Articoli di riviste: "POTASSIUM SODIUM NIOBATE ( KNN )"

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Wang, Shi Ping, Hong Yan Miao e Guo Qiang Tan. "Hydrothermal Synthesis of Sodium-Potassium Niobate Nanopowders". Key Engineering Materials 368-372 (febbraio 2008): 579–81. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.579.

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Sodium-potassium Niobate (K0.4Na0.6NbO3, KNN) nanopowders were prepared by hydrothermal synthesis at the temperature range of 140-180°C for 12-48h using Nb2O5, NaOH and KOH as source materials. By means of XRD and SEM techniques, the effects of composition and hydrothermal treatment process, such as the rate of [R]/[Nb], the concentration of the alkali, the hydrothermal treatment temperature and the hydrothermal treatment time, on the microstructures and the crystallinity of alkali metals niobate were investigated in details. Results show that K0.4Na0.6NbO3 powders could be achieved by hydrothermal synthesis at the temperature range of 140-180°C with the alkalinity concentration of 2-8M. With the increase of hydrothermal reaction temperature and time, the crystallinity of KNN particles was improved. The obtained K0.4Na0.6NbO3 polycrystalline particles have rhombic structure.

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Piskin, Cerem, Levent Karacasulu, Mauro Bortolotti e Cekdar Vakifahmetoglu. "Synthesis of potassium–sodium niobate (KNN) from NbO2". Open Ceramics 7 (settembre 2021): 100159. http://dx.doi.org/10.1016/j.oceram.2021.100159.

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Lin, Jia Qi, Pan Pan Zhang e Wen Long Yang. "Fabrication and Ultraviolet Characterization of Potassium Sodium Niobate/Polyimide Hybrid Films". Applied Mechanics and Materials 395-396 (settembre 2013): 121–24. http://dx.doi.org/10.4028/www.scientific.net/amm.395-396.121.

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A functional potassium sodium niobate/polyimide (KNN/PI) composite films were prepared in this paper. KNN fillers are well dispersed in the PI matrix without any accumulation through in situ polymerization process. The optical band baps of the hybrid films become smaller with the increase of KNN loading. The optical band baps of the films with 0-20 wt% KNN filler are estimated to be 2.61 eV, 2.57 eV, 2.52 eV, 4.29 eV, 2.35 eV respectively.

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Thrivikraman, V. T., e K. Sudheendran. "Structural and optical studies of doped potassium-sodium niobate ceramics". IOP Conference Series: Materials Science and Engineering 1263, n. 1 (1 ottobre 2022): 012014. http://dx.doi.org/10.1088/1757-899x/1263/1/012014.

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In the fields of sensors, actuators and ultrasonic gadgets, piezoelectric ceramics based on lead free KNN(1-8) had been brought due to the development in overall performance. The KNN based substances have the gain of low dielectric constants, excessive coupling coefficient and excessive mechanical electricity than lead containing ceramics that cause them to appropriate for excessive frequency transducers. The traits of KNN may be changed through appropriate dopants. (11).Here we use Bi3+ to dop with KNN to change the properties. Structural determinations of all studied solid solutions are completed through XRD and photoluminescence research had been achieved through the usage of spectrophotometer. Optical spectroscopy evaluation has been accomplished for every solid solution. Doping KNN with Bi3+ at concentrations of 0.5 wt%, 1 wt % and 1.5wt%, respectively, improves the optical properties

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Akça, Erdem, e Hüseyin Yılmaz. "Lead-free potassium sodium niobate piezoceramics for high-power ultrasonic cutting application: Modelling and prototyping". Processing and Application of Ceramics 13, n. 1 (2019): 65–78. http://dx.doi.org/10.2298/pac1901065a.

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The motivation of this study was design, fabrication and characterization of bolt-clamped Langevin type transducers (BLT) from lead-free K0.5Na0.5NbO3 (KNN) based piezoceramics for high-power ultrasonic cutting applications. Hard and lead-free KNN piezoceramics was obtained by adding K4CuNb8O23 (KCN) together with ZnO and SnO2. Densification and high-power characteristics of KNN-KCN piezoceramics were enhanced in the presence of ZnO and SnO2. BLTs made from hard PZT4 (commercial Pb(Zr,Ti)O3) or Zn,Sn co-doped KNN-KCN piezoceramic rings (KNN-KCN-ZnSn) were modelled through ATILA finite element analysis software package. Simulated and experimentally measured impedance spectra, resonance modes and harmonic analysis results of BLTs were compared with each other. Longitudinal vibration displacement at the tip of the horns of BLTs at approximately 30 kHz was measured via photonic sensor device to compare their performances. At the end, based on the simulation and experimental results, a prototype ultrasonic cutting device was fabricated from lead-free KNN-KCN-ZnSn piezoceramic rings. Its cutting action on both plastic and ceramic materials was demonstrated for the first time. In summary, it was found that a hard KNN-KCN based lead-free piezoceramics were good potential replacements for their lead-based counterparts for commercial high-power BLT applications.

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Jenko, Darja, Andreja Benčan, Barbara Malič, Janez Holc e Marija Kosec. "Electron Microscopy Studies of Potassium Sodium Niobate Ceramics". Microscopy and Microanalysis 11, n. 6 (15 novembre 2005): 572–80. http://dx.doi.org/10.1017/s1431927605050683.

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Using electron microscopy, K0.5Na0.5NbO3 (KNN) ceramics sintered at 1030°C for 8 h and 1100°C for 2 and 24 h was studied. The scanning electron microscopy and X-ray spectrometry revealed that the materials consisted of a matrix phase in which the (Na+K)/Nb ratio corresponded closely to the nominal composition and a small amount of Nb-rich secondary phase. A bimodal microstructure of cube-shaped grains was revealed in the fracture and thermally-etched surfaces of the KNN. In the ceramics sintered at 1100°C, the larger grains (up to 30 μm across), contained angular trapped pores. The transmission electron microscopy analysis revealed that the crystal planes of the grains bordering the intragranular pore faces were of the {100} family with respect to the simple perovskite cell. Ferroelectric domains were observed in the grains of this material.

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Bairagi, Satyaranjan, e S. Wazed Ali. "Investigating the role of carbon nanotubes (CNTs) in the piezoelectric performance of a PVDF/KNN-based electrospun nanogenerator". Soft Matter 16, n. 20 (2020): 4876–86. http://dx.doi.org/10.1039/d0sm00438c.

