Dielectric Applications Research Articles

Sintering‐resistant porous BaZrO3 ceramics using a particle‐stabilized foam method for thermal insulation applications

AbstractSintering and phase transitions of materials in current large‐area thermal insulation systems are critical problems for hypersonic vehicles. Searching for thermal insulation materials with good structure stability, thermal stability, and superior insulation performance is urgent for the development of these vehicles. Herein, we reported a novel porous BaZrO3 ceramic fabricated by a particle‐stabilized foam method. By controlling the sintering temperature, the porosity (92.96%–94.62%), thermal conductivity (0.088–0.193 W/(m·K)), and strength (0.30–1.31 MPa) of the porous ceramics are tunable. Most importantly, these porous BaZrO3 ceramics exhibit excellent sintering resistance. After being heat treated at 1300°C for 6 h, the shrinkage of porous BaZrO3 ceramics is nearly 0. The shrinkage of the samples heat‐treated even at 1600°C is still lower than 3%, demonstrating outstanding high‐temperature structure stability. Our results demonstrate that porous BaZrO3 ceramics are promising candidates for high‐temperature thermal insulation applications.

Enhanced Thermal Safety of Hydrophobic SiO2 Aerogels Through Introduction of Layered Double Oxides.

This research enhances the thermal safety of hydrophobic silica aerogel (HSA) by integrating layered double oxides (LDOs). XRD and FTIR confirm that the introduction of LDOs does not affect the formation of SA. The LDO/SA composites demonstrate a low density (0.14-0.16 g/cm3), low thermal conductivity (23.28-28.72 mW/(m·K)), high porosity (93.4-96.1%), and a high surface area (899.2-1006.4 m2/g). The TG-DSC results reveal that LDO/SA shows enhanced thermal stability, with increases of 49 °C in the decomposition onset temperature and 47.4 °C in the peak decomposition temperature. The gross calorific value of LDO/SA-15% (with 15 wt% LDO) exhibits a 23.9% reduction in comparison to that of pure SA. The decrease in gross calorific value, along with improved thermal stability, indicates a boost in the thermal safety characteristics of the LDO/SA composites. This study demonstrates that incorporating LDOs enhances the thermal safety of HSA, while preserving its superior performance, thus broadening its potential applications in thermal insulation.

Boosting High Electric Breakdown Strength for Excellent Energy Storage Performance in Bi0.5Na0.5TiO3-Based Lead-Free Ceramics via a High Entropy Strategy.

High-performance dielectric capacitors featuring large recoverable energy storage density (Wrec) and high discharge efficiency (η) are beneficial to realize the device miniaturization, lightweight property, and sustainability of advanced pulse power systems. The obtainment of a high electric breakdown strength (Eb) is crucial for improving the energy storage performance of dielectric materials. However, as for Bi0.5Na0.5TiO3 (BNT) lead-free relaxor ferroelectric ceramics, the relatively lower Eb directly limits their electrical performance improvement and practical applications. Herein, a popular high entropy strategy was employed to rationally design and prepare the (Bi0.5Na0.5)x(Sr0.25Ba0.25La0.25K0.25)(1-x)TiO3 (BNSLBKT-x) lead-free relaxor ferroelectric ceramics based on the BNT matrix. Encouragingly, the BNSLBKT-0.2 high-entropy ceramic exhibits a high Eb of 510 kV/cm, and this can be ascribed to the refined grains and enhanced activation energy. Moreover, it is confirmed that the polar nanoregions (PNRs) exist in the BNSLBKT-0.2 ceramic by the piezoresponse force microscopy (PFM) and transmission electron microscopy (TEM) characteristics, further strengthening relaxation behaviors and decreasing remanent polarization (Pr). It is anticipated that a high Wrec of 4.6 J/cm3 and a good η of 86% are obtained in this BNSLBKT-0.2 high-entropy ceramic. More importantly, the BNSLBKT-0.2 ceramic displays excellent frequency stability of capacitive energy storage at 10-1000 Hz and good temperature stability at 20-140 °C. The fast discharge rate (τ0.9 = 0.26 μs) and the high PD of 49.2 MW/cm are also achieved in this BNSLBKT-0.2 ceramic. The findings demonstrate that this high entropy design is an effective strategy for developing dielectrics with excellent energy storage capability to meet the requirements of modern dielectric capacitor applications.

