镁砂中Fe2O3、Al2O3、P2O5、TiO2的联合测定

镁砂产品检验中,采用碱熔融法共同预处理样品,在同一母液中,联合测定铁、铝、磷、钛的含量,缩短了检测时间。通过分别控制各元素的显色酸度,各元素线性良好,测得的Fe2O3、Al2O3、P2O5、TiO2的相对标准偏差分别小于1.11%、2.78%、4.84%、5.88%。实验结果表明,方法的准确度和精密度都较高。     

Existence of a solid solution between 3CaO·V2O5 and 3CaO·P2O5

In the present work, a solid solution of 3CaO · V₂O₅ and 3CaO·P2O5 was found below 1573 K. The solution could be described as 3CaO+xV₂O₅+(1−x) P₂O₅. The solid solutions at three compositions, namely, X=1/3, X=1/2, and X=2/3, were synthesized. X-ray diffraction (XRD) patterns revealed that the crystals exhibited a rhombohedra structure. X-ray indexes at these compositions were reported.     

X-射线荧光光谱法测定磷矿中五氧化二磷、氧化钙、三氧化二铁、氧化铝、氧化镁和二氧化硅

采用四硼酸锂和偏硼酸锂混合熔剂[m(Li2B4O7)∶m(LiBO2)=12∶22]熔融磷矿样品制成玻璃样片,用波长色散X-射线荧光光谱仪测定样片中P2O5,CaO,Fe2O3,Al2O3,MgO和SiO2含量。用磷矿标样经同法测定并对测定结果进行理论α系数校正后绘制工作曲线。用本法对一试样测定11次,得到各组分的相对标准偏差小于1.2%。本法已用于磷矿样品分析,测定结果与化学法一致。     

稀土磁性复合微球的制备及表征

以聚乙二醇磁性胶体粒子为种子 ,运用分散聚合法 ,同时掺入稀土离子 ,制备出表面配位有稀土离子的磁性聚苯乙烯微球 ,该微球粒径为 6 0～ 180 nm,考察了稀土磁性微球的形态和结构。并用电镜、原子吸收光谱、红外光谱对其性质进行了表征。     

Chemical potentials of oxygen for mixtures of CaO (s) + Ca4P2O9 (s) + {CaO + P2O5 + FexO} melts and Ca4P2O9 (s) + Ca3P2O8 (s) + {CaO + P2O5 + FexO} melts

Electrochemical measurements involving stabilized zirconia as solid electrode and Mo + MoO₂ as reference electrode were conducted in order to determine the chemical potentials of oxygen for threephase assemblages of CaO (s) + Ca₄P₂O₉ (s) + liquid and Ca₄P₂O₉ + Ca₃P₂O₈ + liquid within the system CaO + Fe_xO + P₂O₅. The results for the former are $$\log (P_{O_2 } /atm) = 6.22 - 27,900 (T/K)$$ while for the latter, $$\log (P_{O_2 } /atm) = 6.35 - 27,600 (T/K)$$      

XRF熔融法测定石灰石、白云石中SiO2、CaO、MgO、Al2O3、Fe2O3、P2O5

采用熔融法制样,消除了共存元素的谱线干扰,通过XRF荧光光谱法测石灰石、白云石中SiO2、CaO、MgO、Al2O3、P2O5、Fe2O3的含量。分析结果与标准物质的标准值、化学法和ICP-AES法分析结果进行对比,测定结果符合国家标准允许差。     

Electrical conductivities of M3P2O8 (M = Ca,Ba)

Two-probe conductivity measurements made for M₃P₂O₈ (M = Ca, Ba) suggested that the electrical conduction of these phosphates would primarily be due to the migration of Ca²⁺ and Ba²⁺ ions. At relatively low temperatures and high oxygen partial pressures, in contrast to Ca₃P₂O₈, however, Ba₃P₂O₈ shows partial electronic conduction.     

CaO-La2O3-B2O3-Eu2O3转光玻璃的合成及荧光性质

X射线衍射研究表明CaO-La2O3-B2O3-Eu2O3体系的玻璃化温度在1025℃附近。荧光光谱和ESR谱研究表明,在CaO-La2O3-B2O3-Eu2O3玻璃体系中存在着Eu2 和Eu3 两种价态离子。316,360,379,394,413,462和532nm锐线激发峰和592,616和650红区发射峰分别对应Eu3 的f-f激发跃迁和5D0-7FJ(J=1,2,3)跃迁发射;351nm和427nm宽带激发峰和蓝区发射分别对应Eu2 的5d-4f激发跃迁和发射。     

