Stress-corrosion mechanisms in silicate glasses

The present review is intended to revisit the advances and debates in the comprehension of the mechanisms of subcritical crack propagation in silicate glasses almost a century after its initial developments. Glass has inspired the initial insights of Griffith into the origin of brittleness and the ensuing development of modern fracture mechanics. Yet, through the decades the real nature of the fundamental mechanisms of crack propagation in glass has escaped a clear comprehension which could gather general agreement on subtle problems such as the role of plasticity, the role of the glass composition, the environmental condition at the crack tip and its relation to the complex mechanisms of corrosion and leaching. The different processes are analysed here with a special focus on their relevant space and time scales in order to question their domain of action and their contribution in both the kinetic laws and the energetic aspects.Comment: Invited review article - 34 pages Accepted for publication in J. Phys. D: Appl. Phy

Analytical investigation of aerosol jet printing

Aerosol jet printing is a technology for contactless printing of narrow line shaped features down to a width of about 20 \u7fm. Until now, process optimization was only done empirically because there was no manageable model to describe it. The process was only modeled numerically regarding Stokes and Saffman force on the aerosol particles. In this article, we introduce a simple analytical model to predict the printed line width. Experimentally, we show that the model is a valid approach for a wide range of parameters. A close look on the quality of the printed lines reveals that depending on the process parameters the droplets are distributed more or less inhomogeneously within the printed lines. We attribute this to the Saffman force, which should be taken into account for a more accurate description, especially when only little sheath gas is applied. However, the printed line width generally agrees with our model, making our model a valuable tool for process control