Ceramic Tapes Research Articles

Enhancing thermoelectric effect with BaTiO3-doped ZrO2 tapes and ferromagnetic nanostructures

The Anomalous Nernst Effect (ANE) emerges as a promising candidate for converting heat into electricity through magnetic nanostructures. However, the substrate plays a central role in optimizing this phenomenon for future technological applications. Tapes of ZrO2 and BaTiO3-doped ZrO2, manufactured by tape casting, possess characteristic flexibility in the green state, which makes them suitable for use as coverings on virtually any curved surface. Moreover, BaTiO3 ceramic materials present piezoelectric properties, which, when combined with thermoelectric properties, can generate interesting heterostructures with simultaneous thermal and vibrational power conversion capabilities. This study explores the combination of tape casting and magnetron sputtering to improve the functionalization of ceramic tapes with ferromagnetic nanostructures. Specifically, it investigates the quasi-static and thermoelectric properties of heterostructures created by depositing NiFe thin films onto sintered ZrO2 and BaTiO3-doped ZrO2 tapes using magnetron sputtering. The results indicate a 71 % increase in the effective thermoelectric coefficient as the amount of BaTiO3 in the ceramic substrate increases. These findings suggest a new approach to integrating these techniques for the production of multifunctional materials for thermoelectric energy conversion.

Comparative investigation on fire resistance of different fire prevention schemes for 1670 MPa steel wires used in bridge cables

This paper mainly investigated the fire resistance of different fire prevention schemes for 1670 MPa steel wires used in bridge cables. The fire resistance tests on bridge cables under different fire protection schemes were carried out. The failure modes and the varied patterns of temperature at different positions of the cables was studied, and the optimal design scheme of fire protection for bridge cables was also obtained. Furthermore, the tensile test of steel wire after fire was carried out to study the degradation law of mechanical properties of steel wire. The results showed that the cables undergo varying degrees of bending deformation after the fire, mainly due to the poor fire protection effect. The wrapping process of the fire protection scheme was a key factor affecting the protective effect. When the premature invalidation of the wrapping mode failed to occur, the aerogel material would have better thermal insulation behavior than the basalt fiber. The temperature rising rate of Schemes D (6 mm ceramic fiber aerogel tape), E (10 mm high silica glass aerogel tape) and F (10 mm nano thermal isolation felt-ceramic fiber aerogel) was relatively gentle, and the temperature of most measuring points within 4500s was not more than 300 °C. Based on the failure mode and the temperature of the cables, it could be judged that Schemes E and F were better than Schemes C (4 mm composite fiber fire-resistant isolation tape) and D while schemes A (4 mm basalt fiber needled felt) and B (4 mm aerogel tape) had the worst fire protection effect. Due to the surface temperature, the fracture morphology of steel wires after fire varied greatly, mainly divided into brittle fracture and ductile fracture. With the increase of temperature, the yield and ultimate strength of steel wire of Schemes A, B, C, D and E decreased greatly after fire, and along with a maximum decrease of 73.78% and 69.02% respectively.

Innovative Silicon-Ceramic (SiCer) Technology for High-Strength Pressure Sensor Applications Using Different Manufacturing Methods

A variety of manufacturing methods can be used to assemble silicon-based piezoresistive pressure sensors, such as anodic bonding or silicon direct bonding. To achieve highstrength pressure sensors, a high quality interface connection is required. The combination of silicon and ceramic creates a new innovative composite system known as Silicon-on-Ceramics, short SiCer. By using a special developed bondable Low Temperature Co-fired Ceramic tape, which corresponds to the thermal expansion coefficient of Si, the combination of both materials is possible through a sintering process. Advantages of the SiCer technology are high temperature stability, manufacturing at wafer-level and a high bond strength at the interface. Different manufactured SiCer-based pressure sensors were fabricated, electrically and mechanically characterized and compared with anodic bonded and silicon direct bonded pressure sensors.

Al2O3 dielectric ceramic tapes containing hBN for applications on high-frequency substrates

In this study, we manufactured dielectric alumina (Al2O3) ceramic tapes incorporated with hexagonal boron nitride (hBN) for applications on high-frequency substrates. The ceramic tapes were produced using the tape casting technique. Structural and morphological analyzes show the presence of hBN nanoplatelets dispersed in the Al2O3 matrix, confirming the efficiency of the tape-casting technique and the sintering process. We verified that the crystalline structure of hBN is essential in the dielectric response, showing a reduction in dielectric losses with the incorporation of hBN into the Al2O3 ceramic matrix, making ceramic tapes attractive in dielectric applications. Furthermore, the mechanical properties of the tapes show satisfactory results, reinforcing our findings. Thus, our results become fascinating for applications in high-frequency substrates for electronic transmission devices.

