Effect of Additive ZrO2 on Sintering Properties of MgO-CaO Bricks

The effect of electric fused ZrO2,m-ZrO2 and zirconite on the sintering properties of MgO-CaO bricks was studied and the effect of the ZrO2 content and temperature on BD (bulk density), AP(apparent porosity)and CCS (Cold Crushing strength) of MgO-CaO bricks was investigated.The microstructure of burned specimens was analyzed by SEM. The result shows that the sintering property is best while 5% m-ZrO2 was added at 1 600 ℃.     

Effect of sintering condition on microstructure and dielectric properties of BSTN composite ceramics

The effect of sintering condition on the phase composition, microstructure and dielectric properties of barium strontium titanate niobate (BSTN) composite ceramics, in which the perovskite phase and the tungsten bronze phase coexisted, was investigated by XRD, SEM and LCZ Meter. The results show that more Sr²⁺ ions dissolved from the grain boundaries into the crystal lattice of the pervoskite phase and the tungsten bronze phase, especially, into the lattice of the pervoskite phase with the increasing of sintering temperature and sintering time, respectively. So the Curie temperature point decreases with the increasing of sintering temperature. The crystal growth rate of the tungsten bronze phase is higher than that of the perovskite phase in BSTN composite ceramics as the sintering temperature increases. The reasonable sintering temperature is about 1275 °C for BSTN composite ceramics. The activation energy to setting up polarization in BSTN composite ceramics increases with the increase of the applied frequency.     

可变时滞系统的控制与仿真

炉温变化时硬质合金真空烧结炉的时滞常数变化很大，常规PID控制不能同时在高温段与低温段满足生产工艺提出的控制品质要求。本文在利用最小二乘法拟合出真空烧结炉时滞常数与炉温变化函数的基础上，PID参数采用经典的CHR整定算法随炉温变化实时整定，并利用MAT—LAB仿真软件对该控制算法在真空烧结炉中的应用进行了仿真研究，结果表明该算法能够实现对真空炉的有效控制，控制系统能够满意地跟踪设定的温度曲线。     

多工位烧结炉智能温度控制系统的设计与应用

针对传统的多工位烧结炉的温度控制精度、生产工艺控制能力等较低的现状，提出了一种多工位烧结炉的智能温度控制系统。该系统以可编程逻辑控制器（PLC）为核心，以模糊PID算法为控制器。在该系统的控制下，可有效地实现对三工位烧结炉温度工艺曲线和辅助工艺的控制，并可在线自整定PID参数，实现了烧结炉生产过程的自动化，提高了温度控制精度以及工作效率。应用结果表明，该温控系统具有良好的自适应性和鲁棒性。     

Compression testing of a sintered Ti6Al4V powder compact for biomedical applications

In this study, the compression deformation behavior of a Ti6Al4V powder compact, prepared by the sintering of cold compacted atomized spherical particles (100–200 μm) and containing 36–38% porosity, was investigated at quasi-static (1.6×10⁻³–1.6×10⁻¹ s⁻¹) and high strain rates (300 and 900 s⁻¹) using, respectively, conventional mechanical testing and Split Hopkinson Pressure Bar techniques. Microscopic studies of as-received powder and sintered powder compact showed that sintering at high temperature (1200 °C) and subsequent slow rate of cooling in the furnace changed the microstructure of powder from the acicular alpha () to the Widmanstätten (+β) microstructure. In compression testing, at both quasi-static and high strain rates, the compact failed via shear bands formed along the diagonal axis, 45° to the loading direction. Increasing the strain rate was found to increase both the flow stress and compressive strength of the compact but it did not affect the critical strain for shear localization. Microscopic analyses of failed samples and deformed but not failed samples of the compact further showed that fracture occurred in a ductile (dimpled) mode consisting of void initiation and growth in phase and/or at the /β interface and macrocracking by void coalescence in the interparticle bond region.     

Microstructural and piezoelectric properties of low temperature sintering PMN-PZT ceramics with the amount of Li2CO3 addition

PMN-PZT ceramics doped with Li₂CO₃ and Bi₂O₃ as sintering aids were manufactured in order to develop the low temperature sintering ceramics for multilayer piezoelectric transformer, and their micro structural, dielectric and piezoelectric properties were investigated. The sintering aids were proved to lower the sintering temperature of doped PMN-PZT ceramics due to the effect of LiBiO₂ liquid phase. Optimal values for multilayer piezoelectric transformer application, such as electromechanical coupling factor (k_p) of 0.50, mechanical quality factor (Q_m) of 2264, and dielectric constant (K) of 1216, and curie temperature (T_c) of 317 °C were found at 0.1 wt.% Li₂CO₃ added ceramics sintered at 940 °C.     

复合助烧剂对Gd2O3-UO2芯块微观结构的影响

Gd2O3-UO2可燃毒物燃料是近年来核电站采用较为普遍的可燃毒物之一。本文研究了在Gd2O3-UO2芯块中添加A12O3、TiO2、V2O5各150μg／g的复合助烧剂对芯块微观结构的影响。研究表明添加复合助烧剂后可以降低Gd2O3-UO2芯块的致密化温度．在H2气氛中，1500℃烧结4h后的Gd2O3-UO2芯块的密度可达～97％TD，芯块的闭口孔在1400～1750℃整个温度范围内一直呈下降趋势．烧结温度为1750℃时芯块中气孔数量比1600℃时减少．但单个气孔体积增大．其主要机制可能是小气孔之间发生融合。添加助烧剂后，在1400～1600℃温度之间晶粒生长速度出现不一致．部分晶粒开始迅速生长，晶粒大小分布出现双峰现象；当温度为1750℃时，晶粒大小分布为正态分布．双峰现象消失，平均晶粒尺寸约为25μm。     

无起拱烧结机新理论的研究

通过多年的试验研究，发现烧结机台车起拱是由台车过剩力矩所引起，提出了一种利用液压阻力矩方法及装置自动消除烧结机尾部台车过剩力矩的理论。依据该理论所设计的烧结机消除了台车起拱，因而避免了台车磨损，减少了漏风率。