材料期刊网

Concentration Heterogeneity in Structure of Ni3Al Intermetallic Synthesized under Compression

O.B.Perevalova , M.B.Fedorischeva , V.E.Ovcharenko , Huihe SU

材料科学技术（英文）

By X-ray analysis, TEM and SEM methods the phase composition, microstructure, and deviation from stoichiometric composition were investigated for the Ni3Al intermetallic compound obtained by cast and self-propagation high-temperature synthesis under compression with followed homogenization anneal, with the Al concentration being 24.0 and 25.0 at. pct with and without B (0.5 at. pct). It was discovered that in SHS intermetallic alloys an average local deviation from stoichiometric composition is significantly more than in the cast alloy. Dependence of the local deviation from the stoichiometric composition on the distance has a zig zag nature at the level of the grain groups. Deviation from the stoichiometric composition at the boundaries of the general type is less than at the boundaries of the special type. When the intensity of boundary migrations of the general type decreases, the degree of deviation from the stoichiometric composition increases. There is correlation between the solubility of B in the crystalline lattice of the Ni3Al phase and the value of the deviation from the stoichiometric composition in the grains. When the B concentration in a solid solution increases, the deviation from stoichiometric composition decreases.

关键词: Ni3Al , null , null , null

Energy of Grain Boundaries of Different Type in fcc Solid Solutions, Ordered Alloys and Intermetallics with L12 Superstructure

O.B.Perevalova , E.V.Konovalova , N.A.Koneva , E.V.Kozlov

材料科学技术（英文）

The study of the triple junctions of the grain boundaries in some fcc solid solutions, ordered alloys and intermetallics with L12 has been carried out using the optical metallography and TEM methods. Two-types of the triple junctions were found in the alloys investigated (1), consisting of the boundaries of the random (RT), and (2), consisting of the RT boundary and the special boundaries (ST). The relative values of the RT and ST boundary energy were determined on the basis of the measurements of the angles between the grain boundary planes. It has been shown that the energy of ST boundaries increases with the increase of the stacking fault (SF) energy. The energy of the RT boundaries does not depend on the SF energy.

关键词: Alloys , null , null , null

ACTIVITIES OF COMPONENTS IN MgO-B_2O_3 MELT

ZHANG Chengtao JI Chunlin Northeast University of Technology , Shenyang , China ZHANG Chengtao , Division of Physical Chemistry of Metallurgy , Northeast University of Technology , Shenyang , China

金属学报(英文版)

The activity of MgO in MgO-B2O_3 melt was experimentally determined at 1773 and 1823 K by means of slag-liquid Sn equilibrium.The activity of B_2O_3 was calculated by integrating Gibbs-Duhem equation.The standard Gibbs energies of formation of binary compounds 2MgOB_2O_3 and 3MgO·B_2O_3 were estimated with the activity data of components in B_2O_3-MgO melt.

关键词: MgO-B_2O_3 , null , null

A NEW ROUTE FOR THE SYNTHESIS OF BORON SUBOXIDE B7O

Journal of Alloys and Compounds

Boron suboxide B7O is synthesized with the aid of the oxidation of boron with zinc oxide ZnO under extreme conditions of high pressure, 3.50 GPa and high temperature, 1200 degrees C, and characterized by means of X-ray powder diffraction. This new route for the synthesis of boron suboxide B7O has several advantages.

关键词: synthesis;boron suboxide;x-ray powder diffraction;zinc oxide

Phase relations in the system La2O3-B2O3-P2O5

Journal of Alloys and Compounds

The subsolidus phase relations in the system La2O3-B2O3-P2O5 were investigated. The system can be divided into 12 three-phase regions. There are nine binary compounds and one ternary compound in this system. The ternary compound La7O6(BO3)(PO4)(2) has a monoclinic structure, space groups P2(1)/n, with lattice constants a = 7.0172 Angstrom, b = 17.9125 Angstrom, c = 12.6500 Angstrom, beta = 97.516 degrees, V = 1576.39 Angstrom(3), and Z = 4.

关键词: La2O3-B-3-B2O3-P2O5 system;phase relations;ternary compounds

Subsolidus phase relations in the system BaO-B2O3-P2O5

Journal of Alloys and Compounds

The subsolidus phase relations in the system BaO-B2O3-P2O5 were determined. The system can be divided into 16 three-phase regions. There are nine binary compounds and three ternary compounds in this system. (C) 1997 Elsevier Science S.A.

关键词: ternary oxide system;alkaline earth borophosphates;crystal structure;crystal-structure;borate

Na2O-Al2O3-B2O3玻璃的热学性质和红外光谱

殷海荣 , 武丽华 , 陈福 , 安百江

硅酸盐通报 doi:10.3969/j.issn.1001-1625.2006.04.035

制备了Na2O-Al2O3-B2O3系统低熔点玻璃,确定了Na2O-Al2O3-B2O3系统玻璃成玻范围,研究了玻璃的转变温度(Tg)、热膨胀系数(α)和玻璃的红外光谱,表明这种玻璃的熔化温度低、转变温度也较低、玻璃的热膨胀系数较大,在近红外区有一水分的吸收带,在中红外区有B-O、Al-O的特征吸收带,以及玻璃的Tg、α与玻璃组成的关系.

关键词: 硼酸盐玻璃 , 低熔点玻璃 , 热性质 , 红外光谱

Phase relations in the SrO-Ga2O3-B2O3 system

Journal of Alloys and Compounds

The subsolidus phase relations in the SrO-Ga2O3-B2O3, system were investigated. The system contains 10 binary compounds and two ternary compounds, and can be divided into 15 three-phase regions. The new ternary compound SrGaBO4 has two modifications (alpha- and beta-phases), both of which crystallize in the orthorhombic system but with different space groups. (C) 2002 Elsevier Science B.V. All rights reserved.

关键词: oxide materials;crystal structure;phase diagram;X-ray diffraction;crystal-structure;srga12o19;compound

CaO-SiO2-B2O3熔渣的热力学计算模型

赵定国 郭培民

钢铁研究学报

根据CaO-SiO2、CaO-B2O3和SiO2-B2O3二元相图确定了熔渣的结构单元，利用熔渣的分子离子共存理论建立了CaO-SiO2-B2O3三元熔渣活度模型。通过对模型求解，可以计算出熔渣中CaO﹑SiO2﹑B2O3﹑CS、C2S、C3B、C2B、CB和CB2的组分活度。分析了熔渣碱度、B2O3含量及温度对熔渣组分活度的影响，其中熔渣碱度的影响最大，B2O3含量的影响次之，温度的影响最小。

关键词: 熔渣;共存理论;活度;计算模型

CaO-SiO2-B2O3熔渣的热力学计算模型

赵定国 , 郭培民 , 赵沛

钢铁研究学报

根据CaO-SiO2、CaO-B2O3和SiO2-B2O3二元相图确定了熔渣的结构单元,利用熔渣的分子离子共存理论建立了CaO-SiO2-B2O3三元熔渣活度模型.通过对模型求解,可以计算出熔渣中CaO、SiO2、B2O3、CS、C2S、C3B、C2B、CB和CB2的组分活度.分析了熔渣碱度、B2O3含量及温度对熔渣组分活度的影响,其中熔渣碱度的影响最大,B2O3含量的影响次之,温度的影响最小.

关键词: 熔渣 , 共存理论 , 活度 , 计算模型