Tensile testing of Yttria-stabilized zirconia ceramic tapes for solid oxide cells

High temperature solid oxide cells (SOCs) play an important role in the worldwide green energy transition due to the high efficiency and great flexibility. For the cost and efficiency optimization of electrolyte-supported SOCs, a crucial property is the mechanical stability of the cell, which is mainly provided by the electrolyte. In this study, the authors investigate the tensile mechanical properties of 3% yittria-stabilized zirconia (3YSZ) ceramic electrolyte tapes, allowing the evaluation of a large material volume compared to the flexural test. A novel gripping system for misalignment minimization is developed. The sample machining is found to have an influence on the strength, as ground samples have an average strength above 1000 MPa, while the laser cut ones show strengths below 500 MPa. The influence of edge roughness and phase transformation during grinding is determined and the crack initiation point is examined.

Low temperature sintering lead‐free dielectric xBiScO3‐(1‐x)BaTiO3 for energy storage applications

AbstractFabrication of ceramic capacitors requires technological breakthroughs to address growing concerns regarding sustainability, cost, and increased power consumption in the manufacturing process. Low temperature sintered xBiScO3‐(1‐x)BaTiO3 (BS‐BT) with x = 0.4 is found to possess excellent energy storage performance and temperature stability. The grain size decreases from 3.5 μm sintered at 1100°C to less than 0.5 μm sintered at 800°C, leading to much improved breakdown field and energy storage properties. Recoverable energy density of 4.7 J/cm3 with a high efficiency of 89% was obtained at an electric field of 390 kV/cm, showing an excellent temperature stability over temperature range of 25–200°C and fatigue endurance for more than 105 cycles. Of particular importance is that the ceramic tape cofired with silver electrode over temperature range of 800–850°C shows no reaction and diffusion of silver at the electrode/ceramic interface, while a recoverable energy density of 3.3 J/cm3 was achieved with satisfactory efficiency of 80% at an electric field of 340 kV/cm when sintered in reduced atmosphere, expanding the electrode selection to low‐cost base metal, such as Cu and Ni. This work provides a good paradigm in ceramic capacitor fabrications that will help reduce overall cost and power consumption by utilizing low temperature sintered lead‐free dielectrics with comparable or even superior energy storage properties over state‐of‐the‐art dielectrics.image

Microstructure and Electrochemical Performance of Rapidly Sintered LiCoO2 Cathodes

