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Large area sputtering systems employing rotary cathodes are essential for the uniform deposition of thin films in various applications. Achieving optimal film uniformity is critical, and this study investigates the influence of the processing zone geometry on plasma production and resulting thin film uniformity in such systems. Using COMSOL Multiphysics, a comprehensive model has been developed to simulate plasma generation and transport within a large area sputtering chamber utilizing rotary cathodes. The simulations reveal a strong correlation between the processing zone geometry, including cathode spacing, target substrate distance, and chamber walls and or shields, and the uniformity of the deposited thin films. Specifically, variations in the geometry significantly alter the plasma distribution and ion flux profiles across the target, directly impacting film thickness uniformity. These findings highlight the crucial role of geometric design in optimizing large area sputtering systems for enhanced thin film uniformity. This work provides valuable insights for the design and operation of next-generation sputtering systems with rotary cathodes, emphasizing the importance of considering processing zone geometry for achieving stringent uniformity requirements.

https://doi.org/10.14332/svc25.proc.0008

Compliant thermal barrier coatings (TBCs) produced via electron beam physical vapour deposition enabled the long-lasting thermal protection of gas turbine components where damage tolerance of the ceramic coating was critical. However, the columnar microstructures produced via EB-PVD, responsible for the coating compliance introduce easy pathways for heat and fluid transport, reducing the effective thermal insulation and resistance to infiltration by molten slags (CMAS ). This work presents the results of series of coating depositions exploring the parameter space. The effect of the substrate temperature and rotation speed were explored and contrasted against the conditions reported in the literature. The coating process was undertaken using the Von Ardenne EBE-150 EB-PVD coater in Cranfield University. The resulting microstructures ranged from columns with periodic porosity features to homogeneously layered coatings, deviating significantly from the standard columnar morphology. The crystallographic phase makeup of the produced coatings was characterized using X-Ray Diffractometry (XRD), and crystalline texture was investigated using Electron Backscattered Diffraction (EBSD). Additionally, the microstructural morphology of the produced coating systems was compared by means of an automated method for column width measurement (CoCo). The obtained results demonstrate the flexibility of the EB-PVD process and the possibility of addressing the durability and performance penalties introduced by the columnar microstructures while maintaining the critical strain compliance of the system.

https://doi.org/10.14332/svc25.proc.0010

Advancing inertial confinement fusion (ICF) technology necessitates the development of innovative physical vapor deposition processes for fabricating millimeter-scale hollow spherical shells used as ICF ablators. Boron carbide (B₄C) is the foremost candidate for the next generation of ICF ablators due to its unique properties. Its compatibility with direct-current magnetron sputtering (DCMS) further enables scalable production of ablators for inertial fusion energy (IFE) applications. Given the complexity of the deposition process—with its nonlinear dependence on various parameters and a large design space—the use of conventional optimization approaches is challenging. Therefore, the understanding of underlying deposition mechanisms is crucial for process refinement. Here, we will discuss our approach to developing the B₄C deposition process via DCMS, focusing on the following two challenges of ultrathick coatings required for ICF and IFE applications: increasing coating rates and achieving process stability for prolonged deposition runs.

https://doi.org/10.14332/svc25.proc.0005

We demonstrate the development of a new atmospheric pressure-atomic layer deposition (AP-ALD) system to coat the inner walls of capillary columns for gas chromatography (GC). Unlike traditional ALD, this reactor operates at near-atmospheric pressure and addresses the challenges of depositing thin films inside capillaries, which include long pump down times, deposition in high-aspect-ratio materials, and temperature control. We show ALD of alumina in 5 and 12 m capillaries (0.53 mm ID) via sequential half reactions of trimethylaluminum and water. Our system yields pinhole-free, uniform thin films. It includes small witness chambers for witness silicon shards before and after the capillary. An engineering flow/transport analysis of the device is provided. Our ALD alumina thin films are characterized by spectroscopic ellipsometry (SE), X-ray photoelectron spectroscopy, transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy. Alumina film growth achieved is 1.4-1.5 Å/cycle, which is consistent with previously reported results. Film thickness measurements by SE on witness shards of silicon and by TEM at both ends of the capillary are in good agreement. A capillary column coated with alumina is used to separate different gases by GC, although the retention times of gases are essentially the same as with an untreated fused silica capillary. This successful deposition of ALD alumina in long capillaries opens the door for other possible ALD coatings, including hybrid organic-inorganic coatings, using the 450+ ALD precursors available today.

