Functional surface design by complementarily matched thermal spray and cutting processes

在热喷涂工艺中，基材表面的细小形状对涂层的附着力有很大影响。此外，某些表面形状设计可能会影响所应用的喷涂层的形态和化学成分。这两个方面都与通过切割对精密后加工和摩擦学配对中的涂层行为产生相应影响有关。然而，从基材表面的特定形状设计到喷涂层的某些特性(如硬度、孔隙率或可加工性)的基本过程尚不清楚。此外，基于这种方法的涂层设计的可能性和局限性也是未知的。因此，该项目确定并研究了基材表面的精细形状、喷涂工艺、涂层微结构、涂层可加工性和涂层性能之间的基本因果关系。例如，使用铁基等离子喷涂层和精密车削。该项目的目的是创建一个模型，该模型绘制了通过切割对基材进行定义的预加工、喷涂工艺参数、由此产生的涂层孔隙率和氧化物水平以及它们对精密后加工的影响以及涂层在磨损负荷下的性能之间的所有相关关系。因此，该模型代表了一种可推广到通过使用切割过程的前加工和后加工来获得热喷涂涂层的特定功能化的方法。

In thermal spray processes, the fine shape of the substrate surface has a significant influence on the resulting coating adhesion. Furthermore, certain surface shape designs can affect the morphology and chemical composition of the applied spray coatings. Both aspects are associated with a corresponding impact on the precision post-machining by cutting and the coating behaviour in tribological pairings. However, the basic processes that lead from a certain shape design of the substrate surface to certain properties of the spray coating like hardness, porosity or machinability are not understood yet. Also, the possibilities and limits of a coating design basing on this approach are not known.The project hence identifies and investigates the elementary causal relation between fine shape of the substrate surface, spray process, coating microstructure, coating machinability and coating performance. Exemplarily, iron based plasma spray coatings and precision-turning are used. Aim of the project is to create a model that draws all relevant relationships between a defined pre-machining of the substrate by cutting, spray process parameters, resulting coating porosity and oxide levels and their impact on the precision post-machining as well as the coating performance under wear load. Thus, the model represents a method that can be generalised to obtain a specific functionalisation of a thermal spray coating by pre- and post-machining using cutting processes.