Gradient materials prepared by powder metallurgy from micro and nano powders


Project start:02.05.2006
Project end:30.04.2009
Programme:APVV
Project number:APVV-20-057805
Institute position in the project:Partner
Project leader at the institute:Jaroslav Kováčik
The project solved the problems that are currently the main field of interest of various research laboratories all over the world. Gradient materials are materials systems that can employ during their applications all material and energy inputs necessary for their preparation.

The main goal of the project was preparation of gradient materials using powder metallurgy from micro and nano powders. Basically, the composite gradient materials were prepared, epecially particulate composite gradient materials. The main characteristics of the project is the fact, that the used embended particles inside the matrix are below 1micron. It means that they can also be a systems of nano size. In the case of nanosize it is necessary to use a special method of preparation to achieve synergic effect on the final properties of given material system.

The project solved the problems concerning the preparation of Cu-C system. In this case the embended phase C was in the form of graphite particle, copper coated graphite and multiwalled carbon nano tubes CMWNTs.

Hot isostatic pressing method was used to prepare gradient Cu-graphite material with stepwise gradient and a sample Cu- MWCNTs (ds= 20-50nm). Further electrophoretic deposition was used to prepare following gradient systems Cu-SiC  (ds= 3micron), Cu-alpha Al2O3 (ds= 150nm), Cu-MWCNTs (ds= 20-50nm) and Cu-MWCNTs– SiC. The homogeneity of the space distribution of micro nad nano phase was investigated. On the basis of experimental results of physical properties of Cu-C system a models describing their composition dependence on the basis of percolation theory and general effective medium theory were created. Using these  models it is possible to predict effective properties not only for Cu-C system, but also for simillar systems such as Au-C, Ag-C, or generally Metal (or other electrically conductive or non conductive material) – C of until now not physically prepared systems.

The obtained results will be used in the field of basic research and also in the field of applied research of new materials for industrial applications.
 
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