https://doi.org/10.14332/svc25.proc.0003

Key aero-engine components are subject gas stream temperatures above the melting point of their metal alloy, a demanding environment that can only be survived thanks to the combination of cooling and protection from Thermal Barrier Coatings (TBCs). Electron-Beam Physical Vapour Deposition (EB-PVD) can deposit TBCs with a unique columnar microstructure that is strain compliant and ideal to survive in cyclic, high-strain, high-thermal load environments, such as those of the rotating parts of the high temperature turbine. TBCs based on yttria-stabilised zirconia (YSZ) are tough and effective, but they are also susceptible to sintering and chemical attack by calcium magnesium alumino-silicates (CMAS) at higher operating temperatures, which are required to improve engine efficiency. Rare Earth Zirconates (REZ) are postulated as potential YSZ substitutes due to their higher resistance to CMAS attack, lower thermal conductivity and high phase stability, although they also exhibit a lower toughness and more manufacturability challenges. This work focuses on two known systems (Gadolinium and Lanthanum Zirconate – GZ and LZ), a novel system (Neodymium Zirconate - NZ), and YSZ references and explores co-evaporation and use of mixed-ingot oxides to overcome the manufacturability challenges in EB-PVD. The columnarity, general microstructure, and uniformity of all systems has been evaluated, with special emphasis on the LZ system that, traditionally, results in heterogeneous composition and lack of columnarity. The use of simple computer models has helped to understand the underlaying mechanisms of these challenges. The performance of the resulting TBCs has been evaluated for CMAS attack and high velocity erosion, considering depth of infiltration and reactive formation of protective compounds for the former, and erosion rates, damage mechanisms and proposed erosion testing alternatives for the latter. Overall, NZ seems a promising system on-par or better than GZ.

https://doi.org/10.14332/svc25.proc.0011

The production of functional coatings on metal, glass, and polymer substrates through sputtering has been established on an industrial scale for 50 years. Porous or highly outgassing substrates such as paper or wood are generally considered incompatible with vacuum coating technologies. While there have been isolated studies on feasibility, systematic research results remain largely absent. Paper is a natural, renewable raw material. The coating of tear-resistant paper in roll form is cost-effective and can significantly contribute to reducing plastic waste, thereby promoting sustainability. Potential applications for coated paper include:

• Sensors: Use in conductivity analyses in chemical process engineering and for paper-based multi-electrode arrays (MEAs) in biotechnological research.
• Electronics: Application as a dielectric in thin-film transistors (TFTs).
• Barrier coatings: Protection against moisture, oxygen, and other gases, e.g., for food packaging to extend shelf life.
• Hygienic applications: Antimicrobial silver coatings for wall coverings, medical packaging, or hygiene papers.

Various sputtering techniques from gas flow sputtering to HIPIMS (High Power Impulse Magnetron Sputtering) allow a broad variation of energy levels of film forming species. In a first study, two different paper types (7×3 cm²) were successfully coated with silver, titanium and titania in a short cycle system using DC sputtering at target power densities up to 7,7 W/cm². Structural investigations by Environmental Scanning Electron Microscopy (ESEM) show that the fibres are well encapsulated by the coating (conformity) and that structural changes occur, indicating improved functional properties. Further investigations include adhesion tests and long-term stability assessments. The study provides valuable insights into the application of vacuum coating on paper and opens new possibilities for sustainable and functional materials across various applications. The results and challenges of implementation will be discussed.

https://doi.org/10.14332/svc25.proc.0004

Vacuum quality is crucial to the performance of coatings produced. This can be compromised if the vacuum system suffers from a leak, whether this is air, water or virtual. There exist traditional methods for assessing vacuum quality, including baseline pressure tests. We instead propose an AI approach. Specifically, we use remote plasma optical emission spectroscopy to collect data of air leaks with varying leak rates. This data is used to train an AI model. We demonstrate the effectiveness of this approach, as it allows real time in-situ analysis of vacuum quality.

