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The aerosol deposition (AD) method is the room temperature process for the formation of thin/thick film. Graphite (for anode, thickness: 250 nm) and C-coated LiFePO 4 (C-LFP, for cathode, thickness: 1 μm) AD films were deposited at room temperature without an annealing process. Nano-size grains were observed at their microstructures and especially a graphite AD film showed the nano-flake microstructure. The AD films showed not only the dense microstructure but also the space for electrolyte. The high capacities (a graphite AD film: 22 μAh cm −2 at 1 μA cm −2 , a C-LFP AD film: 24 μAh cm −2 at 50 μA cm −2 ) were obtained at half cells and their rate capabilities were also excellent. Through the full cell test (the anode: a graphite AD film, the cathode: a C-LFP AD film), it was confirmed that the AD films could work well for the electrodes in Li ion battery. In addition, the high capacity (150 μAh cm −2 at 5 μA cm −2 ) was observed at the AD thick film of a C-LFP-based composite (thickness: 6 μm). The AD thick film of a C-LFP-based composite is fabricated at room temperature without the use of N-Methyl-2-Pyrrolidone (NMP) which is a toxic material. [ABSTRACT FROM AUTHOR]

Magneto‐Mechano‐Electric Generators In article number 2112028, Sam Nyung Yi, Jongmoon Jang, Geon‐Tae Hwang, and co‐workers demonstrate a >50 mW RMS‐output magneto‐mechano‐electric generator achieved by hybridization of piezoelectric and electromagnetic induction effects. The electric output energy is enough to continuously operate multifunctional IoT sensors, thus enabling to verify ambient information such as temperature, humidity, light, ultraviolet index, air pressure, sound level, CO2, volatile organic compounds, and magnetic field. [ABSTRACT FROM AUTHOR]

Metal-supported solid oxide fuel cells consisting of Ni support, a screen-printed Ni–Gd0.1Ce0.9O2−δ anode functional layer, aerosol-deposited dense (La,Sr)(Ga,Mg)O3−δ electrolyte, and an aerosol-deposited porous (La,Sr)(Co,Fe)O3−δ cathode were fabricated and characterized. Both electrolyte and the cathode maintained good adhesion after electrochemical test of the cell at 750°C, after the composition of anode functional layer was optimized. Microstructural analysis of powders and deposited films of electrolyte and cathode layers is presented. Maximum power density of 0.79W/cm2 was achieved at 750°C. [ABSTRACT FROM AUTHOR]

Highlights: [•] Highly dense and well-adhered hydroxyapatite (HA) is deposited on PEEK using aerosol deposition. [•] After hydrothermal annealing, the crystallinity of the HA coating is remarkably enhanced without thermal degradation of the PEEK substrate. [•] Adhesion strength of HA coating to PEEK substrate remained relatively unchanged after hydrothermal annealing. [Copyright &y& Elsevier]

Abstract: Nano-structured porous ∼20μm thick LSCF films were fabricated at room temperature for use as cathodes in low temperature operating solid oxide fuel cells. Fabrication was by the aerosol deposition of ceramic–polymer composite powder. Various amounts of pore forming polyvinylidene fluoride polymer powder were mixed with LSCF ceramic powder as the starting powder for aerosol deposition. Increasing polymer content increased the porosity of films and decreased their adhesion strength. Anode-supported-type cells were created with LSGM electrolyte and nano-structured LSCF cathodes. The cells’ power density was maximized at 0.79 and 1.11W/cm2 at 650 and 750°C, respectively, when the starting composite powder contained 5wt.% polymer. [Copyright &y& Elsevier]

Abstract: 10μm-thick lead zirconate titanate (PZT) films with identical LaNiO3 (LNO) top and bottom electrodes were fabricated on silicon and yttria-stabilized zirconia (YSZ) substrates by aerosol deposition (AD). A Pt electrode was also made for comparison. The dielectric, ferroelectric and fatigue behaviors at different fields were investigated. The PZT films on YSZ/LNO showed the highest dielectric and ferroelectric properties and good fatigue behavior under various fields. PZT films with a Pt electrode also showed good fatigue behavior up to 108 cycles as thicker film can minimize the effect of defect entrapment near the interface. [Copyright &y& Elsevier]

