Geometrically defined surface structuring for the form-locked bonding of thermal sprayed coatings

用于热喷涂涂层的形状锁定粘合的几何定义的表面结构

• 批准号: 380444554
• 负责人: Professor Dr.-Ing. Dirk Biermann
• 金额: --
• 依托单位: Institut für Spanende Fertigung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/380444554?language=en
• 关键词: Geometrically; defined; surface; structuring; form

The pre-treatment of substrates for thermal sprayed coatings is conventionally done by abrasive blasting processes using corundum. This step is characterized by a long process time. Moreover, an additional machine is required to realize this kind of pre-treatment. Because of this, it is necessary to evaluate alternative processes to generate a suitable surface structure for the final coating process. Thus, this research project will investigate the possibility to generate a reproducible surface topology of substrates by the combination of the processes knurl milling and deep rolling. This combination leads to undercuts at the surface that enable an improved adhesion of sprayed coatings onto the substrate. The potential of this innovative pre-treatment process could be pointed out by preliminary investigations. Due to the undercuts the adhesive tensile strength of the coating was significantly increased in comparison to knurled surfaces. By using an additional deep rolling process as post-treatment of the sprayed coating, the adhesive tensile strength can nearly reach the amount of abrasive blasted and coated substrates. Furthermore, a smooth surface and a compaction of the coating is also realized by the rolling process. Investigations pointed out, that the failure of the laminate occurs in the areas between the undercuts which are characterized by a smoothed surface. Based on this, the knurl pitch size will be reduced in the project to affect the dimension of the smoothed surfaces between the undercuts and enable an increased adhesive tensile strength of the coating. All in all, the new process chain can increase the productivity of thermal spraying and enlarge the application area of thermal sprayed coatings. It could be possible to develop innovative wear protection coatings for the usage in engines. Moreover, the smoothed and compacted coatings can be used as functional surfaces.

热喷涂涂层基材的前处理通常是通过使用刚玉的喷砂工艺进行的。这一步骤的特点是工艺时间长。此外，还需要增加一台机器来实现这种前处理。因此，有必要对替代工艺进行评估，以便为最终涂层工艺生成合适的表面结构。因此，这项研究项目将探索通过滚花铣削和深轧相结合的工艺来生成可重复的基材表面拓扑结构的可能性。这种组合导致了表面的底切，从而提高了喷涂涂层与基材的附着力。这种创新的前处理工艺的潜力可以通过初步调查指出。由于底纹的存在，涂层的结合强度与滚花表面相比显着提高。采用深轧工艺作为喷涂层的后处理工艺，涂层的结合强度几乎可以达到喷砂和涂层基材的水平。此外，还通过轧制工艺实现了涂层的表面光滑和致密化。调查指出，层合板的破坏发生在底切之间的区域，这些区域的特征是表面光滑。在此基础上，将在项目中减小滚花间距尺寸，以影响底切之间平滑表面的尺寸，并提高涂层的附着力拉伸强度。总而言之，新的工艺链可以提高热喷涂的生产率，扩大热喷涂涂层的应用范围。有可能开发用于发动机的创新的耐磨涂层。此外，光滑致密的涂层还可以用作功能表面。