Papers by Author: Jian Qing Dai

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Authors: Yao Min Ding, Jian Qing Dai, Jing Bing Xia, Wen Guo Chen, Zhi Gang Hu
Abstract: Fine powder of Zn3Nb2O8 was prepared by chemical co-precipitation using KOH, Nb2O5 and ZnSO4·7H2O as raw materials. Laser particle analyzer was used to investigate the precursor. It showed that the average size (D50) was 3.13μm, and the particle distribution ranged from 1.82µm to 4.47µm. TG-DTA and XRD showed that, the precursor yielded Zn3Nb2O8 ceramics by calcined at 850°C, which was much lower than 1100°C, at which Zn3Nb2O8 ceramics could be obtained by traditional solid state method. The sintering of as-obtained powers with Cuo-Bi2O3-V2O5 sintering aids results in producing Zn3Nb2O8 ceramics with s density 94.20% of the theoretical, and a product up to 19.83 (at 30MHz) at sintering temperature 950°C.
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Authors: Jian Qing Dai, Yong Huang, Jing Tao Ma, Zhi Peng Xie
Abstract: Particular attention is paid in this paper to understanding the surface characteristics and aqueous dispersibility of as-received commercial powders. The different production methods and specific pulverization processes used for the four powders studied (FD1, FD2, M11, UBE) result in obvious differences in such powder properties as surface groups, aqueous dispersibility, and water-soluble ions.
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Authors: Wen Guo Chen, Jian Qing Dai, Jing Bing Xia, Yao Min Ding, Zhi Gang Hu
Abstract: The Y-type hexaferrite precursors was synthesized by co-precipitation, and the pivotal technological conditions, including pH value, temperature (T), rotate speed (R) and the flow velocity of salt solution (V) were discussed. The particles of precursors were studied by Laser particle size analyzer (LPS). The precursor calcined at 900°C was characterized via X-ray Diffraction (XRD), the vibrating sample magnetometer (VSM) and HP4291A impedance analyzer were used to investigated magnetic properties. The results showed that the particle sizes were around 3µm (D50) and the distribution range was from 2.28μm to 4.47μm, in the optimized technological conditions: pH = 10.50, T = 50°C, R = 300 rpm, V = 0.35 ml/min, SDBS = 0.3 g/L, the specific saturation magnetization, coercive force, residual magnetization, initial permeability and factor of quality of the sample were σs ≈ 29.72A·m2·kg-1, Hc ≈ 4.11/kA·m-1, σr ≈ 7.74 A·m2·kg-1, μi ≈ 9 and Q ≈ 18 respectively.
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