Abstract: Nickel manganite spinel (NiMn2O4) based negative temperature coefficient (NTC) thermistors have good thermistor characteristics and stabilities. However, to achieve thermistors with a high B constant, the activation energy should be high, which results in high room temperature (RT) resistivity. To obtain a high B constant and low RT resistivity, NiMn2O4 based nanocomposite thick films with the conducting metal oxide, LaNiO3, were fabricated on a glass substrate by aerosol deposition at room temperature. The NiMn2O4–LaNiO3 nanocomposite thick films showed an RT resistivity as low as 35kΩ cm, which is one order of magnitude lower than that of the NiMn2O4 films, while retaining the high B constant of NiMn2O4 of over 5000K when 25vol.% LaNiO3 was used without any post thermal treatment. [Copyright &y& Elsevier]

Abstract: Dense, crack-free, ∼7.5μm thick, 8mol% yttria stabilized zirconia (YSZ) film was aerosol deposited on porous NiO-YSZ anode substrates at room temperature without additional high-temperature sintering. The films’ microstructures and gas permeability were observed after annealing at various temperatures. The dense, gas-tight film that was observed up to 1000°C became porous at higher temperatures probably due to structural instability related to oxygen non-stoichiometry. A cell using such film as electrolyte showed an open cell voltage of 1.10V and a maximum power density of 0.51W/cm2 at 750°C. [Copyright &y& Elsevier]

Abstract: (La,Sr)(Ga,Mg)O3−δ and (La,Sr)(Ga,Mg,Co)O3−δ electrolytes were aerosol deposited on conventionally sintered NiO-GDC anode substrates at room temperature to minimize reactions between them. Composite cathodes comprising (La,Sr)(Co,Fe)O3−δ and polyvinylidene fluoride were similarly deposited at room temperature. Both electrolytes and cathode maintained good adhesion. Cobalt in the electrolyte reduced open cell voltage (∼0.8V vs. ∼1.1V) probably due to the decrease of ionic transfer number, and increased maximum power density (∼0.8W/cm2 vs. ∼0.5W/cm2 at 650°C) by increasing ionic conductivity. [Copyright &y& Elsevier]

Abstract: The crystal structure, microstructural evolution, and ferroelectric and magnetic properties of BiFeO3 (BFO) ceramic materials, widely known as room temperature multiferroic materials, were investigated with various contents of Ba(Cu1/3Nb2/3)O3 (BCN). The ceramics were synthesized through the solid state reaction and pressureless sintering in air. By adding tetragonal structured BCN phase to the rhombohedral structured BFO phase, a solid solution was formed. The rhombohedral crystal structure and lattice parameter, densification behavior, and microstructure of BFO were noticeably changed upon the addition of BCB. The electrical properties of BFO were slightly enhanced by the addition of BCN. However, the magnetic properties of BFO which is the most critical issue in BFO multiferroics were drastically changed and the 20mol% BCN added BFO ceramics showed extremely enhanced magnetization characteristics compared to the other BFO–BCN ceramics. It is expected that BFO–BCN ceramics with this composition could be one of the most promising multiferroic materials for future multiferroic applications. [Copyright &y& Elsevier]

Abstract: A low temperature (≤650°C) process for fabricating nano-structured (La, Sr) (Ga, Mg, Co)O3−δ (LSGMC) electrolyte/(La, Sr) (Co, Fe)O3−δ –(Gd, Ce)O2−δ (LSCF–GDC) cathode films, ∼7 and ∼25μm in thickness, respectively, was developed using an aerosol deposition (AD) process for use in intermediate temperature solid oxide fuel cells (IT-SOFCs). NiO–GDC was used as an anode substrate in anode-supported type cells. The deposited LSGMC electrolyte and LSCF–GDC composite cathode film maintained good adhesion with the NiO–GDC anode, even though the coating processes were completed at the room temperature. The LSGMC electrolyte was composed of nano-sized grains smaller than 30nm. The electrical conductivity of the LSGMC electrolyte fabricated at room-temperature was ∼30mS/cm at 650°C. The LSCF–GDC composite cathode showed ≥20% porosity with a grain size ≤100nm. The peak power density of the LSGMC electrolyte-based, anode-supported-type cell with the nano-structured LSCF–GDC cathode produced at room-temperature by AD was 0.39W/cm2 at 650°C. [Copyright &y& Elsevier]

