Na Tu

Publications (3)3.51 Total impact

• Article: [Research on diffuse reflectance infrared Fourier transform spectroscopy of kinds of kaolin in various areas].

  Xiao-Hong Li, Xiang-Ping Jiang, Chao Chen, Na Tu
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  ABSTRACT: Respectively using pressed method and diffuse reflectance method, the infrared absorption spectrua of sorts of kaolin in various areas were obtained. The relationship between the structure characteristics of kaolin and its absorption peaks was analyzed. The results showed that compared with pressed method, the use of diffuse reflectance Fourier transform infrared spectroscopy, combined with the K-M function, results in corrected infrared spectra with high sensitivity and is more accurate and easier to analyze. Furthermore, based on a high frequency wave of 3 700-3 600 cm(-1) sections of kaolinite-OH characteristic absorption peaks, the crystallinity of all kinds of kaolnite can be known quickly. The result is consistent with the Hinckley index surveyed by X-ray diffraction technique.
  Guang pu xue yu guang pu fen xi = Guang pu 01/2011; 31(1):114-8. · 0.84 Impact Factor
• Article: Microstructure and Properties of High‐Temperature Materials (1−x) Na0.5Bi2.5Nb2O9–xLiNbO3

  Xiang-Ping Jiang, Qing Yang, Shu-Lan Zhou, Chao Chen, Yan Chen, Na Tu, Zu-Deng Yu
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  ABSTRACT: Bismuth layer-structured ferroelectric ceramics of (1−x)Na0.5Bi2.5Nb2O9–xLiNbO3 (NBN–LN, 0≤x≤0.2) were synthesized by a traditional solid-state reaction. The effects of LN addition on the microstructure and electrical properties of ceramics were studied carefully. It was found that the ceramics with x≤0.10 have a bismuth oxide layered structure. With the increasing of LN addition, the mechanical quality factor Qm firstly increases, and then decreases with a maximum value of 4820 at x=0.02. The Curie temperature Tc increases gradually and the electrical properties of NBN-based ceramics are improved significantly by the addition of LN. The piezoelectric constant d33, dielectric loss tan δ, Curie temperature Tc, and remanent polarization Pr of 0.90Na0.5Bi2.5Nb2O9–0.10LiNbO3 ceramics were found to be 21 pC/N, 0.16%, 789°C, and 7.37 μC/cm2, respectively. Thermal annealing and aging studies indicate that the NBN–LN system possesses stable piezoelectric properties, demonstrating that the NBN–LN ceramics are the promising candidates for high-temperature applications.
  Journal of the American Ceramic Society 11/2010; 94(4):1109 - 1113. · 2.27 Impact Factor
• Article: Effects of NiO on Electric Properties of K0.5Na0.5NbO3 Lead-Free Ceramics

  Xiangping Jiang, Yan Chen, Jie Wang, Na Tu, Chao Chen
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  ABSTRACT: Lead-free piezoelectric K0.5Na0.5NbO3-x wt% NiO ceramics have been synthesized by solid state reaction. The phase, microstructure, electric properties of the samples were characterized by XRD, SEM and Agilent 4294A impedance analyzer. The results reveal that NiO diffuses into the K0.5Na0.5NbO3 lattices to form a solid solution of a single phase orthorhombic perovskite structure for x from 0 to 2. With the increase of NiO content, the grain size of those materials increases evidently. However, when x ≥ 1, the grain size decreases, which indicated that more NiO content can inhibit the grain growth. Furthermore, NiO-doping leads to the improvements of ferroelectric and piezoelectric properties. A relatively larger remanent polarization of 21.26 μC/cm2 has been found in the x = 0.5 sample. The coercive field Ec changed a little. The ceramics with x = 0.8 exhibit excellent piezoelectric properties: Qm = 621, kp = 38.3%, tanδ = 2.9%, d33 = 89pC/N.
  Ferroelectrics 01/2010; 401(1):72-78. · 0.39 Impact Factor