X射线荧光光谱法测定矾土中硅、铁、钾、钙、钛、锰、铝、镁、磷等氧化物含量

建立了X射线荧光光谱法测定矾土中硅、铁、钾、钙、钛、锰、铝、镁、磷等氧化物的方法。以四硼酸锂做熔剂、溴化锂做脱模剂制备玻璃熔片 ,以标准物质和高纯试剂制备标准片做校正曲线 ,并对吸收增强效应和光谱重叠做出校正。通过测定标准样品进行比较 ,本法没有显著性差异。回收率为 86.7%～ 10 6.2 %。     

Wettability of silicon carbide ceramic by Al2O3/Dy2O3 and Al2O3/Yb2O3 systems

Wettability is an important phenomenon in the liquid phase sintering of silicon carbide (SiC) ceramics. This work involved a study of the wetting of SiC ceramics by two oxide systems, Al₂O₃ /Dy₂O₃ and Al₂O₃ /Yb₂O₃, which have so far not been studied for application in the sintering of SiC ceramics. Five mixtures of each system were prepared, with different compositions close to their respective eutectic ones. Samples of the mixtures were pressed into cylindrical specimens, which were placed on a SiC plate and subjected to temperatures above their melting points using a graphite resistance furnace. The behavior of the melted mixtures on the SiC plate was observed by means of an imaging system using a CCD camera and the sessile drop method was employed to determine the contact angle, the parameter that measures the degree of wettability. The results of variation in the contact angle as a function of temperature were plotted in graphic form which showed that the curves displayed a fast decline and good spreading. All the samples of the two systems presented final contact angles of 40° to 10° indicating their good wetting on SiC in the argon atmosphere. The melted/solidified area and interface between SiC and melted/solidified phase were evaluated by scanning electron microscopy (SEM) and their crystalline phases were identified by X-ray diffraction (DRX). The DRX analysis showed that Al₂O₃ and RE₂O₃ reacted and formed the Dy₃Al₅O₁₂ (DyAg) and Yb₃Al₅O₁₂ (YbAg) phases. The results indicated that the two systems had a promising potential as additives for the sintering of SiC ceramics.     

X射线荧光光谱法测定Dy_2O_3及其杂质Eu_2O_3,Gd_2O_3,Tb_4O_7,Ho_2O_3,Er_2O_3和Y_2O_3

当前稀土应用范围越来越广,尤其Dy2O3和金属Dy其出口量不断增大．Dy2O3中所含杂质总量通常在0．1％～5％之间,该范围内的测定方法以XRFR为合适,快速、准确、无破坏．1实验部分1．l原理本法采用粉末直接压片法制样,在各元素分析线峰位上测量X射线强度,根据待测元素的X射线荧光光谱强度与含量的定量关系,选择相应的数学模型,由计算机自动计算出待测成份含量．1．2仪器和试剂荷兰飞利浦PW—1400顺序式X射线荧光光谱仪;康柏486计算机;电动小型油压机;万分之一精度分析天平．DyZO399．999％;EnD3,GdD3,ThAn,HoAn,ErD3…     

Al_2O_3La_2O_3Y_2O_3/Cu复合材料的电弧侵蚀特性研究

采用喷射沉积和内氧化法制备出Al2O3La2O3Y2O3/Cu复合材料,研究该材料在直流20 V/20 A的工作条件下触点的电弧侵蚀特性,并与Al2O3/Cu材料进行了对比分析.利用电子天平、扫描电镜等方法分析电弧侵蚀后触点的质量变化和表面微观结构.结果表明,通过添加Y2O3、La2O3稀土氧化物颗粒,可有效降低触头材料的材料转移量.Al2O3La2O3Y2O3/Cu材料的抗熔焊性和抗烧损性优于Al2O3/Cu材料的性能.在直流阻性负载条件下Al2O3La2O3Y2O3/Cu阳极触头表面形成凹坑,阴极触头表面形成凸起,触点表面显示出浆糊状凝固物和喷发坑等电弧侵蚀形貌特征.     

Vitrification and Crystallization Behavior of CaO-SiO2-MgO-Al2O3-Fe2O3-Cr2O3 System

Metallurgical and Materials Transactions B - The effect of basicity and Cr2O3 content on vitrification of the CaO-MgO-SiO2-Al2O3-Fe2O3-Cr2O3 system during a melt-quenched process and the...     

