Multifunctional Ceramic/Graphene Thick Coatings for New Emerging Applications
Materials in Sintering Processes and Generative Manufacturing Processes
Final Report Abstract
The project aims to develop novel conductive layered systems and coatings based on ceramic/graphene nanocomposites with low-cost manufracture process. This project consists of several technical goals: (1) Development of non-oxide ceramic (Si3N4, SiC)/graphene multi-layered systems and coatings and large-scale graphene powder synthesis that is suitable as additives to ceramics, (2) development and optimization of low-cost sintering processes, (3) characterization and optimization of properties, (4) building 3D model of the material system, (5) evaluation of functional properties with respect to possible applications. This project was was carried out by 3 partners from Hungary, Slovakia and Germany, with regular exchange of information and samples. Hungary team contributed mainly for developing Si3N4/graphene multi-layered system, Slovakia team contributed mainly for developing SiC/graphene multi-layered system, German team contributed mainly for novel characteriaztion methodology develeopment. In this project, non-oxide ceramic (Si3N4, SiC)/graphene multi-layered systems (sandwich structure) were developed using HIP and rapid hot pressing. In particular, the layerd systems (Si3N4/graphene sandwich structure, up to 7 layers) with very high graphene content (up to 30 wt.%) were successfully produced. Large scale graphene powder synthesis suitable as additives to non-oxide ceramics (Si3N4, SiC) were proven to be feasible. The developed manufacturing procedures are low-cost and can be scaled up for producing large scale non-oxide ceramic/graphene coating with multiple layers. Although the sandwich Si3N4/graphene composite using 5 wt.% MLG in the outmost layer can enhance the mechanical property, the low strength of the final sandwich composite is still not encouraging. Scratch test was used to gain a fundamental understanding material removal mechanisms and damage morphology in the ceramic nanocomposite and revealed that graphene platelets seem to be integrated into the matrix very strongly and they do not participate in lubricating processes. Vickers indentation results showed no classical radial cracks occur in the porous Si3N4/MLG composites, which indicating the potential resistance to contact or indentation damage due to the redistributed stress caused by high porosity and shear-weak second phase (MLG). Thermal diffusivities of the 5-layered SiC/GNP composites were slightly lower compared to those measured for the 3-layered composites at RT, due to the higher number of defects at the SiC-GNP interfaces and at the boundaries between the layers. The lower electrical conductivity of the 5-layered composites was caused by the presence of the layers with lower intrinsic electrical conductivities (S5GNP and SiC). The final materials exhibited a sufficient electrical conductivity (600-870 S/m) for elelctrical discharge machining (EDM). Besides, detailed microstructural and compositional information of the sintered complex composite system regarding morphology, type of components, homogeneity of components, oxidation level of graphene, porosity was comprehensively provided using multi-scale microscopic studies, the influence of the various content of the graphene on the structural properties was learnt. In-depth understanding of the mechanical behavior and the fracture mechanism of sintered composites was gained using in-situ wedge indentation tests inside TEM. Multi-scale and in-situ microscopy as a combined unique methodology developed in this project can also be extended to understand the microstructure and mechanical behavior correlation for other complex ceramic systems. Square pillar compression test was developed to understand the fracture behavior, and to reveal the potential to improve the brittle failure of ceramic composite while maintaining sound strength. Complex 3D models for the composites were built by GeoDict software using quantitative data analysed from multi-scale microscopic data. It shows the potential to predict the property and the 3D model could also be refined by comparing the simulated property and the one acquired from experiments. The results for fundamental understanding in this project have generated 5 publications in peer-reviewed journals so far, more manuscripts are in preparation. The generated fundamental knowledge can be used in the future to further develop novel non-oxide ceramic matrix composites with very high graphene content, for instance, porous ceramic composites, multi-layered coating.
Publications
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Examination of milled h-BN addition on sintered Si3N4/h-BN ceramic composites. Processing and Application of Ceramics, 12(4), 357-365.
Balázsi, Katalin; Furko, Mónika; Fogarassy, Zsolt & Balázsi, Csaba
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An economic and facile method for graphene oxide preparation from graphite powder. Resolution and Discovery, 4(1), 21-25.
Furko, Monika; Fogarassy, Zsolt; Balázsi, Katalin & Balázsi, Csaba
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Graphene added multilayer ceramic sandwich (GMCS) composites: Structure, preparation and properties. Journal of the European Ceramic Society, 40(14), 4792-4798.
Balázsi, K.; Furkó, M.; Liao, Z.; Fogarassy, Zs.; Medved, D.; Zschech, E.; Dusza, J. & Balázsi, C.
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Porous sandwich ceramic of layered silicon nitride-zirconia composite with various multilayered graphene content. Journal of Alloys and Compounds, 832, 154984.
Balázsi, K.; Furkó, M.; Liao, Z.; Gluch, J.; Medved, D.; Sedlák, R.; Dusza, J.; Zschech, E. & Balázsi, C.
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Microstructure and Fracture Mechanism Investigation of Porous Silicon Nitride–Zirconia–Graphene Composite Using Multi-Scale and In-Situ Microscopy. Nanomaterials, 11(2), 285.
Liao, Zhongquan; Standke, Yvonne; Gluch, Jürgen; Balázsi, Katalin; Pathak, Onkar; Höhn, Sören; Herrmann, Mathias; Werner, Stephan; Dusza, Ján; Balázsi, Csaba & Zschech, Ehrenfried
