Sufficient Wetting Research Articles

Study of Wettability Alteration of Hydrophobic Carbonate Rock by Surfactant-Containing Chelating Agent Solutions

Chelating agents’ application for well stimulation is gaining more and more interest, as they can perform under harsh conditions. However, the mutual influence of surfactants and chelating agents on the wettability alteration of hydrophobic carbonate rock under conditions of high-temperature well stimulation is relatively unexplored. This paper aims to study interfacial processes on the surface of hydrophobic rock in the presence of the EDTA-based chelating agent and surfactants of different classes. Cationic (cetyltrimethylammonium bromide, CTAB, and cetylpyridinium bromide, CPB), anionic (sodium dodecyl sulfate, SDS), and amhoteric (alkyldimethyl aminooxide, AO) surfactants were studied. Wettability alteration of model hydrophobic rock was studied under conditions specific to well stimulation. It was shown that chelating agent (CA) alone and its mixture with SDS could not lead to sufficient wettability alteration. CTAB, CPB, and AO were able to change the wettability effectively. A synergistic effect between CA and these surfactants was observed and a possible mechanism was proposed. AO was selected as the most promising surfactant. The influence of surfactant on the CA’s dissolution capacity towards carbonate rock was investigated; dissolution capacity strongly depends on wettability alteration. Finally, the effect of CA, AO, and their mixture on the wettability of aged reservoir rock was studied and the absence of negative effects was proven.

A priori evaluation of the printability of water-based anode dispersions in inkjet printing

Inkjet printing represents a disruptive additive manufacturing technology that has emerged as an innovative approach to generate customized lithium-ion batteries by tailored dispersions. However, electrode dispersions cause a complex non-Newtonian behavior which hampers the processability. This paper demonstrates a novel procedure for an a priori evaluation of the printability of aqueous graphite dispersions. Therefore, dispersions with a varying active material content were prepared and the printability was examined through a characterization of the drop formation and the drop deposition behavior. While the drop formation was observed by in-situ monitoring, the drop deposition was analyzed in ex-situ test setups. The rheological properties were systematically determined to calculate nondimensional numbers that describe the dispensing behavior. Consequently, their capability to predict the stability of the drop formation was evaluated. The results revealed that a graphite dispersion with a content of 2 m% allowed for a stable drop formation. No splashing occurred on the substrate during the drop deposition and sufficient wetting can be assumed due to a contact angle of below 90∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ$$\\end{document}. Conclusions were drawn to further enhance the active material content. Due to the universality of the proposed approach, it is expected to be applicable to different dispersion systems.

High capacitance performance of hierarchically SiO2 self-doped porous activated carbon derived from palm empty fruit bunches

Porous activated carbon derived from empty fruit bunch (EFB) has garnered significant attention as an electrode material for supercapacitors due to its low cost, abundance, and sustainability in real energy storage applications. However, there is still room for improvement in their performance compared to other renewable biomass resources. In our study, we successfully converted EFB biomass into porous activated carbon with outstanding performance, achieving a remarkably high specific capacitance of 459.28 F/g at 0.5 A/g, along with a moderate specific surface area (SSA) of 1215.38 m2/g. Furthermore, the quasi-solid-state supercapacitor assembled from the AC700 sample demonstrated excellent energy density, reaching 15.39 Wh/kg at a power density of 50 W/kg. Additionally, it exhibited remarkable cycling stability, with a capacitance retention of 93 % after 10,000 cycles. These exceptional results were achieved by simply adjusting the activation temperature. We utilized KOH as the activating agent and carbonized it at temperatures of 600 °C, 700 °C, and 800 °C for 2 h under an N2 atmosphere. The superior capacitive performance of the AC700 sample can be attributed to the combined effects of its high SSA, surface functional groups, and optimal pore size distribution. The optimum activation temperature of 700 °C resulted in the formation of porous activated carbon with the most structural defects, as well as an appropriate distribution of micropores (63.41 %) and mesopores (31.70 %), facilitating ion diffusion and providing multiple sites for charge storage. Additionally, the AC700 sample exhibited the highest SiO2 content, measuring at 34.33 %, and the lowest contact angle of 75°. The presence of SiO2 in the carbon framework promotes the formation of more hydrophilic active sites, thereby enhancing the pseudocapacitance performance and facilitating sufficient wetting between the electrolyte and electrode interface.