Solid-phase reactions of Ta2O5 with Ga2O3 and In2O3

Conclusions Using the techniques of DTA and x-ray phase analysis, a study was made of the reactions between Ta₂O₅ and M₂O₃ (M = Ga or In), and the phase compositions of the relevant binary systems were determined. The existence was confirmed of stable compounds of composition MTaO₄ and eutectoidally decomposing phases containing 7.5–12.5 mole % M₂O₃. MTaO₄ are dielectrics, whose room-temperature _v is of the order of 10¹⁰ -cm. The temperature dependence of _v of MTaO₄ was investigated in the range 293–873°K and their energies of activation for conductivity were calculated. The melting points, pyknometric densities, dielectric losses, and relative dielectric permeabilities of MTaO₄ were determined.Translated from Poroshkovaya Metallurgiya, No. 2 (110), pp. 69–73, February, 1972.     

Catalytic Synthesis of Tert-Butyl Acetate by Nd2O3/Al2O3-Nd2O3/ZnO

Nd2O3 was used to support Al2O3 and ZnO to prepare a supported solid base catalyst and investigate the effect of catalyst and reaction conditions on the synthesis of tert-butyl acetate. The composited oxide of Nd2O3/Al2O3-Nd2O3/ZnO exhibited excellent catalytic activity for the synthsis of tert-butyl acetate. The molar ratio of tert-butanol to acetic anhydride is 31, the catalyst in total amount of reactant nearly 0.5%, and reaction time 6 h. With the above conditions, yield of the reaction could reach to 65%. The structure of product were verified by the FT-IR, Element analysis, and MS, which proved that the product was tert-butyl acetate.     

Research on Glass Forming Ability of Er2O3 -Al2O3 -B2O3 -SiO2 System

The glass forming range of Er2O3-Al2O3-B2O3-SiO2 system was explored, and the effect of the content of Al2 O3 and Er2 O3 on glass-forming region was experimentally examined. It is shown that the region of glass formation range expends when the content of Al2O3 is changed from 15% to 20%, while it shrinks when the content of Er2O3 is changed from 20% to 30%. At the same time, the glass forming ability of Er2O3-Al2O3-B2O3-SiO2 system was also discussed using a value of β, which is an indication of crystallization tendency of glasses, calculated from thermo-analysis data. It is found that the glass forming ability of Er2O3-Al2O3-B2O3- SiO2 glasses is poor, while the glasses network may be enhanced when Al2O3 is added to the system, the glass forming ability being heightened. In addition, the crystallization temperatures of the rare earth glasses were determined using differential thermal analysis technique. The Er2O3-Al2O;-B2O3-SiO2 glass samples were heat treated at 1000,1100 and 1260℃ respectively. The results show that it is the Er2O3 phase that separates out from the glasses after crystaline heat treatment, and it is tiered up in glasses, as detected through XRD and SEM. This indicates that the phase separation occurs when the glasses are heated, Er3 being mainly distributed in the boron rich phase, then separated out from glasses, while the silicate rich phase remaining glassy state.     

掺杂 Eu3+ 的 Na24P2Mo22O83 的合成及其发光特性

采用固相反应法合成了掺杂Eu3 的新型杂多酸盐Na2 4 P2 Mo2 2 O83 荧光体 ,并通过元素分析、红外光谱、X射线粉末衍射对其组成及结构进行了表征 ,新型杂多酸盐Na2 4 P2 Mo2 2 O83 属正交晶系 ,晶胞参数a =1 4774nm ,b =1 1896nm ,c=1 10 42nm ,属D2 4 -P2 12 12 1(No.19)空间群。测定了其激发光谱和发射光谱 ,探讨了掺杂Eu3 离子的Na2 4 P2 Mo2 2 O83 的发光特性。     

Nitrogen solution in BaO-B2O3 and CaO-B2O3 slags

The nitrogen solubility and nitride capacity of the BaO-B₂O₃ and CaO-B₂O₃ systems were measured at 1698 and 1773 K, respectively, using a gas-liquid equilibration technique. These systems were chosen because they have wide liquidus regions at the temperature of interest and were expected to show two types of nitride solution behavior. The nitride capacities of both systems showed minimum values with changing composition. This was explained by considering that nitrogen can dissolve into slag as “free nitride” at high basicities and as “nitride incorporated” with the network for acidic slags. The change of the nitride capacity with optical basicity and the activity of the basic component followed the predicted behavior for the proposed solution mechanism. The nitride capacity of the BaO-B₂O₃ system is considerably greater than for the CaO-B₂O₃ system because BaO is a more basic oxide than CaO. The activity of BaO in the BaO-B₂O₃ system was also measured by equilibration with liquid silver, at known oxygen potentials, and the activities show large negative deviations from ideal behavior.