Investigations of a nanostructured FeMnSi shape memory alloy produced via severe plastic deformation

Low-cost iron-based shape memory alloys (SMAs) show great potential for engineering applications. The developments of new processing techniques have recently enabled the production of nanocrystalline materials with improved properties. These developments have opened avenues for newer applications for SMAs. The influence of severe plastic deformation induced by the high-speed high-pressure torsion (HSHPT) process on the microstructural evolution of an Fe–Mn–Si–Cr alloy was investigated. Transmission electron microscopic analysis of the alloy revealed the existence of nanoscale grains with an abundance of stacking faults. The high density of dislocations characteristic of severe plastic deformation was not observed in this alloy. X-ray diffraction studies revealed the presence of ε-martensite with an HCP crystal structure and γ-phase with an FCC structure.     

以SiHCl3为工作介质生产高丰度28Si

为了获得高丰度的28S i同位素,生产高纯度的单晶硅,利用气体离心机对硅同位素进行离心分离。通过对S iH-C l3中组成元素的不同同位素丰度的分析,计算了天然S iH-C l3中不同相对分子质量的分子组成。分析结果表明:虽然氯有两种同位素,但也可以将S iHC l3作为分离28S i同位素的工作介质。通过4台离心级联的分离实验,得到了28S i丰度达到99%的S iHC l3样品。离心分离得到的高丰度S iHC l3不用经过化学转化就可以直接用于单晶硅的生产。实验结果表明,采用离心法分离S iHC l3可以得到高丰度28S i。     

基于ATT7022A的Y/Δ切换抽油机节能控制器的研制

Y/Δ转化器在低负载率时,节电效果较好。可控硅调压控制器在高负载率时,节电效果较好。采用高精度三相电能计量芯片ATT7022A,设计了一种结合两者优点的抽油机节能控制仪。对抽油机电动调压节能系统的软硬件设计做了较详细的分析。通过在多口油井上安装Y/Δ可控硅调压组合式抽油机节能控制仪,并对5口井进行了现场对比测试,单口井年节电约2.1万kW.h。     

车用大功率电力电子器件研究进展

 车用电机驱动变流器是电动汽车电机驱动的关键部件,大功率电力电子器件是其核心。对比分析了国内外电动车辆用电机驱动变流器的拓扑结构、变流器控制特点及体积功率密度等关键指标,指出车用电机驱动变流器的技术创新重点在于硅基绝缘栅双极性晶体管(IGBT)芯片及封装技术持续改进碳化硅(SiC)器件的应用。综述了硅基IGBT芯片的演进和IGBT模块封装技术的创新,介绍了碳化硅器件的技术特点。     

Dielectric properties of spark plasma sintered AlN/SiC composite ceramics

In this study, we have investigated how the dielectric loss tangent and permittivity of AlN ceramics are affected by factors such as powder mixing methods, milling time, sintering temperature, and the addition of a second conductive phase. All ceramic samples were prepared by spark plasma sintering (SPS) under a pressure of 30 MPa. AlN composite ceramics sintered with 30wt%–40wt% SiC at 1600℃ for 5 min exhibited the best dielectric loss tangent, which is greater than 0.3. In addition to AlN and β-SiC, the samples also contained 2H-SiC and Fe₅Si₃, as detected by X-ray difraction (XRD). The relative densities of the sintered ceramics were higher than 93%. Experimental results indicate that nano-SiC has a strong capability of absorbing electromagnetic waves. The dielectric constant and dielectric loss of AlN-SiC ceramics with the same content of SiC decreased as the frequency of electromagnetic waves increased from 1 kHz to 1 MHz.     

多孔硅在射频/微波电路中的研究进展

多孔硅介质膜在射频/微波电路中具有很好的应用前景. 阐述了多孔硅作介质膜的优点,比较研究了不同厚度的多孔硅厚膜上平面电感器的性能参数比较和不同介质膜上螺旋电感性能比较,介绍了多孔硅在射频/微波电路的研究进展,并对存在的主要问题作了讨论.     

耐摩擦抗高温钻头胎体材料研究

主要阐述了热机钻头的工作原理及工作环境 ,论述了碳化硅 (陶瓷 )替代硬质合金作为热机钻头摩擦材料的可行性以及陶瓷热机钻头的应用效果。     

高铝硅氰化渣中铁回收工艺

研究一种处理磁选前高铝硅氰化渣的新工艺。采用复合添加剂焙烧-水浸-磁选工艺对一种铁品位为27.69%(质量分数),SiO2含量为23.9%,Al2O3含量为6.35%的高铝硅氰化渣进行杂质与铁分离的研究。研究结果表明:在最佳焙烧条件下,当水浸温度为60℃,液固比为15:1,水浸时间为5 min,转速为20 r/min,在激磁电流为2 A时,可获得铁品位57.11%,铁的回收率为72.58%的铁精矿。铁的品位和回收率都比单纯的复合添加剂还原焙烧-磁选法所获得的铁精矿的指标高,铁的品位提高了10%左右,回收率提高了30%左右。X线荧光(XRF),X线衍射(XRD)及能谱(EDS)分析研究结果表明:经水浸后,复合添加剂焙烧过程中所产生的可溶性复杂杂质化合物被洗除,不溶性物质经磁选后随之进入非磁性物,实现铁与杂质矿物之间的有效分离。     

二氧化硅增强石英纤维复合材料高温电性能温度特性

运用静电学理论,建立计算二氧化硅增强石英纤维复合材料介电参数的经验模型,实现材料高温介电性能的温度特性模拟,并对材料介电性能的变化规律作出预测.模拟结果与实际结果基本相符,为材料改性提供依据.     

云南德宏硅工业发展问题探析

发展德宏硅工业,必须坚持以科学发展观为指导,从战略高度进行系统思考,充分把握当今世界经济发展的新趋势和国家经济社会发展的新形势给其发展带来的机遇和挑战,清楚认识其自身存在的优势和劣势,并在此基础上结合当地实际情况进行整体谋划,明确其发展定位,理清发展思路,才能促进德宏硅工业的可持续发展。