Bocker C.,Friedrich - Schiller University of Jena |
Muoz F.,Institute Cermica y Vidrio CSIC |
Durn A.,Institute Cermica y Vidrio CSIC |
Rssel C.,Friedrich - Schiller University of Jena
Journal of Solid State Chemistry | Year: 2011
The transparent glass-ceramics obtained in the silicate system Na 2O/K2O/SiO2/BaF2 show homogeneously dispersed BaF2 nano crystals with a narrow size distribution. The X-ray diffraction and the nuclear magnetic resonance spectroscopy were applied to glasses and the respective glass-ceramics in order to clarify the crystallization mechanism and the role of fluorine during crystallization. With an increasing annealing time, the concentration and also the number of crystals remain approximately constant. With an increasing annealing temperature, the crystalline fraction increases until a saturation limit is reached, while the number of crystals decreases and the size of the crystals increases. Fluoride in the glassy network occurs as AlFBa, AlFNa and also as BaF structures. The latter are transformed into crystalline BaF2 and fluoride is removed from the AlFBa/Na bonds. However, some fluorine is still present in the glassy phase after the crystallization. © 2010 Elsevier Inc. All rights reserved.
Trenado C.,Leibniz Institute for New Materials |
Trenado C.,Saarland University |
Wittmar M.,Leibniz Institute for New Materials |
Veith M.,Leibniz Institute for New Materials |
And 6 more authors.
Modelling and Simulation in Materials Science and Engineering | Year: 2011
A novel hybrid sol-gel coating has recently been introduced as an alternative to high toxic chromate-based corrosion protection systems. In this paper, we propose a multiscale computational model to estimate the amount and time scale of inhibitor release of the active corrosion protection coating. Moreover, we study the release rate under the influence of parameters such as porosity and viscosity, which have recently been implicated in the stability of the coating. Numerical simulations obtained with the model predicted experimental release tests and recent findings on the compromise between inhibitor concentration and the stability of the coating. © 2011 IOP Publishing Ltd.