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Metal reinforced ceramics are willingly used in many industries, for example as anti-corrosion covers, construction material in nuclear power plants or cutting tools with increased durability. The outstanding properties of these materials cause a high interest in ceramic-metal composites. Metals are capable of plastic deformation, which is why even a small addition of metallic particles can significantly improve the mechanical properties of single-phase ceramics, such as fracture toughness while maintaining the key advantages of ceramics, for example, resistance to high temperatures and aggressive chemical environment as well as high hardness. Manufacturing of composites with the use of metallic powders has some disadvantages. For example, micron-size metallic particles prevent the preparation of nanocomposites, whereas the use of metallic nanopowders requires special conditions for storage and handling. A good solution to overcome these problems is a replacement of the metallic powders with suitable precursors. 

My research aims to obtain ceramic-metal nanocomposites in which the matrix is alumina or zirconia. The metallic phase is molybdenum or nickel, introduced into ceramic dispersions in the form of salts - molybdenyl or nickel acetylacetonates. These compounds decompose into metallic nanoparticles during the sintering process in an Ar/H2 reducing atmosphere. In the fabrication of composites, I use traditional methods of colloidal processing (slip casting, gelcasting, tape casting) as well as additive manufacturing techniques (e.g. DLP – Digital Light Processing, DIW – Direct Ink Writing).

During the research, attention is paid to ensure that appropriate rheological properties characterise the colloidal suspensions. That’s why I focus on finding proper organic additives, such as dispersing agents, photoinitiators, organic monomers, solvents and polymeric binders. The research also includes reagents characterization (thermal analysis of substrates using thermogravimetry coupled with mass spectroscopy, density and specific surface area measurements and morphology analysis) as well as suspensions stability tests. After shaping, sintering parameters are selected to obtain materials with the highest possible densification, avoiding the oxidation of the metallic phase. The characterization of the composites includes Vickers’ hardness and fracture toughness tests, mechanical strength measurements, microstructure analysis using SEM with EDS detector and XRD measurements.

If you are interested in this topic, don’t hesitate to contact me. I would be pleased to answer all your questions.

Joanna Tanska, PhD Student

Warsaw University of Technology

Faculty of Chemistry

Department of Chemical Technology

Advanced Ceramics Group

joanna.tanska.dokt@pw.edu.pl

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