透明陶瓷的制备技术及其透光因素的研究

简要地介绍了国内外透明陶瓷的制备技术,同时探讨了气孔和晶界组织结构等因素对透明陶瓷的透光性能的影响,并展望了透明陶瓷研究的发展趋势.     

The Impact Failure and Energy Dissipation Mechanism of Polyethylene Laminates

The damage mechanism and energy dissipation of the Polyethylene(PE) laminates in impacting was investigated. It was found that the dissipated energy of the impacting sphere bullet by the 1-mmthick PE plate firstly increased with the impacting velocity increasing from 50 to about 300 m/s, and then decreased with the impacting velocity increasing up to 600 m/s. According to the measured deformation and damage degree, a numerical simulation of the dissipated energy was made and obvious offset was found with the experimental results. The quasi-static properties of the PE fibers, decreasing with increase in tensile velocity, may be the main reason for the offset.     

自蔓延高温合成细晶六硼化钙陶瓷粉末(英文)

基于Mg–B2O3–CaO原料体系,采用自蔓延高温合成(self-propagating high-temperature synthesis,SHS)和后期酸处理工艺,制备出高纯度、均匀分布、小粒径的立方晶型细晶六硼化钙粉末。分析了Mg–B2O3–CaO自蔓延高温反应体系的燃烧产物成分及反应机理,测量了不同SHS反应物原始坯体成型压力的燃烧温度曲线,探讨了不同镁掺量和不同气氛对燃烧产物成分和形貌的影响。研究了原始坯体成型压力与最终CaB6产物粒径的关系。结果表明:采用氩气保护能抑制镁挥发;合适的原始坯体压力有利于合成分布均匀的细晶CaB6粉末。     

陶瓷/金属的自蔓延高温合成焊接研究现状

陶瓷与金属是两类组织结构及物化性质相差悬殊的材料 ,将两者接合在一起 ,必将成为一种具有较大应用潜力的新型结构材料。本文在对陶瓷与金属的性能进行比较的基础上 ,阐述了自蔓延高温合成焊接陶瓷 /金属的特点 ,并综述了自蔓延高温合成焊接陶瓷 /金属的研究现状     

TiB2在球磨中的氧化行为

用行星球磨对TiB2原粉进行处理,并用X射线光电子能谱仪,X射线衍射仪,能量色散X射线荧光光谱仪等对TiB2在球磨过程中的氧化行为进行分析.结果表明:在室温下TiB2粉末存在表面氧化,而球磨加速TiB2粉末氧化,随着球磨时间的延长,TiB2粉末的氧化程度加大;酸洗及离心作用造成硼的流失,使B和Ti的摩尔比失调,最终形成TiO2和少量硼酸包覆TiB2结构;通过改变不同球磨工艺,发现湿磨加Ar保护工艺使TiB2被氧化程度明显降低.     

透明陶瓷的发展

综述和分析了研究和发展中的几种透明陶瓷，介绍了透明陶瓷的性能及有关用途。     

TiB2-TiC复合粉的自蔓延高温还原合成

热分析结果表明,对于B₂O₃-TiO₂-Mg-C体系,可利用SHS还原技术合成出TiB₂-TiC陶瓷复合粉。其化学反应机理为:Mg先还原B₂O₃和TiO₂,新生的Ti与B和C反应生成TiB₂和TiC; TiO₂的还原经历了TiO₂→TiO→Ti的逐步过程。采用一定的酸洗工艺得到了纯净的TiB₂-TiC陶瓷复合粉。复合粉中包含六方片状TiB₂和圆球状TiC;复合粉中1μm以下颗粒质量百分数超过45%,87%以上的颗粒大小在3μm以下。在TiB₂-TiC中,TiC_<em>y以一种贫碳结构存在,物料中Ti被B或C结合形成TiB₂和TiC_<em>y,y的值为0.7483。     

自蔓延高温合成锶铁氧体的研究

介绍了自蔓延高温合成技术合成SrFe12O19的工艺过程，对产物物相和性能进行了分析。将均匀混合后的原料直接在空气中点燃，并自发完成整个反应。合成产物经过后处理，用X射线衍射分析了产物的物相，用振动样品磁强计测试产物的磁性能，Hc为204．8kA／m，Ms为12．47emu／g。试验结果表明：SHS方法合成的SrFe12O19纯度高并具有良好的磁性能。同时介绍了用SHS方法合成锶铁氧体的一些影响因素，有原料中铁粉的含量、燃烧温度对燃烧过程和合成产物性能的影响。     

TiB2/Al2O3复合粉体的喷雾干燥造粒与特性研究

利用喷雾干燥技术对TiB_2/Al_2O_3复合粉体进行造粒,研究了浆料固相含量及粘结剂含量对喷雾干燥粉体颗粒形貌、结构、松装密度、流动性等的影响。结果表明：当浆料固相含量为47．6%,分散剂和粘结剂分别为固相质量的0．4%和1．0%时,浆料具有合适的粘度和最佳的分散稳定性,喷雾造粒得到的粉体为球形或近球形,具有较高的松装密度和流动性,能满足各种压制成型的需要。     

Fabrication of homogenous dispersion TiB<Subscript>2</Subscript>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> composites

In order to get a homogenous mixture and compact of TiB2-Al2O3, hybridization as a surface modification method was used to prepare nano-scale Al2O3 coated TiB2 particles. PE-wax particles were first coated onto TiB2 particles by hybridization, and then the nano-scale Al2O3 particles were coated onto the surface of TiB2 coated by PE-wax particles again. SEM, TEM and EDS were used to characterize the microstructure of as-received core/shell particles and its compacts. The experimental results show that a particle-scale homogenous dispersion of TiB2 and Al2O3 can be formed not only in mixed powder but also in dewaxed compacts. The compacts then were sintered by gas-pressing sintering (GPS). Finial products show improved mechanic properties comparing with reference samples fabricated by normal ways.