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- Multifunctional Advanced Ceramics for Aeronautical and Aerospace Applications: Study of MgO Al2O3, MgO CaZrO3, and YSZ Ceramic CompositesPublication . Shvydyuk, Kateryna Oleksandrivna; Silva, Abílio Manuel Pereira da; Pereira, João Pedro Nunes; Rodrigues, Frederico Miguel FreireThe premise that materials permeate all aspects of our day-a-day lives is well established. The relentless pursuit for increased performance in aeronautical and aerospace industries over the last decades has provided a solid driving force for the study, research, and investigation of advanced ceramics for numerous future investments. The advanced ceramics field is believed to be an enabling technology with the potential to deliver high-value contributions for meeting both future needs and challenges. Moreover, the advanced ceramics industry is quite distinctive due to its high diversity and interdisciplinary nature that encompasses an engaging number of different processing methodologies and a variety of applications. In this sense, this dissertation project focused to perform an extensive and comprehensive literature review research, in addition to further selection, fabrication, testing, and analysis of MgO Al2O3 , MgO CaZrO3 , and YSZ ceramic materials which are intended to satisfy the condition of advanced multifunctional ceramic in the aeronautical and aerospace fields. Within this framework of thought, thermal protection systems, thermal barrier coatings, and dielectric barrier discharge plasma actuator applications were perceived and adopted as a jumping-off point. A step–by–step approach was adopted for the experimental procedure. More precisely, initially, ceramic compositeMgO Al2O3 , MgO CaZrO3 , and YSZ samples were manufactured through a four stages process, i.e., material preparation, processing, sintering, and finishing. After the rectangular plates, bars, and disc specimens were obtained for the three referred compositions, the in-depth study under the microstructural, physical, mechanical, thermal, and electrical characterization followed. Ultimately, many fine ceramics are multifunctional and therefore predestined to solve the forthcoming technological and engineering challenges. It is believed that ceramics offer an enormous potential to be exploited with the knowledge of material science, i.e., through correlations between microstructural, physical, mechanical, thermal, and electrical features.
- Multifunctional Ceramics for Aeronautical and Aerospace ApplicationsPublication . Shvydyuk, Kateryna; Nunes-Pereira, João; Rodrigues, Frederico; Pascoa, Jose; Lanceros-Mendez, Senentxu; Pereira Silva, AIn the areas of aeronautics and aerospace, ceramic composites play an essential and increasing role due to their superior performance and tailorable properties, exhibiting highly specialized mechanical, thermal, and electric features1. Their main applications include thermal protection systems (TPS), thermal barrier coatings (TBC), and dielectric barrier discharge (DBD) plasma actuators, both for instrumentation and control purposes2. This work reports the manufacture and characterization of three ceramic composites capable of fulfilling the multifunctional ceramic condition according to the aforementioned applications. Accordingly, MgO-Al2O3 (MA), MgOCaZrO3 (MCZ), and Y2O3 stabilized ZrO2 (YSZ) are introduced for TPS, TBC, and DBD dielectric elements. To this aim, MA, MCZ, and YSZ ceramic composites were fabricated via a sequential process, encompassing the selection of raw powders and milling, die pressing, and sintering. Further, the samples were polished for surface optimization. Overall, the results obtained, including mechanical (Young’s and shear moduli, flexural strength, hardness, and fracture toughness), thermal (thermal conductivity and thermal expansion (CTE)), and electrical (dielectric constant) properties, report evidence that the developed ceramics show suitable multifunctional characteristics and therefore fulfil the aeronautical and aerospace demands for increased materials performances. The combined analysis of the Young’s and shear moduli (Fig.1a) with the CTE – the latter over a wide range of temperatures (Fig. 1b) – allows concluding that the cost-effective and widely used alumina appears suitable for bulk monolithic (TPS) and joint applications (TPS, TBC, and DBD).
