Papers by Author: Xiang Chun Liu

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Authors: Wei Min Wang, Xiang Chun Liu, Ming Zhao, Chang Sheng Tian
Abstract: The aim of this paper is to investigate the effects of V2O5 additive on the electrical properties of NTC thermistors based on Ni0.5Co0.5Mn2O4.The XRD analyses indicate that single spinel phase can form, and V2+ions are in the octahedral interspace. The cell can be enlarged due to the V2O5 additive. The resistivities (ρ) and the material constant (B) increase obviously, the reasons of which are mainly attributed to the outer electron configuration of V2+ and cell enlargement.
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Authors: Ming Zhao, Wei Min Wang, Xiang Chun Liu, Chang Sheng Tian
Abstract: The effects of pre-synthesized V2O5/Sb2O3 compound, SbVO4 and Sb2O3 on the microstructure and electrical properties of ZnO-V2O5 based varistor ceramics have been studied. The general homogeneous microstructure and phase composition of the ceramics have not been influenced by the antimony doping form changes, except for the gradual decrease in average grain size and the increase in spinel formation within the ceramics. The ultimate cause of micro-structural variations with the antimony doping form changes seems to have been the gradual increase in Sb3+ concentration within the ceramics. This change in micro-composition, together with the changes in microstructure, caused the electrical characteristics of the ceramics to vary. The pre-synthesized V2O5/Sb2O3 compound is the most effective antimony dopant in term of its effect on the ceramics.
735
Authors: Kai Xuan Zhou, Xiang Chun Liu, Xue Li Feng, Yang Yang, Chen Guang Zuo
Abstract: Adopting laminated dry pressure molding process, the HH2 (mixing powder of (Zn0.7, Mg0.3)TiO3(ZMT3) and (Ni0.8Zn0.12Cu0.12)Fe1.96O4(NZC) in weight ratio of 1:1) and (Zn0.9, Mg0.1)TiO3(ZMT1) were designed to be interlayer, which was co-fired with ZMT3((Zn0.7, Mg0.3)TiO3) and NZC((Ni0.8Zn0.12Cu0.12)Fe1.96O4) at 900°C to synthesize layer composition. The study of interfacial microstructure SEM and diffusion mechanism shows that the co-fired layer composition could alleviate the interfacial stress and eliminate warp defects resulting from the co-fired process. The interfacial diffusion behavior of co-fired layer composition was researched,which provide a promising solution of warp and distortion resulting from different materials co-fired process.
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Authors: Xiang Chun Liu, Feng Gao, Ming Zhao, Chang Sheng Tian
Abstract: The dielectric ceramics comprised of (Zn1-xMgx)TiO3 (x=0.1~0.5, abbreviated to ZMT) were developed by conventional mixed-oxide method combined with a semi-chemical processing. V2O5 was used as sintering aids to lower the sintering temperature of ceramics. The results showed that the hexagonal phase stability region extended from 900 to 1150°C as the amount of magnesium increased. The densification temperature of ZMT ceramics could be reduced from 1200 to 875°C by V2O5 additions and using semi-chemical processing, the relative density of ZMT ceramics with 1.00wt% V2O5 addition reach 95% at 875°C. The dielectric properties of ZMT were measured at different frequencies and the results showed that there existed a decreasing tendency of the loss tangents (tg δ) with increasing measuring frequency. It is concluded that εr=22 and tg δ= 5.7×10-4 can be obtained for ZMT ceramics at sintering temperature 875°C.
2215
Authors: Yang Yang, Xiang Chun Liu, Xue Li Feng, Kai Xuan Zhou, Chen Guang Zuo
Abstract: The thermal physical properties, thermal stability and corrosion resistance of the ternary nitrate salts 55%NaNO3-35% KNO3-10% LiNO3 have been studied by the thermal analysis TG-DSC, weight method and so on. The results show that the melting point of mixed molten salt is 380 °C and the maximum operating temperature is 750 °C. Compared with the binary system, this molten salt system has a higher operating temperature upper limit and a wider operating temperature range of 400 ~ 750 °C, which could meet the temperature requirement of solar power generation and be a solar high-temperature heat transfer and thermal storage medium material of better comprehensive performance.
787
Authors: Feng Gao, Chang Song Zhang, Xiang Chun Liu, Chang Sheng Tian
Abstract: The multilayer composites were prepared by cofiring Pb(Ni1/3Nb2/3)O3-based ferroelectrics and NiCuZn ferrite using tape casting processes. The interface and grain growth of the composites were investigated. The results show that the sintered interface of composites is solid, continuous with no delamination and cracks, which should be attributed to the chemical compatible of the two materials. The grain growth of ferroelectrics adjacent to the interface is different from that far from the interface. It should attribute to Fe3+ diffused from the ferrite to ferroelectrics and soluted into the perovskite lattice. The difference factor dD is proposed to describe the microstructure difference between the interface and the inner parts.
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