Spanish
German
Japanese
French
Portuguese
Italian
KoreanNiobate lead-free piezoelectric ceramics
Niobate series of lead-free piezoelectric ceramics (referred to as NKN or KNN), bismuth-containing lead-free piezoelectric ceramic layered structure, sodium bismuth titanate series of lead-free piezoelectric ceramics, tungsten bronze structure-based lead-free piezoelectric ceramics and free BaTiO_3 Lead piezoelectric ceramics. In the above lead-free piezoelectric ceramic materials, niobate lead-free piezoelectric ceramics because of its series of excellent piezoelectric activity and concern, but difficult niobate ceramics sintered shortcomings. With in-depth study of lead-free piezoelectric ceramics, it was found that control of calcination, sintering temperature and improve the preparation process, changing the composition of stoichiometric ceramic, control the size of raw material powder so you can get high-density NKN ceramics, the piezoelectric performance also has been improved to some extent. Modified in these experiments, the most commonly used alternative is the same price, that the introduction of Li elements of the A, B bit into Ta, Sb element. In this regard in recent years, researchers have done a lot of research work, and has made great progress, this paper has also done some of this research work. Perovskite structure is an important feature of the location A and B positions of the ions can be different types of electricity and the radius of the ions over a wide concentration range of single or composite replacement, which can be adjusted in a wide range of materials performance to meet the requirements of different occasions.
Research in this area is still small, the current study focused on the alkaline earth elements on the A-site donor doped alkali and alkaline earth elements on the titanate doped elements, rare earth elements and variable elements doped price research also very small. This paper studied the equivalent of replacing the A elements Li, Ta, Sb is equivalent to replace the B-site elements on lead-free piezoelectric ceramics NKN impact, prepared Curie point, high-voltage activity of lead-free piezoelectric ceramic samples. In view of NKN-based lead-free piezoelectric ceramics sintered hard shortcomings, this paper focuses on the rare earth elements Ce, Pr, Nd and variable price elements of W-doped lead-free piezoelectric ceramics of NKN in the preparation process, physical properties, piezoelectric properties, dielectric nature of the impact of NKN to find out the optimal conditions for lead-free piezoelectric ceramic sintering method, its narrow sintering temperature range extended from 10 ℃ to 40 ℃, and significantly improved the temporal stability of piezoelectric ceramic samples for NKN-based lead-free piezoelectric ceramic materials for industrial production provides a theoretical and experimental basis. In the second chapter of the same price instead of the A Li NKN lead-free piezoelectric ceramic materials microstructure, piezoelectric and dielectric properties. Experimental studies confirm the Li-doped NKN-based lead-free piezoelectric ceramic materials (referred to as NKLN) in quadrature - the same type of quasi-tetragonal phase boundary exists and the material found in the first phase the second phase of tungsten bronze structure exists . And preparation of the performance of lead-free piezoelectric ceramics NKLN sample: d_ (33) = 202-212pC / N, tgδ = 1.7% -1.9%, k_p = 44.4% -46.8%, T_c = 490 ℃ -510 ℃. High Curie temperature and excellent piezoelectric properties of lead-free piezoelectric ceramic materials that NKLN is a promising high-temperature lead-free piezoelectric ceramics. And later studied with the price B-Ta Li substitution and replacement of the A NKN-based lead-free piezoelectric ceramics piezoelectric, dielectric properties. Experiment from the X-ray diffraction and dielectric spectroscopy warm start, focused on analysis of relative changes in the structure and found that there is a second phase, to explore NKLNT orthogonal lead-free piezoelectric ceramics - the same type of quasi-tetragonal phase boundary with the Li content changes in the law. The study found that the introduction of small amounts of Ta, enhanced the effect of substitutional Li, improve NKLN lead-free piezoelectric properties of piezoelectric ceramics. Content in the 0.053 ≤ Ta ≤ 0.057 when the NKN-based lead-free piezoelectric ceramics of the same type of quasi-phase boundary (MPB), a high piezoelectric properties of the sample at this time, piezoelectric strain constant, electromechanical coupling coefficient and loss were d_ (33) = 248pC / N, k_p = 49.3%, k_t = 49.1%, tgδ =% 1.96%. In the third chapter of the valuable elements Sb content with the change of (Li, Ta)-doped NKN-based lead-free piezoelectric ceramic materials (referred to as NKLNT) the phase structure, piezoelectric and dielectric properties. By regulating the content of Sb element, pseudo-cubic phase and in quadrature phase found similar between the MPB region. In this area, prepared by high performance (Li, Sb, Ta)-doped NKN-based lead-free piezoelectric ceramics (referred to as NKLNST) samples, piezoelectric constant d_ (33) 300pC / N, the relative density ρ ≥ 94.6 % dielectric loss tgδ ≤ 4.4%, planar electromechanical coupling coefficient k_p ≥ 49%, the thickness electromechanical coupling coefficient k_t ≥ 43%. Excellent piezoelectric properties of lead-free piezoelectric ceramic materials that NKLNST is a great potential to replace lead-free piezoelectric ceramics PZT. Equivalent alternative in the study, based on the start in the fourth chapter of NKN-based lead-free piezoelectric ceramic materials doped with rare-earth modification of the work is not equivalent. In view of Li and Sb on the NKN-based lead-free piezoelectric ceramics greater impact study of the variable price element Ce on 95NKN-5LiSbO_3 lead-free piezoelectric ceramic materials (referred to as NKLNS) microstructure, physical properties, piezoelectric properties and the aging rate , moisture-proof performance. In the sintering temperature, mass loss before and after sintering and piezoelectric properties, microstructure, etc., has been the rich significance of the experimental laws. The study found that adding different amounts of CeO_2, NKLNS ceramic samples from the preparation process to the electrical properties, have shown significant differences. Start from the microscopic structure of this paper, a detailed analysis of the physical mechanisms causing these differences, were prepared by high-voltage constant (260pC / N), low aging rate and highly moisture resistant NKLNS-xCeO_2 lead-free piezoelectric ceramics. In the fifth chapter, the first study of rare earth elements Ce, Na, K excess on NKLN lead-free piezoelectric ceramics sintering temperature, physical properties, piezoelectric and dielectric properties, and found that the combination of these two methods can improve density and piezoelectric materials, dielectric stability.