- Plasma Actuators Based on Alumina Ceramics for Active Flow Control ApplicationsPublication . Rodrigues, Frederico; Shvydyuk, Kateryna; Nunes-Pereira, João; Pascoa, Jose; Silva, AbilioPlasma actuators have demonstrated great potential for active flow control applications, including boundary layer control, flow separation delay, turbulence control, and aircraft noise reduction. In particular, the material used as a dielectric barrier is crucial for the proper operation of the device. Currently, the variety of dielectrics reported in the literature is still quite restricted to polymers including Kapton, Teflon, poly(methyl methacrylate) (PMMA), Cirlex, polyisobutylene (PIB) rubber, or polystyrene. Nevertheless, several studies have highlighted the fragilities of polymeric dielectric layers when actuators operate at significantly high-voltage and -frequency levels or for long periods. In the current study, we propose the use of alumina-based ceramic composites as alternative materials for plasma actuator dielectric layers. The alumina composite samples were fabricated and characterized in terms of microstructure, electrical parameters, and plasma-induced flow velocity and compared with a conventional Kapton-based actuator. It was concluded that alumina-based dielectrics are suitable materials for plasma actuator applications, being able to generate plasma-induced flow velocities of approximately 4.5 m/s. In addition, it was verified that alumina-based ceramic actuators can provide similar fluid mechanical efficiencies to Kapton actuators. Furthermore, the ceramic dielectrics present additional characteristics, such as high-temperature resistance, which are not encompassed by conventional Kapton actuators, which makes them suitable for high-temperature applications such as turbine blade film cooling enhancement and plasma-assisted combustion. The high porosity of the ceramic results in lower plasma-induced flow velocity and lower fluid mechanical efficiency, but by minimizing the porosity, the fluid mechanical efficiency is increased.
- Long-lasting ceramic composites for surface dielectric barrier discharge plasma actuatorsPublication . Shvydyuk, Kateryna; Rodrigues, F.F.; Nunes-Pereira, João; Pascoa, José; Lanceros-Mendez, Senentxu; Silva, A PereiraThe developed research presents a novel experimental study of the cost-effective MgO-Al2O3, MgO-CaZrO3 perovskite, and thermally stable YSZ ceramic composites for DBD plasma actuators in aerospace applications. This study focuses on the implementation of ceramic DBD plasma actuators for aerodynamic flow control and ice creation mitigation. For this purpose, electrical power consumption analysis, induced flow velocities assessment, and mechanical and thermal characterization were performed. MgO-Al2O3 presented higher induced velocities than its zirconia-based counterparts of up to 3.3 m/s, and lower heat dissipation, achieving a ceiling temperature of 46 ºC, being thereby the best-suited candidate for active flow control mechanisms. In contrast, YSZ had very high-power consumption translated into a maximum surface temperature of 155.4 ºC, establishing itself for ice mitigation. This extensive research evinces that the strategic combination of the developed ceramics’ thermomechanical, thermoelectric, and electromechanical properties allows them to be a promising breakthrough material for DBD plasma actuators.
- Review of Ceramic Composites in Aeronautics and Aerospace: A Multifunctional Approach for TPS, TBC and DBD ApplicationsPublication . Shvydyuk, Kateryna O.; Nunes-Pereira, João; Rodrigues, Frederico Miguel Freire; Silva, AbilioThe quest for increased performance in the aeronautical and aerospace industries has provided the driving force and motivation for the research, investigation, and development of advanced ceramics. Special emphasis is therefore attributed to the ability of fine ceramics to fulfill an attractive, extreme, and distinguishing combination of application requirements. This is impelled by ensuring a suitable arrangement of thermomechanical, thermoelectric, and electromechanical properties. As a result, the reliability, durability, and useful lifetime extension of a critical structure or system are expected. In this context, engineered ceramic appliances consist of three main purposes in aeronautical and aerospace fields: thermal protection systems (TPS), thermal protection barriers (TBC), and dielectric barrier discharge (DBD) plasma actuators. Consequently, this research provides an extensive discussion and review of the referred applications, i.e., TPS, TBC, and DBD, and discusses the concept of multifunctional advanced ceramics for future engineering needs and perspectives.