Abstract: The crystallinity of hydroxyapatite (HA) coatings prepared by aerosol deposition may be increased by heating in air or low-temperature hydrothermal processing. From the X-ray diffraction and Fourier transform infrared spectroscopy results, it was revealed that the crystallinity of the HA coatings significantly increased after the post-annealing. Transmission electron microscopy showed that the conventional furnace heating induced the substantial growth of the HA crystallites, whereas the hydrothermal treatment did not bring about any remarkable change in the HA crystallite size, which remained below 20nm. The bioactivity of the HA coatings was estimated by the acellular simulated body fluid immersion test. After immersion for 7days, newly-precipitated apatite crystals were only observed on the surfaces of the samples hydrothermally treated at 170 and 190°C. In addition, the alkaline phosphatase activity of MC3T3-E1 preosteoblast cells cultured on the hydrothermally treated samples was significantly higher than those on the as-deposited coating and conventional furnace heated samples. The enhanced bioactivity and excellent biological in vitro cellular response of the hydrothermally treated samples were attributed to their nanostructured nature and high degree of crystallinity. [Copyright &y& Elsevier]

Abstract: Hydroxyapatite (HA) coatings with different surface roughnesses were deposited on a Ti substrate via aerosol deposition (AD). The effect of the surface roughness on the cellular response to the coating was investigated. The surface roughness was controlled by manipulating the particle size distribution of the raw powder used for deposition and by varying the coating thickness. The coatings obtained from the 1100°C-heated powder exhibited relatively smooth surfaces, whereas those fabricated using the 1050°C-heated powder had network-structured rough surfaces with large surface areas and were superior in terms of their adhesion strengths and in vitro cell responses. The surface roughness (Ra) values of the coatings fabricated using the 1050°C-heated powder increased from approximately 0.65 to 1.03μm as the coating thickness increased to 10μm. The coatings with a rough surface had good adhesion to the Ti substrate, exhibiting high adhesion strengths ranging from 37.6 to 29.5MPa, depending on the coating thickness. The optimum biological performance was observed for the 5μm-thick HA coating with an intermediate surface roughness value of 0.82μm. [Copyright &y& Elsevier]

Abstract: Magnesium (Mg) and its alloys are potential biometallic materials for their good biocompatibility and excellent biological performances. However, Mg alloys corrode too quickly in chloride containing solutions, including the human body fluid and blood plasma, which may result in the abrupt failure of implants made of Mg alloys. Dense and well-adherent HA–chitosan composite coatings were deposited on AZ31 Mg alloy substrate using aerosol deposition (AD) in order to improve both the corrosion resistance and biocompatibility of AZ31 Mg alloy. The HA–chitosan composite powders having chitosan contents of up to 20wt.% were prepared by a simple dry-powder mixing process and then used for coating by AD. The coatings obtained from the corresponding powders were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and electrochemical measurement. The results revealed that the coating layers had similar compositions to the corresponding powders and exhibited fairly dense microstructures and, hence, AD was found to be a very effective method for the fabrication of dense ceramic–polymer composite coatings with a well-controlled composition. All of the coatings exhibited high adhesion strengths ranging from 24.6 to 27.7MPa and showed higher corrosion resistances than the bare AZ31 Mg substrate, implying that the corrosion resistance of AZ31 Mg alloy is enhanced by the HA–chitosan composite coating deposited using AD. In addition, the biocompatibility of the alloy was remarkably improved by the HA coating and the incorporation of chitosan into the coating. [Copyright &y& Elsevier]

Abstract: Piezoelectric thick films of Pb(Zr,Ti)O3–Pb(Mn1/3Nb2/3)O3 (PZT–PMnN) with Zr:Ti ratios ranging from 0.45:0.55 to 0.60:0.40 were fabricated on a platinized silicon wafer by aerosol deposition (AD). All the films were deposited with a thickness of 10μm with high density. By adding PMnN to 57:43 PZT, a dielectric constant as low as ∼660 was achieved while the effective piezoelectric constant was over 140 pC/N. PZT–PMnN with a Zr:Ti ratio of 57:43 thus showed a maximum piezoelectric voltage constant (g 33) of 23.8×10−3 Vm/N and is a good candidate for high quality thick films for application to high-energy density or high sensitivity, piezoelectric energy harvesters and sensors. [Copyright &y& Elsevier]