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In the present study, the effect of varying the concentration of carbon nanotubes (CNTs) on the piezoelectric performance of a poly(vinylidene fluoride) (PVDF)/potassium sodium niobate (KNN)-based electrospun nanocomposite has been revealed.

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Serrazina, Ricardo, Julian S. Dean, Ian M. Reaney, Luis Pereira, Paula M. Vilarinho e Ana M. O. R. Senos. "Mechanism of densification in low-temperature FLASH sintered lead free potassium sodium niobate (KNN) piezoelectrics". Journal of Materials Chemistry C 7, n. 45 (2019): 14334–41. http://dx.doi.org/10.1039/c9tc03117k.

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Lead-free potassium sodium niobate (K_0.5Na_0.5NbO₃, KNN) piezoelectric ceramics have been densified at temperatures lower than 300 °C using atmosphere-water assisted FLASH sintering.

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Dolhen, Morgane, Amit Mahajan, Rui Pinho, M. Elisabete Costa, Gilles Trolliard e Paula M. Vilarinho. "Sodium potassium niobate (K0.5Na0.5NbO3, KNN) thick films by electrophoretic deposition". RSC Advances 5, n. 6 (2015): 4698–706. http://dx.doi.org/10.1039/c4ra11058g.

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Luo, Luying, Chao Chen, Hang Luo, Ye Zhang, Kechao Zhou e Dou Zhang. "The effects of precursors on the morphology and microstructure of potassium sodium niobate nanorods synthesized by molten salt synthesis". CrystEngComm 17, n. 45 (2015): 8710–19. http://dx.doi.org/10.1039/c5ce01382h.

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The effects of Nb₂O₅ and K₂Nb₄O₁₁ precursors on the morphology, composition, and piezoelectric properties of potassium sodium niobate (KNN) nanorods were investigated.

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Berksoy, Ayse, e Ebru Mensur Alkoy. "Preperation of Lead-Free Potassium Sodium Niobate Based Piezoelectrics and their Electromechanical Characteristics". Advanced Materials Research 445 (gennaio 2012): 492–96. http://dx.doi.org/10.4028/www.scientific.net/amr.445.492.

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In this study, %7 Li modified and 0.67 % copper oxide added potassium sodium niobate (KNN) ceramics were investigated. Copper oxide was used as a sintering aid. The ceramics were prepared with conventional solid state calcination technique. All samples were crystallized in pure perovskite phase with no additional peak. The density of the samples increased with copper addition and lithium modification. The Curie temperature of KNN ceramics was found to shift to lower temperatures by CuO addition. The Curie temperature was measured as 414°C and 504°C for copper oxide added and lithium modified KNN samples, respectively. The maximum strain of copper oxide added sample was 0.12%, whereas Li modified KL ceramics yielded up to 0.10 %.

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Zhang, Hui, Xiao Hui Wang, Jian Fang e Zheng Bo Shen. "Low Sintering Temperature for Li-, Sb-, and Ta- Modified (K,Na)NbO₃-Based Ceramics from Nanopowders". Key Engineering Materials 591 (novembre 2013): 70–74. http://dx.doi.org/10.4028/www.scientific.net/kem.591.70.

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In this paper, (Na0.52K0.44Li0.04)(Nb0.86Ta0.06Sb0.08)O3 (LTS-KNN) ultrafine-grained ceramic were fabricated over a low and wide temperature range, by using the nanopowder prepared from a water-based sol-gel method. nanopowders are demonstrated to be suitable for preparing fine-grained potassium-sodium niobate ceramics with desirable properties.

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Xing, Jie, Ting Zheng, Jiagang Wu, Dingquan Xiao e Jianguo Zhu. "Progress on the doping and phase boundary design of potassium–sodium niobate lead-free ceramics". Journal of Advanced Dielectrics 08, n. 03 (giugno 2018): 1830003. http://dx.doi.org/10.1142/s2010135x18300037.

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Potassium–sodium niobate (K,Na)NbO3/(KNN) lead-free ceramics have drawn vast amount of attention as one of the effective alternatives to lead-based ones. In recent years, the author’s group concentrated their work on KNN-based ceramics. This paper reviews the main obtained results in authors’ laboratory on how to enhance the piezoelectric properties of KNN-based ceramics, including the ions or compounds substitution, the constructing and types of phase boundaries near room temperature, the investigation of other tools (sintering aids, synthesis technique, poling conditions) on properties. All the published papers up to now show the developing higher performance with maintaining high Curie temperature of KNN-based ceramics which has great potential for the future and is the key to success for the field.

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Song, Yaya, Yanfei Huang, Weiling Guo, Xinyuan Zhou, Zhiguo Xing, Dongyu He e Zhenlin Lv. "Electrical Properties of Li+-Doped Potassium Sodium Niobate Coating Prepared by Supersonic Plasma Spraying". Actuators 11, n. 2 (26 gennaio 2022): 39. http://dx.doi.org/10.3390/act11020039.

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The current work aims to compare the effects of systematic A-site substitutions on the electrical properties of potassium sodium niobate (KNN)-based coating. The A-site elements were replaced by Li+ to form (K0.4675Na0.4675Li0.065) NbO3 (KNLN). The pure KNN coating and the Li+-doped potassium sodium niobate (KNLN) coating with dense morphology and single perovskite structure were successfully prepared by supersonic plasma spraying, and the phase composition, microscopic morphology and electrical properties of the two coatings were compared and analyzed in detail by XRD, XPS, three-dimensional morphology and SEM on an Agilent 4294A (Santa Clara, CA, USA) and FE-5000 wide-range ferroelectric performance tester. The results show that: as the polarization voltage increases, the pure KNN coating is flatter and fuller, but the leakage current is large. The KNLN coating has a relatively long hysteresis loop and is easily polarized. The domain deflection responds faster to the external electric field, and the resistance of the domain wall motion to the external electric field is small. The dielectric constant of KNLN coating is 375, which is much higher than that of the pure KNN coating with 125, and the dielectric loss is stable at 0.01, which is lower than that of pure KNN coating at 0.1–0.35. This is because Li+ doping has successfully constructed a polycrystalline phase boundary in which O-T phases coexist, and has higher dielectric properties, piezoelectric properties and ferroelectric properties. At the same time, due to the high-temperature acceleration process in supersonic plasma spraying, the violent volatilization of the alkaline elements Li+, Na+ and K+ leads to the presence of oxygen vacancies and part of Nb4+ in the coating, which seriously affects the electrical properties of the coating.

