Lorenz Sigl

Recent Development Aspects of Metal Supported Thin-Film SOFC

In recent years, the metal supported solid oxide fuel cell (MSC) technology has attained high interest for the electrical power supply in vehicles as an Auxiliary Power Unit (APU) that operates independently from the main engine. Its advantages compared with other fuel cell technologies can be seen in a higher mechanical stability and in a better thermo and redox behaviour. Those attributes are urgently needed for mobile applications.

When the going gets tough PM gears can cope

Highly stressed applications such as automotive gearboxes have long been a major target for PM manufacturers. And the evidence is piling up to show that surface densified powder metal parts can deliver the goods for vehicle manufacturers…

OpenFOAM Modeling of Particle Heating and Acceleration in Cold Spraying

In cold spraying, a powder material is accelerated and heated in the gas flow of a supersonic nozzle to velocities and temperatures that are sufficient to obtain cohesion of the particles to a substrate. The deposition efficiency of the particles is significantly determined by their velocity and temperature. Particle velocity correlates with the amount of kinetic energy that is converted to plastic deformation and thermal heating. The initial particle temperature significantly influences the mechanical properties of the particle. Velocity and temperature of the particles have nonlinear dependence on the pressure and temperature of the gas at the nozzle entrance. In this contribution, a simulation model based on the reactingParcelFoam solver of OpenFOAM is presented and applied for an analysis of particle velocity and temperature in the cold spray nozzle. The model combines a compressible description of the gas flow in the nozzle with a Lagrangian particle tracking. The predictions of the simulation model are verified based on an analytical description of the gas flow, the particle acceleration and heating in the nozzle. Based on experimental data, the drag model according to Plessis and Masliyah is identified to be best suited for OpenFOAM modeling particle heating and acceleration in cold spraying.

Metal-supported palladium membranes for hydrogen separation

The demand for clean and green energy has raised the consumption of hydrogen continuously during the last years. Hydrogen is most economically produced in large scale systems by methane steam reforming followed by pressure swing adsorption (PSA). However, with a rising demand for small-scale production of hydrogen, and as down-scaling to smaller PSA-systems ( < 500 Nm3/h H2) is not economic, a substantial demand for hydrogen generation using palladium membranes has emerged. Porous tubes made of an oxide dispersion strengthened powder metallurgy Fe-Cr alloy (trade name ITM) constitute the backbone for the thin solid Pd films. The tubes provide mechanical and chemical long-term stability in atmospheres with hydrogen- and carbon-species at operation temperatures up to 600°C. A porous ceramic diffusion barrier layer (DBL) is deposited between the ITM-backbone and the Pd thin-film to avoid Pd diffusion into the Fe-Cr substrate and thereby ensure long-term integrity of the system. The Pd thin-film with a thickness < 10 μm is applied onto the DBL by a proprietary coating technology. This paper describes the production route of a tube/diffusion-barrier-layer/Pd-membrane system, its structure and permeation properties.

Sparking new design ideas for electricity generation

The traditional economic advantages of near net shape powder metallurgy technology can be combined with mathematical and finite element modelling and deployed to produce satisfactory results in the gritty and down to earth industrial environment of day-to-day power generation, where breakdowns can cost both money and reputation…

Timing right for PM to gear up for competition

Synchronisation components in manual transmission gear boxes are a challenging opportunity that has the potential to fuel PM industry growth over the next years. Validation of new PM components including sliding sleeves and load-bearing gears is in progress and has already generated new applications in the market…