Lithium ion battery technology based upon liquid carbonate electrolytes and intercalation electrodes has achieved widespread commercial success. The batteries power mobile devices like cell phones, laptop computers and cordless power tools. They are used in hybrid and all electric vehicles to reduce greenhouse gas emissions and dependency on limited petrochemical resources. They have been demonstrated to stabilize electric grids at local and national levels under periods of high demand. Even with these remarkable achievements, improvements in energy density are sought in batteries for most applications. Lithium metal batteries are being pursued around the world to meet this need.Rapid, continuous, roll-to-roll sintering of alumina ceramic tapes was recently demonstrated at Corning Incorporated [1]. The process is based on the pioneering work of Ketcham et al [2]. The ceramic tape, because it is thin, is flexible and may be heated, sintered, and cooled back to room temperature in less than one hour without cracking. One application of this technology is for manufacture of thin, <30 µm, solid electrolyte separators. Another is to enable novel, cathode-supported battery architectures. To that end, rapid sintering has been extended to lithium cobaltite (LCO). Continuous sintering and winding of LCO is shown in Fig. 1. The LCO cathode because it is sintered and self-supporting may be used to reduce the proportions of inactive components to dramatically increase energy density. Both composite and dense cathodes can be envisioned.One possible way of creating a solid-state battery with LCO ribbon is to capitalize on the LiPON solid electrolyte originally developed at ORNL for thin-film micro-batteries (TFMB’s) [3, 4]. The materials in TFMB’s have proven track records and attractive performance attributes. The LiPON solid electrolyte in contact with a lithium metal anode is resistant to dendrite formation even at current densities >5 mA/cm²; a claim that cannot be made for lithium garnet and lithium phosphosulfide glass [5, 6].TFMB’s also have tremendous cycling longevity and retain more than 90% of capacity after over 104 charge-discharge cycles [7]. The challenge with the technology is the high cost associated with growth of the cathode by sputtering processes; thicknesses are limited to ~2-3 µm. As a consequence, TFMB’s are a good fit for applications where small size power sources are needed like smart cards, medical implants, RFID tags, and wireless sensing. A thicker, rapidly sintered cathode could address the cost-capacity limitation. The cathode for this architecture could be made in a dense, closed pore form or with 15-25% porosity to host and electrolyte. The later would be expected to offer greater rate performance due to shorter diffusion distances and greater surface area for charge transfer. Energy density of more than 1,500 Wh/L is theoretically achievable.The performance of cathode materials like LCO depends upon synthesis conditions, process history, design and microstructure. We explore the electrochemical attributes of free standing LCO cathodes with thickness of 15 to 80 µm and porosity ranging from closed (dense) to ~25%. Cathodes were tested in 2032 coin cells using Whatman glass fiber as the separator and 1 M LiPF6 in 1:1 EC:DMC. Capacity of the cathodes regardless of microstructure is near the theoretical value. Lithium diffusivity of dense polycrystalline cathodes was characterized by galvanostatic intermittent titration and averages 1.13×10-9 cm²/s over the potential window of 3.0 to 4.3 V. Surface XRD shows the grain texture to be nominally random. Approximately 50% capacity was available at C/2 at a 23 µm thickness. Resistance of porous cathodes decreased with perimeter-to-surface area, and effective resistances below 10 Ωcm² were observed. Cycling endurance of porous sintered cathodes with 2.4 mAh/cm² capacity was evaluated with lithium titanate working electrodes. More than 90% capacity was retained after 1000 cycles between 3.0 and 4.3 V vs Li at 3C rate.[1] C. Kim, et al, “5G mm Wave Patch Antenna on Multi-layered Alumina Ribbon Ceramic Substrates,” IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting, July 2020, pp. 65-66.[2] T.D. Ketcham, et al., US 5,089,455, Feb 18, 1992.[3] J.B. Bates, et al., Solid State Ionics, 53-56 (1992) 647-654.[4] J.B. Bates, et al., U.S. 5,561,004, Oct 10, 1996.[5] F.D. Han, et al., Nat. Energy, (2019) 1-10.[6] J.C. Li, et al., Adv. Energy. Mater., 5 (2015) 1401408.[7] J. Xie, et al., Solid State Ionics, 178 (2008) 362-370. Figure 1

A Three-Dimensionally Interconnected Composite Polymer Electrolyte for Solid-State Batteries

High energy density of solid-state batteries requires a thin solid electrolyte separator layer (<30 μm), that can sustain high currents and is easily processable. Polymer-ceramic composite electrolytes can potentially fulfill these requirements by combining the advantages of each type. Ceramic electrolytes have high room-temperature ionic conductivity, transference number of one, and mechanical strength to suppress lithium dendrites, whereas polymer electrolytes are easily processable and can form conformable interfaces with the electrodes. High interfacial-impedance between polymer and ceramic electrolytes make the composites with dispersed ceramic particles less attractive.1 A composite electrolyte architecture where a three-dimensionally interconnected porous ceramic is filled with polymer electrolyte, previously reported by our group, can avoid the interfacial impedance issue, although for thin composite membranes, the interfacial impedance between ceramic framework and excess polymer layer on top/bottom surface will still dominate the overall impedance.2 Here we will present fabrication and electrochemical evaluation of ~150 μm thick composite electrolytes with the above-described 3D-interconnected ceramic architecture. The 3-D framework is obtained by partially sintering Ohara ceramic particle tapes obtained via tape casting, which are filled with curable polymer electrolyte precursors. To obtain a thin (5 μm), uniform polymer electrolyte layer on both surfaces, spray coating was employed. The resulting composite membrane exhibited good dendritic resistance in symmetric cell cycling, improved transference number compared to the polymer electrolytes. We also found significantly improved flexibility of the composite electrolytes with plasticization, however, at the cost of reduction in ionic conductivity due to damage to the ceramic network caused by plasticizer-induced swelling of the cross-linked polymer electrolyte. This research was sponsored by the U.S. Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy for the Vehicle Technologies Office’s Advanced Battery Materials Research Program (Tien Duong, Program Manager). This abstract has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). References Chen, X. C.; Liu, X.; Samuthira Pandian, A.; Lou, K.; Delnick, F. M.; Dudney, N. J., Determining and Minimizing Resistance for Ion Transport at the Polymer/Ceramic Electrolyte Interface. ACS Energy Letters 2019, 4 (5), 1080-1085.Palmer, M. J.; Kalnaus, S.; Dixit, M. B.; Westover, A. S.; Hatzell, K. B.; Dudney, N. J.; Chen, X. C., A three-dimensional interconnected polymer/ceramic composite as a thin film solid electrolyte. Energy Storage Materials 2020, 26, 242-249.