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Serrazina, Ricardo, Alexander Tkach, Luis Pereira, Ana M. O. R. Senos e Paula M. Vilarinho. "Flash Sintered Potassium Sodium Niobate: High-Performance Piezoelectric Ceramics at Low Thermal Budget Processing". Materials 15, n. 19 (23 settembre 2022): 6603. http://dx.doi.org/10.3390/ma15196603.

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Alternative sintering technologies promise to overcome issues associated with conventional ceramic sintering such as high thermal budgets and CO2 footprint. The sintering process becomes even more relevant for alkali-based piezoelectric ceramics such as K0.5Na0.5NbO3 (KNN) typically fired above 1100 °C for several hours that induces secondary phase formation and, thereby, degrades their electrical characteristics. Here, an ability of KNN ceramics to be of high performance is successfully demonstrated, using an electric field- and current-assisted Flash sintering technique at 900 °C only. Reported for the first time, Flash sintered KNN ceramics have room-temperature remnant polarization Pr = 21 μC/cm2 and longitudinal piezoelectric coefficient d33 = 117 pC/N, slightly superior to that of conventional ones due to the reduced content of secondary phases. High-performance KNN ceramics Flash sintered at a low-thermal budget have implications for the development of innovative low carbon technologies, electroceramics stakeholders, and piezoelectric energy harvesters.

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Serrazina, Ricardo, Camila Ribeiro, Maria Elisabete Costa, Luis Pereira, Paula M. Vilarinho e Ana M. O. R. Senos. "Particle Characteristics’ Influence on FLASH Sintering of Potassium Sodium Niobate: A Relationship with Conduction Mechanisms". Materials 14, n. 5 (9 marzo 2021): 1321. http://dx.doi.org/10.3390/ma14051321.

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The considerable decrease in temperature and time makes FLASH sintering a more sustainable alternative for materials processing. FLASH also becomes relevant if volatile elements are part of the material to be processed, as in alkali-based piezoelectrics like the promising lead-free K0.5Na0.5NbO3 (KNN). Due to the volatile nature of K and Na, KNN is difficult to process by conventional sintering. Although some studies have been undertaken, much remains to be understood to properly engineer the FLASH sintering process of KNN. In this work, the effect of FLASH temperature, TF, is studied as a function of the particle size and impurity content of KNN powders. Differences are demonstrated: while the particle size and impurity degree markedly influence TF, they do not significantly affect the densification and grain growth processes. The conductivity of KNN FLASH-sintered ceramics and KNN single crystals (SCs) is compared to elucidate the role of particles’ surface conduction. When particles’ surfaces are not present, as in the case of SCs, the FLASH process requires higher temperatures and conductivity values. These results have implications in understanding FLASH sintering towards a more sustainable processing of lead-free piezoelectrics.

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Morshed, T., E. Ul Haq, C. Silien, S. A. M. Tofail, M. A. Zubair e M. F. Islam. "Piezo and pyroelectricity in spark plasma sintered potassium sodium niobate (KNN) ceramics". IEEE Transactions on Dielectrics and Electrical Insulation 27, n. 5 (ottobre 2020): 1428–32. http://dx.doi.org/10.1109/tdei.2020.008820.

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Karacasulu, Levent, e Cekdar Vakifahmetoglu. "Cold sintering assisted two-step sintering of potassium sodium niobate (KNN) ceramics". Materials Science and Engineering: B 297 (novembre 2023): 116709. http://dx.doi.org/10.1016/j.mseb.2023.116709.

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Serrazina, Ricardo, Luis Pereira, Paula M. Vilarinho e Ana M. Senos. "Atmosphere-Assisted FLASH Sintering of Nanometric Potassium Sodium Niobate". Nanomaterials 12, n. 19 (29 settembre 2022): 3415. http://dx.doi.org/10.3390/nano12193415.

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The request for extremely low-temperature and short-time sintering techniques has guided the development of alternative ceramic processing. Atmosphere-assisted FLASH sintering (AAFS) combines the direct use of electric power to packed powders with the engineering of operating atmosphere to allow low-temperature conduction. The AAFS of nanometric Potassium Sodium Niobate, K0.5Na0.5NbO3, a lead-free piezoelectric, is of great interest to electronics technology to produce efficient, low-thermal-budget sensors, actuators and piezo harvesters, among others. Not previously studied, the role of different atmospheres for the decrease in FLASH temperature (TF) of KNN is presented in this work. Additionally, the effect of the humidity presence on the operating atmosphere and the role of the compact morphology undergoing FLASH are investigated. While the low partial pressure of oxygen (reducing atmospheres) allows the decrease of TF, limited densification is observed. It is shown that AAFS is responsible for a dramatic decrease in the operating temperature (T < 320 °C), while water is essential to allow appreciable densification. In addition, the particles/pores morphology on the green compact impacts the uniformity of AAFS densification.

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Piah, Hidayah Mohd Ali, Mohd Warikh Abd Rashid, Umar Al-Amani Azlan e Maziati Akmal Mohd Hatta. "Potassium sodium niobate (KNN) lead-free piezoceramics: A review of phase boundary engineering based on KNN materials". AIMS Materials Science 10, n. 5 (2023): 835–61. http://dx.doi.org/10.3934/matersci.2023045.

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<abstract> <p>Lead zirconia titanate (PZT) is the most often used piezoelectric material in various electronic applications like energy harvesters, ultrasonic capacitors and motors. It is true that PZT has a lot of significant drawbacks due to its 60% lead content, despite its outstanding ferroelectric, dielectric and piezoelectric properties which influenced by PZT's morphotropic phase boundary. The recently found potassium sodium niobate (KNN) is one of the most promising candidates for a new lead-free piezoelectric material. For the purpose of providing a resource and shedding light on the future, this paper provides a summary of the historical development of different phase boundaries in KNN materials and provides some guidance on how to achieve piezoelectric activity on par with PZT through a thorough examination and critical analysis of relevant articles by providing insight and perspective of KNN, which consists of detailed evaluation of the design, construction of phase boundaries and engineering for applications.</p> </abstract>

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Tkach, Alexander, André Santos, Sebastian Zlotnik, Ricardo Serrazina, Olena Okhay, Igor Bdikin, Maria Elisabete Costa e Paula M. Vilarinho. "Effect of Solution Conditions on the Properties of Sol–Gel Derived Potassium Sodium Niobate Thin Films on Platinized Sapphire Substrates". Nanomaterials 9, n. 11 (11 novembre 2019): 1600. http://dx.doi.org/10.3390/nano9111600.

