Thematic research areas

This thematic area focuses on engineering materials for which mechanical properties of both the bulk material and its coating are of interest.

Please note that in the framework of the Education & Research Unit “SPERU” the development of engineered bulk material is limited to particles or powder-based materials such as sintered metal parts, ceramics or construction materials. Concerning coatings, there is no limitation regarding neither the nature of the substrate material (metal, ceramic, polymers), nor the coating material, nor the selected coating processes.

The manufacture of a bulk material or a surface exhibiting a large variety of combinaed functionalities can be achieved by processing thermodynamically unstable particulate mixtures. Besides the chemical composition of the starting raw material(s), additional characteristics such as the particle features (size, shape, size distribution), the spatial arrangement of these particles (random, ordered, monolayers) and their processing (i.e. chemical consolidation, sintering, compaction) influence the properties of the final material. Additionally, using nanoparticles may very strongly influence or enable novel physical, chemical and biological properties.

Surface properties are very often key in successfully using a given material. The chemical composition and the morphology of the surface are also of high importance. Several processing technologies, for instance atomic monolayer, nanometer thin multilayers or micrometer thick coatings are available to achieve optimal structures. A first typical surface property consists of the wetting/non-wetting phenomenum ubiquitous in the natural and technological worlds. Understanding this has been the subject of intensive investigations over the past decades. A promising strategy to regulate wetting behaviour is the combination of surface patterning and chemical surface modification. Such non-wetting surfaces have recently attracted much attention due to their particular anti-contamination, self-cleaning and nonstick properties, which are desirable for present-day applications (i.e. antibiofouling paints for boats; snow and ice rain nonstick coating for antennas, airplane and power line; self-cleaning coating for automobiles and buildings). Besides wettability properties, adhesion and abrasion properties are also of high interest.

Understanding adhesion is still challenging, not only from a scientific point of view but also because only a limited number of investigation techniques are available. They are most often adapted to very specific material combinations and applications. The novel investigation methods AFM, HRTEM, Focussed Ion Beam, TOF-SIMS have substantially increased the possibilities for investigating adhesion but the transfer of the generated knowledge from science to engineering is still under-developed.  Additionally new coatings engineered with a thickness of several atoms or exhibiting a structure at the nanoscale still require demanding characterisation.

Abrasion properties of materials and coatings are of high importance for many applications but only limited theories describe such a complex behaviour.  Though plentiful investigations have been undertaken, generally focussing on a specific material and a particular application, there is still room for both detailed and general investigations of abrasion and most interestingly of structure–properties relationships.

In summary, this thematic area:

• focuses on engineering novel bulk materials from particles and powders and on the development of novel powder processing steps including modification of particle surfaces, independently of the category of material and application.
• is concerned with coatings on any type of substrate - provided research focuses on processing and surface structure - property relationships, novel characterisation methods and applications.
• covers functional properties if combined with mechanical properties (for instance abrasion and wettability, adhesion and thermal conductivity).

• High adhesive thick films with controlled hierarchical structured porosity enabling tailored structural and functional properties - Project approved, to start in 2010