Abstract: Composite ceramic thick film of lanthanum strontium manganate (LSM) and yttria-stabilized zirconia (YSZ), 2–6μm in thickness, were deposited on ferritic stainless steel (STS444) by aerosol deposition (AD), as an oxidation resistance coating layer in the metallic interconnector of a solid oxide fuel cell (SOFC). The YSZ volume ratio in the LSM–YSZ composite layer was adjusted from 0 to 100vol% and the electrical resistivity was measured at 800°C using a DC 4-probe method. The interface microstructure and composition of the coating layer and stainless steel after oxidation at 800°C in air was examined. The coated oxide layers were highly dense without pores or cracks and maintained good adhesion, even after oxidation at 800°C for 250h at all compositions. The LSM–YSZ composite ceramics showed higher stability and electrical conductivity than the sole LSM layer at 800°C, possibly due to the high microstructural stability of YSZ against grain growth at 800°C. [Copyright &y& Elsevier]

Abstract: Silicon-substituted hydroxyapatite (Si-HA) coatings on commercially pure titanium (Ti) were prepared by aerosol deposition using Si-HA powders. Si-HA powders with the chemical formula Ca10(PO4)6− x (SiO4) x (OH)2− x , having silicon contents up to x =0.5 (1.4wt.%), were synthesized by solid-state reaction of Ca2P2O7, CaCO3, and SiO2. The Si-HA powders were characterized by X-ray diffraction (XRD), X-ray fluorescence spectrometry, and Fourier transform infrared spectroscopy. The corresponding coatings were also analyzed by XRD, scanning electron microscopy, and electron probe microanalyzer. The results revealed that a single-phase Si-HA was obtained without any secondary phases such as α- or β-tricalcium phosphate for both the powders and the coatings. The Si-HA coating was about 5µm thick, had a dense microstructure with no cracks or pores, and showed a high adhesion strength ranging from 28.4 to 32.1MPa. In addition, the proliferation and alkaline phosphatase activity of MC3T3-E1 preosteoblast cells grown on the Si-HA coatings were significantly higher than those on the bare Ti and pure HA coating. These results revealed the stimulatory effects induced by silicon substitution on the cellular response to the HA coating. [Copyright &y& Elsevier]

Abstract: 3–0 type of TiO2-β-TCP photocatalytic nanocomposite thin films were fabricated by aerosol-deposition. The fabricated films consisted of nano-sized, TiO2 photocatalytic crystallites with a dispersion of β-TCP adsorbent crystalline phase. The nanocomposite films showed strong photocatalytic activities such as degradation of methylene blue aqueous solution and bactericidal effect under both UV and dark conditions due to the adsorption effect of β-TCP. [Copyright &y& Elsevier]

Abstract: A nano-sized, TiO2 photocatalytic thin film with a dispersion of anatase crystallites was successfully fabricated from a micron-sized powder by aerosol deposition (AD) at room temperature (RT). Extremely rough, network-structured, photocatalytic thin films were obtained without any binder or heat treatment. The films were photocatalytically active under both ultraviolet (UV) and solar light as a result of their nano-sized, anatase grains and amorphous phase. Various photocatalytic evaluations confirmed the excellent photocatalytic performance of the AD TiO2 film in terms of organic degradation, pathogen disinfection, and hydrophilicity. This enhanced photocatalytic performance was attributed not only to the nano-crystalline anatase grains, but also to the exceptionally rough, network microstructure and nano-projections capable of supporting the enhanced loading of organic contaminants onto the film surface. Furthermore, because the nano-grained, AD TiO2 photocatalytic thin films were fabricated from low-cost, micron-sized powder with a deposition rate as high as 3μm/min at RT, this process promises to be one of the most cost-effective methods for many practical photocatalyst applications. [Copyright &y& Elsevier]