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If piezoelectric micro-devices based on K0.5Na0.5NbO3 (KNN) thin films are to achieve commercialization, it is critical to optimize the films’ performance using low-cost scalable processing conditions. Here, sol–gel derived KNN thin films are deposited using 0.2 and 0.4 M precursor solutions with 5% solely potassium excess and 20% alkali (both potassium and sodium) excess on platinized sapphire substrates with reduced thermal expansion mismatch in relation to KNN. Being then rapid thermal annealed at 750 °C for 5 min, the films revealed an identical thickness of ~340 nm but different properties. An average grain size of ~100 nm and nearly stoichiometric KNN films are obtained when using 5% potassium excess solution, while 20% alkali excess solutions give the grain size of 500–600 nm and (Na + K)/Nb ratio of 1.07–1.08 in the prepared films. Moreover, the 5% potassium excess solution films have a perovskite structure without clear preferential orientation, whereas a (100) texture appears for 20% alkali excess solutions, being particularly strong for the 0.4 M solution concentration. As a result of the grain size and (100) texturing competition, the highest room-temperature dielectric permittivity and lowest dissipation factor measured in the parallel-plate-capacitor geometry were obtained for KNN films using 0.2 M precursor solutions with 20% alkali excess. These films were also shown to possess more quadratic-like and less coercive local piezoelectric loops, compared to those from 5% potassium excess solution. Furthermore, KNN films with large (100)-textured grains prepared from 0.4 M precursor solution with 20% alkali excess were found to possess superior local piezoresponse attributed to multiscale domain microstructures.

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Cheng, Chien Min, Shih Fang Chen, Jen Hwan Tsai, Kai Huang Chen e Hsiu Hsien Su. "Electrical and Physical Properties of Sodium Potassium Niobates Thin Films Prepared by rf Magnetron Sputtering Technology". Advanced Materials Research 239-242 (maggio 2011): 532–35. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.532.

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Lead-free potassium sodium niobate ceramic thin films were synthesized using rf magnetron sputtering technology for MFIS structures. The optimal sputtering parameters of the as-deposited KNN thin films for depositing times of 1h were obtained. Regarding the measured physical properties, the micro-structure and thickness of as-deposited KNN thin films for different oxygen concentration were obtained and compared by XRD patterns and SEM images. The surface roughness of KNN thin film was also observed by AFM morphology. The average grain size and root mean square roughness were 250 and 7.04 nm, respectively. For KNN thin films in the MFIS structure, the capacitance and leakage current density were 280 pF and 10-8A/cm2, respectively. We investigated that the leakage current density and the memory window increased, the capacitance critically increased as the oxygen concentration increased from 0 to 40%. However, the excess oxygen concentration process was decreased the electrical and physical of as-deposited KNN thin film. The effect of oxygen concentration on the physical and electrical characteristics of KNN thin films was investigated and determined.

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Ho, Kuan-Ting, Daniel Monteiro Diniz Reis e Karla Hiller. "Resistance degradation in sputtered sodium potassium niobate thin films and its relationship to point defects". Applied Physics Letters 121, n. 16 (17 ottobre 2022): 162902. http://dx.doi.org/10.1063/5.0106382.

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The reliability of piezoelectric thin films is crucial for piezoelectric micro-electromechanical system applications. The understanding of resistance degradation in piezoelectric thin films requires knowledge about point defects. Here, we show the resistance degradation mechanism in the lead-free alternative sodium potassium niobate (KNN) thin films and the relationship to point defects in both field-up and field-down polarities. The conduction mechanism of KNN thin films is found to be Schottky-limited. Furthermore, a reduction in Schottky barrier height accompanies the resistance degradation resulting from interfacial accumulation of additional charged defects. We use thermally stimulated depolarization current measurements and charge-based deep level transient spectroscopy to characterize the defects in KNN thin films. Our results show that oxygen vacancies accumulate at the interface in field-up polarity, and multiple defects accumulate in field-down polarity, potentially oxygen vacancies and holes trapped by potassium vacancies. We use wafer deposition variation to create samples with different film properties. Measurement results from these samples correlate resistance degradation with the defect concentration. We find the natural logarithm of leakage current to be linearly proportional to the defect concentration to the power of 0.25. The demonstrated analysis provides a precise and meaningful process assessment for optimizing KNN thin films.

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Gao, Rui, Weiling Guo, Hongxing Wang, Xuewu Li e Zhiguo Xing. "Effect of Mn Doping on the Microstructure and Electrical Properties of Potassium Niobate Ceramics Using Plasma Spraying". Actuators 11, n. 12 (23 novembre 2022): 343. http://dx.doi.org/10.3390/act11120343.

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KNN piezoelectric ceramics are of great importance in the field of scientific research due to their high Curie temperature, good electrical properties, etc. The application of potassium sodium niobate K0.5Na0.5NbO3 (KNN) is strictly limited due to the volatility of Na+ and K+ in KNN and its leakage current. In order to investigate the effect of Mn doping on KNN-based piezoelectric ceramic coatings, KNN and KNN-0.02Mn (KNMN) coatings were successfully prepared using a plasma spraying technique. The phase structure, microscopic morphology, and electrical properties of the coatings were studied in the research. The results showed that both the KNN and KNMN coatings had chalcogenide structures. The KNN coating had an orthogonal phase structure, whereas the KNMN coating had a tetragonal phase structure. Compared with the KNN coating, the microhardness of the KNMN coating was improved through doping with Mn ions. The doping of Mn ions could replace both the A and B sites in the KNN piezoelectric ceramics, further reducing the oxygen vacancies and leakage currents in the coating, and its dielectric properties were improved.

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Yang, Zetian, Hongliang Du, Shaobo Qu, Yudong Hou, Hua Ma, Jiafu Wang, Jun Wang, Xiaoyong Wei e Zhuo Xu. "Significantly enhanced recoverable energy storage density in potassium–sodium niobate-based lead free ceramics". Journal of Materials Chemistry A 4, n. 36 (2016): 13778–85. http://dx.doi.org/10.1039/c6ta04107h.