Urbanization as a limiter and catalyst of watershed-scale sediment transport: Insights from probabilistic connectivity modeling

The conversion of rural lands to urban areas exerts considerable influence on the hydrologic processes governing sediment transport at the watershed scale. While the effects of urbanization on hydrology have been well-studied, the corresponding impact to the spatial and temporal variability of sediment detachment, transport, and connectivity is less certain. To address this knowledge gap, we apply process-based hydrologic simulation, probabilistic connectivity modeling, and in situ turbidity sensing to five watersheds positioned along a steep land use gradient in Kansas, USA. Connectivity modeling results show that urbanization systematically decreases the maximal extent of watershed-scale connectivity on the wettest days of the study period, from 51 % in the most rural watershed to 28 % in the most urban watershed. On the other hand, urbanization focuses sediment transport into fewer, more frequently wetted pathways, such as roadway drainage networks, which are activated 3.5 times more frequently than the equivalent pathways in rural basins. In this way, urbanization limits maximal connectivity as impervious surfaces indefinitely disconnect source zones from the sediment cascade, but also catalyzes hot spots of connectivity as these same impervious areas generate excess runoff and channel it to drainage systems. The 23.9 ± 4.2 % of days that exhibit watershed-scale functional connectivity account for 85.0 ± 9.5 % of sediment export with most of the export tied to a few highly connected days. Sensing results show that increases in watershed-scale connectivity only translate to larger fluvial sediment loads after a connectivity threshold (the median connected day) has been exceeded, suggesting a transition from functional to structural connectivity control on sediment dynamics after sufficient wetting. This study highlights the role of land use impacts on the sources and mechanisms of sediment transport, which will be an important consideration for land managers as urban areas continue to expand to accommodate global migration patterns.

Enhanced Adhesion of Electrospun Polycaprolactone Nanofibers to Plasma-Modified Polypropylene Fabric.

Excellent adhesion of electrospun nanofiber (NF) to textile support is crucial for a broad range of their bioapplications, e.g., wound dressing development. We compared the effect of several low- and atmospheric pressure plasma modifications on the adhesion between two parts of composite-polycaprolactone (PCL) nanofibrous mat (functional part) and polypropylene (PP) spunbond fabric (support). The support fabrics were modified before electrospinning by low-pressure plasma oxygen treatment or amine plasma polymer thin film or treated by atmospheric pressure plasma slit jet (PSJ) in argon or argon/nitrogen. The adhesion was evaluated by tensile test and loop test adapted for thin NF mat measurement and the trends obtained by both tests largely agreed. Although all modifications improved the adhesion significantly (at least twice for PSJ treatments), low-pressure oxygen treatment showed to be the most effective as it strengthened adhesion by a factor of six. The adhesion improvement was ascribed to the synergic effect of high treatment homogeneity with the right ratio of surface functional groups and sufficient wettability. The low-pressure modified fabric also stayed long-term hydrophilic (ten months), even though surfaces usually return to a non-wettable state (hydrophobic recovery). In contrast to XPS, highly surface-sensitive water contact angle measurement proved suitable for monitoring subtle surface changes.

Profiling interfacial reaction features between diamond and Cu-Sn-Ti active filler metal brazed at 1223 K

• When the TiH 2 content is below 5 wt.%, completely uncoated and partially coated diamond particles with sharp edges can still be observed. When above 5 wt.%, all diamond particles are completely coated, indicating sufficient wettability has been achieved. • The interfacial reaction layer is found to be composed of TiC, the thickness of which is demonstrated to increase as a function of TiH 2 content, arriving at the peak value of 1.70 µm and remaining almost constant afterwards. • Further increasing TiH 2 content above 5 wt.% is unnecessary or even harmful, as it may encourage the formation of brittle Cu 41 Sn 11 phase, leading to significantly reduced wear resistance and potentially downgraded grinding efficiency. Diamond/Cu-Sn-Ti composites have been successfully prepared by cold-press forming in conjunction with high-temperature vacuum active brazing at 1223 K. Ensuing wetting behaviors between diamond and filler metal, interfacial characteristics of the reaction layer, and wear resistance of the bulky composite have been fully investigated. It is revealed that all diamond particles can only be fully coated when the TiH 2 content exceeds 5 wt%, below which sharp edges on diamond can still be observed. The interfacial reaction layer is found to be composed of TiC, the thickness of which is demonstrated to increase as a function of TiH 2 content, arriving at the peak value of 1.70 µm and remaining almost constant afterwards. It is further shown that the maximum wear resistance occurs approaching 5 wt% TiH 2 content. Potential mechanisms responsible for such interesting phenomena have been postulated.

