不同进料速率沉积的25毫米厚的陶瓷涂层变体，并使用相同的试样几何形状在平面内和平面外方向上评估了宏观的机械和热性能。如预期的那样，并确认选择了过去的工作，涂层各向异性对测量的性能有直接影响。每个特性的响应都取决于微观结构，从而突出了特定的相互作用：例如，在热老化后，贯穿厚度方向的断裂韧性比平面内高120％，而贯穿过程的导热率低24％。 -厚度。前者受益于层状界面，该界面为裂纹扩展提供了障碍，而后者则将这些界面视为有效的声子散射。这些结果为通过可靠的性能测量进行设计提供了见识，并为此类高度缺陷的陶瓷提供了深入的工作机制。而热导率则降低了24％。前者受益于层状界面，该界面为裂纹扩展提供了障碍，而后者则将这些界面视为有效的声子散射。这些结果为通过可靠的性能测量进行设计提供了见识，并为此类高度缺陷的陶瓷提供了深入的工作机制。而热导率则降低了24％。前者受益于层状界面，该界面为裂纹扩展提供了障碍，而后者则将这些界面视为有效的声子散射。这些结果为通过可靠的性能测量进行设计提供了见识，并为此类高度缺陷的陶瓷提供了深入的工作机制。