Service project for the production of surface-modified reference materials to alter the contact properties

• Applicant: Dr. Werner Hintz
• Subject Area: Mechanical Process Engineering
• Term: from 2010 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 169209886

The aim of the project in the third funding period is the production of surface-modified reference particles through targeted and easily controllable modification processes to alter the contact properties. As substrate materials for coating inexpensive, spherical glass particles (Spheriglass 5000 CP00) and polystyrene particles will be used. In this project, the relatively rigid (amorphous) glass particles are to be coated with polystyrene, which is a polymer material and, accordingly, has soft mechanical contact behaviour. In addition to that, hybrid - particle systems which consist of a soft organic polystyrene core and rigid (SiO2) and soft (TiO2) inorganic shell will be produced. The coating on the carrier-particle surface will be produced in the following form: (a) a thin, smooth layer with controllable and reproducible layer thickness and (b) a thin, rough layer of narrowly distributed, non-agglomerated nano-disperse guest particles. The morphology of the layers plays a crucial role in the interaction between the particles and is decisive for the behaviour of the modified powder. So the application of a thin, rubbery layer shall intensify the adhesion forces between the glass particles, giving rise to a deteriorated flowability of these particles. The coating with nanoparticles from the same materials, on the other hand, shall lead to a better flowability of the cohesive (micro-scale) glass particles. The coatings of the organic (soft) polymer particles with inorganic oxides (TiO2 and SiO2) shell improve their dispersibility and dosability. The coated reference particles are produced both in small quantities for convenient determination of the contact properties (e.g. nanoindenter and atomic force microscopy measurements) as well as in larger amounts with the help of a mini-plant system to measure the continuum-mechanical properties (e.g. shear tests).

• DFG Programme: Priority Programmes
• Subproject of: SPP 1486: Particles in Contact - Micromechanics, Microprocess Dynamics and Particle Collectives
• Participating Person: Professor Dr.-Ing. Jürgen Tomas (†)