Challenges of fabricating catalyst layers for PEM fuel cells using flatbed screen printing

In this work, flatbed screen printing is evaluated regarding its capability to produce catalyst layers of PEM fuel cells. In the field of printed electronics, screen printing is regarded as robust and high-throughput coating technology. The possibility of in-plane structuring could be an additional degree of freedom, enabling more complex designs of catalyst layers in the future. In this study, process parameters are varied to investigate their effect on resulting layer thickness, homogeneity, and Pt-loading. With the usage of different screens, the Pt-loading can be adjusted. Additionally, two different pastes with and without water content are investigated. The catalyst paste without water showed a better process stability during printing and performed best under dry conditions (RH = 40%) and worst under wet conditions (RH = 100%) during electrochemical in-situ testing. Overall, the reproducibility of the CCM production process was verified. The viscosity of the catalyst paste with 19.55 wt% water in solvent was higher compared to the paste without water. Furthermore, a carbon paste (Pt-free) is developed in a similar viscosity range as the catalyst pastes. The main challenge of screen printing process development lies in the paste optimization to prevent evaporation effects over time, ensuring sufficient wetting of the paste on the substrate and sufficient fuel cell performance.

A reusable nanofibrous air filter with anti-wetting microbead coating

Filtration technologies for fine dust particles have garnered attention as public awareness of air pollution has increased. In this study, we report a microbead-coated polyacrylonitrile nanofibrous membranes (MB-NFMs) filter, which is a reusable PAN nanofiber-based air filter with high dust-filtration efficiency. The MB-NFMs filter comprises a dual-layer structure composed of hydrophilic PAN nanofibers coated with hydrophobic microbeads to produce high filtration efficiency and water droplet cleaning ability. This membrane has water contact angles of approximately 144°, which allows water droplets to roll off its surface and carry captured dust particles with them. Furthermore, we discovered that the MB-NFMs filter has sufficient wetting resistance to maintain its hydrophobicity under raindrop impacts. The MB-NFMs filter had a removal efficiency of over 99.8% for PM2.5. Repetitive dust-filtration and water droplet-cleaning cycles were performed to evaluate the MB-NFMs filter's ability to clean water droplets. The filtration efficiency was higher than 99.8% throughout the tests, and the pressure drop was recovered by 99% after each cleaning cycle. The fabricated MB-NFMs filter is a viable solution for highly efficient and reusable dust-particle filtration. The MB-NFMs filter does not require periodic maintenance due to its water droplet cleaning ability, providing an economic advantage over conventional air filters.

An overlooked parameter in Li-S batteries: The impact of electrolyte-to-sulfur ratio on capacity fading

The Lithium-Sulfur (Li-S) system has gained a lot of interest as a promising next-generation rechargeable battery due to the high theoretical energy density, high theoretical capacity and abundance of sulfur. Many parameters of Li-S batteries such as sulfur loading, electrolyte-to-sulfur (E/S) ratio, type of the conductive network, electrode design, etc. have a profound impact on the capacity, energy density and cycling performance. But the effect of E/S ratio on the electrochemical performance of Li-S batteries is often neglected, although it is one of the most important parameters. A high electrolyte amount in the cells could decrease the energy density and increase the cost, therefore it could limit the practical use of Li-S batteries. In this work, we first presented a statistical study on the sulfur loading and electrolyte quantity in Li-S cells by reviewing 240 selected papers from the state-of-the-art Li-S research. This analysis revealed that the electrolyte quantity was not reported as often as the sulfur loading in the literature, and the reported E/S values differ by a fair amount from each other. Second, in order to explore the effect of different E/S ratios on the performance of Li-S cells, batteries with 5:1, 10:1, 20:1 and 30:1 E/S ratios were prepared. Galvanostatic cycling with potential limitation (GCPL), electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT) were used to analyze the effect of E/S ratio on the capacity fade, impedance, internal resistance and ion diffusivity in Li-S batteries. The effects of different electrolyte penetration conditions on the electrochemical performance of cells with the same E/S ratios were also studied by preparing cells with different resting times. It was shown that E/S ratio has a strong influence on the electrochemical performance of Li-S batteries, and an optimal E/S ratio should be achieved, which is low enough to minimize the free migration of active materials between the electrodes, and at the same time high enough in order to have a sufficient electrolyte wetting of the active material. It is suggested that capacity decay in batteries with low E/S ratios could be originating from electrolyte depletion, whereas the capacity decay in batteries with high E/S ratios could be due to the dissolved lithium polysulfide species in the liquid electrolyte and their diffusion to the lithium anode surface.

