4M Knowledge base - papers

F. Dauchy, R.A.Dorey
Nanotechnology Group, School of Industrial and Manufacturing Science, Cranfield University, Cranfield, Bedfordshire, UK

Abstract

The fabrication and structuring of multilayer thick film piezoelectric (PZT – lead zirconate titanate) structures, using composite sol gel techniques and wet etching, will be described.

The composite sol gel technique involves producing a PZT powder/sol composite slurry, which when spun down yields films a few micrometers thick. Repeated layering, and infiltration, has been used to produce PZT films between 10 and 40μm thick. Due to the low firing temperature (<720oC) it has also been possible to produce PZT films with embedded thin (ca 200nm thick) metal electrodes.

The PZT thick films have also been structured using a wet etching technique. Examples of features and cavities with lateral dimensions in the order of 10’s of micrometers are presented.

The ability to fabricate and structure thick functional films, with embedded metal electrode structures, offers the possibility to create novel micro-device structures suitable for use in micro electromechanical systems (MEMS)

T. Hanemann (a,b), K. Honnef (b), J. Hausselt (a,b)
a Forschungszentrum Karlsruhe, Institut f. Materialforschung III, D-76021 Karlsruhe, Germany
b Albert-Ludwigs-Universität Freiburg, Institut f. Mikrosystemtechnik (IMTEK), D-79110 Freiburg, Germany

Abstract

Different variants of reaction molding techniques like UV-embossing, UV-RIM, Photomolding, a.o., exploiting the rapid light induced photopolymerization of reactive resins are widely used in microsystem technologies for the fabrication of microoptical components or for rapid prototyping purposes. The solidification based on photocuring limits the suitable materials to transparent resins and yields only plastic microstructured parts. In this paper the further development of micro reaction molding with respect to a rapid prototyping of ceramic and metal parts will be described. As in the different variants of powder injection molding additional process stages have to be considered and individually optimized. First a free-flowing reactive resin based composite with a large filler load (microsized ceramic or metal powder) of at least 45 vol% has to be prepared. The addition of suitable thermal initiators allows the solidification of the composite subsequently after mold filling in a molding tool equipped with microstructured mold inserts. The mold filling and hence the accurate reproduction of surface details depend strongly on the composite’s viscosity, which is a function of the filler load. The further process stages like debinding and sintering have to be optimized with respect to the polymer based reactive resin used and the ceramic filler. Especially an improved process control of the composite formation prior to molding and the thermal debinding is crucial for the realization of ceramic or metal parts carrying a microstructured surface. The development of the whole process chain and some microstructured ceramic or metal parts will be presented.

E. Bouyer, P. Juliet
Laboratory for Innovation in Technology Energy and Nanomaterials (LITEN), CEA, Grenoble, France

Abstract

SMART is a Specific Support Action funded within the 6th Framework Programme of the European Union. The SMART-project aims to create a European map of excellence in materials science with special focus on multifunctional and highly sophisticated materials, and to identify trends and visions in the respective materials R&D for the next two decades. The SMART-process is a two folded approach consisting of a traditional forecast branch with data screening, trend extrapolation and roadmapping and an innovative foresight branch taking studies with economic, social and security focus into consideration.

The methodology used for this roadmap will be presented. Some key examples will be extracted from the three thematic topics which are focusing on “Materials powering Europe”, “Materials for a Better Life” and “Materials for a Safe Europe”. By crosschecking these three topics with the five materials main fields (smart materials, nanomaterials, tailored macroscale materials, bioconceptional materials and modelling for materials technology) it was found, that all fields of materials technology are addressed. For advancement in materials technology not only scientific bottlenecks have to be solved by addressing them in European research strategies but non technical problems have to be addressed as well.

T. Hanemann(a)(b), R. Heldele(a)(b), J. Haußelt(a)(b)
a: Forschungszentrum Karlsruhe, Institut f. Materialforschung III, 76021 Karlsruhe, Germany
b: Albert-Ludwigs-Universität Freiburg, Institut f. Mikrosystemtechnik (IMTEK), 79110 Freiburg, Germany

Abstract

With respect to polymer-filler composite (feedstock) development for the different variants of powder injection molding the use of dispersants or surfactants is essential for a large filler load and a homogenous feedstock quality. In this paper the influence of a series of citrate derived dispersants on the viscosity of feedstock systems with different binder composition and ceramic fillers will be described. Citrates posses four polar functionalities, which can interact with the hydroxy-groups at the alumina or zirconia surface. The investigated surfactants differ in the extension of the lipophilic end chains (ethyl or butyl) and in the presence of one free hydroxy group, which is masked partially by an acetic acid group. The impact of the dispersant concentration, molecular structure, dipole moment and the used binder composition will be discussed in terms of the resulting composite feedstock flow behaviour, some structure-property relationships can be found.

I. Markova – Deneva(a), K. Alexandrova, I. Dragieva
a: University of Chemical Technology and Metallurgy, Institute of Electrochemistry and Energy Systems-Bulgarian Academy of Sciences, Sofia, Bulgaria

Abstract

Cobalt (Co) nanoparticles and nanowires were synthesized at room temperature and atmospheric pressure by chemical reduction in aqueous solutions of Co salts with NaBH4. Two types of reactors were used ensuring various hydrodynamic conditions of mixing for both solutions (CoSO4.7H2O solution and NaBH4 solution). Co nanoparticles in amorphous state were synthesized using an ideal mixing conditions reactor (T-method), as well as Co nanoparticles with a crystalline structure in a reactor with an ideal displacement regime (A–method) were synthesized too. From the synthesized Co nanoparticles and micronized AlN powder (10-30 mass %) were prepared composites by pressing and sintering in the temperature range from 550 o to 750 oC for a potential application as getters or catalysts. Co nanowires were synthesized also by reduction in the presence of SiO2, SiMCM и AlMCM supports. The content of B, H2, and O2 by elemental analysis of nanoparticles and their specific surface area by the BET method were determined. Some physical-mechanical properties such as density and electro conductivity of samples of sintered amorphous and crystalline nanoparticles and their composites with micronized AlN powder heat treated in 200 o to 850 oC range were measured. IR spectroscopic studies of Co nanoparticles and their AlN composites were carried out by FTIR in 4000 to 400 cm-1 frequency range, as well as SEM micrographs of the Co nanowires were made which allow determining their diameters.