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Tkach, Alexander, André Santos, Sebastian Zlotnik, Ricardo Serrazina, Olena Okhay, Igor Bdikin, Maria Elisabete Costa e Paula M. Vilarinho. "Strain-Mediated Substrate Effect on the Dielectric and Ferroelectric Response of Potassium Sodium Niobate Thin Films". Coatings 8, n. 12 (6 dicembre 2018): 449. http://dx.doi.org/10.3390/coatings8120449.

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If piezoelectric thin films sensors based on K0.5Na0.5NbO3 (KNN) are to achieve commercialization, it is critical to optimize the film performance using low-cost scalable processing and substrates. Here, sol–gel derived KNN thin films are deposited using a solution with 5% of potassium excess on Pt/TiO2/SiO2/Si and Pt/SrTiO3 substrates, and rapid thermal annealed at 750 °C for 5 min. Despite an identical film morphology and thickness of ~335 nm, an in-plane stress/strain state is found to be tensile for KNN films on Pt/TiO2/SiO2/Si, and compressive for those on Pt/SrTiO3 substrates, being related to thermal expansion mismatch between the substrate and the film. Correspondingly, KNN films under in-plane compressive stress possess superior dielectric permittivity and polarization in the parallel-plate-capacitor geometry.

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Sharma, J. P., Dewashish Kumar e Ashwini K. Sharma. "Structural and dielectric properties of pure potassium sodium niobate (KNN) lead free ceramics". Solid State Communications 334-335 (agosto 2021): 114345. http://dx.doi.org/10.1016/j.ssc.2021.114345.

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Wu, Bo, Jiagang Wu, Dingquan Xiao e Jianguo Zhu. "Modification of both d33 and TC in a potassium–sodium niobate ternary system". Dalton Transactions 44, n. 48 (2015): 21141–52. http://dx.doi.org/10.1039/c5dt03680a.

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In this work, we simultaneously achieved a giant d₃₃ and a high T_C in a lead-free piezoelectric ternary system of (1 − x − y)K_0.48Na_0.52NbO₃–xBiFeO₃–yBi_0.5Na_0.5ZrO₃ {(1 − x − y)KNN–xBF–yBNZ}.

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Dumitrescu, Cristina Rodica, Ionela Andreea Neacsu, Roxana Trusca, Roxana Cristina Popescu, Iuliana Raut, Mariana Constantin e Ecaterina Andronescu. "Piezoelectric Biocomposites for Bone Grafting in Dentistry". Polymers 15, n. 11 (25 maggio 2023): 2446. http://dx.doi.org/10.3390/polym15112446.

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In this research, Hydroxyapatite—Potassium, Sodium Niobate—Chitosan (HA-KNN-CSL) biocomposites were synthesized, both as hydrogel and ultra-porous scaffolds, to offer two commonly used alternatives to biomaterials in dental clinical practice. The biocomposites were obtained by varying the content of low deacetylated chitosan as matrix phase, mesoporous hydroxyapatite nano-powder, and potassium–sodium niobate (K0.47Na0.53NbO3) sub-micron-sized powder. The resulting materials were characterized from physical, morpho-structural, and in vitro biological points of view. The porous scaffolds were obtained by freeze-drying the composite hydrogels and had a specific surface area of 18.4—24 m2/g and a strong ability to retain fluid. Chitosan degradation was studied for 7 and 28 days of immersion in simulated body fluid without enzymatic presence. All synthesized compositions proved to be biocompatible in contact with osteoblast-like MG-63 cells and showed antibacterial effects. The best antibacterial effect was shown by the 10HA-90KNN-CSL hydrogel composition against Staphylococcus aureus and the fungal strain Candida albicans, while a weaker effect was observed for the dry scaffold.

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Khorrami, Gh H., A. Kompany e A. Khorsand Zak. "Structural and optical properties of KNN nanocubes synthesized by a green route using gelatin". Functional Materials Letters 08, n. 02 (aprile 2015): 1550030. http://dx.doi.org/10.1142/s1793604715500307.

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Sodium potassium niobate nanoparticles [( K 0.5 Na 0.5) NbO 3, KNN ], KNN-NPs, were synthesized using a modified sol–gel method. Structural and optical properties of the prepared samples were investigated by thermogravometric analyzer (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman and UV–Vis spectroscopy. The XRD patterns showed that the formation of the orthorhombic KNN-NPs starts at 500°C calcination temperature. Raman spectroscopy was used to investigate the crystalline symmetry and the structural deformation of the prepared KNN-NPs. TEM images showed that the morphology of the prepared particles is cubic, with the average size of about 50 nm. From diffused reflectance spectroscopy along with using Kubelka–Munk method, the energy bandgaps were determined to be indirect with the values of 3.13 eV and 3.19 eV for the samples calcined at 500°C and 600°C, respectively.

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Pinho, R., M. Asif, M. E. Costa e P. M. Vilarinho. "Texturization of potassium sodium niobate (KNN) ceramics in the presence of CuO and MnO". Microscopy and Microanalysis 21, S6 (agosto 2015): 130–31. http://dx.doi.org/10.1017/s1431927614014354.

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32

Rutkowski, Paweł, Jan Huebner, Adrian Graboś, Dariusz Kata, Bogdan Sapiński e Marek Faryna. "Dense KNN Polycrystals Doped by Er2O3 Obtained by Hot Pressing with Hexagonal Boron Nitride Protective Layer". Materials 13, n. 24 (16 dicembre 2020): 5741. http://dx.doi.org/10.3390/ma13245741.

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Analysis of dense Potassium Sodium Niobate (KNN) ceramic obtained by hot pressing (HP) method at 1100 °C are presented in this paper. The synthesis of KNN-based piezoelectrics meets the following challenges—low density of material, uncontrolled K/Na ratio, multiphase composition and formation of different KNN structures. The classical hot pressing approach results in contamination by carbon originating from graphite molds. The proposed hexagonal Boron Carbide (h-BN) layer between green sample and graphite mold could protect samples from carbon contamination. Additionally, the presence of h-BN may decrease the formation of oxygen vacancies, which allows us to maintain the semiconductor features of the KNN structure. Remaining issues were addressed with the addition of excess Na and Er2O3 doping. The results showed that excess Na addition allowed us to compensate evaporation of sodium during the synthesis and sintering. Er2O3 was added as sintering aid to limit abnormal grain growth caused by h–BN addition. The modification of amount of Na and Er2O3 addition resulted in high purity KNN samples with tetragonal structure and apparent density higher than 97%. Finally, piezoelectric features of prepared dense samples were measured and presented.