A Review on Mechanical Properties of Al-Alloy with B4C and Fly ash Reinforced Metal Matrix Composite

Most of the style of production strategies available for discontinuous metallic matrix composites, stir casting is generally regularly occurring as an especially promising route, presently practiced commercially. Its benefits lie in its simplicity, flexibility and applicability to massive amount production with value benefit. The major trouble of this manner is to reap sufficient wetting of particle with the aid of liquid metallic and to get a homogenous dispersion of the particulates. the present assessment is at the technique employed in stir casting which include, how the base steel is melted, at what temperature and kingdom it's miles to be maintained, what conditions the particulates are brought and how the stirring time and stirring speed have an effect on the final composite cloth. The effect of stirrer design and feeding mechanism has additionally been discussed. The variation in the type of mixing the particulates into the metallic matrix has additionally been handled within the paper. in the introductory component the stir casting method with a diagram has been laid out to present an overview of the general system of casting of steel matrix composites. the limitations of the process also are listed in the paper. Key Words: Metal matrix composites; Particulates, reinforcement, stir casting

Reinforced tensile strength and wettability of nanofibrous electrospun cellulose acetate by coating with waterborne polyurethane and graphene oxide

Nanotechnology has made biocompatible nanofibers grow in the healthcare industry. Herein, a cellulose acetate (CA) electrospun membrane was characterized by nanofibers of 438 (nm) in diameter between virus and bacteria, pore areas of 36.3%, and a pore size of 395 ± 263 (nm). This structure led to excellent air-water transfer through pore connectivity, contributing to sufficient wettability, air permeability, and water vapor transmission rate (WVTR). The air permeability of pristine CA membranes became predictable through multiple linear regression, based on the correlation to thickness, bulk density (Pearson’s coefficients: 0.754, −0.538). Nonetheless, the tensile strength of the pristine CA needed to be reinforced by spray coating with waterborne polyurethane (WPU) and graphene oxide (GO). The WPU/GO 6:1 (v/v) ratio was optimal due to the increase in ultimate tensile stress to 132.96% due to a synergy of GO’s covalent bonds with WPU’s hard segments and elongation at break to 113.40% from WPU polyols. The WPU/GO 6:1 coated CA membrane possessed still comparable air permeability (36.53 l/m2/s), and WVTR (5736 g/m2/day). Its rapid wetting transition from the Cassie-Baxter’s to Wenzel’s state was attributed to GO’s hydrophilic functional groups. These achievements in reinforcement of tensile strength and wettability would pave the way for filtration, and wound dressing.

LiCoO2/Graphite Cells with Localized High Concentration Carbonate Electrolytes for Higher Energy Density

Widening the working voltage of lithium-ion batteries is considered as an effective strategy to improve their energy density. However, the decomposition of conventional aprotic electrolytes at high voltage greatly impedes the success until the presence of high concentration electrolytes (HCEs) and the resultant localized HCEs (LHCEs). The unique solvated structure of HCEs/LHCEs endows the involved solvent with enhanced endurance toward high voltage while the LHCEs can simultaneously possess the decent viscosity for sufficient wettability to porous electrodes and separator. Nowadays, most LHCEs use LiFSI/LiTFSI as the salts and β-hydrofluoroethers as the counter solvents due to their good compatibility, yet the LHCE formula of cheap LiPF6 and high antioxidant α-hydrofluoroethers is seldom investigated. Here, we report a unique formula with 3 mol L−1 LiPF6 in mixed carbonate solvents and a counter solvent α-substituted fluorine compound (1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropylether). Compared to a conventional electrolyte, this formula enables dramatic improvement in the cycling performance of LiCoO2//graphite cells from approximately 150 cycles to 1000 cycles within the range of 2.9 to 4.5 V at 0.5 C. This work provides a new choice and scope to design functional LHCEs for high voltage systems.

