MgO—B2O3—SiO2—Al2O3—CaO中含硼组分析晶动力学

根据玻璃形成动力学理论，计算了ＭｇＯ－Ｂ２Ｏ３－ＳｉＯ２－Ａｌ２Ｏ３－ＣａＯ渣系中含硼组分２ＭｇＯ·Ｂ２Ｏ３的成核速度（Ｉ）和晶体长大速度（Ｕ），获得了２ＭｇＯ·Ｂ２Ｏ３晶体形成的最佳温度．采用化学分析、Ｘ射线衍射分析（ＸＲＤ）和差热分析（ＤＴＡ）等方法研究了热处理温度对ＭｇＯ—Ｂ２Ｏ３—ＳｉＯ２—Ａｌ２Ｏ３—ＣａＯ渣系硼提取率的影响．结果表明：硼渣最佳热处理温度与２ＭｇＯ·Ｂ２Ｏ３晶体形成最佳温度一致。     

MgO—B4C自蔓延高温合成的反应机理

对Ｂ２Ｏ３－Ｍｇ－Ｃ体系和Ｂ２Ｏ３－Ｍｇ体系不同加热速率下的ＤＴＡ曲线进行了分析。发现Ｂ２Ｏ３－Ｍｇ－Ｃ体系的自蔓延高温反应中,温度略低于６５０℃时Ｍｇ与Ｂ２Ｏ３发生强放热反应,释放出单质Ｂ;然后中间态Ｂ与Ｃ通过固态扩散反应生成Ｂ４Ｃ。     

一种新型湿化学方法合成Ba(Mg1/3Ta2/3)O3纳米粉末的研究

介绍了一种工艺简便且成本较低的Ｂａ（Ｍｇ１／３Ｔａ２／３）Ｏ３（ＢＭＴ）纳米粉末的湿化学制 备方法．实验过程以Ｔａ２Ｏ５作为起始物，通过热碱反应与钽离子浓度控制法合成Ｔａ２Ｏ５·ｎＨ２Ｏ 胶体，然后与Ｂａ、Ｍｇ醋酸盐按化学计量比混合，经热处理制得ＢＭＴ纳米粉末．实验结果表 明该方法制备ＢＭＴ粉体所需的合成温度仅为８００℃；比传统固相反应法合成温度降低４００℃ 左右，平均粒径仅为７０ｎｍ此外所制得的纳米陶瓷材料具有较佳的低温烧结性能和微波介电 特性，比目前报道的醇盐系湿化学制备技术更具有实用性．     

CaO—MgO—Fe2O3—Al2O3—SiO2渣系玻璃晶化动力学

根据玻璃形成动力学理论,计算了ＣａＯ－ＭｇＯ－Ｆｅ２Ｏ３－Ａｌ２Ｏ３－ＳｉＯ２渣系中成核速率（Ｉ）和晶体长大速度（Ｕ）,获得晶体形成的最佳温度,研究了热处理温度对ＣａＯ－ＭｇＯ－Ｆｅ２Ｏ３－Ａｌ２Ｏ３－ＳｉＯ２渣系晶体的影响,计算的晶体形成的最佳温度结果表明与该体系的最佳热处理温度一致。     

常压MOCVD制备MgO薄膜的研究

本文首次报道用常压金属有机化学气相沉积（ＡＰ－ＭＯＣＶＤ）在Ｓｉ（１００），ＳｉＯ２／Ｓｉ（１００）和Ｐｔ／Ｓｉ（１００）衬底上外延高质量的ＭｇＯ薄膜。研究了衬底温度与薄膜的取向性关系和ＭｇＯ薄膜的潮解特性。高纯ｍａｇｎｅｓｉｕｍａｃｅｔｙｌａｃｅｔｏｎａｔｅ［ｂｉｓ（２，４－ｐｅｎｔａｎｅｔａｎｅ－ｄｉｏｎｏ）ｍａｇｎｅｓｉｕｍ］［Ｍｇ（ＣＨ２ＣＯＣＨ２ＣＯＣＨ３）２］作为金属有机源，扫描电镜（ＳＥＭ），透射电镜（ＴＥＭ）和Ｘ－ＲＡＹ衍射实验显示，在较低的衬底温度（～４８０℃）下一次淀积成单晶膜。薄膜均匀，致密，结晶性和取向性很好，衬底温度（Ｔｓ）在４００℃到６８０℃之间，在Ｓｉ（１００）衬底上生长的ＭｇＯ薄膜都具有［１００］取向，在Ｓｉ（１００）、ＳｉＯ２／Ｓｉ（１００）和Ｐｔ／Ｓｉ（１００）衬底上生长的ＭｇＯ薄膜也都具有［１００］取向。     