Na and K doping CeO_2 appropriate excess and can greatly improve NKLN lead-free piezoelectric ceramic materials, the best sintering temperature range, from the initial 1070 ℃ -1080 ℃ to 1070 ℃ -1110 ℃. Later studied the rare earth elements Pr, Nd and variable price elements of W-doped lead-free piezoelectric ceramic materials for NKLN the sintering temperature, physical properties, piezoelectric properties and dielectric properties. Polarization of the piezoelectric and dielectric loss of the former relationship between the optimization of the preparation process, discusses the causes and the resulting breakdown of the material properties of piezoelectric and dielectric effects of space charge on the material discussed dielectric properties. Experiments show that doping can increase the amount of WO_3 NKLN lead-free piezoelectric ceramic materials, the best sintering temperature range, and the optimal sintering temperature range of sintering of the samples with high piezoelectric, dielectric stability, d_ ( 33) = 170 ± 7pC / N, ε_r = 634 ± 17, tgδ = 2.0% ± 0.3%. Study found that W doping elements can reduce the NKLN dielectric constant of lead-free piezoelectric ceramic materials, making such material has a high piezoelectric voltage constant, is expected in the ignition, ignition off the field of potential applications. Finally, in view of NKN-based lead-free piezoelectric ceramic materials difficult to sinter, not dense, easy breakdown of the shortcomings, first proposed the preparation of multi-layer structure NKN-based lead-free piezoelectric ceramics vision, and specific double-layer structure prepared NKN-based non- Lead piezoelectric ceramics. Experiments show that the double-layer structure of the sintered ceramic materials in a wide range of sintering temperature can be achieved best performance materials, and samples with greater density and smaller dielectric loss, that this is a great potential The piezoelectric ceramic preparation process.
This paper developed two-layer structure NKLN based lead-free piezoelectric ceramics with high piezoelectric activity, the higher the relative density, low dielectric loss and a strong dielectric strength. By the NKN-based lead-free piezoelectric ceramics and doped composition, structure and piezoelectric, dielectric and ferroelectric properties of the study, for the NKN-based lead-free piezoelectric ceramics research and development applications in a reliable experimental and theoretical basis to enrich material science, physics piezoelectric knowledge, to promote the practical use lead-free piezoelectric ceramics. It should be noted that, in order to make research results as soon as possible and the actual production, application integration, preparation methods used in this paper are suitable for large-scale industrial production of electronic ceramics. Lead-free piezoelectric ceramic niobate mainly refers to the alkali metal niobate and two types of tungsten bronze structure niobate piezoelectric ceramics.
The discovery of barium titanate piezoelectric ceramics is the third year after 1949, it is synthesized NaNbO3, KNbO3, LiNbO3 and other crystals perovskite-type compounds, such compounds of general formula ANbO3 (A for the Na, K, Li), the piezoelectric greater attention over the years as the electro-optic materials. K0.5Na0.5NbO3 (KNN) system is a class of niobate-based piezoelectric ceramics may replace lead in lead-free piezoelectric ceramics. The use of Ta and Sb-doped KNN or replace the relevant ions in the ceramics of the same type of quasi-phase boundary (MPB) at the show high piezoelectric and dielectric properties using traditional techniques to produce a new high density Lead-free piezoelectric ceramics (1-x (K0.5Na0.5) (Nb0.96Sb0.04) O3-xLiTaO3 (abbreviated as KNNS-LT). All the components are present in the MPB at the pure perovskite structure The main piezoelectric properties of the MPB at a great value, the electromechanical coupling coefficient kp was 40%, piezoelectric constant d33 of 225pC / N, Curie temperature Tc is 355 ℃.
more:
piezo Transducer ultrasonic welding transducer
Ultrasonic Cleaner ultrasonic generator
ultrasonic cleaning machine ultrasonic single tank cleaner
US equipment for biodiesel Ultrasonic reactor for biodiesel
ultrasonic transducer circuit ultrasonic welding generator
Piezo ceramic(PZT) ring chip for industrial ultrasonic cleaner Piezo Ceramic(PZT) chip for Ultrasonic Welding Machine