https://doi.org/10.14332/svc25.proc.0037

Water splitting electrolysis is a promising pathway to meet the global demand for clean and renewable energy. Electrocatalysts play a critical role in water splitting technologies and thus represent a key component to achieve highly efficient hydrogen production. However, platinum group metals (PMG) are commonly used as catalysts in these technologies, which implies high costs and makes large-scale commercialization difficult. Transition metal-based catalysts are an appealing option to replace PGM catalysts because of their low-cost, high efficiency and long stability. Nickel nanoparticles (Ni-NPs) have demonstrated excellent catalytic activity for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), which makes them a viable bifunctional catalyst for water splitting systems. In this work, Ni-NPs for HER were embedded in graphitic carbon nitride (gCN) supports by using two distinct manufacturing routes: chemical synthesis and magnetron sputtering. The morphology and structure of chemically produced and sputtered electrodes were evaluated using scanning electron microscope (SEM) transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Electrode systems and cyclic voltammetry (CV) were employed to understand the electrochemical activity of the HER. The results reveal the catalytic activity of Ni-NP embedded in gCN and the reaction rate for HER compared to pristine gCN by controlling the particle size, enlarging the active sites, and boosting charge transfer properties, and compare the catalytic efficiency for the two manufacturing routes. This contribution provides a cheaper and stable HER electrocatalyst that can be used in water splitting systems for efficient hydrogen generation.

https://doi.org/10.14332/svc25.proc.0007

Even though flash lamp annealing is not a new technology, commercially viable applications within the realm of coatings, thins films and surface engineering are still largely unexplored. Instead, static annealing procedures and/or deposition at elevated temperatures are frequently employed to adjust materials and/or surface properties for given applications. However, the applicable temperatures are often limited by substrate materials as well as unwanted side effects, such as diffusion, and/or economic considerations. Therefore, rapid (<50 ms) thermal annealing processes are an alternative technology enabling thermal treatment of functional layers and coatings. The limited penetration depth of the imposed heat can even allow the thermal treatment on temperature sensitive substrates. By superimposing periodic flashes and moving the substrate perpendicular to the lamp axis, large areas can be continuously and homogeneously annealed. Recent developments transferred this technology from lab-scale to a pilot scale level and even beyond providing a reproducible and effective large area treatment in air, controlled atmosphere or even in-line with vacuum processes. In comparison to conventional furnace processing, a superior energy efficiency is demonstrated at a comparatively small machine footprint at high throughput. This talk introduces the principles of flash lamp annealing as well as the available equipment options for (large area) thin film and surface treatment for up to pilot-level. These will be related to selected applications and use cases explored at Fraunhofer FEP over the last decade. Examples are crystallization of large area TCO coatings in combination with inline FLA on rigid and ultra-thin bendable glass, treatment of Ag-based lowE multilayer stacks, formation of antimicrobial as well as plasmonic nanoparticles, surface activation of TiO_x thin films as well as toughening of plain glass surfaces. Furthermore, the FLA process itself is in the focus of research and commercial validation. Therefore, topics like long-term stability, scalability and energy efficiency will also be addressed.

https://doi.org/10.14332/svc25.proc.0039

Redwire’s heritage efforts have included manufacturing prototypes and science enablers for individuals doing work in orbit and can find their foundation in work performed on Space Shuttle missions starting over 30 years ago. A recent focus for us has been the systems that facilitate the development of pharmaceutical crystals.

In general, both small and large molecule drugs, are often best formulated as crystals. The crystalline state is more easily handled, isolated and is relatively stable but can suffer from polymorphism and size coefficients of variation that are too large. A potential solution to these problems was impressed upon us by the result found in the microgravity enabled crystal growing experiment of the monoclonal antibody, Pembrolizumab marketed by Merck as the product, Keytruda. Creating new forms and potentially improving the existing forms of drugs in microgravity with greater crystalline uniformity and less variation in size allows for new polymorphs could lead to faster development times, less waste in the process of making the drugs, and possibly lead to new modes of delivery. We will present results demonstrating the difference in crystals formed terrestrially vs those generated on the International Space Station Platform and describe the use of those crystals for future terrestrial production of pharmaceuticals.

https://doi.org/10.14332/svc25.proc.0002