This study aims at evaluating the effects of surface mechanical attrition treatment (SMAT) on mechanical properties and corrosion resistance of NiCrBSi coatings deposited by high-velocity oxygen-fuel (HVOF) spraying. The as-deposited coating has a typical HVOF-sprayed morphology with unmelted and deformed particles, associated with voids and porosities, whereas after SMAT, the affected zone morphology is more compact, without porosity or crack. The thickness of the affected zone varies from about 30 to 100 µm according to the SMAT parameters. The surface roughness is much lower for SMAT-treated coatings (from Ra = 6.8 µm to a Ra ≈ 2.3 µm). Whatever the SMAT parameters used in this work, the treated materials are harder compared to the as-deposited coating (from 6.6 to 7.6 GPa). They exhibit compressive residual stresses around − 360 MPa, while tensile stresses with an average value of 180 MPa were evaluated for the as-deposited coating. In addition, the treated coatings show better wear resistance as well as better corrosion resistance in a 3 wt.% NaCl solution. The better compromise in terms of SMAT parameters corresponds to amplitude of vibration of the SMAT sonotrode of 15 μm and SMAT duration of 810 s.

中文翻译：

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通过机械磨损处理 (SMAT) 提高 HVOF 喷涂 NiCrBSi 涂层的机械性能和耐腐蚀性

本研究旨在评估表面机械磨损处理 (SMAT) 对高速氧气燃料 (HVOF) 喷涂沉积的 NiCrBSi 涂层的机械性能和耐腐蚀性的影响。沉积态涂层具有典型的 HVOF 喷涂形态，具有未熔化和变形的颗粒，伴有空隙和孔隙，而在 SMAT 之后，受影响的区域形态更加致密，没有孔隙或裂纹。根据 SMAT 参数，受影响区域的厚度从大约 30 到 100 µm 不等。SMAT 处理涂层的表面粗糙度要低得多（从 Ra = 6.8 µm 到 Ra ≈ 2.3 µm）。无论在这项工作中使用什么 SMAT 参数，与沉积态涂层相比，处理过的材料都更硬（从 6.6 到 7.6 GPa）。它们表现出大约 - 360 MPa 的压缩残余应力，而对沉积态涂层的拉伸应力的平均值为 180 MPa。此外，处理过的涂层在 3 wt.% NaCl 溶液中显示出更好的耐磨性和更好的耐腐蚀性。在 SMAT 参数方面更好的折衷对应于 15 μm 的 SMAT 超声波发生器的振动幅度和 810 s 的 SMAT 持续时间。