Effects of Copper-Modified Activated Carbon on Natural Rubber Composite for Dielectric Materials

This study reports the development of an elastomeric dielectric material based on natural rubber (NR) composites reinforced with copper-modified activated carbon (Cu-Ac) derived from coconut shells. The Cu-Ac content was varied systematically (0, 5, 10, and 15 phr) at a fixed Cu concentration (2 wt%). The investigation focused on the influence of Cu-Ac content on various material properties, including curing time (tc⁹⁰), density, crosslink density, mechanical behavior, morphology, and dielectric response. The results revealed a significant impact of Cu-Ac content on the curing process, with an observed decrease in tc90 at higher Cu-Ac loadings (10 and 15 phr). However, crosslink density exhibited a decreasing trend with increasing Cu-Ac content. Encouragingly, the inclusion of Cu-Ac demonstrated a positive influence on the mechanical properties of the composite. Notably, the dielectric properties confirmed the effect of Cu-Ac on NR, with enhancements observed within the frequency range of 1.35 to 2.03 GHz. This study provides valuable insights into the influence of Cu-Ac content on NR composites, suggesting their potential for improved performance in dielectric applications.

Geopolymer Foam with Low Thermal Conductivity Based on Industrial Waste.

Geopolymer materials are increasingly being considered as an alternative to environmentally damaging concrete based on Portland cement. The presented work analyzed waste from mines and waste incineration plants as potential precursors for producing geopolymer materials that could be used to make lightweight foamed geopolymers for insulation applications. The chemical and phase composition, radioactivity properties, and leachability of selected precursors were analyzed. Then, geopolymer materials were produced, and their strength properties were examined through compression and flexural tests. The results of the strength tests guided the material selection for foamed geopolymer materials. Next, geopolymer foams were foamed with hydrogen peroxide and aluminum powder. The produced foamed materials were subjected to strength and thermal conductivity tests. The results demonstrated the great potential of mine waste in the synthesis of geopolymers and the production of lightweight geopolymer foams with good insulating properties.

Ultra-High Capacitive Energy Storage Density at 150°C Achieved in Polyetherimide Composite Films by Filler and Structure Design.

Polymer dielectrics are crucial for electronic communications and industrial applications due to their high breakdown field strength (Eb), fast charge/discharge speed, and temperature stability. The upcoming electronic-electrical systems pose a significant challenge, necessitating polymeric dielectrics to exhibit exceptional thermal stability and energy storage capabilities at high temperatures. Here, ultra-high dielectric constant (ɛr) and charge/discharge efficiency (η) of 0.55Bi0.5(Na0.84K0.16)0.5TiO3-0.45(Bi0.1Sr0.85)TiO3 (BNKT-BST) ceramics are prepared by the solid-phase reaction method and added to polyetherimide (PEI) to form BNKT-BST/PEI nanocomposites with various structures. The findings indicate that the sandwich-structured BNKT-BST/PEI nanocomposite achieves the highest discharged energy density (Ud) of 7.7 Jcm-3 with η of 80.2% when the Eb is 650 MVm-1 at 150°C. This is primarily due to the incorporation of BNKT-BST nanoparticles and the multilayer structure design, which significantly improves the composite's ɛr and Eb. Additionally, the sandwich-structured composites show excellent cycling stability at 500 MVm-1 and 150°C, with Ud of ≈ 4.7 Jcm-3 and η greater than 90%. The research presents nanocomposites with high energy storage density and excellent stability, crucial for the practical application of polymer dielectrics in high-temperature environments.

INFLUENCE OF BOUNDARY CONDINIONS ON THE PLASMA POTENTIAL IN A HELICON DISCHARGE WITH PLANAR ANTENNA

In a helicon discharge excited by a flat inductive antenna, situated at the discharge chamber end, distributions of plasma parameters have been measured by a thermo-emissive probe. The aim of the work was to define an influence producing by the bias potential of the surface being processed on plasma parameters in discharge chambers with either the dielectric or with conducting side walls. It was found that in the dielectric chamber application of a positive voltage and taking electron current to the surface under treatment causes increasing the plasma potential because the opposite sine current can not flow to the insulating wall. In the metal chamber increase of positive voltage on the surface leads to the discharge instability and break off for considerable taking electrons away from the discharge volume.

