黄振国
,
修稚萌
,
孙旭东
材料研究学报
以Y$_{2}$O$_{3}$粗粉、碳酸氢铵、硝酸和氨水为原料,
通过沉淀法制备了Y$_{2}$O$_{3}$纳米粉体.
发现沉淀工艺和煅烧温度显著影响Y$_{2}$O$_{3}$纳米粉的颗粒大小和尺寸分布,
从而影响烧结体的密度和透光性. 用X射线衍射分析仪、透射电镜、图像分析仪等研究发现,
pH=8时制得的沉淀先驱物经1000℃煅烧, 可得到粒度为33 nm, 近球形, 分散性好,
尺寸分布窄的Y$_{2}$O$_{3}$粉体. 该粉体不加任何添加剂,
在1700℃真空烧结4 h可得到透明Y$_{2}$O$_{3}$陶瓷.
关键词:
无机非金属材料
,
yttria
,
nanopowder
,
precipitation
,
sintering
Montasser M.Dewidar
,
Jae-Kyoo LIM
,
K.W.Dalgarno
材料科学技术（英）
Layer manufacture technologies are gaining increasing attention in the manufacturing for the production of polymer mould tooling. Layer manufacture techniques can be used in this potential manufacturing area to produce tooling either indirectly or directly, and powder metal based layer manufacture systems are considered as an effective way of producing rapid tooling. Mechanical properties and accuracy are critical for tooling. This paper reports the results of an experimental study examining the potential of layer manufacturing processes to deliver production tooling for polymer manufacture. A comparison between indirectly selective laser sintering and directly selective laser sintering to provide the tooling was reported. Three main areas were addressed during the study: mechanical strength, accuracy, and build rate. Overviews of the results from the studies were presented.
关键词:
Selective laser sintering
,
laser
,
sintering
,
layer
,
manufact
Y.Y. Zhu
金属学报(英文版)
A modified two-sphere model of sintering neck has been proposed, wherein three diffusion mechanisms including surface diffusion, grain-boundary diffusion and coupled surface and grain-boundary diffusion are assumed. Sintering neck is appropriately simulated using the modified model. The dynamic change of sintering neck is presented using the simulation. The variational shape of sintering neck in surface diffusion mechanism is continuous, whereas in grain-boundary diffusion mechanism, besides the variational shape of sintering neck being continuous, the center distance between the particles is also assumed to contract. However, the variational shape of sintering neck in coupling diffusion mechanism is integrated using the two diffusion mechanisms mentioned above.
关键词:
sintering simulation
,
simulation
,
neck
,
growth
,
Visual
Junhua LIU+
,
Dept. of Manufacturing Engineering
,
Beijing University of Aeronautics and Astronautics
,
Beijing 100083
,
ChinaZutang WANG
,
Dept. of Mechanical Engineering
,
Tsinghua University
,
Beijing
,
100084
,
China
材料科学技术（英）
The effects of sintering on the microstructure and the critical current density of Ag-sheathed BiPbSrCaCuO (2223) superconducting tapes prepared by the powder-in-tube technique were in- vestigated. The microstructure of oxide layer and the J_C at 77 K were strongly dependent on the sintering condition. The optimum sintering temperature, time and cooling rate to maximize J_C values were in the range about 840-850℃, 100-200 h and 50-100℃/h, respectively.
关键词:
BiPbSrCaCuO
,
null
,
null
,
null
LI Dongchun TIAN Yongjun CHEN Shizhen YU Dongli HE Julong ** Yanshan University
,
Qinhuangdao
,
066004
,
China+ To whom correspondence should be addressed
材料科学技术（英）
Nickel,as the carrier through which Fe atoms diffuse,obviously enhances the densification of sintered compact containing short cast iron fibre. When Ni content is above 4.5 wt-% there are some austenites in microstructure at room temperature, discontinuous cementite networks at the interfaces between austenites and pearlites,free graphite pre- cipitated in austenite and pores and Widmannst(?)tten carbide precipitated in austenite. When Ni content is about 12 wt-%,it leads to de- crease in densification ratio and change in fracture morphology of sintered compact from ductile to brittle.
关键词:
short metal fibre
,
null
,
null
何木光
,
蒋大军
,
杜斯宏
,
宋剑
钢铁钒钛
doi:10.7513/j.issn.1004-7638.2013.04.009
攀枝花钒钛磁铁矿矿物组成复杂,其精矿产品含铁品位低、TiO2含量高,采用阶磨阶选工艺可使精矿品位达到54％,但TiO2仍高达13％左右.该精矿具有“低铁、低硅、高钛、高铝、高亚铁、高硫”的特点,同时精矿粒度粗,制粒性能差,影响烧结透气性.该精矿初始熔点高,生成液相量少,烧结矿矿物组成复杂,严重影响强度与冶金性能.近十多年来,通过采取使用生石灰,提高烧结矿碱度,燃料分加,配加普通矿粉,烧结机技术升级,采取高负压大风量烧结等一系列强化技术,烧结利用系数达到1.4 t/(m2·h),烧结矿转鼓指数在73％以上,改变了钒钛磁铁精矿烧结多年的落后状况,满足了高炉精料要求.