Abstract: A large-area multilayer ceramic actuator composed of piezoelectrically active Pb(Zn1/3Nb2/3)0.2(Zr1/2Ti1/2)0.8 (PZN-PZT) layers and silver metal layers was fabricated by the tape-casting method. Low-temperature sinterable PZN-PZT ceramics were used as piezoelectric layers, and silver paste containing PZN-PZT ceramic frits was used as conductive inner-electrode layers. PZN-PZT powder was prepared by conventional mechanical mixing of the raw powders in ethanol. The green sheet was fabricated using methyl ethyl ketone (MEK) as a solvent, polyvinyl butyral (PVB) as a binder, dibutyl phthalate (DBP) as a plasticizer, and KD-1 as a dispersant. Silver inner-electrode containing ceramic frits was pasted on the green-tape sheets and the sheets were stacked, warm-pressed, and sintered at 900°C for 4h after burn-out. The thickness of the piezoelectric and electrode layers was about 120 and 20μm, respectively. The electrical properties and piezoelectric displacement of the actuator were characterized. [Copyright &y& Elsevier]

Designing a piezoelectric energy harvester (PEH) with high power density and high fatigue resistance is essential for the successful replacement of the currently using batteries in structural health monitoring (SHM) systems. Among the various designs, the PEH comprising of a cantilever structure as a passive layer and piezoelectric single crystal-based fiber composites (SFC) as an active layer showed excellent performance due to its high electromechanical properties and dynamic flexibilities that are suitable for low frequency vibrations. In the present study, an effort was made to investigate the reliable performance of hard and soft SFC based PEHs. The base acceleration of both PEHs is held at 7 m/s2 and the frequency of excitation is tuned to their resonant frequency (fr) and then the output power (Prms) is monitored for 107 fatigue cycles. The effect of fatigue cycles on the output voltage, vibration displacement, dielectric, and ferroelectric properties of PEHs was analyzed. It was noticed that fatigue-induced performance degradation is more prominent in soft SFC-based PEH (SS-PEH) than in hard SFC-based PEH (HS-PEH). The HS-PEH showed a slight degradation in the output power due to a shift in fr, however, no degradation in the maximum power was noticed, in fact, dielectric and ferroelectric properties were improved even after 107 vibration cycles. In this context, the present study provides a pathway to consider the fatigue life of piezoelectric material for the designing of PEH to be used at resonant conditions for long-term operation. [ABSTRACT FROM AUTHOR]

Abstract: Highly dense magnetoelectric composite films with 10μm-thick of high piezoelectric voltage coefficient material, 0.9Pb(Zr57Ti43)O3–0.1Pb(Mn1/3Nb2/3)O3 (PZT–PMnN) and magnetostrictive material, Ni0.8Zn0.2Fe2O4 (NZF), were fabricated on a platinized Si substrate using aerosol deposition (AD). With increasing magnetic NZF content, dielectric and ferroelectric properties were gradually decreased while magnetizations were improved. The 20% NZF added composite thick film were found to exhibit the maximum ME coefficient. This optimal NZF content is the same as that of bulk ME composite materials. It is noticeable that AD can control the content ratio of ME composite films by controlling the powder composition. The fabricated ME composite films have high ME voltage coefficient coupling because of high density without severe inter-reactions of two phases. [Copyright &y& Elsevier]

Relaxor ferroelectrics (RFEs) are being actively investigated for energy-storage applications due to their large electric-field-induced polarization with slim hysteresis and fast energy charging-discharging capability. Here, a novel nanograin engineering approach based upon high kinetic energy deposition is reported, for mechanically inducing the RFE behavior in a normal ferroelectric Pb(Zr 0.52 Ti 0.48 )O 3 (PZT), which results in simultaneous enhancement in the dielectric breakdown strength (E DBS ) and polarization. Mechanically transformed relaxor thick films with 4 µm thickness exhibit an exceptional E DBS of 540 MV m -1 and reduced hysteresis with large unsaturated polarization (103.6 µC cm -2 ), resulting in a record high energy-storage density of 124.1 J cm -3 and a power density of 64.5 MW cm -3 . This fundamental advancement is correlated with the generalized nanostructure design that comprises nanocrystalline phases embedded within the amorphous matrix. Microstructure-tailored ferroelectric behavior overcomes the limitations imposed by traditional compositional design methods and provides a feasible pathway for realization of high-performance energy-storage materials., (© 2023 Wiley-VCH GmbH.)

