The coating of highly stressed components with chemical vapor deposition (CVD) diamond can extend their lifetime. In particular, the combination of steel substrates with diamond layers would find many applications in industrial production. However, there are some challenges, for example, the high mismatch in the thermal expansion between steel and diamond, which commonly leads to the delamination of the coating. Thus, a pre-treatment of the substrate surface is needed. Particle blasting has been established in some studies as a suitable process. However, apart from particle residues in the surface of the substrate, these surfaces have a stochastic character, which limits their reproducibility and modification options. This paper presents some instructions for the recording and derivation of defined properties of those surfaces. The conversion of characteristic surface features into quantitative process parameters could serve as the foundation for the manufacturing of deterministic microstructures, especially those produced by ultrasonic vibration superimposed machining. This should increase the reproducibility and the possibilities of the modification with regard to the structural shaping of the functional surface. The design was developed using both a kinematic surface simulation tool as well as a finite elements analysis for the cooling process of the coating–substrate–composite. A high accordance with real finished surfaces was achieved.

In this article, the performance of double corrugated tubes applied in a tube-in-shell heat exchanger is analysed and compared to the performance of a heat exchanger equipped with straight tubes. The CFD (computational fluid dynamics) analysis was performed considering a turbulent flow regime at several mass flow rates. It is observed that the double corrugated geometry does not have a significant impact on the pressure drop inside the analysed heat exchanger, while it has the potential to increase its thermal performance by up to 25%. The ε–NTU (effectiveness–number of transfer units) relation also demonstrates the advantage of using double corrugated tubes in tube-in-shell heat exchangers over straight tubes.

Elastocaloric cooling is a promising alternative to conventional cooling using the vapour compression cycle, with potentially higher theoretical exergy efficiency. Nevertheless, there is a number of challenges to be tackled before the technology can be commercially available world-wide. In this study, the potential of double corrugated regenerators to enhance the cooling power of an elastocaloric device that would be operating under compression loading was investigated. The numerical performances of two types of double corrugated geometries are presented and compared to a flat plate regenerator as a reference. The double corrugated geometry significantly increases the surface area to volume ratio and convection of the regenerator, which allows an increase in the power density of the device.

A novel, environmentally friendly, fast, and flexible polishing process for Nitinol parts is presented in this study. Nitinol samples with both superelastic and shape memory properties at room temperature were investigated. The chemical contamination and surface roughness of superelastic Nitinol plates were examined before and after plasma electrolytic polishing. The shift in phase transformation temperature and tensile strength before and after the polishing process were analysed using Nitinol wire with shape memory properties. The obtained experimental results were compared to the data obtained on reference samples examined in the as-received condition. It was found that plasma electrolytic polishing, when the right process parameters are applied, is capable of delivering Nitinol parts with extremely high surface quality. Moreover, it was experimentally proven that plasma electrolytic polishing does not have a negative impact on functionality or mechanical properties of polished parts.

Das von der EU geförderte Forschung- und Entwicklungsprojekt Thermaco zielt auf die Entwicklung von Materialen und Fertigungstechnologien für extrem effiziente Lösungen zur Wärmeabfuhr ab. Im Mittelpunkt der Untersuchungen steht die Kombination von Aluminium mit Kohlenstoff-basierten Einsätzen, die die Wärmeleitfähigkeit signifikant erhöhen. Das Ziel ist die definierte Wärmeabfuhr für Anwendungen in kritischen Bereichen, wie in der Mikroelektronik, der Elektromobilität, der (erneuerbaren) Energieerzeugung sowie bei Höchstleistungs-Verbrennungsmotoren.