Preparation of multilayer ceramic tapes by aqueous gel-tape co-casting

The method for the production of multilayer tapes by the aqueous epoxy-based gel-tape co-casting of ceramic suspensions is described. The method enables preparing multilayer tapes with a defect-free interface. The method extends the applicability scope of the epoxy-based gel-tape casting method from high quality single-layer materials towards multilayer materials or materials with gradient doping. A triple-layer material was prepared and the quality of the interface was investigated down to grain level using microscopy techniques. A sharp interface between adjacent layers was obtained with no delamination detected. The areal quality of the interface in co-cast tapes was demonstrated on transparent bi-layer alumina tapes. The relative density of the bi-layer alumina tapes reached 99.99% after pressure-less sintering. The results proved the epoxy gel-tape co-casting method to be applicable for the preparation of high-quality fine powder ceramic stacks.

Optimisation of Slurry Compositions for Improving the Mechanical Properties of Low Temperature Co-Fired Ceramic (LTCC) Tapes

In the era of miniaturization and hybridization, the quest for novel materials for multilayer packaging had been increased. The multilayer packaging includes High Temperature Co-Fired Ceramics (HTCC), LTCC and ULTCC. LTCC which is the mixture of ceramic and glass (which reduces the firing temperature of ceramics) has attracted many researchers due to its lower firing temperature(<900°C). Due to this lower sintering temperature, it can be cofired with the low resistance metals like Ag and Au which increases its value in multilayer packaging field. The standard package fabrication process uses LTCC in the form of tapes. Each layer can be processed separately for punching, via filling and Screen printing and then stacked, laminated and sintered to get a multilayer package. The green sheet of LTCC should have sufficient adhesion to carrier film as well as mechanical properties to withstand the fabrication processes that it undergoes. These properties are mainly affected by the organic compositions used in the slurry preparation. The tape casting slurry was prepared by blending the LTCC powder with solvents, dispersants and binders for a predefined time in ball mill. The as prepared slurry was casted on a Mylar sheet in a continuous tape caster for varied thickness. The present study aims at reporting the effect of plasticizers and binders on the adhesion and mechanical properties of the tape. The starting material which was the mixture of Cordierite and Anorthite based recrystallizable glass was prepared through solid-state method. The powder was then characterised for its phase purity, microstructure and elemental compositions using XRD, FESEM and EDAX. The green tapes were characterised for its thickness, uniformity, green and sintered density, surface defects such as pinholes and cracks, adhesion and tensile strength. The dielectric properties as well as thermal properties are also evaluated. The results are reported.

Large Thermal Expansion LTCC System for Cofiring with Integrated Functional Ceramics Layers.

We have studied the sintering behavior of CT708 LTCC tapes with large CTE of 10.6 ppm/K. This low-k dielectric LTCC material is a quartz-based glass ceramic composite system with partial crystallization of celsian upon firing. The shrinkage, densification and dielectric properties were examined using different heating rates and a sintering temperature of 900 °C. The maximum shrinkage rate is at 836 °C (for a heating rate of 2 K/min) with a sintering density of 95% and a permittivity of ε’ = 5.9 and tan δ = 0.0004 (at 1 GHz). Due to their similar shrinkage and thermal expansion properties, CT708 tapes may be cofired with functional ceramic layers. As an example, we report on cofiring of a multilayer laminate of CT708 and a Sc-substituted hexagonal ferrite for applications as integrated microwave circulator components. This demonstrates the feasibility of cofiring of functional ceramic tapes and tailored LTCC tapes and documents the potential for the realization of complex LTCC multilayer architectures.

