Fundamental research on deposition of amorphous coatings on surfaces of inner geometries and evaluation of phase stability under tribological loading

内部几何形状表面非晶涂层沉积的基础研究和摩擦载荷下相稳定性的评估

• 批准号: 419126987
• 负责人: Professorin Dr.-Ing. Kirsten Bobzin
• 金额: --
• 依托单位: Institut für Oberflächentechnik (IOT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/419126987?language=en
• 关键词: Fundamental; research; deposition; amorphous; coatings

In comparison to crystalline materials, amorphous alloys exhibit unique properties.This type of materials can only be manufactured if the alloy allows high undercooling and if rapid cooling rates can be realised. Required high cooling rates can be achieved by the coating technology "Thermal Spraying", allowing the deposition of amorphous coatings. The applicability of coatings on outer surfaces by means of powder based APS and HVOF as well as by means of wire based WAS is investigated intensively. Thereby the stand-off distance is known to be one of the key parameters influencing the amount of amorphous phases. For WAS coatings, stand-off distances between s = 100 and 200 mm are common. In the context of this project, it will be investigated whether amorphous Fe-based coatings can be deposited on inner geometries exhibiting small diameters. Thereby very small stand-off distance of s<40 mm needs to be realized. Due to the short stand-off distance and the utilization of a cored wire, the time for the formation of the alloy is short as well. Within this project the influence of the short stand-off distance on the formation of the alloy as well as the amorphous phases will be investigated. Thereby the effect of further process parameters will be considered. Besides metallographic analysis, the crystallization energy will be determined. These results will be correlated with the process parameters, particle in-flight properties and results from metallography. Subsequently, suitable samples will be heat treated in a vacuum furnace at crystallization temperature. Due to the heterogeneity especially with regard to the chemical composition, crystallization will occur locally. These areas will be identified and analysed in order to clarify the crystallization mechanisms of amorphous coatings. Afterwards, selected coatings will be characterized with regard to the tribological behaviour by means of a model test. Thereby, it will be investigated under which conditions crystallization might occur. In addition, temperature treated samples exhibiting a partially amorphous and a fully crystalline microstructure will be characterized as well. Knowing the characteristics of the wear track of crystallized coatings, assumptions with regard to the crystallisation process on the samples, which are not heat treated, can be made. In order to confirm these results analysis by means of XRD and TEM will be conducted.

与晶体材料相比，无定形合金具有独特的特性。这种材料只有在合金允许较高的底冷且可以实现快速冷却速率时才能制造这种材料。所需的高冷却速率可以通过涂料技术“热喷涂”来实现，从而使无定形涂层的沉积。深入研究了通过粉末基AP和HVOF以及通过基于电线的基于粉末的AP在外表面上的适用性。因此，已知对峙距离是影响无定形阶段量的关键参数之一。因为涂层，s = 100至200 mm之间的对峙距离很常见。在该项目的背景下，将研究是否可以将非晶的Fe基涂层沉积在表现出小直径的内几何形状上。因此，需要实现S <40毫米的非常小的隔离距离。由于僵化的距离短和芯线的利用，合金的形成时间也很短。在该项目中，将研究较短的对峙距离对合金形成以及无定形阶段的影响。因此，将考虑进一步的过程参数的效果。除了金理分析外，还将确定结晶能。这些结果将与过程参数，粒子在飞行中的特性以及金理图结果相关。随后，在结晶温度下将在真空炉中进行合适的样品。由于异质性，特别是在化学成分方面，将在局部发生结晶。这些区域将被识别和分析，以阐明无定形涂层的结晶机制。之后，通过模型测试将所选涂层在摩擦学行为方面进行表征。因此，将研究可能发生结晶的情况。此外，经过部分无定形的温度处理样品也将表征完全结晶的微观结构。知道结晶涂层的磨损轨迹的特征，可以做出关于样品上的结晶过程的假设（未进行热处理）。为了通过XRD和TEM确认这些结果分析。