Presentation

This project is focused on preparing new Metal-Ceramic matirials using colloidal processing in order to disperse ceramic particules in a metal matrix.
Two materials have been selected to develop two different research lines. The common objective is to improve their properties through control of the metal-ceramic microstructure.

1) Fe-based Cermets: Steel (Fe-Cr) matrix composites with 50 vol % of TiCN particles as reinforcement (minimum). The colloidal chemistry of suspensions will be used to obtain homogeneous blending of powders, which, after granulation, will be processed by conventional powder-metallurgical (PM) techniques or by metal injection molding (MIM).

2) Ti-based materials: composite materials Ti/Al2O3, in which the ceramic phase Al2O3 is added in low quantity (1 -10 vol. %, in contrast to the Fe-based system). There is a double objective for this system. On one hand, dealing with the manufacturing of bulk materials by conventional PM and colloid-chemical NNS techniques. In this case, the objective is to control the grain growth by the homogeneous distribution of nanosized and sub-micron ceramic particles into the Ti matrix. This task will be tackled by designing a composite powder Al2O3/Ti which can be processed by PM and colloid-chemical techniques. Changes in pH, ionic concentration or binders will be used to vary surface potentials and to obtain different arrangements of the powders that form the suspensions: granules constituted by a homogeneous dispersion of the components, or core-shell structures, where bigger size particles are surrounded by small size particles. On the other hand,the synthesis of metallic powder is proposed, covering ceramic particles and creating core-shell structures. Those materials can be dispersed in a metallic matrix and processed by pressing, as the metallic shell will contribute to the deformation ability to reach high green density.

Within the Ti-based system, the development of multilayered structures, as well as ceramic coatings on metal-ceramic substrates is considered. This will be done by application of colloidal techniques available and commonly used at the ICV laboratory. The aim of these materials is to improve the mechanical behaviour by metal-ceramic interactions. The metal contributes with ductility and toughness, whereas the ceramic phase contributes with dimensional stability, refractoriness, and wear resistance. It is suggested the use of coatings formed by Al2O3 and TiAl2O5 multilayers based on their good mechanical properties and chemical compatibility with the Ti-based system.

The last objective for this system is the functionalization of Ti surface. The aim is to explore new materials design
routes by the electro-conducted assembly of ordered structures on the metallic surface. On one hand a system with Osseointegration, like the coating of Ti substrates with HAp is suggested. On the other hand,the arrangement of ZnO nanoparticles in film shape will be studied. As for this material in particular, the design of ordered micro- and nanosized ordered systems will determine its properties for a wide range of applications.