Advanced Materials Research Vols. 535-537

Abstract: The combustion technology of Circulating Fluidized Bed Boilers is a Cleaning and high efficent of Coal Powder Combustion technology. Traditional control methods can hardly get ideal control effect. To Realize datas reading and writing by self_control software throgh DCS, when coal quality, loading altered, realized automatic closed-loop control of combustion process of circulating fluidized bed, to implement primary air flow, secondary air flow and air-induced automatic cordinated control and reached cleaning of coal quality and combustion high efficiency.

Abstract: (W,Ti)C-10%Co system cermets doped with Ta, Nb or V grain growth inhibitor were prepared in this work. The effect of Ta, Nb and V on the microstructure and mechanical properties of (W0.8783Ti0.0976VB0.0242)C-10%Co systems was investigated. The results show that the three elements play an important role on the WC grain growth and shape; the cermets appeared uniformly distributed as whiskers or thin platelets. V results in the hardest material, Ta causes the material to become harder compared with (W0.9Ti0.1)C-10%Co cermets. But the hardness of cermets with Nb addition decrease because of the increasing of porosity.

Abstract: The properties of YSZ-Ni-Cr cermet fabricated by Sol-Gel Method（YSZ-Ni-Cr powder was synthesized by coprecipitation method at 850°C for 2 h and was processed into YSZ-Ni-Cr cermet by hot-press sintering at 1350°C for 1 h）was explored. The identification of phases was carried out using a X-ray diffractometer (XRD). The particle size and morphology was determined by electron microscopys(SEM/TEM) The conductivity had a tendency to decrease with increasing temperature. This behavior can be accounted for that there are two conduction paths through the cermet, an electronic path through the (Ni,Cr) metal phase and an ionic path through the ZrO2-Y₂O3 phase.

Abstract: The surface coating processing technique was utilized to modify hydrothermally synthesized Ba(Zr0.10Ti0.90)O3 (BZT) with Nb-organic compound and Zn-organic compound and Mn-organic in organmetallic precursor (Nb-EDTA and Zn-EDTA and Mn-EDTA), which were coated on the powders uniformly. The sintering temperature was decreased and dense ceramics were obtained with well-developed grain growth at 1300 0 C. With increasing the amount of (Nb2/3Zn1/3) from 0 to 1.3 mol%, the Curie temperature was monotonously lowered from 85 0C to 20 0C. The corresponding dielectric maximum decreased first and then increase. The shift rate of the phase transition point of (Nb2/3Zn1/3) codoped BZT was -48.5 0 C/mol%. With increasing of the amount of Mn, the Curie point temperature was lowered greatly, accompanied by a decrease in the corresponding dielectric maximum and an enhancement of the ferroelectric relaxor characteristic.

Abstract: A facile one-pot hydrothermal method has been developed for synthesis of porous and non-porous BaTiO3 ceramics using Ba(OH)2.8H2O, BaCO3 as barium source. In this paper, we research the effect of different barium source on the nanostructure of BaTiO3 ceramics in a solid state reaction, and the results indicated that the two different morphologies of BaTiO3 ceramics can be easily prepared by using these two different barium source. The phase composition and morphology of the as-obtained products were investigated by X-ray diffraction and field emission scanning electron microscopy (SEM).

Abstract: High quality, transparent 1.0at% Nd:YAG ceramics were fabricated successfully by a solid-state reaction and vacuum sintering, and the characteristics were also identified in different methods. The lowest transmittance is 44.85% and the highest is 71.98%. 9 samples were used for thermal diffusivity detecting using laser flash method. Thermal diffusivity decreases as temperature increases, and The diffusivity increases as average grain size grows. However, when average grain size is smaller than 8μm, the diffusivity decreases much faster. Mechanical advantages be ensured, the average grain size should be above 8μm.

Abstract: The effects of ZnO-B2O3-Na2O(ZBN) glass on the sinterability and microwave dielectric properties of Ca[(Li1/3Nb2/3)0.92Zr0.08]O3−δ ceramics were investigated . ZBN glass doping can effectively reduce sintering temperatue by 100~150°C. The temperature coefficient of resonator frequency τf increased with an increase of ZBN glass content and sintering temperatue. When ZBN glass of 1.8wt% were added, the optimum microwave dielectric properties: εr =22.1,Qf =18360GHz and τf = − 9.8×10−6/°C were obtained at the sintering temperature of 1000°C.

Abstract: The roasting process of leachable alumina based ceramic core has been systematically studied in this paper, the results show that, the roasting process should be divided into two parts, i.e., dewaxing process and sintering process, and the plasticizer can be removed completely from the ceramic green body by the dewaxing process with little residue left behind. The sintering temperature and mineralizer are the decisive factors to ensure the strength of ceramic core. The apparent porosity of ceramic core will decrease obviously while the room temperature flexural strength will increase when the sintering temperature is rising. The room temperature flexural strength can exceed 14MPa when the ceramic core samples sintered at 1550°C. The ceramic core samples will present excellent comprehensive properties when the sintering temperature is 1550°C and the added quantity of SiO2 is 8~10%, i.e., apparent porosity is 44.7~46.9%, bulk density is 1.93~1.99 g/cm3, room temperature flexural strength is 10.65~11.93MPa.

Abstract: In order to reduce its costs and increase its strength and toughness, 3Y-ZrO2/Al2O3 nanocomposite ceramics is fabricated through pressureless sintering process. Microstructure is detected by SEM and composition is analyzed by EDS. The results show that some of ZrO2 combined with Al2O3 forms ZrO2+Al2O3 solid solutions, and the others form particles which are distributed on grain boundaries and matrixes with different shapes. Those ZrO2 particles locating in the boundaries enhance the ceramic’s toughness by two modes: fracturing and tearing, and which one to be occur depends on the location relationship between load and boundary interface. The composition transition, i.e. the solid solution consisting of ZrO2+Al2O3 has formed encircling ZrO2 particles, and it has a positive contribution to ceramics toughness through the combination of chemical bond.

Abstract: Li2O-MgO-Al2O3-SiO2(LMAS) system glass-ceramics had been prepared by sintering method. The effect of different nucleating agents on the phase composition, microstructure and properties of LMAS system glass-ceramics were investigated by DTA, XRD and SEM. The results indicate that the introduction of nucleating agents could contribute to decreasing the crystallization temperature of the glass-ceramics, the effect of the nucleating agent TiO2 is most obvious, and the crystallization temperature is the lowest(798.9°C). Main crystal phase of the glass-ceramics without the nucleating agents is β-quartz solid solution, while main crystal phase of the glass-ceramics with different nucleating agents changes into β-spodumene solid solution. The glass-ceramics with composite nucleating agents (TiO2+ZrO2+P2O5) are the lowest coefficient of thermal expansion (0.86×10-6/°C)and the highest flexural strength (95MPa). Composite nucleating agents have the best effect of crystallization, and contribute to the formation of a large number of short columnar crystals, which is the main reason for obtaining glass-ceramics with low expansion coefficient and high flexural strength.