B.H. Kim N.H. Kang W.T. Oh C.H. Kim J.H. Kim Y.S. Kim Y.H. Park
材料科学技术（英文）
For Al 6k21-T4 overlap weld joint, the shear-tensile strength by using the weaving laser was improved as compared to the case of linear laser. For the specimen of low strength, the porosity was distributed continuously along the intersection between the plates and fusion line. However, for the optimized welding condition, large oval-shaped porosities were located only in the advancing track of the concave part. Therefore, the continuity of cracks and porosities played a key role to determine the strength. And, the weaving width was also the important parameter to control the strength. Furthermore, the concave part had more significant hot and cold cracking in the weld and heat-affected zone (HAZ), respectively, than the convex part.
关键词:
Weaving laser
,
Weld microstructure
,
Void
,
Al alloy
B.H. Kim N.H. Kang W.T. Oh C.H. Kim J.H. Kim Y.S. Kim Y.H. Park
材料科学技术（英文）
For Al 6k21-T4 overlap weld joint, the shear-tensile strength by using the weaving laser was improved as compared to the case of linear laser. For the specimen of low strength, the porosity was distributed continuously along the intersection between the plates and fusion line. However, for the optimized welding condition, large oval-shaped porosities were located only in the advancing track of the concave part. Therefore, the continuity of cracks and porosities played a key role to determine the strength. And, the weaving width was also the important parameter to control the strength. Furthermore, the concave part had more significant hot and cold cracking in the weld and heat-affected zone (HAZ), respectively, than the convex part.
关键词:
Weaving laser
,
Weld microstructure
,
Void
,
Al alloy
材料科学技术（英文）
The corrosion of an Fe-based alloy containing 15 wt pet Y in H-2-H2S mixtures under 10(-3) Pa S-2 was studied at 600 similar to 800 degrees C in an attempt to find materials with improved sulphidation resistance with respect to pure Fe. The presence of Y has been shown to be beneficial, but not sufficient to the level expected. In fact, the alloy is able to form at all tested temperatures an external FeS layer, beneath which a zone containing a mixture of the two sulphides is also present. Thus, Fe can still diffuse through this region to form the outer FeS layer with non-negligible rate. The corrosion rate of Fe is considerably reduced by the Y addition, but the alloy corrodes still much more rapidly than Y. The sulphidation kinetics is generally rather irregular for both the pure metals, while the corrosion rate of the alloy decreases with time and tends to become parabolic after an initial period of 12 similar to 17 h. The sulphidation behaviour of the alloys is discussed by taking into account the presence of an intermetallic compound Fe17Y2 and the limited solubility of Y in Fe.
关键词:
high-temperature sulfidation;most-reactive component;ni-nb alloys;h2-h2s mixtures;behavior;600-degrees-c-800-degrees-c;oxidation
NIU Yan
,
F.GESMUNDO
,
WU Weitao
,
ZENG Chaoliu
,
F.VIANI
,
(State Key Laboratory for Corrosion and Protection
,
Institute of Corrosion and Protection of Metals
,
Chinese Academy of Sciences
,
Shenyang.110015
,
China)(Istituto di Chimica
,
Facolta'di Ingegneria
,
Universita'di Genova
,
Fiera del Mare
,
Pad.D
,
16129 Genova
,
Italy)Manuscript received 3 July 1995
金属学报(英文版)
The corrosion properties of a Co-15wt% Y alloy were studied in H_2-H_2S mixtures under a sulfur pressure of 10-3 Pa at 600-800℃ and of 10-2 Pa at 800℃ to examine the effect of Y on the resistance of pure cobalt to sulfur attack at high temperatures.The alloy is nearly single-phase.containing mostly the intermetallic compound Co17Y2 plus a little amount of the solid solution of Y in cobalt.At 600-700℃ and at 800℃ under 10-2 Pa of S2 the alloy forms multi-layered scales consisting of an outer region of pure cobalt sulfide,an intermediate region of a mixture of the sulfides of the two metals and finally an innermost layer of a mixture of yttrium sulfide with metal cobalt.At 800℃ under 10-3Pa of S2,below the dissociation pressure of cobalt sulfide, the alloy forms only a single layer composed of a mixture of metallic cobalt with yttrium sulfide.Pure Y produces only the oxysulfide Y2O2S, as a result of the good stability of this compound and of the presence of some impurities in the gas mixtures used The corrosion kinetics is generally rather complex and irregular except al 800℃under 10-3 Pa of S2.The addition of yttrium always reduces the sulfidation rate of cobalt, even though the formation of a continuous protective external layer of yttrium sulfide is never achieved.The internal sulfidation of Y in Co-15% Y is not associated with a depletion of Y in the alloy.This kind of diffusionless internal attack is typical of alloys with a very small solubility of the most reactive component Y in the base metal A.which restricts severely the Y flux from the alloy towards the alloy-scale interface.