Improvement in interfacial fracture toughness of multi-material additively manufactured composites through thermal annealing

An experimental investigation is performed to investigate the effect of post-processing heat treatment on the interfacial fracture toughness of bi-material additively manufactured semi-crystalline polymer composite. An asymmetric double cantilever beam (ADCB) and single-leg bending (SLB) specimens made of polylactic acid (PLA) and Nylon are considered for the mode-I and mixed-mode fracture characterization, respectively. Specimens are isothermally heated in a forced convection oven for a wide range of temperatures and durations. Fracture toughness decreases significantly for both mode-I and mixed-mode conditions when specimens are annealed below the melting temperature of PLA (150 °C). An increase of the crystallinity at the high-temperature annealing prevents the polymer chain mobility, hinders the neck growth, and provides poor intermolecular diffusion resulting in decrease of fracture toughness by 88% as compared to the unannealed specimen. Annealing at 160 °C improves the bi-material interfacial fracture toughness by a maximum of 1225% via sufficient interfacial wetting, higher molecular diffusion, and a longer polymer chain entanglement process. Material transfer, void collapse, and filament impression on the fracture surface of high temperature annealed specimen indicate a better molecular diffusion and strong interlaminar bond at the interface.

Salt-rejecting rGO-coated melamine foams for high-efficiency solar desalination

Solar-driven interfacial desalination has been emerged as a promising water treatment technology to generate drinkable water out of seawater. The accumulated salt crystals generated from seawater, however, have adverse effects on solar-driven interfacial evaporation. In this work, we prepared a salt-rejecting reduced graphene oxide (rGO) foam by depositing rGO particles on a hydrophilic melamine foam for solar desalination. Benefitting from the intrinsic porous microstructure and hydrophilicity, the rGO-coated melamine foam has sufficient wettability to draw water to the evaporation region, leading to rapid replenishment of water and simultaneously avoiding salt precipitation. Based on the rGO-coated melamine foam, the interfacial evaporation system can achieve a steady-state evaporation efficiency of 89.6% under a solar flux of 1 kW m−2 and has good durability under one sun over 12 h. With the high solar-to-thermal conversion efficiency and excellent long-term stability, this interfacial evaporation system exhibits the potential of commercial seawater desalination.Graphic abstract

High-performance electrospun membrane for lithium-ion batteries

Lithium-ion battery separator is one of the core battery components, owing to its assistance in ion migration and prohibiting electron transport inside the battery. Traditional separators made of polyolefin do not provide sufficient wettability to provide high energy density required for applications in high-end field. Although electrospun lithium ionized poly(ethylene-co-vinyl alcohol) (EVO-Li) membranes were considered earlier, their mechanical properties still appear to be inferior. In this work, the surface modification of EVO-Li membranes by poly-dopamine (PDA) with benzene structure and excellent adhesion ability to enhance their mechanical properties is reported. PDA was found to react with EVO-Li and form the C-N-O bonds, which further improved the ultimate tensile strength of the membrane. Simultaneously, its uptake property and thermostability were also improved.

Effect of moisture content on the electromagnetic shielding ability of non-conductive textile structures

Electromagnetically shielding textile materials, especially in professional or ordinary clothing, are used to protect an implanted pacemaker in the body. Alternatively, traditional textiles are known for their non-conductivity and transparency to an electromagnetic field. The main goal of this work was to determine whether the high moisture content (sweat) of the traditional textile structure significantly affects the resulting ability of the material to shield the electromagnetic field. Specifically, whether sufficient wetting of the traditional textile material can increase its electrical conductivity to match the electrically conductive textiles determined for shielding of the electromagnetic field. In this study, cotton and polyester knitted fabric samples were used, and two liquid medias were applied to the samples to simulate human sweating. The experiment was designed to analyse the factors that have a significant effect on the shielding effectiveness that was measured according to ASTM D4935. The following factors have a significant effect on the electromagnetic shielding effectiveness of moisturised fabric: squeezing pressure, drying time and type of liquid media. Additionally, the increase of electromagnetic shielding was up to 1 dB at 1.5 GHz frequency at the highest level of artificial sweat moisturised sample.

In-Situ Laser Polishing Additive Manufactured AlSi10Mg: Effect of Laser Polishing Strategy on Surface Morphology, Roughness and Microhardness.

