6 Materialchemie
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Erscheinungsjahr
- 2020 (3) (entfernen)
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- Beitrag zu einem Tagungsband (3) (entfernen)
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- Biofilm (1)
- Corrosion (1)
- Diffusion (1)
- Ettringen tuff (1)
- High-entropy alloy (1)
- Hydrogen (1)
- Pore structure (1)
- Scanning kelvin probe force microscopy (1)
- Silver nanoparticle (1)
- Starch (1)
Organisationseinheit der BAM
- 6 Materialchemie (3)
- 5 Werkstofftechnik (1)
- 5.1 Mikrostruktur Design und Degradation (1)
- 6.2 Material- und Oberflächentechnologien (1)
- 6.3 Strukturanalytik (1)
- 6.5 Synthese und Streuverfahren nanostrukturierter Materialien (1)
- 7 Bauwerkssicherheit (1)
- 7.4 Baustofftechnologie (1)
- 9 Komponentensicherheit (1)
- 9.0 Abteilungsleitung und andere (1)
Development and characterization of starch film and the incorporation of silver nanoparticles
(2020)
Starch is one of the biopolymers being used for bioplastic synthesis. For production, starch can be combined with different plasticizers, starches from different plant sources and even with nanomaterials to improve or to add film properties. The challenge of adding these, e.g. in the form of silver nanoparticles (AgNp) is to determine the concentration so as to avoid impairing the properties of the film, agglomeration or altering the visual characteristics of the film. In this study, a starch film synthesis route and the incorporation of silver nanoparticles has been proposed in order not to alter the properties of the film while maintaining the transparency and a clear colour of the starch film. The results showed that the proposed synthesis route is promising, efficient, reproducible, fast and the film has good mechanical properties.
High-entropy alloys (HEAs) are characterized by a solid solution of minimum five and medium-entropy alloys (MEAs) of minimum three principal alloying elements in equiatomic proportions. They show exceptional application properties, such as high-strength and ductility or corrosion resistance. Future HEA/MEA-components could be exposed to hydrogen containing environments like vessels for cryogenic or high-pressure storage where the hydrogen absorption and diffusion in these materials is of interest. In our study, we investigated the HEA Co20Cr20Fe20Mn20Ni20 and the MEA Co33.3Cr33.3Ni33.3. For hydrogen ingress, cathodic charging was applied and diffusion kinetic was measured by high-resolution thermal desorption spectros-copy using different heating rates up to 0.250 K/s. Peak deconvolution resulted in high-temperature desorption peaks and hydrogen trapping above 280 °C. A total hydrogen concentration > 40 ppm was identified for the MEA and > 100 ppm for HEA. This indicates two important effects: (1) delayed hydrogen diffusion and (2) considerable amount of trapped hydrogen that must be anticipated for hydrogen assisted cracking phenomenon. Local electrochemical Volta potential maps had been measured for the hydrogen free condition by means of high-resolution Scanning Kelvin Probe Force Microscopy (SKPFM).
Stone deterioration is the result of a complex interaction of external physical, chemical and biological forces with the mineralogical-petrophysical properties of the stone. With a better understanding of how these properties are linked to material behavior and durability, more effective measures for stone conservation can be developed. Studying these interactions in tuff is particularly complex due to the naturally high heterogeneity of tuff rocks.
The first aim of a current research project is to combine the results of recent and older studies on tuff deterioration. Furthermore, the literature overview is complemented by our own investigation of Weibern and Ettringen tuff, with a focus on pore structure characteristics.