Development of highly durable thin-film sensors for studying pressure and temperature distribution in contacts under mixed friction

润滑的滑动触点在确保几乎所有带机械部件的技术系统的功能方面起着决定性的作用。润滑故障会导致相关接触部件损坏，通常会导致停机和昂贵的维修。虽然流体力学和弹性流体力学（EHD）的机理已被很好地理解和科学地解释，但边界摩擦和混合摩擦条件的研究仍处于起步阶段，尽管过去进行了许多相关的研究活动。对于混合摩擦条件的理论解释和模拟有具体的研究工作，但是由于缺乏合适的测量方法，其实验验证失败。特别是对于混合摩擦接触中的局部温度和压力的测量，没有合适的传感器可用。因此，拟议的研究项目的目标是扩展已经成功应用于弹性流体动力学研究的薄膜传感器的应用领域，以便能够在配合物之间的临时接触和由此产生的高载荷的混合摩擦条件下进行测量。因此，传感器层的耐磨性和粘合强度有待提高。在该研究项目中，将研究是否可以通过电绝缘类金刚石无定形碳基层系统（材料：a-C，a-C：H，ta-C，ta-C：H，CBNC;层概念：单层，多层和梯度层）实现所需的改进。高粘合强度、硬度、导热性、耐化学性以及物理特性的高度可变性是这些层的突出属性。此外，弹性流体动力学接触中应用的传感器布局和几何形状必须针对混合摩擦条件进行优化。虽然在EHD中可以使用具有细长测量点的线接触传感器，但在混合摩擦下的接触中需要具有几乎点状测量点的传感器。新的传感器系统将在IPEK的滑动轴承试验台上进行验证。通过测量混合摩擦接触中的压力和温度分布，可以加深对摩擦学相互关系的理解，并可以验证相应的模型。

Lubricated sliding contacts play a decisive role in ensuring the function of almost any technical system with mechanical components. Lubrication failure leads to damage of the involved contact partners often followed by downtime and costly repairs. While the mechanisms of hydrodynamics and elastohydrodynamics (EHD) are well understood and scientifically explained, research on boundary friction and mixed friction conditions is still in its beginning, in spite of numerous related research activities carried out in the past. There are specific research works regarding the theoretical explanation and simulation of mixed friction conditions, however, its experimental validation fails due to the absence of suitable measurement methods. Especially for the measurement of local temperatures and pressures in mixed friction contacts, there are no suitable sensors available.Hence, the objective of the proposed research project is the extension of the field of application of thin-film sensors already successfully applied within research on elastohydrodynamics, in order to enable a measurement under mixed friction conditions with temporary contact between the partners and the resulting high loads.Therefore, wear resistance and adhesive strength of the sensor layers are to be improved. Within this research project, it will be studied whether the required improvement can be realized by means of electrically insulating diamond-like amorphous carbon-based layer systems (materials: a-C, a-C:H, ta-C, ta-C:H, CBNC; layer concepts: single, multi and gradient layer). High adhesive strength, hardness, thermal conductivity, chemical resistivity, as well as a high variability of the physical properties are prominent attributes of these layers.Furthermore, sensor layout and geometry applied in elastohydrodynamic contacts, have to be optimized for mixed friction conditions. While in EHD line contacts sensors with elongated measuring points can be used, in contacts under mixed friction sensors with almost punctiform measuring points are needed. The new sensor systems will be validated with one of the journal bearing test benches at IPEK.By means of measuring pressure and temperature distribution in mixed friction contacts, both understanding of tribological interrelations can be deepened as well as corresponding models can be verified.