Cofiring of LTCC multilayer assemblies with integrated NTC thermistor temperature sensor layers

We have studied the integration of Ni–Co–Zn–Mn spinel NTC thermistor layers into LTCC multilayer modules. Sintering of the cubic spinel Ni0.5Co0.5Zn0.75Mn1.25O4 with addition of 3 wt% Bi2O3 additive at 900 °C resulted in samples with 96% density and with good electrical performance. Thermistor spinel tapes, fabricated using doctor blade tape casting, were stacked with layers of a commercially available low-k dielectric LTCC tape, and cofired at 900 °C. Free or constrained cofiring did not give crack-free multilayer samples. Thermistor layers were then integrated combining the commercial LTCC tape with a Zn titanate-based tape in one multilayer laminate, and error-free multilayer samples with a room-temperature resistivity of ρ298 = (2,9 ± 0.08) kΩcm and a thermistor constant of B = (4280 ± 200) K were obtained. This demonstrates the possibility of cofiring of functional ceramic and low-k LTCC tapes and shows the potential of NTC spinel thermistor layers as temperature sensors integrated in complex LTCC multilayer architectures.

Thin high-strength zirconia tapes with extreme flexibility

ABSTRACT The yttria stabilized zirconia ceramics (Y-TZP) are known for their high fracture toughness and high strength. Due to their excellent mechanical properties, the thin zirconia tapes can possess extraordinary behavior – extreme flexibility. In the present work, we introduce an adaptation of gel-tape casting method for the preparation of thin, high-strength zirconia tapes from water-based suspensions. Fine ceramic powder with a particle size of around 100 nm was used. The negative effect of sodium ions on the strength and toughness of sintered ceramic samples was revealed and explained. Ceramic tapes with a thickness of 190 µm with as-sintered surfaces reached a characteristic biaxial strength of 1805 MPa. The huge elastic deformation of ceramic tapes was demonstrated in a 3- point bend test, and a bending radius of 25 mm for a 75 µm thick tape was reached.

Low Loss LTCC Ag System for 5G Applications

Abstract Low dielectric constant/low loss LTCC materials have drawn much attention with the emergence of 5G wireless telecommunications. LTCC offers unique properties in the millimeter wave frequency range. The low dielectric constant and dielectric loss enable low latency devices with enhanced performance. To meet the market demands of higher performance and lower cost, Ferro has developed a new M7 LTCC/Ag cofireable system suitable for antenna in 5G and other high frequency applications. M7 LTCC ceramic green tape and cofireable Ag conductors have been developed and tested. Properties of the LTCC/Ag system are included herein including high frequency dielectric properties.

Improved the Comprehensive Properties of Low‐Temperature Co‐Fired Ceramic Composites Based on ZnO–B2O3–Na2O–Al2O3–SiO2 Glass by Introducing AlN Nano particles

ZnO–B2O3–Na2O–Al2O3–SiO2 (ZBNAS) glass/Al2O3/AlN biphasic ceramics are prepared by a standard tape casting process and solid phase sintering. The low‐temperature co‐fired ceramic (LTCC) tapes are sintered at 850 °C for 2 h under a nitrogen atmosphere. The new phase of ZnAl2O4 is formed by the reaction between glass phase and ceramic fillers during the sintering process. The addition of AlN improves the comprehensive properties of the ZBNAS glass/Al2O3 composites. The samples with 30 wt% AlN exhibit a thermal conductivity of 5.48 W m−1 K−1, a low dielectric constant of 2.99 and a dielectric loss of 0.029 at 18 GHz, and a coefficient of thermal expansion (CTE) of 6.98 × 10−6 °C−1. The obtained composite ceramic with good comprehensive performance may be the promising candidates for high‐power devices.

Well-Dispersed Garnet Crystallites for Applications in Solid-State Li-S Batteries.

A uniform ceramic tape of well-dispersed garnet-type Li6.4La3Zr1.4Ta0.6O12 particles (LLZTO) with a high solid content of 70 wt % is prepared as an electrolyte in solid-state Li-S batteries. The use of appropriate dispersants is crucial for achieving fine dispersion and uniform distribution of LLZTO particles in the ceramic tape. This leads to improved surface flatness and mechanical strength of the ceramic tape. Moreover, the ionic conductivity increases remarkably at the same time from 10-5 to 10-4 to 10-4 to 10-3 S cm-1, and the Li+ transport number doubles from 0.35 to 0.70. The Li-S battery constructed with the dispersed LLZTO electrolyte shows an adequate capacity of above 600 mA h g-1 after 100 cycles at a discharge current of 84 mA g-1, and it is capable of charging/discharging at a high current of 1672 mA g-1. In comparison, the battery with a nondispersed LLZTO electrolyte functions only at the lower current of 84 mA g-1 and fails to work after 25 cycles.