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Mat Daud, Norni Hidayawati, Dzetty Soraya Abdul Aziz, Idza Riati Ibrahim, Dayang Salyani Abang Mahmod, Amir Azam Khan, Nor Amalina Ahmad e Nurul Aisyah Farhani Mohd Fuad. "INFLUENCE OF DOUBLE CALCINATION-MILLING ROUTE ON THE STRUCTURAL AND MICROSTRUCTURAL PROPERTIES OF LEAD-FREE K0.5NA0.5NBO3 (KNN) CERAMICS". Jurnal Teknologi 85, n. 3 (19 aprile 2023): 75–81. http://dx.doi.org/10.11113/jurnalteknologi.v85.19202.

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Potassium sodium niobate (KNN) has always been one of the most potential candidates to replace lead-based piezoelectric ceramics due to its strong piezoelectric properties and environmentally friendly composition. A strong piezoelectric property is constantly influenced by the sample's densification as well as its microstructural characteristics. One of the current main issues with this KNN lead-free piezoelectric material is the difficulty in creating high-density samples by conventional preparation and sintering. Thus, KNN lead-free ceramics were synthesised using an improved solid-state method by introducing the double calcination-milling route to this process. The outcome demonstrates that, despite the presence of additional KNN secondary phases, the double calcination-milling approach contributed to the early creation of the KNN phase. When sintered pellets are subjected to a double calcination milling process, the XRD pattern revealed that the main peaks of the sample are indexed to orthorhombic K0.5Na0.5NbO3. The double calcination KNN pellet have a relative density of 90% densification which is slightly higher than that of single calcination KNN pellet which shows 88% densification.

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Kuan, Min Chang, Fann Wei Yang, Chien Min Cheng, Kai Huang Chen e Jian Tz Lee. "Electrical and Physical Properties of (K_0.5Na_0.5)NbO₃ Ferroelectric Thin Films". Key Engineering Materials 602-603 (marzo 2014): 800–803. http://dx.doi.org/10.4028/www.scientific.net/kem.602-603.800.

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Lead-free potassium sodium niobate ceramic thin films were synthesized using rf magnetron sputtering technology for MFIS structures. The optimal sputtering parameters of the as-deposited KNN thin films for depositing times of 1h were obtained. Regarding the measured physical properties, the micro-structure and thickness of as-deposited KNN thin films for different oxygen concentration were obtained and compared by XRD patterns and SEM images. The surface roughness of KNN thin film was also observed by AFM morphology. The average grain size and root mean square roughness were 250 and 7.04 nm, respectively. For KNN thin films in the MFIS structure, the capacitance and leakage current density were 280 pF and 10-8A/cm2, respectively. We investigated that the leakage current density and the memory window increased, the capacitance critically increased as the oxygen concentration increased from 0 to 40%. However, the excess oxygen concentration process was decreased the electrical and physical of as-deposited KNN thin film. The effect of oxygen concentration on the physical and electrical characteristics of KNN thin films was investigated and determined.

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Yang, Fann Wei, Chien Min Cheng e Kai Huang Chen. "Processing and Electrical Properties of Ta and Li-Modified KNN-Based Lead-Free Thin Films Prepared by the RF Sputtering Technology". Key Engineering Materials 512-515 (giugno 2012): 1372–75. http://dx.doi.org/10.4028/www.scientific.net/kem.512-515.1372.

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Abstract (sommario):

Lead-free potassium sodium niobate ceramic thin films were synthesized using rf magnetron sputtering technology for MFIS structures. The optimal sputtering parameters of the as-deposited KNN thin films for depositing times of 1h were obtained. Regarding the measured physical properties, the micro-structure and thickness of as-deposited KNN thin films for different oxygen concentration were obtained and compared by XRD patterns and SEM images. The surface roughness of KNN thin film was also observed by AFM morphology. The average grain size and root mean square roughness were 250 and 7.04 nm, respectively. For KNN thin films in the MFIS structure, the capacitance and leakage current density were 280 pF and 10-8A/cm2, respectively. We investigated that the leakage current density and the memory window increased, the capacitance critically increased as the oxygen concentration increased from 0 to 40%. However, the excess oxygen concentration process was decreased the electrical and physical of as-deposited KNN thin film. The effect of oxygen concentration on the physical and electrical characteristics of KNN thin films was investigated and determined.

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Khorrami, Gh H., M. Mousavi e M. Dowran. "Structural and optical properties of KNN nanoparticles synthesized by a sol–gel combustion method". Modern Physics Letters B 31, n. 15 (26 maggio 2017): 1750175. http://dx.doi.org/10.1142/s0217984917501755.

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Abstract (sommario):

In this paper, potassium sodium niobate (KNN) nanopowders were successfully obtained by sol–gel combustion method. According to thermogravimetric analysis (TGA) results, the produced xerogel was calcined at 500[Formula: see text]C, 600[Formula: see text]C, and 700[Formula: see text]C to obtain KNN powders. The structural and optical properties of the prepared powders were studied using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, transmission electron microscopy (TEM), and UV–vis spectroscopy. The XRD patterns indicated formation of orthorhombic KNN samples. The Scherrer formula and size–strain plot (SSP) method were employed to calculate crystallite size and lattice strain of the KNN powders. The TEM image revealed that the average particle size of the prepared samples is about 30 nm and they have cubic shape. The optical band gap energy of the samples was calculated using UV–vis absorbance spectra of the samples along with Tauc relation.

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Tao, Hong, Jie Yin, Chunlin Zhao, Bo Wu, Lin Zhao, Jian Ma e Jiagang Wu. "Large electrocaloric effect under electric field behavior in potassium sodium niobate ceramics with incompletely overlapped phase boundaries". Journal of Materials Chemistry A 10, n. 10 (2022): 5262–72. http://dx.doi.org/10.1039/d1ta10899a.

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38

Shalini, K., e N. V. Giridharan. "Coexistence of electric polarization and magnetic ordering in acceptor doped potassium sodium niobate (KNN) ceramics". Materials Research Express 5, n. 9 (8 agosto 2018): 096104. http://dx.doi.org/10.1088/2053-1591/aacf28.

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Madani, Ali, Ridha Ben Mrad e Anthony N. Sinclair. "Characterization of RF sputtered thin film potassium sodium niobate (KNN) with silicon and nickel electrodes". Microsystem Technologies 23, n. 6 (17 agosto 2016): 1943–48. http://dx.doi.org/10.1007/s00542-016-3106-x.

