Xiaobing REN and Xiaotian WANG (College of Materials Science and Engineering
,
Xi'an Jiaotong University Xi'an 710049
,
China)K.Shimizu and T.Tadaki (Institute of Scientific and Industrial Research
,
Osaka University
,
8-1
,
Mihoga-oka
,
Ibaraki
,
Osaka
,
567
,
Ja
材料科学技术（英文）
A theoretical study is developed on the evolution and mechanism of an ordering coupled phase separation, and on the origin of a resultant tweed microstructure. It is found that long-range elastic interaction among atoms with different atomic sizes plays a key role in the phase sep aration, and that the evolution of the phase separation is very similar to that Of conventional spinodal decomposition except that the separation is dependent on an elastic interaction order ing (EIO). This "EIO coupled spinodal decomposition" is shown to exhibit a periodical or tweed microstructure being accompanied by an EIO. It is also found that a large atomic size factor yields a large positive contribution of EIO to spinodal decomposition. Generally it is thermodynamically and kinetically favorable for the EIO to precede the onset of spinodal decomposition,though the former is not separable from the latter as a whole. We suggest that an initially disordered solid solution undergoes an EIO first, and then the partially ordered solid solution starts to decompose via a spinodal mechanism. Solute-enriched regions increase their degree of order along with an increase in solute content, and solute-depleted regions decrease their degree of order together with a decrease of solute content. The final microstructure is characterized by a periodical array of highly ordered solute-enriched regions and nearly disordered solute-depleted regions. The notion of EIO coupled spinodal decomposition is in general agreement with the transformation behaviour of a large number of alloy systems.
关键词:
王向东
,
逯福生
,
贾翃
,
郝斌
,
马云风
钛工业进展
doi:10.3969/j.issn.1009-9964.2008.01.001
根据中国海关的统计,叙述了2007年上半年我国钛矿的进出口情况:我国进口钛矿567 565.165 t,净进口554 312.061 t;进口的主要地区是广西自治区的钦州地区和江苏省的镇江市;钛矿的来源地主要是越南、澳大利亚和印度.
关键词:
钛矿
,
进出口
,
海关
,
统计
,
地区
邹娟
,
杨雨
,
钱国栋
,
王智宇
,
王民权
稀有金属材料与工程
通过在溶胶-凝胶工艺中引入不同的有机改性硅先驱体,将激光染料PM567掺杂于锆-有机改性硅酸盐凝胶玻璃(Zr-ORMOSIL)中.通过旋涂法,将所得的Zr-ORMOSIL溶胶旋涂在载波片上,并测量了薄膜的折射率和厚度.在紫外连续辐照下,以染料荧光强度下降的幅度来表征染料在介质中的光学稳定性.实验结果表明:有机改性体的适当加入可提高染料的光稳定性,染料在乙烯基三乙氧基硅烷(VTES)、甲基三乙氧基硅烷(MTES)中,光稳定性较好.当Zr的含量为25%或50%时,激光染料PM567具有较好的光稳定性.随着Zr含量的增加,波导薄膜的折射率增加.综合考虑光稳定性和折射率,可对染料掺杂Zr-ORMOSIL波导薄膜的制备工艺进行优化.以Nd:YAG激光器作为光源,实现了激光染料掺杂Zr-ORMOSIL薄膜的动态分布反馈(DFB)的连续可调谐激光输出.
关键词:
Zr
,
溶胶-凝胶
,
染料
,
光稳定性
,
DFB
罗光富
,
尚静
,
李明翠
,
黄应平
冶金分析
doi:10.3969/j.issn.1000-7571.2005.04.015
在阴离子表面活性剂十二烷基磺酸钠(SDS)存在下,研究了新型苯基荧光酮类显色试剂2,3,7-三羟基-9-(4'-硝基苯基)苯基荧光酮(p-NPF)与锌离子显色反应的光度性质和反应特性.在pH 9.3的NH3·H2O-NH4Cl缓冲溶液介质中,所形成的络合物的最大吸收值位于567 nm处,表观摩尔吸光系数为4.01×104.拟定方法用于废水中微量锌的测定,结果满意.
关键词:
2,3,7-三羟基-9-(4'-硝基苯基)苯基荧光酮
,
锌
,
分光光度法
解挺
,
吴玉程
,
张立德
功能材料
介绍了用一种简单的气相合成方法制备出了大量高纯单晶氮化硅(α-Si3N4)纳米线,所形成的纳米线粗细均匀、表面光滑,直径为30～80nm,其长度可达数百微米.同时讨论了氮化硅纳米线的生长机理,其生长过程中气-固机制起主导作用.荧光测试结果表明,氮化硅纳米线的发光有一个宽的发光带(波长从500～700 nm),发光峰位于567 nm.
