Dr. Hanaor - Department of Ceramic Materials - TU Berlin's blog

Exceptionally high saturation magnetisation in Eu-doped magnetite stabilised by spin–orbit interaction

Unusual ferrimagnetic ground state in rhenium ferrite

Abstract

Towards the development of reusable space systems, high emissivity coatings on fibrous ceramic substrates with improved thermal resistance are needed. In this study WSi2–MoSi2–Si–SiB6-borosilicate glass coatings were prepared on fibrous ZrO2 by slurry dipping and subsequent high temperature rapid sintering. A coating with 20 wt% WSi2 and 50 wt% MoSi2 presents optimal thermal stability with only 10.06 mg/cm2 mass loss and 4.0% emissivity decrease in the wavelength regime 1.27–1.73 μm after 50 h oxidation at 1773 K. The advantages of double phase metal-silicide coatings combining WSi2 and MoSi2 include improved thermal compatibility with the substrate and an enhanced glass-mediated self-healing ability.

Heavy ion irradiation can be used to modify the atomic structure of a material and improve its dissolution characteristics as shown here. This has implication for the design of bioceramics

Abstract

The morphology of MAX phase composites is examined here. Specifically, crack branching is examined in Al - Ti2AlC composites showing the role of MAX phase distribution on the fracture performance of such materials. Ductile alloy phases serve to deflect cracks in the hard, yet tough, MAX phase.

Full text available here

Highlights

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A semi-analytical model is developed for the notch tip maximum stress.

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Application of the formula to U and blunt V-notches is demonstrated.

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The results can be used to assess the brittle failure of notched components.

Abstract

Abstract

in recent years the technique of freeze casting has undergone tremendous development. New techniques and novel nanoscale building blocks have given rise to porous materials with extraordinary properties. As an example, by spinning freeze cast fibre with aligned pores fabrics with unprecedented levels of thermal insulation could be produced. This 

The relationships between surface roughness, contact pressure and contact resistance are studied in this work published three years ago.

It is imporant to distinguish between the different conduction mechanisms acting at contacts at different scales, in order to better understand how surface structure and surface chemistry can alter the behaviour of electrical contacts

Freeze casting presents exciting new avenues towards high performance materials with aligned pore structures.

Bone scaffolds, highly elastic composites and nacre mimetic materials can all be produced by means of freeze casting methods. 

This comprehensive review presents recent development in terms of materials and processing

Tuning capillary penetration in porous media: Combining geometrical and evaporation effects

https://doi.org/10.1016/j.ijheatmasstransfer.2018.02.101

In the work shown here:

Multiscale modeling of effective elastic properties of fluid-filled porous materials

The elastic deformation and its dependence on fluid displacement is studied at two distinct scales, to address the multi-scale nature of porous structures in nature.

Two-dimensional modeling of the self-limiting oxidation in silicon and tungsten nanowires

https://doi.org/10.1016/j.taml.2016.08.002

Influence of gas pressure on the effective thermal conductivity of ceramic breeder pebble beds

https://doi.org/10.1016/j.fusengdes.2017.03.073

Static friction at fractal interfaces

https://doi.org/10.1016/j.triboint.2015.09.016

Contact stiffness of multiscale surfaces by truncation analysis

In this concise piece of work, an effective method is shown to gain new understandings into the role of surface structure in the field of contact mechanics. In particular, normal contact stiffness is correlated to parameters of surfaces' fractal dimension and amplitude. 

Dynamics of Viscous Entrapped Saturated Zones in Partially Wetted Porous Media

Available also here

Abstract

3D printable geomaterials

https://doi.org/10.1680/jgeot.15.P.034

This work, dating back to 2015 demonstrates the simulation of grain morphologies for subsequent fabrication of surrogate geomaterials