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40

Jiang, Xiang-Ping, Xing-An Jiang, Chao Chen, Na Tu, Yun-Jing Chen e Ban-Chao Zhang. "Effect of potassium sodium niobate (KNN) substitution on the structural and electrical properties of Na0.5Bi4.5Ti4O15ceramics". Journal of Physics D: Applied Physics 49, n. 12 (24 febbraio 2016): 125101. http://dx.doi.org/10.1088/0022-3727/49/12/125101.

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41

Sareein, Thanapong, Muangjai Unruan, Athipong Ngamjarurojana, Supon Ananta e Rattikorn Yimnirun. "Effects of Compressive Stress on Dielectric Properties of Lead-Free (Bi_1/2Na_1/2)TiO₃-(K_1/2Na_1/2)NbO₃ Ceramic Systems". Key Engineering Materials 421-422 (dicembre 2009): 54–57. http://dx.doi.org/10.4028/www.scientific.net/kem.421-422.54.

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Lead-free, bismuth sodium titanate-potassium sodium niobate piezoelectric ceramics (Bi1/2Na1/2)TiO3-(K1/2Na1/2)NbO3 have been prepared by a conventional mixed-oxide method via vibro-milling technique. The (K1/2Na1/2)NbO3 (KNN)-based compositions with a morphotropic phase boundary (MPB) have shown greater advantages over another typical lead-free piezoelectric candidate material system, (Bi1/2Na1/2)TiO3 (BNT)-based MPB materials. More importantly, when used this type of material is often subjected to self-induced or external stress. It is, therefore, of interest to investigate influence of stress on properties of the ceramics. In this study, the influences of compressive stress on the dielectric properties of BNT-KNN ceramics were investigated. The dielectric properties were determined under compressive stress applied parallel to electric field. The results indicate significant changes of both properties with the imposed compressive stress. The results were explained in terms of non-180˚ domain switching and de-aging of the dielectric properties under the influence of the applied stress.

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Pang, Qianyi, Lanruo Han e Xiang Yu. "Doping modification in lead-free piezoelectric ceramics". Highlights in Science, Engineering and Technology 55 (9 luglio 2023): 166–75. http://dx.doi.org/10.54097/hset.v55i.9952.

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Piezoelectric ceramics are functional information ceramic materials that can convert mechanical and electrical energy into each other. They are widely used in high-tech fields, such as the electronics industry, machinery, and aerospace. Currently, Pb(ZrTi)O3 (PZT) piezoelectric materials are most commonly used, but the main component, PbO, is toxic and volatile during production and manufacturing, thus causing certain damage to human health and the environment. Therefore, research on green and environmentally friendly lead-free piezoelectric materials has been attracting much attention. This paper will therefore present two lead-free piezoelectric ceramics that have the potential to replace PZT-based lead-containing piezoelectric materials: Potassium Sodium Niobate (KNN)-based piezoelectric ceramics and Bismuth Sodium Titanate (BNT)-based lead-free piezoelectric ceramics. The piezoelectric constants of lead-free piezoelectric ceramics represented by systems such as KNN and BNT are now comparable to those of lead-containing piezoelectric ceramics and are gradually replacing traditional lead-based piezoelectric ceramics in fields such as ultrasonic atomization and hydroacoustic energy transfer.

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Deng, Yunfeng, Junjun Wang, Chunxiao Zhang, Hui Ma, Chungeng Bai, Danqing Liu, Fengmin Wu e Bin Yang. "Structural and Electric Properties of MnO2-Doped KNN-LT Lead-Free Piezoelectric Ceramics". Crystals 10, n. 8 (15 agosto 2020): 705. http://dx.doi.org/10.3390/cryst10080705.

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Structural, ferroelectric, dielectric, and piezoelectric properties of K0.5Na0.5NbO3-LiTaO3-xmol%MnO2 lead-free piezoelectric ceramics with 0.0 ≤ x ≤ 0.3 were studied. The ceramic samples were synthesized through the conventional solid-state reaction method. The MnO2 addition can reduce the sintering temperature of KNLNT ceramics. Compared with undoped KNLNT ceramic, the piezoelectric measurements showed that piezoelectric properties of K0.5Na0.5NbO3-LiTaO3-xMnO2 were improved (d33 = 251 pC/N) when x = 0.1. In addition, KNLNT-xMnO2 ceramics have larger Pr(20.59~21.97 μC/cm2) and smaller Ec(10.77~6.95 kV/cm), which indicates MnO2 has excellent softening property, which improves the ferroelectric properties of KNLNT ceramics This work adds relevant information regarding of potassium sodium niobate K0.5Na0.5NbO3 (KNN) when doped Li, Ta, Mn at the B-site.

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Han, Ruilin, Tingting Gao, Yining Xie, Lixu Xie, Yuan Cheng, Xu Li, Hao Chen, Jie Xing e Jianguo Zhu. "The Effect of Nb2O5 Precursor on KNN-Based Ceramics’ Piezoelectricity and Strain Temperature Stability". Crystals 12, n. 12 (7 dicembre 2022): 1778. http://dx.doi.org/10.3390/cryst12121778.

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Abstract (sommario):

The performance of potassium sodium niobate ((K, Na) NbO3, KNN)-based lead-free piezoelectric ceramics has significantly improved over the past decade. However, the performance bottlenecks of KNN-based ceramics cannot be ignored. Here, the Nb2O5 precursor is obtained after thermal pretreatment, which can evidently improve the piezoelectric properties and strain temperature stability of KNN-based ceramics. With the help of the Nb2O5 precursor treated at 800 °C, the optimal piezoelectric constant d33 of 303 pC/N, inverse piezoelectric constant d*33 of 378 pm/V, Curie temperature TC of 310 °C and electromechanical coupling factor kp of 42% are obtained, and the value of d33 improves by about 30% compared with that of the ceramic prepared with untreated Nb2O5 as raw material. Additionally, in comparison with the strain temperature stability of the ceramics prepared with untreated Nb2O5 as raw material, the temperature stability is enhanced. Therefore, this study provides a useful approach to break the existing performance bottleneck and further improve the properties of KNN-based ceramics.

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Wu, Jiagang, Hong Tao, Yuan Yuan, Xiang Lv, Xiangjian Wang e Xiaojie Lou. "Role of antimony in the phase structure and electrical properties of potassium–sodium niobate lead-free ceramics". RSC Advances 5, n. 19 (2015): 14575–83. http://dx.doi.org/10.1039/c4ra14271c.

