The Laboratory for Surface Engineering at the Faculty of Mechanical and Process Engineering has made a significant expansion to its research and teaching capacities. Under the direction of Professor Dr. Markus Lake, head of the STAR competence centre and the Laboratory for Surface Engineering, a state-of-the-art suspension spraying system was successfully put into operation.

This system can be used to produce very thin and finely structured coatings using suspensions in a high-speed flame spraying process (S-HVOF technology). Suspensions are complex mixtures of a solid and a carrier liquid.

The suspension spraying system, developed and manufactured by GTV Verschleißschutz GmbH from Luckenbach (Rhineland-Palatinate), is a technological milestone for the university. This system allows coating and process development to be raised to a new level. This opens up completely new possibilities, particularly in the field of synthesizing catalytic material and surface systems. The S-HVOF system is used in both teaching and research and enables students to be introduced to highly specialized technologies in a practical orientation.

The system was officially handed over by University President Dr. Thomas Grünewald, GTV Managing Director Dr. Klaus Nassenstein and Head of Development Dr. Andreas Wank. "We are delighted to place this innovative technology in the hands of such experienced and committed scientists," emphasized Dr. Klaus Nassenstein during the ceremony. Nassenstein was also President of the SME Research and Transfer Network of the German Federation of Industrial Research Associations "Otto von Guericke" e.V. (AiF) until April 2024.

The HSNR is one of the few research facilities in Germany that has this advanced application technology at its disposal. "The development and optimization of the suspensions is carried out in close cooperation with Prof. Dr. Andreas Roppertz from the Faculty of Chemistry," says Prof. Dr. Lake. This interdisciplinary collaboration enables tailor-made solutions to be developed for various industrial applications.

With the new suspension spraying facility, the university is strengthening its position as a leading research facility in the field of Surface Engineering and at the same time creating new opportunities for the development of future-oriented materials and processes.

We are pleased to announce that Prof. Dr. Markus Lake has been accepted into the prestigious Graduate School for Applied Research in North Rhine-Westphalia. This honor recognizes his scientific contributions and dedicated research in the field of process and application development as well as his successful supervision of his doctoral students.

As a professorial member of the "Resources and Sustainability" department of the Graduate School for Applied Research, Markus Lake and his development team M. Sc. Nikolai Desch and B. Eng. Theresa Gielen focus on research into innovative surface systems. One specialization of their activities is the application development of catalytic surface systems. With this work, he and his team are driving forward the development of sustainable technologies that make a significant contribution to environmental protection and resource conservation.

His admission to the Graduate School for Applied Research is a significant milestone in his scientific career and underlines his outstanding achievements in research and in the supervision of young scientists.

About the Graduate School for Applied Research in North Rhine-Westphalia

The Graduate School for Applied Research a leading institution for the promotion of young academics in North Rhine-Westphalia. It offers outstanding researchers the opportunity to complete their doctorates in an interdisciplinary environment and to benefit from an excellent supervision and support program.

Since November 2023, the Laboratory for Surface Engineering has had a new XRD system of the "STADI MP" model from Stoe, Darmstadt. The application for the X-ray diffractometer was submitted by Professor Andreas Roppertz, who is a member of the STAR competence center and a player in the Laboratory for Surface Engineering, in close cooperation with Dr. Sabrina Keil and Professor Markus Lake. Financial support is provided by the German Research Foundation (DFG).

The acquisition of an X-ray diffractometer at The Hochschule Niederrhein offers the opportunity to directly combine theoretical contexts from courses with practical experience. Application-relevant issues such as the influence of dopants on phase formation or temperature-induced phase transformation and much more can be illustrated in a sustainable way during internships. Unrestricted access to this method is particularly advantageous for material and phase analysis in project assignments, theses and dissertations. The new device is used for crystallographic analysis of powders, bulk materials and thin films and has an automatic multiple sample changer, which enables time-efficient analysis of large sample volumes. The device also has a modular in-situ cell in which the samples can be gassed and heated during analysis. At temperatures of up to 900 °C and a reactive gas phase, in-situ phase formations and transformations can be investigated. The high power of the X-ray tube and the high intensity of the detector enable very short analysis times, so that the temporal resolution for in-situ experiments is given. These analyses enable the elucidation of reaction mechanisms in solid-state chemistry, which are of enormous importance in the field of reactive surfaces and material systems.

