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| JoinHEC – Vývoj nových metód spájania vysoko-entropických keramických materiálov | |
| Development of new joining methods for high entropy ceramics | |
| Program: | Bilateral – other |
| Project leader: | Ing. Tatarko Peter, PhD. |
| Annotation: | The main aim of the proposed project is to develop new joining techniques for high entropy ceramics (HEC) in order to improve the operational limits of the joints for aerospace applications. The project proposes an innovative way of manufacturing of HEC joints with potentially improved high temperature properties, using a direct solid-state diffusion bonding (without an interlayer) or diffusion bonding with refractory metal interlayers. For the first time, refractory high entropy alloys (HEA) will be used as the joining interlayers between a pair of HEC, or as the interlayer for joining of HEC to ceramic matrix composites (CMCs). The project aims to generate new fundamental knowledge on the understanding of the effect of electric field and surface preparation on the direct diffusion bonding of HEC, as well as the interfacial physico-chemical phenomena occurring at the HEC/HEA and HEA/CMCs interfaces. The mechanical performance of the joints at room and high temperatures will be investigated to define the operational limits of the joints. The project will provide a comprehensive insight on the joining of high entropy ceramics for potential aerospace applications. This may significantly expand the application potential of the recently developed next generation ultra-high temperature ceramics, i.e. high entropy ceramics. |
| Duration: | 1.7.2022 – 30.6.2025 |
National
| NEOCAR – Ultra-vysokoteplotné karbidy so zvýšenou oxidačnou odolnosťou | |
| Novel enhanced oxidation-resistant ultra-high temperature carbides | |
| Program: | SRDA |
| Project leader: | Ing. Tatarko Peter, PhD. |
| Annotation: | The improvement of oxidation resistance of ultra-high temperature ceramics (UHTCs) has critical importance in meeting the growing need for applications used at temperatures exceeding 2000 °C in oxidizing atmospheres such as hypersonic vehicles and spacecraft. Recently, with the aid of the exploration of multi-principal element ceramics, consisting of four or more different cations or anions stabilized by the configurational entropy, a vast new compositional space has opened up to develop novel UHTCs with enhanced oxidation resistance. However, to design such materials through the prediction of their complex oxidation processes, it is fundamental to establish a comprehensive understanding of the mono and binary transitional metal carbides that is targeted in the present project, something that is currently missing. Thus, the main aim of the project is to develop novel oxidation-resistant UHTCs through a systematic experimental based study in which the high-temperature properties (oxidation/ablation resistance, thermal shock resistance etc.) and mechanical behaviour of mono and binary refractory carbides will be studied. Different secondary phase materials with the incorporation of silicon will also be tested in the form of SiC and transitional metal silicides, which are known as protective glassy phase-forming compounds that can further improve the oxidation resistance of newly developed UHTCs. In addition to the understanding of the oxidation and mechanical behaviour of these ceramics and composites, the prediction of the models established will be validated by the synthesis of new oxidation-resistant 3-, 4- and 5-metal carbide systems that will be also tested experimentally. The accomplishment of the present project will generate fundamental knowledge that is needed for the design of novel more complex multi-principal element ceramics. Filling this lack of knowledge would be of great importance for whole materials science community. |
| Duration: | 1.7.2022 – 30.6.2027 |
| ComCer – Vývoj nových keramických materiálov komplexného zloženia pre extrémne aplikácie | |
| Development of new compositionally-complex ceramics for extreme applications | |
| Program: | SRDA |
| Project leader: | Ing. Tatarko Peter, PhD. |
| Annotation: | The main aim of the proposed project is to develop next generation ultra-high temperature ceramics capable of withstanding temperatures up to 3000°C for propulsion systems, rocket engines and other aerospace applications. This will be achieved by the synthesis of diboride ceramics with unique compositionally -complex structures, comprising of at least five metal elements. A systematic study will be conducted to generate new knowledge on the understanding of the effect of various molar ratios of individual metal cations in diboride structures on the stability, synthesis, sintering and mechanical properties of bulk diboride ceramics. The results will significantly contribute to the expansion of the high entropy ceramics concept with equimolar compositions towards the development of compositionally-complex ceramics with non-equimolar compositions. The project also proposes an innovative way of manufacturing ultra-high temperature ceramics, consisting of the development of ceramic composites based on the high-entropy and compositionally-complex diboride matrix, reinforced with the refractory additives. The output of the project will be new fundamental knowledge on the formation of disordered diboride structures, and their effect on mechanical properties of the materials at room, intermediate, and ultra-high temperatures. |
| Duration: | 1.7.2022 – 30.6.2026 |
| In-situ tvorba bioaktívneho funkčne gradientného nitridu kremičitého počas spekania v elektrickom poli | |
| The in-situ formation of bioactive functionally graded silicon nitride by field assisted sintering | |
| Program: | VEGA |
| Project leader: | Mgr. Tatarková Monika, PhD. |
| Annotation: | This project proposes an innovative approach to develop new type of functionally graded Si3N4 bioceramics, consisting of electric field assisted sintering and post-sintering oxyacetylene flame treatment. Different experimental set-ups for field assisted sintering will be investigated in order to maximize a directional effect of electric current on the migration of bioactive additives towards one surface of the material. This will lead to the in-situ formation of a continuous graded Si3N4 biomaterials from a homogenous powder mixture. The bioactivity of the materials will be further improved by the flame treatment, forming a porous layer with bioactive additives. For the first time, the proposed approach will ensure the in-situ formation of a continuous graded structure without any distinct interfaces, typical of layered ceramics, which often act as stress concentrators. The effect of gradient structure on the mechanical and biological properties of novel functionally graded Si3N4 will be investigated. |
| Duration: | 1.1.2022 – 31.12.2024 |