Research project SU/03 (Research action SU)
Coordinator: Prof. R. DE BATIST.
1. Objectives
The project comes from a group of eight laboratories specialised in materials science and engineering. It is based on the extensive expertise gained by the partners in the field of superconductivity and in various manufacturing techniques as well as in microstructural analysis and the study of physical properties of materials. The project is construed along three strongly interlinked orientations.
The first orientation involves empirically optimising the processes used to produce precursor materials suitable for making ceramic superconductors of various compositions (YBaCuO, BiSrCaCuO, TIBaCaCuO). It will also involve exploring promising variants of new materials. Specimens of various well-specified materials will be prepared.
Synthesis techniques will be studied by thermal analysis of reaction products, the main emphasis being on wet chemical techniques. Powder-metallurgical methods will be used for pretreatment and production of precursors. Special attention will focus on controlling the particle size distribution and morphology during powder synthesis.
The second orientation involves exploratory research into shaping techniques for both bulk conductors (mono- or multifilament wires or tapes) and layered structures, for electrotechnica1 and electronic applications respectively. Without excluding other compounds, the main focus will be YBaCuO and, possibly, Bi compounds. Thin films will be produced by metal-organic chemical vapour deposition and reactive sputtering. Thick films and bulk conductors will be produced by various techniques, including plasma deposition, rolling, tape casting, extrusion, etc.
The third orientation involves characterising superconducting ceramic materials, with a view not only to increasing basic understanding of their properties but also to determining and optimising those functional characteristics (critical parameters) which are essential to eventual technological applications. Partners will make extensive use of various experimental techniques including thermal, chemical, structural, electrical, magnetic analysis techniques.
2. Coordinated research programme
A Optimisation and control of production processes for precursors and samples of well-specified materials :
1. powder metallurgy ;
2. wet chemical techniques:
a. aerosol formation ;
b. oxalate precipitation
c. sol-gel method ;
3. thermodynamic analysis.
B. Thin-film production :
1. magnetron sputtering using an electron cyclotron resonance
2. metal-organic chemical vapour deposition.
C. Thick film and bulk material production :
1. plasma deposition ;
2. tape casting, rolling, extrusion
a. YBaCuO ;
b. Bi compounds.
D. Characterision of the materials' basic properties :
1. microstructural analysis (TEM)
2. mechanical damping ;
3. thermoelectric properties, thermal conductivity.
E. Support for precursor preparation and for the making of films and bulk conductors:
1. powder characterisation;
2. thermal analysis ;
3. chemical analysis;
4. surface, interface and structural analysis;
5. mechanical properties.
F. Functional characterisation :
1. resistivity, magnetisation ;
2. critical current (ac, dc) (as a function of temperature, magnetic field and mechanical stress).
The various research lines are strongly interlinked. A schematic representation of the interconnections between the research lines is given below.
A. Optimisation of synthesis methods and production of specific superconducting materials. Current activity whose objectives will be continuously adapted to the needs of the partners and the evolution of knowledge.
B, C. Evaluation of shaping techniques.
Bl. Sputtering: optimisation of the process parameters according to the substrate and buffer layer. After two years of exploratory research, application to sandwich structures and semiconducting substrates.
B2. MOCVD: mounting the installation, choosing the initial materials, choosing the initial materials and investigating the process parameters. After two years, optimisation of the process implementation for the most suitable initial materials.
C. Bulk conductors (wires and/or tapes).Investigation of the materials and process parameters. After two years, optimisation of the process implementation in order to improve the operating characteristics.
Moreover, several quantitative objectives (current density, dimension, etc) will be defined after two years.
D,E, F. Characterisation. Current activity, in constant interaction with the other research lines.