We herein report a facile molten-salt synthetic strategy to prepare transparent and uniform Li, Ba-doped (K,Na)NbO 3 (KNN) single-crystal microcuboids (∼80 μm). By controlling the degree of supersaturation, different growth modes were found and the single-crystal microcuboids were synthesized via island-like oriented attachment of KNN particles onto the growing surface. The distinct relaxor ferroelectric (RFE) properties were achieved in the single-crystal microcuboids, which were different from the normal ferroelectric (FE) properties found in their KNN ceramic counterparts prepared through a solid-state reaction using the same initial precursors. The RFE properties were realized by dislocation-induced nanodomain formation during oriented attachment growth of single-crystal microcuboids, which is different from the current strategies to derive the nanodomains by the local compositional inhomogeneity or the application of an electric field. The dislocations served as nucleation sites for ferroelectric domain walls and block the growth of domains. The KNN single-crystal microcuboids exhibited a higher effective piezoelectric coefficient (∼459 pm/V) compared to that of the bulk KNN ceramic counterpart (∼90 pm/V) and showed the broad diffuse maxima in the temperature dependence dielectric permittivity. The high maximum polarization (69.6 μC/cm 2 ) at a relatively low electric field (30 kV/cm) was beneficial for energy storage applications. Furthermore, the KNN-based transparent, flexible pressure sensor directly monitored the mechanical motion of human activity without any external electric power. This study provides insights and synthetic strategies of single-crystal RFE microcuboids for other different perovskites, in which nanodomain structures are primarily imposed by their chemical composition.

Various supraparticles have been extensively studied owing to their excellent catalytic properties that are attributed to their inherent porous structure; however, their mechanical properties have not garnered attention owing to their less dense structure. We demonstrate a rational approach for fabricating assembled supraparticles and, subsequently, highly dense microspheres. In addition, 3 mol % yttria-stabilized zirconia (3YSZ) and alumina particles were selected as building blocks and assembled into higher-order architectures using a droplet-based template method (spray drying) for validation with proof-of-concept. Moreover, structural features such as density, size, sphericity, and morphology of supraparticles were controlled by adjusting the competing kinetics occurring between the assembly of building blocks and evaporation of the solvent in the droplets. The preparatory aqueous suspension and process parameters were optimized as well. A detailed understanding of the formation mechanism facilitated the yield of tailor-made supraparticles and, thereafter, highly dense microspheres (approximate relative density = 99%) with excellent sphericity (>98%) via heat treatment. The microspheres displayed highest hardness (26.77 GPa) and superior elastic modulus (210.19 GPa) compared with the mechanical properties of the 3YSZ samples reported to date. Ultimately, the proposed supraparticle engineering provided insight for controlling the structural features and resultant micromechanical properties, which widely extends the applicability of supraparticle-based functional materials for practical purposes that require materials with high density and excellent mechanical properties.

In this paper, we demonstrated a multiscale micro- and nano-structured magneto-mechano-triboelectric nanogenerator (MMTENG) enabled by a salt particle imprinting process to power an internet of thing (IoT) sensor. The fine salt particles were utilized to form a multiscale structure on a triboelectric polymer film by mechanical pressure via an eco-friendly, low-cost, and simple process, thereby reinforcing the contact triboelectrification and electrostatic induction. The surface modified MMTENG can generate an open-circuit peak-to-peak voltage of 851 V, a short-circuit current of 155 μA, and a maximum peak power of 10.3 mW under an AC magnetic field of 8 Oe. The energy device also presented output stability over 124 million operating cycles. Finally, the electricity of the surface enhanced MMTENG device was directly utilized to power an IoT temperature sensor with integration of an energy harvester, energy conversion circuit, and storage capacitor.

