As solid-state deposition technique avoiding oxidation, cold gas spraying is capable of retaining feedstock material properties in the coatings, but typically fails to build up coatings of brittle materials. Ceramic MAX phases show partial deformability in particular lattice directions and may thus successfully deposit in cold spraying. However, deformation mechanisms under high strain rate, as necessary for cohesion and adhesion, are not fully clear yet. A MAX-phase deposit only builds up, if the specific mechanical properties of the MAX phase allow for, and if suitable spray parameter sets get realized. To investigate the influence of material properties and deposition conditions on coating microstructure and quality, three MAX phases, Ti3SiC2, Ti2AlC and Cr2AlC, were selected. Up to ten passes under different spray parameters yielded Ti2AlC and Cr2AlC coatings with thicknesses of about 200-500 µm. In contrast, Ti3SiC2 only forms a monolayer, exhibiting brittle laminar failure of the impacting particles. In all cases, the crystallographic structure of the MAX-phase powders was retained in the coatings. Thicker coatings show rather low porosities (< 2%), but some laminar cracks. The deposition behavior is correlated with individual mechanical properties of the different MAX-phase compositions and is discussed regarding the particular, highly anisotropic deformation mechanisms.

中文翻译：

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MAX相变形性对冷喷涂涂层形成的影响

作为避免氧化的固态沉积技术，冷气喷涂能够在涂层中保留原料材料的特性，但通常无法建立脆性材料的涂层。陶瓷 MAX 相在特定晶格方向显示出部分变形能力，因此可以在冷喷涂中成功沉积。然而，内聚力和粘附所必需的高应变速率下的变形机制尚不完全清楚。仅当 MAX 相的特定机械性能允许并且实现合适的喷涂参数设置时，才会形成 MAX 相沉积物。为了研究材料特性和沉积条件对涂层微观结构和质量的影响，选择了三种 MAX 相 Ti3SiC2、Ti2AlC 和 Cr2AlC。在不同的喷涂参数下进行多达 10 次的喷涂，产生厚度约为 200-500 µm 的 Ti2AlC 和 Cr2AlC 涂层。相比之下，Ti3SiC2 仅形成单层，表现出冲击颗粒的脆性层流破坏。在所有情况下，MAX 相粉末的晶体结构都保留在涂层中。较厚的涂层显示出相当低的孔隙率 (< 2%)，但有一些层状裂纹。沉积行为与不同 MAX 相成分的单独机械性能相关，并针对特定的高度各向异性变形机制进行了讨论。MAX 相粉末的晶体结构保留在涂层中。较厚的涂层显示出相当低的孔隙率 (< 2%)，但有一些层状裂纹。沉积行为与不同 MAX 相成分的单独机械性能相关，并针对特定的高度各向异性变形机制进行了讨论。MAX 相粉末的晶体结构保留在涂层中。较厚的涂层显示出相当低的孔隙率 (< 2%)，但有一些层状裂纹。沉积行为与不同 MAX 相成分的单独机械性能相关，并针对特定的高度各向异性变形机制进行了讨论。