关键词:
氮化硅
,
纳米线
,
制备
,
气-固机制
,
荧光
Journal of the American Ceramic Society
Titanium diboride (TiB2) was successfully hot-pressed at 1500 degrees C using titanium aluminum carbide (Ti3AlC2) as a sintering aid. The mechanisms for the improved sinterability of TiB2 by the addition of Ti3AlC2 involve, first, the Al coming from the decomposition of Ti3AlC2 can eliminate the oxide layer on the surface of TiB2; second, the TiCx (also from the decomposition of Ti3AlC2) has a positive influence on the densification of TiB2 due to its plasticity at high temperatures. TEM observations reveal that the interface between TiB2 and TiCx is coherent and strong, free of amorphous layers and oxide phases. An optimized composition of TiB2-10 wt% Ti3AlC2 was obtained with the unique combination of mechanical properties, including the elastic modulus of 567 GPa, the fracture toughness of 4.8 MPa.m(1/2), the flexural strength of 711 MPa, and the hardness of 25 GPa.
关键词:
titanium diboride ceramics;orientation relationship;state properties;silicon-nitride;densification;stability;temperature;composites;iron;aluminum
武秀兰
,
张晋春
,
朱建锋
,
任强
人工晶体学报
采用高温固相法制备了白光LED用NaGd(1-x)TiO4∶xSm3+系列红色荧光粉,并对样品分别进行了X射线衍射分析和荧光光谱测试.结果表明,样品可以被紫外、近紫外和蓝光有效激发,在409 nm激发下,该荧光粉有三个主要发射峰,位于567 nm、607 nm和652 nm处,分别对应于Sm3+的4G/2→6H5/2、4G5/2→6H7/2、4G5/2→6H9/2的跃迁发射,其中607 nm处发射最强,呈现红色发光.当Sm3+的掺杂浓度为2.5mol％时,达到最佳的发光效果.因此,这种荧光粉是一种有应用潜力的白光LED红色荧光粉.
关键词:
NaGdTiO4∶Sm3+
,
红色荧光粉
,
LED
,
固相法
张景超
,
李立
,
丁瑞
,
韩志平
材料科学与工程学报
为了分析玻璃退火过程中永久应力的形成规律以及应力值的大小,基于玻璃永久应力的成因分析,建立了弹性体数值模型,给出了永久应力的计算方法和步骤。根据所建模型,利用ansys软件模拟了玻璃退火过程中结构应力和残余温差应力的形成过程,发现结构应力产生于膨胀系数开始发生变化的温度567℃,停止于膨胀系数稳定时的温度480℃。并根据模拟结果,计算出了玻璃中永久应力值的大小：边部压应力1.022MPa,中部张应力0.602MPa。模拟过程比较准确地反应了实际玻璃退火过程中应力的形成过程,根据模拟值求出的应力值大小基本符合玻璃实际应力值情况。
关键词:
膨胀系数
,
结构应力
,
温差应力
,
永久应力
肖婷刘波王新练王春芬任丁
材料研究学报
采用含异丙醇(IPA)的TMAH溶液腐蚀经Si3N4掩膜形成10 μm×10 μm窗口的单晶硅片。在硅片表面得到了内壁光滑的倒金字塔V型口阵列。研究发现: 与纯TMAH对硅的各向异性腐蚀特性相比, 添加IPA使TMAH溶液对硅各个晶面的腐蚀速率减小, 致使含IPA的TMAH溶液对硅的腐蚀速率和各向异性因子比在纯TMAH中要小。通常认为, 腐蚀形成的倒金字塔结构侧壁晶面为(111)面, 但本研究表明, 由各向异性腐蚀形成倒金字塔的侧壁晶面随腐蚀时间发生了一系列转化。在腐蚀开始时, 倒金字塔侧面由(567)面逐渐向(111)面转化; 继续腐蚀时, 腐蚀面偏离(111)面, 向(443)面转化。
关键词:
材料表面与界面
,
wet etching
,
TMAH
,
inverted pyramid-shape structures
,
intersection angles between side planes and (100) plane
原浩杰
,
吕春祥
,
张寿春
,
吴刚平
新型炭材料
doi:10.1016/S1872-5805(15)60179-2
采用一种不含有机溶剂的聚酰胺酸上浆剂实施上浆处理,为在T300级炭纤维(3 k)表面制备聚酰亚胺( PI)涂层提供一种绿色途径。通过傅里叶变换红外光谱和扫描电子显微镜对PI涂覆炭纤维的表面进行分析,结果表明,在炭纤维表面形成一层连续且均一的PI涂层。通过热重分析和单丝拉伸测试,考察炭纤维的热稳定性。与包含环氧上浆剂的炭纤维相比,在耐高温树脂的加工温度范围(300~400℃)内PI涂覆炭纤维表现出优异的热稳定性,起始分解温度与5%热失重温度分别高达567℃及619℃。此外,在空气中、400℃条件下氧化1 h后,PI涂覆炭纤维的拉伸强度仅下降6%,明显低于包含环氧上浆剂炭纤维(拉伸强度下降22%)。
关键词:
炭纤维
,
表面改性
,
热稳定性
,
聚酰亚胺涂层