Partial discharge characteristics of syntactic foam filled with hollow polymer microspheres

AbstractSyntactic foam materials, due to their advantages of low densities, low water absorption, and high dielectric strengths, have significant application potential in the cores of post insulators. However, because of a large number of microbubble structures within the syntactic foam, it might decrease the partial discharge inception voltage. It is necessary to investigate the partial discharge characteristics of the foam to assess the feasibility of its internal insulation application. In this study, the syntactic foam samples with four different microsphere contents (0%–2%) were prepared, and the physical structures of the materials were characterised by using Fourier transform infrared spectroscopy, scanning electron microscopy, and three‐dimensional computed tomography. Subsequently, finite element simulations of the electric field were performed to analyse the influence of the microsphere content and distribution on the internal electric field of the syntactic foam. The results suggested that both the microsphere content and distribution affected the partial discharge activity. When the microsphere content was low, the doping of microspheres essentially meant that more air gap defects were present, leading to a decrease in the partial discharge performance. However, when the microsphere content was high, the microspheres were distributed in a dense and orderly manner, improving the field concentration phenomenon and hence inhibiting the partial discharge to a certain extent. In conclusion, the findings of this study provide a data reference and theoretical support for the application of syntactic foam in the cores of composite post insulators.

Humidity Resistant Biodegradable Starch Foams Reinforced with Polyvinyl Butyral (PVB) and Chitosan.

In this study, water-insoluble, moisture-resistant starch foams were prepared using an optimized one-step extrusion-foaming process in a ZSK-30 twin screw extruder. The extrusion parameters, including temperature, screw configuration, die diameter, water content, and feeding rates, were optimized to achieve foams with the lowest density and controlled expansion. A screw configuration made up of three kneading sections was found to be the most effective for better mixing and foaming. Polyvinyl butyral (PVB) acted as a plasticizer, resulting in foams with a density of 21 kg/m3 and an expansion ratio of 38.7, while chitosan served as a nucleating agent, reducing cell size and promoting a uniform cell size distribution. The addition of PVB and chitosan reduced the moisture sensitivity of the foams, rendering them hydrophobic and water-insoluble. The contact angle increased from 0° for control foams to 101.5° for foams containing 10% chitosan and 10% PVB. Confocal laser scanning microscopy (CLSM) confirmed the migration of chitosan to the foam surface, enhancing hydrophobicity. Aqueous biodegradation tests, conducted at 30 °C in accordance with ISO 14852 standards, demonstrated that despite enhanced moisture resistance, the foams remained readily biodegradable, achieving approximately 80% biodegradation within 80 days. These modified starch foams present a sustainable solution for packaging and insulation applications that demand long-term humidity resistance.

Ultralight and robust polyimide aerogels with tunable porous structures based on cation-π interactions for superior thermal insulation

Polyimide (PI) aerogels, renowned for their ultra-low density and exceptional porosity, exhibit substantial potential for thermal insulation applications. However, conventional freeze-drying method often produces irregular and large pore structures, which compromise the mechanical properties of PI aerogels and limit their practical applications. In this work, the enhanced PI-Cu aerogels by cation-π interactions are fabricated through the introduction of Cu ions and benzimidazole. The findings reveal that cation-π interactions facilitate the transformation of PI aerogels from two-dimensional layered structure to three-dimensional honeycomb structure characterized by smaller and more uniform pores, significantly reducing shrinkage and leading to ultra-light properties. Remarkably, a significant improvement of mechanical performance is also achieved after introducing cation-π interactions, even at a decreased density (0.046 g/cm3). Specifically, for samples with 3.5 wt% solid content, the yield strength and modulus of PI-Cu aerogels increase to 0.71 MPa and 13.58 MPa, respectively, representing improvements of 344 % and 520 % over pristine PI aerogels, which are superior to those of many other previously reported PI aerogels/foams with similar or even higher densities. Additionally, the toughness is significantly elevated from 13.5 MPa to 48.8 MPa. More importantly, after introducing cation-π interactions, the thermal insulation of PI-Cu aerogels are also improved with thermal conductivity decreasing from 0.04214 to 0.03997 W/m·K in axial direction and from 0.0399 to 0.03688 W/m·K in radial direction at 25°C. Interestingly, the thermal conductivity show only a slight increase under 180°C less than 0.05741 W/m·K in axial direction and 0.04923 W/m·K in radial direction owning to their exceptional thermal stability (Tg = 404 °C, T5%=524 °C). These exceptional properties position PI-Cu aerogels as promising candidates for diverse functional applications in the field of energy conservation.

