肖瑗
,
王哲飞
,
龚志杰
,
王丽熙
,
张其土
功能材料
采用固相合成法制备了(Y0.99R0.01)2 Ti2O7(R=Pr、Tb、Ho、Er、Tm、Yb、Lu)陶瓷,研究了Pr、Tb、Ho、Er、Tm、Yb及Lu掺杂对Y2Ti2O7陶瓷物相组成、烧结性能和微波介电性能的影响.结果表明A位取代能改进其微波介电性能.烧结样品为单相的烧绿石结构,主晶相为Y2Ti2O7.当R=Er,1450℃烧结4h时,(Y0.99Er0.01)2Ti2O7陶瓷的微波介电性能最佳:εr=44.3,Q×f=12021GHz(5.371GHz),τf=+44×10-6/℃,优于Y2Ti2O7陶瓷的介电性能(εr=54,Q×f=6565 GHz,τf=-31×10-6/℃).
关键词:
无机非金属材料
,
微波介质陶瓷
,
Y2Ti2O7
,
烧绿石结构
,
掺杂
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:
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
丁栋舟
,
陆晟
,
潘尚可
,
张卫东
,
王广东
,
任国浩
无机材料学报
doi:10.3724/SP.J.1077.2008.00434
采用提拉法制备了LuxY1-xAlO3:Ce晶体样品, 通过XRD物相分析和成分分析, 并结合Lu2O 3-Al2O3二元体系相图以及LuxY1-x AlO3:Ce结构稳定性方面的分析与讨论, 结果表明: 随着熔体中Lu元素含量的增加, 熔体分层加剧, 析晶LuxY1-xAlO3:Ce相的熔体组成区间将向富Lu一侧偏移, 这使得晶体上部易伴生(Lu,Y)3Al5O12:Ce相; 而随着Lu元素含量的提高, LuxY1-xAlO3:Ce晶体的热稳定性降低, 氧空位的存在则使晶体的热稳定性进一步降低, 在接种过程中籽晶表面易发生相分解反应生成(Lu,Y)3 Al5O12:Ce和(Lu,Y) 4 Al2O9:Ce, 籽晶表面相分解产物(Lu,Y)3Al5O12:Ce提供了诱导析晶(Lu,Y)3Al5O12 :Ce相所需的晶核, 这使得晶体的外
表面处易伴生(Lu,Y)3Al5O12:Ce相. 调整配料组成使 n(Lu,Y)2O3 ): n (Al2O3)=1.17～1.00, 加大熔体内部和固液界面处的温度梯度以改善熔体对流、抑制熔体分层以及籽晶表面处的相分解等有助于高Lu元素含量LuxY1-xAlO3 :Ce晶体的获得.
关键词:
铝酸钇镥晶体
,
perovskite
,
garnet
,
accompany
丁栋舟
,
陆晟
,
潘尚可
,
张卫东
,
王广东
,
任国浩
无机材料学报
doi:10.3321/j.issn:1000-324X.2008.03.004
采用提拉法制备了LuxY1-xAlOa:Ce晶体样品,通过XRD物相分析和成分分析,并结合Lu2O3-Al2O3二元体系相图以及LuxY1-xAlO3:Ce 结构稳定性方面的分析与讨论,结果表明:随着熔体中Lu元素含量的增加,熔体分层加剧,析晶LuxY1-xAlO3:Ce相的熔体组成区间将向富Lu一侧偏移,这使得晶体上部易伴生(Lu,Y)3Al5O12:Ce相;而随着Lu元素含量的提高, LuxY1-xAlO3:Ce晶体的热稳定性降低,氧空位的存在则使晶体的热稳定性进一步降低,在接种过程中籽晶表面易发生相分解反应生成(Lu,Y)3Al5O12:Ce和(Lu,Y)4Al2O9:Ce,籽晶表面相分解产物(Lu,Y)3Al5O12:Ce提供了诱导析晶(Lu,Y)3Al5O12:Ce相所需的晶核,这使得晶体的外表面处易伴生(Lu,Y)3Al5O12:Ce相.调整配料组成使n((Lu,Y)2O3):n(A12O3)=1.17～100,加大熔体内部和固液界面处的温度梯度以改善熔体对流、抑制熔体分层以及籽晶表面处的相分解等有助于高Lu元素含量LuxY1-xAlO3:Ce晶体的获得.
关键词:
铝酸钇镥晶体
,
钙钛矿
,
石榴石
,
伴生
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
王逸群
,
宋鹏
,
季强
,
廖红星
,
陆建生
材料工程
doi:10.11868/j.issn.1001-4381.2015.000379
分别利用真空等离子沉积和超音速火焰喷涂技术制备含有Y和含Y氧化物的NiCoCrAl涂层,用差热分析和光学及电子显微镜研究两种涂层在Ar-16.7%O2,Ar-3.3%H2O和Ar-0.2%H2-0.9%H2O气氛中1100℃时的氧化动力学和断面微观结构,通过第一性原理计算对比在不同气氛中含Y氧化物对涂层氧化的影响机理.结果表明:对于NiCoCrAl+Y涂层,Y倾向于向界面扩散并在界面富集导致Al2O3膜生成更多有利于内氧化的孔洞,水蒸气更会对内氧化产生促进作用.而对于NiCoCrAl+Y(O)涂层,由于Y在涂层制备过程中被氧钉扎,导致NiCoCrAl+Y(O)涂层在上述气氛中生成了平直而均匀的Al2O3层,不同气氛对其氧化行为影响较小.上述研究进一步揭示NiCoCrAl涂层中活性元素Y的存在状态和氧化气氛中的水蒸气对氧化铝组织结构和生长速率有重要影响.
关键词:
含钇氧化物
,
水蒸气
,
NiCoCrAl涂层
,
热障涂层
,
内氧化
Journal of Solid State Chemistry
A serial of samples in Y2O3-Ga2O3-Tm2O3 pseudo-ternary system are prepared by solid-state chemical reaction method. The range of solid solution in (Y1-xTmx)(3)GaO6 is 0 < x < 0.384. Powder X-ray diffraction shows that the compounds crystallize in Gd3GaO6 (Cmc2(1))-type structure. The solid solubilities of Y3+xGa5-xO12 (x = 0-0.77) and Tm3+xGa5-xO12 (x = 0-0.62) are 37.5-47.11 at% Y2O3, and 37.5-45.26 at% Tm2O3, respectively. PL spectra of Tm-doped Y3GaO6 show that there is a sharp blue emission at similar to 456 nm from the D-1(2) -> F-3(4) transition at room temperatures with two lifetimes (similar to 5 and similar to 15 mu s) and a narrow saturation range of PL intensity for the Tm3+ content from x = 0.005 to 0.03. The sharp emission and long lifetime of (Y1-xTmx)(3)GaO6 indicate that Y3GaO6 is a potential phosphor and laser crystal host material. (c) 2005 Elsevier Inc. All rights reserved.
关键词:
Tm3+ -doped Y3GaO6;Y2O3-Ga2O3-Tm2O3 system;(Y1-xTmx)(3)Ga5O12 solid;solution;luminescence;crystal-structure;luminescence;phosphor;cations;ions;tb3