All surfaces with which one comes into contact in daily life play a special role, particularly with regard to the spread of pathogens. Titanium dioxide in its modification anatase is photocatalytically active and can therefore be used as a self-cleaning, antimicrobial surface system. Particularly with regard to the development and spread of bacteria (e.g. coli bacteria), germs (e.g. MRSA), fungi and algae, Anatas can thus make a contribution to minimizing their development and spread. Highly frequented surfaces such as door handles can thus be equipped with antimicrobial agents.

Another potential field of application for photoassisted catalysis is the treatment of water. Titanium dioxide can decompose organic substances by means of an advanced oxidation process (AOP) and help to reduce the contamination of wastewater with pollutants, pharmaceutical products, bacteria or pesticides.

In this master's thesis, a process using magnetron sputter ion plating technology was developed to synthesize titanium dioxide in the anatase modification in a low-temperature process. The low process temperatures and the process control allow the reproducible deposition of this antimicrobial coating on different materials, e.g. metals, ceramics and plastics.

In the project "Electrochemical oxidation on boron-doped diamond electrodes for the treatment of electroless nickel baths", a pilot plant is to be set up as part of an upscaling to oxidize hypophosphite and phosphite electrochemically to phosphate. Hypophosphite is a component of the baths, while phosphite is a by-product of electroless nickel plating, a process known as electroless plating.

For economic and ecological reasons, the disposal of spent solutions from the process of electroless plating is the focus of the platers. Likewise, the purification of wastewater has gained in importance. If phosphorus species get into the environment, this leads in most cases to above-average growth of plants, the so-called eutrophication. For this reason, The Hochschule Niederrhein is working within the project 'Elimination of phosphite in wastewater from the coating industry' on the treatment of wastewater and spent baths generated by the coating process 'electroless nickel'. A treatment technology patented by the university is available for this purpose (DE102012100481, rod bundle electrode). The main focus of the work is on the elimination of the heavy metal nickel and the oxidation of the phosphorus species to phosphate.

The rod bundle electrode and the electrochemical processes taking place are suitable for increasing the oxidation state of phosphorus when conventional methods fail. The rod bundle electrode works particularly well in the range of low concentrations. Phosphorus species present in the electroless nickel bath are oxidized to phosphate at a boron-doped diamond (BDD) rod bundle electrode. The anodic oxidation of hypophosphite (^H2PO2-) and phosphite (^HPO32-) to phosphate (^PO43-) takes place at the electrode surface. The biggest advantage of the rod bundle electrode, compared to the conventional plate electrodes, is the relatively large surface area. To avoid a back reaction of the phosphate, a shielding of the bath on the cathode side by a diaphragm is necessary. The experiments show that the current density, the volume current, the bath composition and the electrolysis time in the cell have an influence on the phosphorus conversion.

We would like to thank the state of NRW for supporting this research project as part of the ERDF project Patent Validation. EFRE 2014-2020, Investments in Growth and Employment, funding code EFRE 0400090, duration 2 years.

In the project "Model-based reactive joining to increase process safety and reliability (MoReBond)", the temporal heat and stress distribution in joining processes using reactive multilayers (RMS) are simulated and reproduced on different demonstrators. By modeling as accurately as possible, the spatial and temporal heat and stress distribution both within the joining zone and in the adjacent component are to be determined in order to find the optimum material and process parameters in reactive joining without prior, time-consuming test series.

In this project, the Institute for Modeling and High Performance Computing (IMH) and the competence centre Surface Technology Applied Research (STAR) of the Hochschule Niederrhein are working together with the research partners Hahn Schickard Institute in Villingen-Schwenningen and Fraunhofer Institute for Material and Beam Technology in Dresden.

Sponsor: German Federal Ministry for Economic Affairs and Energy
Project sponsor: German Federation of Industrial Research Associations (AiF)
Funding number: 20896 BG
Duration: 01.11.2019 to 30.04.2022

The video shows the high-speed recording of a reaction front in the Zr-Al system [source: master project "RMS-Speed" in SoSe 2021].