UTILIZATION OF WASTE MATERIALS FOR ULTRA-LIGHTWEIGHT AND THERMAL INSULATING CONCRETE BLOCKS

This study investigates the feasibility of utilizing waste materials—specifically fly ash, residual fuel catalytic cracking catalyst (RFCC), and honeycomb briquette ash—in the production of ultra-lightweight concrete blocks for thermal insulation applications. Physical properties such as dry density, water absorption, and compressive strength were evaluated alongside thermal conductivity and microstructural analysis. Additionally, the materials' compliance with hazardous substance regulations and fire resistance were examined. Economic analysis demonstrated substantial cost savings compared to conventional materials. Results indicate that while higher cement replacement ratios with waste materials generally reduce compressive strength, they enhance thermal insulation properties. The study concludes that these materials offer a viable solution for sustainable building construction, aligning environmental benefits with economic advantages.

Understanding the dielectric properties of silicone rubber‐BN nanocomposites under DC voltage

AbstractThe present study explores the dielectric and structural properties of silicone rubber composites with low‐weight percentages of boron nitride (BN) fillers aimed at insulation applications. The incorporation of BN fillers into the silicone rubber matrix significantly enhances the glass transition temperature (Tg), melting temperature (Tm), and crystallization temperature (Tc). Notably, the dielectric constant increases while the loss factor remains minimal with a low concentration of BN fillers with silicone rubber matrix. J–V characteristics from space charge limited current (SCLC) measurements were employed to evaluate trap density. The addition of 3 wt% BN filler notably improves the crossover voltage and trap density in the silicone rubber matrix. A strong correlation has been observed between trap density values derived from SCLC measurements and surface potential decay experiments. Furthermore, the SCLC measurements at different temperatures exhibit an Arrhenius behavior, providing insights into the charge transport and trapping mechanisms. Overall, the experiment results indicate that the inclusion of 3 wt % of BN filler has significant improvement in dielectric as well as charge trap characteristics.Highlights BN filler impacts permittivity and tan (δ) based on concentration levels. Differential scanning calorimetry shows crystallinity changes with increased BN filler in silicone rubber. Surface potential relates to J–V characteristics, following SCLC mechanism. Arrhenius relation to temperature‐based SCLC shows thermally activated conduction. Trap density trends align in SCLC and surface potential decay methods.

Closed-loop recylcing of thermoset poly(vinylogous urethane) foams

Foams are an intriguing class of porous and lightweight materials which have found widespread applications in thermal insulation, pollutant adsorption, catalyst support, and energy storage. However, their covalently cross-linked structure makes foam unable to be recycled resulting in serious environmental burden. To address this challenge, we report the first example of closed-loop chemically recyclable foam. A simple, catalyst-free cryo-polymerization process with multifunctional amines and acetoacetates was utilized to successfully prepare a series of poly(vinylogous urethane) foams, containing dynamic covalent bonds which can selectively be cleaved on demand. The resulting foams exhibit macroporous structure with diameters exceeding 14 μm, pronounced thermal stability (Td,5% > 262.5 °C), robust hydrophobicity (WCA > 93°) and unique reactivity. Applications have been demonstrated for efficient adsorption of organic solvents and anionic dyes. More importantly, the foams show excellent recyclability under acidic conditions with high monomer recovery yields of up to 97 % and high purity levels. Fresh foams could be regenerated from the retrieved building blocks, thus demonstrating efficient closed-loop recycling. This work provides a new “monomer-foam-monomer” ecological chain and may inspire the advancement of next-generation closed-looped recyclable foam materials.