CA-CA_2-C_2AS-MgO系统中C_2AS转变为Q相的研究

本文研究了１３００℃下ＣＡ－ＣＡ２－Ｃ２ＡＳ－ＭｇＯ系统中Ｃ２ＡＳ转化为Ｑ相的条件。结果表明：在ＣＡ－ＣＡ２－Ｃ２ＡＳ－ＭｇＯ系统中的Ｃ２ＡＳ只有补钙的条件下才能转化为Ｑ相，转化后的矿物组成为ＣＡ－Ｃ１２Ａ７－Ｑ－ＭｇＯ。     

纳米MgO和MgAl2O4尖晶石的制备与表征

本文较详细地介绍了用无机盐Ａｌ（ＮＯ３）３９Ｈ２Ｏ和Ｍｇ（ＮＯ３）２．６Ｈ２Ｏ为原料，醇凝胶分段程序升温超临界流体干燥法，制备纳米ＭｇＯ和ＭｇＡｌ２Ｏ４尖晶石新型功能材料的方法，并对所制得的纳米粒子采用ＴＥＭ、ＸＲＤ和ＦＴ－Ｒ等现代分析测试手段进行了表面形貌、结构、晶型和组成等的表征，掌握了纳米粒子的一些特征。     

CA—CA2—C2AS—MgO系统中C2AS转为为Q相的研究

本文研究了１３００℃下ＣＡ－ＣＡ２－Ｃ２ＡＳ－ＭｇＯ系统中Ｃ２ＡＳ转化为Ｑ相的条件，结果表明，在ＣＡ－ＣＡ２－Ｃ２ＡＳ－ＭｇＯ系统中的Ｃ２ＡＳ只有补钙的条件下才能转化为Ｑ相，转化后的矿物组成为ＣＡ－Ｃ１２Ａ７－Ｑ－ＭｇＯ。     

纳米氧化物的合成新方法

以草酸和醋酸盐为原料,用低热固相化学反应合成出前驱配合物ＮｉＣ２Ｏ４·２Ｈ２Ｏ,ＣｕＣ２Ｏ４ 和ＺｎＣ２Ｏ４·２Ｈ２Ｏ,再分别在３５０℃,３００ ℃和４６０℃热分解２ｈ,得到纳米ＮｉＯ,ＣｕＯ和ＺｎＯ。用Ｘ－ 射线粉末衍射、透射电镜对产物的组成、大小、形貌进行表征。结果表明,纳米ＮｉＯ为球形立方晶系结构,平均粒径约为４０ｎｍ 左右;纳米ＣｕＯ为球形单斜晶系结构,平均粒径约为３０ｎｍ 左右;ＺｎＯ为粒度分布均匀的球形六角晶系结构,平均粒径约为２０ｎｍ 。     

Co2O3掺杂对SnO2 - MgO- Nb2 O5压敏材料性能的影响

研究了Ｃｏ２Ｏ３含量对ＳｎＯ２－ＭｇＯ－Ｎｂ２Ｏ５压敏材料的密度、非线性特性的影响。实验结果表明,Ｃｏ２Ｏ３不仅能够增大ＳｎＯ２－ＭｇＯ－Ｎｂ２Ｏ５材料的质量密度,而且能提高非线性系数,减小漏电流,在较大程度上提高了ＳｎＯ２－ＭｇＯ－Ｎｂ２Ｏ５压敏材料的性能。     

Low-firing binders from magnesium containing carbonate raw materials

This paper presents scientific and experimental data for low-firing hydraulic binders: hydraulic lime and Roman cement based on local mineral raw materials. The binders were prepared by firing representative samples of carbonate–clay magnesian raw materials from Tatarstan. Using X-ray diffraction, we identified the firing products, including a hydraulically active phase, and determined the structural characteristics of its minerals. The compositions of the binders were determined as functions of firing conditions. We examined the influence of the firing temperature and duration of magnesian raw materials in the preparation of binders on MgO activity and demonstrated for the first time the possibility of ensuring an active state of the MgO resulting from firing (up to 21%) and suppressing its negative effect on Roman cement and hydraulic lime hardening processes.     

硬脂酸溶胶凝胶法制备氧化镁纳米微粒的研究

以硬脂酸为分散剂，采用溶胶凝胶法研究了制备氧化镁纳米微粒的条件，探讨了分散剂用量，反应时间，反应温度，烧结温度和时间对产物粒径与转化率的影响，取得了最佳工艺条件，分别用红外光谱（IR），X射线射末衍射（XRD），透射电镜（TEM）和比表面积（BET）测定，对该纳米微粒的结构与性能进行了表征，结果表明：Mg(NO3)2与CH3（CH2）16COOH的摩尔配比控制在1：1，于90℃反应20min，在470℃热处理3h，得到立方相氧化镁钠米微粒，形貌为椭球体，分散性好，平均粒径约为36nm.     