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Abstract (sommario):

In the past ten years, antimony has been reported to strongly affect the developments in the piezoelectric properties of (K,Na)NbO₃ (KNN) lead-free ceramics, that is, its enhanced piezoelectric activity is closely related to the doped antimony as well its content.

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Wu, Mengjun, Ting Zheng, Haiwu Zheng, Jifang Li, Weichao Wang, Mingsai Zhu, Fengzhu Li, Gentian Yue, Yuzong Gu e Jiagang Wu. "High-performance piezoelectric-energy-harvester and self-powered mechanosensing using lead-free potassium–sodium niobate flexible piezoelectric composites". Journal of Materials Chemistry A 6, n. 34 (2018): 16439–49. http://dx.doi.org/10.1039/c8ta05887c.

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A flexible piezoelectric nanogenerator (PENG) was fabricated based on a new inorganic piezoelectric KNN–BNZ–AS–Fe, which exhibited the great potential in energy harvesting and self-powered mechanosensing.

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Tang, Yan, Lingyan Wang, Wei Ren, Yi Quan, Jinyan Zhao, Zhe Wang, Kun Zheng, Jian Zhuang e Gang Niu. "Effect of Sintering Conditions on the Electrical Properties of Lead-Free Piezoelectric Potassium Sodium Niobate-Based Ceramics". Crystals 12, n. 12 (8 dicembre 2022): 1784. http://dx.doi.org/10.3390/cryst12121784.

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Lead-free piezoelectric 0.92(K0.445Na0.5Li0.05)NbO3-0.08BaZrO3 (KNLN-BZ) ceramics were prepared via conventional sintering. Single-step, 2-step and 3-step temperature-controlled conditions were designed. The structure and electrical properties of ceramics obtained using different temperature-controlled procedures were systematically studied. It was found that ceramic prepared using the 3-step method with a holding time of 20 h showed the highest electrical properties. The Curie temperature was approximately 286 °C, and the dielectric constant and dielectric loss at room temperature were 1350 and 4.5% at the frequency of 1 kHz, respectively. The highest remanent polarization, piezoelectric strain and piezoelectric coefficient, d33*, were obtained 60 °C, indicating a phase transition between ferroelectric phases. Although the ceramics did not show excellent piezoelectric properties, the 3-step sintering method can be considered an effective method to optimize the electrical performances of KNN-based ceramics. Combined with an appropriate composition, ceramics with excellent electrical properties could be obtained. This study provides a path to enhance the density and electrical properties for KNN-based ceramics with simple composition and potential for industry application.

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Ibn-Mohammed, T., S. C. L. Koh, I. M. Reaney, A. Acquaye, D. Wang, S. Taylor e A. Genovese. "Integrated hybrid life cycle assessment and supply chain environmental profile evaluations of lead-based (lead zirconate titanate) versus lead-free (potassium sodium niobate) piezoelectric ceramics". Energy & Environmental Science 9, n. 11 (2016): 3495–520. http://dx.doi.org/10.1039/c6ee02429g.

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Contrary to conventional knowledge, LCA of PZT vs. KNN indicates the presence of niobium in KNN constitutes far greater impact across all the 16 categories considered in comparison with PZT. The increased environmental impact of KNN occurs in the early stages of the LCA due to raw material extraction and processing.

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Yongsiri, Ploypailin, Wipada Senanon, Pratthana Intawin e Kamonpan Pengpat. "Dielectric Properties and Microstructural Studies of Er₂O₃ Doped Potassium Sodium Niobate Silicate Glass-Ceramics". Key Engineering Materials 766 (aprile 2018): 258–63. http://dx.doi.org/10.4028/www.scientific.net/kem.766.258.

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In this work, electrical and structural properties of ferroelectric glasses and glass-ceramics from K0.5Na0.5NbO3-SiO2 doped with 0.5-1.0 mol%Er2O3 system have been investigated. The influent of Er2O3 dopant was also compared with the original glass. The K0.5Na0.5NbO3 (KNN) powder was mixed with SiO2 in composition of 75KNN-25SiO2 and doped with Er2O3. Well-mixed powder was subsequently melted at 1300°C for 15 min in a platinum crucible using an electric furnace. The quenched glasses were then subjected to heat treatment at various temperatures for 4 h. From the study, KNN single phase in transparent glass was successfully prepared via incorporation method. The maximum Ԑr of about 360 at 10 kHz with a low tanδ of 0.07 could be obtained from the glass-ceramic sample of 75KNN–25SiO2 doped 0.5 mol% Er2O3 and heat treated at 600°C. It can be seen that the higher percent of Er2O3 can lower the dielectric loss of KNN glass-ceramics. This interesting value suggesting the opportunity of using them in electronic applications in the future.

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Shibata, Kenji, Kazutoshi Watanabe, Toshiaki Kuroda e Takenori Osada. "KNN lead-free piezoelectric films grown by sputtering". Applied Physics Letters 121, n. 9 (29 agosto 2022): 092901. http://dx.doi.org/10.1063/5.0104583.

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Abstract (sommario):

Potassium sodium niobate [(K,Na)NbO3, KNN] films are promising lead-free piezoelectric materials for microelectromechanical systems (MEMS) devices. We previously developed technologies for forming high-quality KNN films by sputtering, which showed excellent piezoelectric properties comparable to lead zirconate titanate (PZT) films. In the present study, we addressed several challenges with the aim of introducing KNN films into commercialized MEMS devices. First, we optimized the dielectric and piezoelectric properties to realize a suitable performance for actuator and sensor devices. The sensor-type KNN films had a low dielectric constant (248) and a self-poling function, which are greatly beneficial for sensor device performance and the fabrication process. The actuator-type KNN films had a very high e31 value of −13.5 C/m2, which is almost comparable to the top level of PZT films. Next, we found that the DC stress lifetime of KNN films strongly depended on the material used for the adhesion layer of the top electrode. When we used a Pt/RuO2 top electrode, the actuator-type KNN films had a long lifetime (>130 000 s, 300 kV/cm and 200 °C), which is long enough to be used for commercialized MEMS devices. Furthermore, we realized 8-in. KNN wafers with good thickness uniformity across the wafer (±3.5%) by introducing a mass-production-ready sputtering tool: the EB-2500 produced by Canon Anelva. In the near future, these promising results will open the way to replace PZT with KNN in the piezoMEMS industry.

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