Preparation and Characterization of Waste Cotton Fabric Reinforced Polylactic Acid Green Composites with Multifunctional Properties in a Low-Carbon Process

The development and design of eco-friendly materials prove crucial for promoting the recycling of waste cotton textiles and reducing environmental pollution. In this study, waste cotton fabric (WCF) and polylactic acid (PLA) serve to produce cotton fabric-reinforced PLA composite material (CF/P). The CF/P is then integrated with traditional porous sound-absorbing materials to create a novel composite plate. This research highlights the potential of WCF reinforced plates for sound absorption and thermal insulation applications in the construction field of construction and reports the effects of variables such as hot pressing temperature, WCF mass fraction, and WCF layer alignment angle on the material properties. The optimum tensile strength, water absorption, and thermal conductivity of the prepared CF/P are 64.2 ± 1.8MPa, 1.98% ± 0.04%, and 0.03W/(m·K), respectively. By combining with porous sound-absorbing materials and modifying the layering structure of composite plates, its acoustic performance can be adjusted. The highest Sound Absorption Average (SAA) of plates with a multilayer composite structure is 0.67. Direct shaping through hot pressing diminishes the use of adhesives, thereby reducing costs and health hazards. This approach offers a practical and efficient solution for the recycling and repurposing of natural fibers.

Development of a high-strength lightweight geopolymer concrete for structural and thermal insulation applications

Investigating the thermal insulation properties of lightweight geopolymer concrete is essential. This paper aims to develop a lightweight aggregate geopolymer concrete (LWAGC) with good density, compressive mechanical and thermal insulation properties. The dry density of LWAGC was adjusted by incorporating expanded perlite (EP). The variation in physical and mechanical properties of LWAGC with different EP content was discussed, including dry density, P-wave velocity, ultimate compression strength and elastic modulus. Based on infrared thermal imaging technology, a rapid measurement method was proposed to simulate the indoor temperature change of buildings at high ambient temperatures. The thermal insulation performance of the LWAGC with different EP contents was further evaluated. The findings show that as the EP content in LWAGC increases, there is a corresponding decrease in P-wave velocity, dry density, ultimate compressive stress, and elastic modulus. The lowest dry density of LWAGC reaches 1209kg/m3 while the ultimate compressive stress is still larger than 25.0MPa, which can used as LC25 building materials in load-bearing structures. The results also show that the addition of EP can improve the thermal insulation properties of LWAGC. The LWAGC with 50% EP content has the highest reduction rate of temperature and can maintain the indoor temperature lower than 35 °C under high ambient temperature, which have potential application prospects in the load-bearing structures and thermal insulation of tall buildings.

Synthesis and Characterization of Acrylic Resin/Kaolin Composites for Dielectric Applications.

This study investigates the synthesis and characterization of acrylic resin/kaolin composites for dielectric applications. Acrylic resin, while widely used for its mechanical strength and ease of processing, exhibits limited dielectric properties, which restrict its use in high-performance electrical insulation. To address this, varying concentrations (0-70%) of raw kaolin, containing 71% kaolinite, were incorporated into an acrylic resin matrix to enhance its dielectric strength and thermal stability. Characterization techniques such as Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and dielectric spectroscopy were used to analyze the molecular structure, morphology, thermal behavior, and dielectric properties of the resulting composites. The study found that with up to 30% kaolin, the composites demonstrated good dielectric performance and thermal resistance, with good particle dispersion and minimal agglomeration. However, beyond 30% filler content, the dielectric and mechanical properties began to decline drastically. The results suggest that these composites could be potentially used for moderate dielectric applications such as insulators and capacitors.

Novel fabrication of polyethylene glycol/ceramic composite pellets with an excellent phase change shape stable trait and their potential applications for greenhouse insulation

Organic solid–liquid phase change materials (PCMs) face challenges in practical applications due to their susceptibility to leakage during phase transitions. To address this issue, we constructed the polyethylene glycol (PEG)/ceramic pellets (CPs) composite phase change shape stable materials (PCSHs) with thermal energy storage capability, thermal stability, and a firm texture using the melting impregnation method. The PCSHs exhibit remarkable shape stability in the leakage test due to the capillary action and surface tension generated by the micropore structure on their surface. They also can convert light energy into heat and store it as latent heat, achieving an optimal photothermal conversion efficiency of 45.21 % and a maximum melting enthalpy of 13.33 kJ/kg at a PEG loading of ∼ 12 %. An outdoor greenhouse insulation simulation experiment confirmed that the PCSHs can maintain soil temperatures above 30 °C for over 30 min after illumination ceases. This work presents a facile synthesis strategy for shape-stable PCMs with potential applications in greenhouse insulation.