Effect of composition on the fracture strength of hot-pressed silicon nitride

The hot-pressing behaviour and fracture of silicon nitride as a function of composition was investigated. Two compositions were studied: 95 wt% Si₃ N4 + 5 wt% MgO, Material A, and 88 wt% Si₃N₄ + 2wt% MgO + 10wt% Y₂O₃, Material B. The effect of composition, hot-pressing time and temperature on the properties of the product were examined. The room-temperature fracture strengths of the two materials were evaluated using the diametral-compression disc test.     

纳米铌镁酸铅机械化学法低温快速合成

采用一种新型螺杆研磨机,以氧化物为原料,仅需3h的研磨,即可得到钙钛矿相结构的纳米铌镁酸铅(PMN)粉体.并研究了原料粉质量、研磨功率、研磨时间等不同因素对于合成的影响.通过对比分析发现,提高研磨功率,可以缩短合成时间、提高产物纯度、减小粉体粒径.通过原料交叉反应实验,确定剪切力机械化学法合成铌镁酸铅的反应机理为:MgO与Nb2O5反应生成MgNb2O6,然后与PbO反应获得铌镁酸铅.     

纳米氧化锌的制备工艺研究

以均匀沉淀法作为纳米氧化锌的制备方法,通过单因素实验和正交实验,系统地分析了溶液水解反应温度、水解反应时间、原料摩尔配比、煅烧温度等对氧化锌粉体产率和粒径的影响。结果表明,最佳工艺是:以直接混合的方式混合原料液,聚乙二醇-400作表面活性剂,反应温度90℃,原料摩尔配比c(尿素)/c(硝酸锌)=3:1,反应时间5.5h,前驱体碱式碳酸锌的最佳煅烧温度为500℃。通过所制得纳米氧化锌的XRD、SEM的粒径分析,证明了所制得的纳米氧化锌晶形为六方晶相,纯度大于99.9%、平均粒径约为68nm,产率为89.6%。     

Ba(Mg1/3Ta2/3)O3合成过程及烧结性的研究

利用DTA／TGA、XRD、SEM等分析手段，研究了不同起始原料制备的BMT合成过程及其烧结行为，发现以Ta2O5·xH2O为起始原料，可减少合成过程中产生的中间相，在较低的温度下合成单相BMT，改善了其烧结性．     

低温制备微晶Al2O3-MgAlON复合材料的反应机理

采用热压烧结,以Al、Al2O3、MgO为原料,在850℃制备微晶Al2O3-MgAlON复合材料。通过XRD、SEM、粒度分析等表征手段对所制备的MgAlON刚玉复合材料进行机理研究发现:在压力存在的情况下,熔融的铝在低温反应过程中对物质的传输和反应的进行起到了"通道"作用,从而使反应能在较低的温度下顺利进行,并使MgAlON的晶粒随温度的升高不断长大。     

Preparation of rutile TiO2 nanofibers by TiO2 sol intercalation of ultrafine layered titanate

To prepare TiO₂ intercalated tetratitanate, TiO₂ solution and ultrafine layered titanate K₂Ti₄O₉ obtained via solid-state reaction by using nanometer-sized TiO₂ as raw material were used as guest and host materials respectively. The structure and morphology of the resulting samples were characterized by XRD and TEM experiments. It was found that during the intercalation process, the interlayer distance was expanded step-by-step and the interlayer structure of titanate might be destroyed and degraded to slits by prolonging the solution intercalation time. Rutile TiO₂ nanofibers with the average size of 5 × 50 nm were obtained at room temperature while the duration time was prolonged to 72 h.     

Direct observation of the growth process of MgO nanoflowers by a simple chemical route

Novel flowerlike nanostructures consisting of MgO nanofibers were successfully synthesized by a simple chemical route with H(2)O at 950 degrees C in an Ar atmosphere. Various durations of heating gave different growth stages that led to varied product morphologies. The synthesized products were systematically studied by X-ray powder diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray analysis. The results show that the nucleation and growth process of the nanoflowers seems to be a vapor-solid mechanism, and that the total heating time during the reaction process is a critical factor for the development of MgO nanoflowers. Initially, Mg particles formed on the Si substrate, followed by the formation of MgO clusters as nucleation centers on the magnesium melt surface and the nucleation of short MgO nanofibers, then growth of the MgO nanofibers occurred, and finally MgO nanoflowers were formed. Besides nanoflowers, novel hierarchical MgO nanostructures were also observed. These nanostructures may be used as three-dimensional composite materials and as supports for other materials.