Laser polishing is a widely used technology to improve the surface quality of the products. However, the investigation on the physical mechanism is still lacking. In this paper, the established numerical transient model reveals the rough surface evolution mechanism during laser polishing. Mass transfer driven by Marangoni force, surface tension and gravity appears in the laser-induced molten pool so that the polished surface topography tends to be smoother. The AlSi10Mg samples fabricated by laser-based powder bed fusion were polished at different laser hatching spaces, passes and directions to gain insight into the variation of the surface morphologies, roughness and microhardness in this paper. The experimental results show that after laser polishing, the surface roughness of Ra and Sa of the upper surface can be reduced from 12.5 μm to 3.7 μm and from to 29.3 μm to 8.4 μm, respectively, due to sufficient wetting in the molten pool. The microhardness of the upper surface can be elevated from 112.3 HV to 176.9 HV under the combined influence of the grain refinement, elements distribution change and surface defects elimination. Better surface quality can be gained by decreasing the hatching space, increasing polishing pass or choosing apposite laser direction.

Wiped film evaporators: Segmental assessment of wetting behavior and heat transfer performance

An analysis of different operating points during the evaporation of a subcooled feed in a wiped film evaporator (WFE) allows a conceptual segmental assessment, distinction and quantification of various wetting behaviors and heat transfer situations during the liquid film flow. In detail, single-phase heating, evaporation from a fully covered surface and evaporation from a partly covered surface may be distinguished. For each section the wetting situation is extracted. This knowledge is essential for operating wiped film evaporators within a suitable and appropriate range to prevent e.g. product damage. The experiments were conducted at a stainless steel and steam-heated wiped film evaporator with a spring-loaded, inclined comb wiper system and monoethylene glycole as evaporation fluid. Process pressure, wiper type and rotational velocity were kept constant. Variations of feed rate and driving temperature difference mark out the characteristic operating points. In case of sufficient wetting of the evaporation surface, overall heat transfer coefficients of 1800 W/(m²·K) are reached. By decreasing feed rate and assessing the achieved distillate rate minimum sump loads can be derived for a given driving temperature difference. This quantifies the position of film break-up leading to a partly covered heat transfer surface. Active heat transfer areas are extracted from the experimental data and quantified to get a more precise view on suitable process conditions of WFE and its principal operation.

Field-Induced Wettability Gradients for No-Loss Transport of Oil Droplets on Slippery Surfaces.

Transporting oil droplets is crucial for a wide range of industrial and biomedical applications but remains highly challenging due to the large contact angle hysteresis on most solid surfaces. A liquid-infused slippery surface has a low hysteresis contact angle and is a highly promising platform if sufficient wettability gradient can be created. Current strategies used to create wettability gradient typically rely on the engineering of the chemical composition or geometrical structure. However, these strategies are inefficient on a slippery surface because the infused liquid tends to conceal the gradient in the chemical composition and small-scale geometrical structure. Magnifying the structure, on the other hand, will significantly distort the surface topography, which is unwanted in practice. In this study, we address this challenge by introducing a field-induced wettability gradient on a flat slippery surface. By printing radial electrodes array, we can pattern the electric field, which induces gradient contact angles. Theoretical analysis and experimental results reveal that the droplet transport behavior can be captured by a nondimensional electric Bond number. Our surface enables no-loss transport of various types of droplets, which we expect to find important applications such as heat transfer, anticontamination, microfluidics, and biochemical analysis.

Microstructure and Mechanical Properties of Reactive-Air-Brazed 3YSZ/Crofer 22 APU Joints at Ambient Temperature

The growth of inventive high-temperature electrochemical devices such as solid oxide fuel cells constitutes a major task in brazing technology of ceramic–metal joints. In this work, reactive air brazing was used and the joining characteristics of 3YSZ with Crofer 22 APU have been systematically analyzed for three different brazing temperatures (1000, 1050 and 1100 °C) and two dwell times (5 and 30 min). The joints have been brazed successfully using the Ag–4CuO filler alloy. This braze filler metal was manufactured by an arc PVD (physical vapor deposition) process. Further, sufficient wetting of the zirconium oxide was achieved. The morphology of the oxide reaction layer at the steel side had a major influence on the shear strength of the brazed joints. A maximum average shear strength of 101 ± 4 MPa was obtained for a temperature of 1050 °C and a dwell time of 5 min.