Investigation of a Novel Approach in Free Cooling Degree Hour Calcula-tions for Muğla Province

In order to reduce cooling energy without compromising comfort conditions, insula-tion applications on external walls, columns, and beams, as well as the use of double glazing in windows, play a significant role. Another effective method in reducing cooling energy is the implementation of free cooling systems. In this system, cooling systems achieve energy savings by bypassing the fresh air taken from outside directly into the indoor space without passing through cooling coils. The implementation of this system requires the examination of reliable outdoor air temperature distributions throughout the cooling season during the project planning phase. In this study, various analyses were conducted using five different computer programs. According to the analysis results, the operation times of free cooling systems and the Free Cooling Degree Hour Value (FCDHV) to meet cooling loads were determined for every hour of each month for the province of Muğla. The estimated highest seasonal FCDHV for Muğla was found to be 11810.7, with the highest hourly FCDHV being 177.5 occur-ring between 05:30-06:30, and the highest 24-hour FCDHV being 2209 in September. When these data were converted to percentage values, it was determined that a 70.6% energy savings were achieved from free cooling systems.

Unravelling the role of filler surface wettability in long-term mechanical and dielectric properties of epoxy resin composites under hygrothermal aging

Epoxy resin (EP) incorporating inorganic fillers has garnered significant attention in the electrical and electronic industries due to its enhanced dielectric and mechanical properties, but its long-term performance under harsh conditions remains a critical concern. This study investigates the effects of filler surface wettability on the durability of EP-SiO2 composites. Micro-sized SiO2 with hydrophilic (HP) and hydrophobic (HB) surfaces are prepared via surface treatment, before they are incorporated into epoxy resin and subjected to hygrothermal aging at 95 °C and 95 % relative humidity for up to 1200 h. Comprehensive characterizations of wettability, microstructure, mechanical properties, and dielectric performance are conducted. Results show that the composite with hydrophilic fillers, HP-SiO2-EP, exhibits superior dispersion and interfacial adhesion compared to its hydrophobic counterpart, HB-SiO2-EP. Consequently, HP-SiO2-EP demonstrates higher initial tensile strength, Young’s modulus, and dielectric breakdown strength. Finite element simulations reveal the breakdown mechanism, highlighting that the hydrophobic SiO2 filler with interfacial defects results in earlier mechanical and dielectric failure. Furthermore, HP-SiO2-EP shows better resistance to hygrothermal aging compared to HB-SiO2-EP, with smaller increases in dielectric constant (+13 % vs. +28 %) and dielectric loss (+234 % vs. +311 %), as well as lower decrease in volume resistivity (−89 % vs. −93 %). This study provides valuable insights into the relationship between filler surface wettability and long-term composite performance, contributing to the design of more reliable materials for advanced dielectric applications.

Effect of Rb substitution on dielectric, ferroelectric, mechanical and biocompatibility properties of Na0.2K0.3Bi0.5TiO3 ceramics

This study focuses on the strategically developed Rb-substituted lead-free Na0.2K0.3Bi0.5TiO3 (NKBT) ceramic, highlighting its applications in energy storage, bio-implants, actuators, dielectric capacitors, and various other fields. The significant decrement of average grain size of ∼0.31 μm from ∼0.62 μm has been observed via surface morphology analysis with ultra-high Vickers hardness of ∼8 GPa in Na0.2K0.24Rb0.06Bi0.5TiO3 (RB 6) which is within the range to use bio-implants. The biocompatibility of samples verified cell growth and was monitored using two fluorescence dyes: fluorescein diacetate (FDA for live cell staining) and propidium iodide (PI for dead cell staining) under a fluorescence microscope. Also, the findings reveal that Rb-NKBT exhibits excellent biocompatibility with normal fibroblast cells and possesses impressive mechanical strength. Moreover, The X-ray and Raman inquiry confirms the tetragonal crystal structure of the samples. Frequency-dependent dielectric curve and shifting of Tm reveal the enhanced relaxor property with broadening signifies the increase in thermal stability. It is an important parameter for biological applications, particularly those involving functional temperatures, as the material must remain ferroelectric within the operating temperature range. Furthermore, the higher breakdown strength of ∼110 kV/cm with a recoverable energy storage density of 0.62 J/cm3 was found in the RB 6. The S-ve of the material decreases with the substitution of the Rb, which has been useful for actuator application. This study offers a comprehensive discussion on the utility of NKBT FCs as an active functional material for biomedical applications and dielectric applications with the advantage of non-invasive evaluation for potential failure with their sensing applications.