关键词:
烧结
,
钒钛磁铁矿
,
矿物特性
,
生石灰
,
碱度
,
矿物组成
,
冶金性能
,
强化技术
汤效平
,
褚玥
,
魏飞
催化学报
doi:10.1016/S1872-2067(09)60071-1
在不同的焙烧温度下制备了Pt-Sn/SAPO-34催化剂,并使用X射线衍射、N2吸附、X射线荧光光谱、O2脉冲烧炭、H2程序升温还原和透射电镜等手段对催化剂进行了表征.在微型反应器中评价了Pt-Sn/SAPO-34催化剂对丙烷脱氧制丙烯反应的催化性能,考察了焙烧温度和反应气氛对催化剂性能的影响.结果表明,焙烧温度为500℃时,催化剂具有最佳的反应活性.当焙烧温度高于500℃时,催化剂出现不希望的表面变化,例如活性Pt位点的聚集、Pt的团聚、Sn的流失等.当反应温度为595℃时,Pt-Sn/SAPO-34催化性能稳定,且能够保持表面金属状态.
关键词:
铂
,
锡
,
SAPO-34
,
焙烧温度
,
丙烷
,
脱氢
,
丙烯:团聚
韩秀丽
,
王海峰
,
刘丽娜
,
姚明艳
,
王艳红
钢铁钒钛
采用光学显微镜研究了碱度对钒钛烧结矿显微结构的影响.研究表明:碱度由2.1提高到2.5,烧结矿中钛磁铁矿、铁酸钙与硅酸二钙含量增加,钛赤铁矿与玻璃质含量降低;骸晶状赤铁矿与包边结构减少,显微结构由斑状向交织熔蚀结构过渡;相应的烧结矿强度增加.碱度为2.5时,铁酸钙主要以柱状、针状形态存在,钛磁铁矿主要以他形粒状形态存在,钙钛矿主要呈十字形和他形晶形态存在.
关键词:
烧结
,
钒钛磁铁矿
,
碱度
,
显微结构
,
烧结矿强度
,
铁酸钙
,
钙钛矿
张家敏
,
易健宏
,
甘国友
,
严继康
,
杜景红
,
刘意春
材料工程
doi:10.3969/j.issn.1001-4381.2013.10.011
以TiH2粉末为原料,通过组元球磨混合、压制成形和烧结工艺制备钛合金.用扫描电镜对球磨过程TiH2粉末的粒度、形貌变化以及烧结CP Ti,Ti-6Al-4V合金的组织形貌进行了观察;采用热重分析方法研究了TiH2粉末脱氢的特性;用热膨胀技术研究了TiH2,TiH2-Al-V两种粉末压坯的烧结致密化特性.结果表明:TiH2粉末经过球磨后迅速变细,其粒度随球磨时间的延长而减小,粉末形貌由原来的不规则形状逐渐变为等轴状;TiH2粉末在烧结过程的脱氢将使α-Ti产生强烈收缩、同时因脱氢后获得的新鲜钛表面所发生的快速粘接而使烧结体迅速致密、得到相对密度大于99％的烧结坯体;TiH2-Al-V粉末压坯在烧结时因为伴随着合金元素的溶解而使其烧结致密特性不如纯TiH2粉末压坯的好;TiH2粉末经过成型、烧结脱氢工艺可获得典型的等轴状纯钛组织,TiH2-Al-V粉末经过相同工艺可获得典型的层片状α+β钛合金组织、且合金元素分布均匀.
关键词:
粉末冶金
,
TiH2
,
球磨
,
成型
,
烧结
,
脱氢
,
显微组织
付建秋
,
黄小凤
,
潘学军
,
马丽萍
,
刘红盼
,
丁新悦
硅酸盐通报
利用底泥制备陶粒是底泥资源化的重要途径之一,具有广泛的应用前景.本文进一步分析了底泥制备陶粒的可行性,介绍了底泥制备陶粒过程各环节的作用及目前的研究成果,阐述了目前底泥陶粒主要的应用方向;同时展望了底泥制备陶粒工艺和底泥陶粒应用两方面的研究方向,为底泥制备陶粒的机理研究及工艺改进提供参考.
关键词:
底泥
,
陶粒
,
烧结
,
制备
,
应用
