Papers by Author: Cheng Zhang

Abstract: CaF₂ nano-power was prepared by direct precipitation methods with Ca(NO₃)₂ and KF as raw materials. The influences of presintering temperature and sintering temperature on the particle size and distribution of CaF₂ nano-power were studied by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM). This study provided an experimental method for preparation of CaF₂ nano-power. The results show that the best presintering temperature of CaF₂ nano-power is 500°C and the best sintering temperature of CaF₂ ceramic is 900°C.

Abstract: Glazed hollow bead, a kind of inorganic lightweight aggregate that has been recently developed, has raised high concern in the field of thermal insulation of building wall due to its low thermal conductivity, low water absorption, good fireproof performance and relatively high compression strength. In this paper, the preparation of this thermal insulation glazed hollow bead material was introduced in detail, the influence of the amount of gel material on bulk density, porosity, thermal conductivity, compression strength of the thermal insulation glazed hollow bead material was investigated, the surface morphology and surface components were characterized by means of SEM and EDS. Results showed that the density, thermal conductivity and compression strength increased while the porosity decreased with the amount of gel material increasing. Appropriate temperature enables gel material to work at optimal level under which the compression strength increases, on the other hand, the porosity also increases, therefore, the thermal conductivity decreases.

Abstract: In this study, Yttria-stabilized zirconia (YSZ) electrochemical sensors attached with the WS₂ sensing electrode (SE) were fabricated and examined for NO₂ sensing properties. Due to its internal stratiform structure, surface and edge of the lamella have high chemical activity, WS₂ was used as a kind of highly efficient catalyst. WS₂ was partial oxidated to WO₃ at 400°C, and with the increment of temperature, oxidation will accelerate. The ΔEMF to 500 ppm NO₂ was as high as 125mv at 400°C, while the value of WO₃-based sensor was as small as 10 mv in the same condition. These WS₂-attached devices gave a linear correlation between EMF and the logarithm of NO₂ concentration from 30 to 500 ppm in the temperature range 350–500°C. The response time of the device is about 1 min at 400°C.

Abstract: ZnO quantum dots (QDs) are anchored on graphene oxide (GO) by a wet chemical self-assembling technique. Firstly, GO are functionalized with thiol (f-GO) by a series of chemical reactions and the ZnO alcogel are prepared by a sol–gel process. Secondly, the f-GO/ZnO composite is obtained by a self-assembling technique. Typically, X-ray diffraction (XRD), scanning electron microscopy (SEM) and EDS spectrum are employed to characterize the structure, morphology and composition of the obtained samples, moreover, the electrochemical performance of the as-prepared electrode is also detected by cyclic voltammetry and galvanostatic charge–discharge experiments. It is found that the f-GO/ZnO-1 possesses the highest specific values of 149.4F/g and good long-term cycle stability. The results show that the f-GO/ZnO nanocomposite could be used as electrode material for high performance supercapacitors.

Abstract: CaF₂ could be used as inner protection liner material of the cavity which is chemical etched by H₂O and HF. This is because CaF₂ is not easy deliquescence, corrosion resistance and self-lubricating properties. This paper mainly analysis and research the three kinds of powder form different manufacture factory. The powder is burned in the air at 1360°C for 0.5h, the result display that the density of block we get after a powder is burned is the biggest and the width of the peak gets narrow after were calcined, which indicates the crystallinity has improved. The powder did not react with water at 90°C,but the powder was burned react with water at 90°C。

Abstract: Polymers and their composites are extensively used in commercial applications^[.Wearing is one of the forms which makes materials damage and failure, especially the materials by friction, impact, erosion like rocks, minerals etc, the wear caused huge losses. Therefore, high-strength wear-resistant engineering machinery rational use of materials is very important. So chose a method that simple, rapid, low cost, good effect to prevent and repair the parts wear is necessary. In recent years, there has been much interest in particle-reinforced polymers not only because to produce this kind of polymer is cheaper, but also they can be used as high quality engineering materials^[2]. In abrasive wear, the low stress also occupied a certain proportion of erosion^[. Current polymeric coatings, although corrosion resistant, do not satisfactorily resist wear, but these studies provided many ways to improve the erosion resistance of particle-reinforced polymers^[410].

Abstract: Coating thickness plays an important role in the performance of coated tools and machine parts. In the paper, a straightforward and simple method-crater grounding method is introduced to measure Zn coatings thickness. Coating section observation measurement are used to test the thickness, and the comparative result show that crater grounding method is accuracy vary within a certain error range. The influencing factors of this measuring method is analyzed in this paper.

Abstract: PZO (PbZrO₃) coatings with different thicknesses were deposited onto Indium Tin Oxide ITO glass substrates at room temperature by magnetron sputtering technique. UV-Vis absorption spectra method and microhardness testing method were used to measure the thickness of coating. It was proved that the measuring results of film thickness by two kinds of methods were equivalent, and either one method can be alternatively used to determine the thickness of deposited films.

Abstract: In this paper, firstly, the BIT powder was synthesized by ball grinding and the sequent calcinations, starting from TiO2 and Bi2O3. Typically, the grinding technique was facile to form the smaller particles, and the sintering process was utilized to obtain the pure BIT phase. The influence of heated temperature, time and the content of doped rare earth metal (La, Y) on BIT matrix have been investigated in details. The procedure consisted of being pressed, sintered, silver coated to obtain the BIT ferroelectric blocks. Lastly, the BIT density and ferroelectric properties of obtained blocks have been studied. The results showed that via the milling process and the addition of La and Y elements, BIT could be shaped at the lower temperature. Meanwhile, the ferroelectric properties have been improved.

Abstract: In this work, plasma combined with maleic anhydride induced-graft polymerization method was employed to fabricate highly-functionalized carbon nanotubes, whose surface was coated by uniform polymaleic anhydride thin film. Their compositions and structures were characterized by FTIR, SEM and XPS techniques. In order to evaluate the modification effect, they were further used as modifier to improve the tensile and surface properties of fluorinated polyurethane elastomers.