As one of the perovskite families, potassium sodium niobates (K 1- x Na x )NbO 3 (KNN) have been gaining tremendous attention due to their various functional properties which can be largely determined by their crystallographic phase and composition. However, a selective evolution of different phases for KNN with controlled composition can be difficult to achieve, especially in solution chemical synthesis because of its strong tendency to stabilize into orthorhombic phase at conventional synthetic temperature. We herein developed a facile solution approach to control the phase and composition of dopant-free KNN particles selectively through the modification of reaction parameters. A conventional hydrothermal synthesis method yielded orthorhombic KNN particles, while the monoclinic phase, which has never been observed in a bulk counterpart, was kinetically generated by the compositional modification of an intermediate phase under a high-intensity ultrasound irradiation. Cubic KNN particles were stabilized when ethylene glycol was used as a co-solvent together with deionized water through bonding between ethylene glycol molecules and the surface of the KNN. Composite-structured piezoelectric harvesters were fabricated using each phase of KNN particles and the β-phase poly(vinylidene fluoride- co -trifluoroethylene) polymer. Maximum output power was found for the harvester containing orthorhombic KNN particles. This facile synthetic methodology could pave a new pathway for fabricating numerous phase-controlled materials.

We report the effect of epoxy adhesion layers with different mechanical or physical property on a magnetoelectric (ME) composite laminate composed of FeBSi alloy (Metglas)/single-crystal Pb(Mg 1/3 Nb 2/3 )O 3 -Pb(Zr,Ti)O 3 /Metglas to achieve an improved ME conversion performance. Through theoretical simulation, it was revealed that the Young's modulus and the thickness of interfacial adhesives were major parameters that influence the conversion efficiency in ME composites. In the experimental evaluation, we utilized three epoxy materials with a distinct Young's modulus and adjusted the average thickness of the adhesion layers to optimize the ME conversion. The experimental results show that a thin epoxy layer with a high Young's modulus provided the best performance in the inorganic-based ME conversion process. By tailoring the interfacial adhesion property, the ME laminate generated a high conversion coefficient of 328.8 V/(cm Oe), with a mechanical quality factor of 132.0 at the resonance mode. Moreover, we demonstrated a highly sensitive alternating current magnetic field sensor that had a detection resolution below 10 pT. The optimization of the epoxy layers in the ME laminate composite provided significant enhancement of the ME response in a simple manner.

We fabricated and characterized the magnetoelectric (ME) properties of 3-0 ME composite materials comprised of the high piezoelectric voltage coefficient material, 0.9Pb(Zr0.52Ti0.48)O3-0.1 Pb(Zn1/3Nb2/3)O3 + 0.005Mn (PZT-PZN), and the magnetostrictive material, Ni0.8Zn0.2Fe2O4 (NZF). As the ME effect is generated by the product coupling between the piezoelectric properties and the magnetostrictive properties, the NZF content should be optimized for a higher ME coefficient. The dielectric constant and spontaneous polarization (P) were decreased with increasing NZF content before the percolation of the NZF particulates. However, as the NZF content exceeded the percolation content, the dielectric loss was dramatically increased due to the low resistivity of NZF. While the piezoelectric constant was decreased with increasing NZF content, the maximum magnetization was linearly increased. When we combined the piezoelectric and magnetostrictive effects, the ME composite sintered at 1200 degrees C with 20% NZF showed a maximum dE/dH of 27 mV/cm x Oe at a magnetic bias of 1240 Oe.

Hydroxyapatite (HA)-carbon nanotube (CNT) composite coatings on Ti plate, produced by aerosol deposition using HA-CNT powders, were developed for biomedical applications. For the deposition process HA-CNT powder mixtures with CNT contents of 1 and 3 wt.% were used. Dense coatings with a thickness of 5 microm were fabricated, irrespective of the content of CNTs. No pores or microcracks were observed in the coatings. The coatings had good adhesion to the substrate, exhibiting a high adhesion strength, ranging from 27.3 to 29.0 MPa. Microstructural observation using field-emission gun scanning electron microscopy and transmission electron microscopy showed that CNTs with a typical tubular structure were found in the HA-CNT composite coatings. Nanoindentation tests revealed that the mechanical properties, such as the hardness and elastic modulus, were significantly improved by the addition of the CNTs to the HA coating. In addition, the proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 pre-osteoblast cells grown on the HA-CNT composite coatings were higher than those on the bare Ti and pure HA coating. The ALP activity of the composite coatings considerably improved as the CNT content increased. These results suggest that CNTs would be an effective reinforcing agent to enhance both the mechanical and biological performances of HA coatings.