关键词:
:cobalt-yttrium alloy
,
null
,
null
Yan NIU
,
Weitao WU and Chaoliu ZENG (State Key Lab. for Corrosion and Protection
,
Institute of Corrosion and Protection of Metals
,
Chinese Academy of Sciences
,
Shenyang 110015
,
China)F. Gesmundo and F. Viani (Instituto di Chimica
,
Facolta di Ingegneria
,
Un
材料科学技术（英文）
The corrosion of an Fe-based alloy containing 15 wt pct Y in H2-H2S mixtures under 10-3 Pa S2 was studied at 600~800℃ in an attempt to find materials with improved sulphidation resistance with respect to pure Fe. The presence of Y has been shown to be beneflcial, but not sufficient to the level expected. In fact, the alloy is able to form at all tested temperatures an external FeS layer, beneath which a zone containing a mixture of the two sulphides is also present. Thus,Fe can still diffuse through this region to form the outer FeS layer with non-negligible rate. The corrosion rate of Fe is considerably reduced by the Y addition. but the alloy corrodes still much more rapidly than Y. The sulphidation kinetics is generally rather irregular for both the pure metals, while the corrosion rate of the alloy decreases with time and tends to become parabolic after an initial period of 12~17 h. The sulphidation behaviour of the alloys is discussed by taking into account the presence of an intermetallic compound Fe17Y2 and the limited solubility of Y in Fe
关键词:
王世铭
,
黄金凤
,
林深
,
郑瑛
稀土
doi:10.3969/j.issn.1004-0277.2002.01.003
由三元杂多化合物(NH4)13[Y(SiMo11O39)2]·36H2O与喹啉反应合成了电荷转移化合物(C9H8N)10(NH4)3[Y(SiMo11O39)2]*20H2O.采用元素分析、X射线粉末衍射、红外光谱、固体漫反射电子光谱进行了表征.结果表明:喹啉通过N原子结合质子形成阳离子与稀土杂多阴离子成盐,固体化合物中阴离子和阳离子之间存在较强的相互作用;化合物在光激发下发生分子内电荷转移,导致有机C9H8N+大阳离子的氧化和稀土杂多阴离子的还原,标题化合物颜色由黄转变为深蓝色.
关键词:
电荷转移配合物
,
钇
,
多金属氧酸盐
,
合成
,
表征
牛焱
,
晏人芸
腐蚀学报（英文）
研究了纯Fe、纯Y、Fe-15Y和Fe-30Y合金在600～800℃高硫压(10-3Pa)-低氧压(10-19Pa于600℃或10-15Pa于700℃和800℃)混合气中的腐蚀行为.Y在600℃和700℃发生加速腐蚀,但在800℃形成的腐蚀膜有保护性.加入Y能够降低合金的腐蚀速率,但在所有条件下,合金都形成FeS最外层膜、由两金属的化合物组成的中间层和由α-Fe和Y的硫氧化物的细微混合物所组成内硫化-氧化区.Fe似以相当高的速率穿过中间层形成FeS外层.在合金/氧化膜界面内侧不产生Y的贫化现象.从Y在Fe
关键词:
Fe-Y合金
,
yttrium
,
sulfidation
,
oxidation
潘春阳
,
麦海登
,
卢静
,
李大光
,
杨红梅
,
赵丰华
,
郑颖琳
硅酸盐通报
以二甲胺和硼酸为原料,通过水热反应合成有机模板硼酸盐[C2H8N][B5O6 (OH)4],通过单晶X射线衍射对其晶体结构进行分析,该晶体属于单斜晶系,空间群为C2/c,晶胞参数为a=1.3381(75) nm,b=1.1468(56)nm,c=1.7137(92) nm,α=90.032(64)°,β=112.292(82)°,γ=89.988(85)°,V=2.433(2.000) nm3.粉末衍射(PXRD),红外(IR),热重(TGA)以及荧光(PL)等手段对其晶体进行分析表征.在不同温度下对该物质进行热处理,观察其IR和PXRD的变化判断其内部的结构是否能够保持稳定,并通过热重分析进行补充说明.荧光光谱结果表明在经过不同温度热处理后,该物质的发光特性发生明显的变化.实验证实[C2H8N] [B5O6(OH)4]一种可能用在白光LED上的荧光粉.
关键词:
模板硼酸盐
,
水热合成
,
晶体结构
,
发光
卢静
,
潘春阳
,
李大光
,
杨红梅
,
赵丰华
人工晶体学报
以离子液体氯化三甲基羟乙基铵为原料合成了一种有机模板硼酸盐[C4H12N][B5O6(OH)4],通过单晶衍射仪对其的晶体结构进行了检测.此外,对其进行了PXRD,红外,热重以及固态荧光等表征.X射线单晶结构分析结果表明,该晶体属于单斜晶系,空间群为P21/C,晶胞参数为a=9.2546(19)(A),B=16.855(3)(A),c=9.2894(19)(A),β=96.13(3)°,V=1440.73(467) (A)3.[B5O6(OH)4]-通过氢键形成三维的骨架结构并形成孔道,用来平衡骨架电荷的[C4H12N]+嵌在这些孔道中.荧光光谱分析结果表明,在波长为290 nm的激发光下,该硼酸盐发射出326 nm、365 nm的紫外光.对样品进行不同温度的热处理后,样品的荧光性质发生了明显的变化.这种变温的改性实验证实该有机模板硼酸盐有可能作为一种单一发射组分荧光材料应用在显示和照明等白光LED领域.
关键词:
有机模板硼酸盐
,
水热合成
,
晶体结构
,
发光
,
LED