Enhanced Piezoelectric Properties of Pb0.976K0.012Bi0.012[(Zr0.53 Ti0.47)0.99 Nb0.01]O3 Ceramic Tape Casting by Three Step Sintering

A problem of fabricating piezoelectric tape ceramic is poor density after sintering. Three-step sintering (3ss) techniques were prepared to obtain tape casting ceramic with density and piezoelectric properties better than conventional sintering (CS). Pb0.976K0.012 Bi0.012[(Zr0.53 Ti0.47)0.99 Nb0.01]O3 tape ceramic was synthesized using tape casting accompanied with the sintering techniques. The green tapes were sintered on three temperature steps that are 870, 970, and 1070 °C, respectively, and compared with two temperature steps that are 870, and 1070 °C. The optimum density, dielectric properties, polarization electric field loop, piezoelectric coefficient (d33), was attained by three step sintering. The enhanced remanent polarization of 44 μC cm−1 and the recoverable energy storage density was characterized on P-E loop. In addition, d33 value of 226 pC N −1, and kp of 0.36 was enhanced to attain for the tape ceramic on 3SS.

Influence of hBN content on dielectric properties of calcium silicate for high-frequency substrate application

We report a method for the fabrication of multilayer calcium silicate (Sc) ceramic composite containing 1, 3, and 5 wt. $$\%$$ of hexagonal boron nitride (hBN). The multilayer ceramic tapes were engineered using aqueous tape casting, laminating process, and pressureless sintering at 1050 $$^{\circ }$$ C in an argon atmosphere. The structural and dielectric properties of the multilayer hBN-doped Sc ceramic tapes were investigated through several characterization techniques. We observed a stable behavior of the relative dielectric constants (1.99–2.22 range) for the multilayer hBN-doped Sc ceramic tapes at high-frequency regime. Also, we verified a considerable reduction of the dielectric losses of around 20 $$\times $$ as the amount of hBN increases. Our results show that multilayer hBN-doped Sc ceramic tapes are promising candidates for high-frequency substrate applications.

Low κ Mg2SiO4 ceramic tapes and their role as screen printed microstrip patch antenna substrates

Despite their intolerance to fine machining, certain ceramics possess a unique combination of low dielectric constant and ultra-low dielectric loss, which is ideal for fabricating a patch antenna on them, with increased efficiency. In a candid attempt, we have qualified an ultra-low loss ceramic, magnesium silicate (abbreviated as Mg2SiO4), for microwave antenna applications. Flexible ceramic tapes are prepared through organic solvent-based tape casting method, stalked, isostatically pressed, sintered, and polished. The new substrate possesses excellent microwave dielectric properties on par with commercial polymer composite wafers, while thermal conductivity is two orders better than them. The feasibility of using Mg2SiO4 as microwave substrate was demonstrated by fabricating a microstrip patch antenna for WLAN applications. The radiation characteristics of the antenna show excellent agreement with the simulated ones. The patch antenna fabricated on Mg2SiO4 substrate radiated at 2.44 GHz with a gain of 3.2 dB and a return loss of −20 dB.

Tricalcium phosphate sheets with chitosan obtained via aqueous tape casting

Abstract Tricalcium phosphate (TCP) is a biomaterial produced in several biomedical applications, in addition to having biocompatibility and osteoconductive capacity. Biodegradable polymers of natural or synthetic origin such as chitosan and polyvinyl alcohol (PVA) have been used for tissue engineering applications because they have the properties of the native organic phase of bone tissue. Thus, the objective of this study was to obtain ceramic tapes based on TCP, chitosan, and PVA through the tape casting method. The viscosity data for all suspensions were ideal for the chosen processing. The thermogravimetric curves showed similar profiles, and it was possible to observe that a greater total mass loss occurred with the increase in the chitosan content. XRD reflections related to the β-TCP phase of the orthorhombic structure were found, showing no phase transformation. SEM analysis showed degrees of roughness on the film surfaces with little influence from the increase in chitosan content.