钙铁硅铁磁体微晶玻璃热处理气氛的研究

使用XRD,DTA,VSM和穆斯堡尔谱等分析测试手段,对不同气氛下晶化热处理的含水量的B2O3,P2O5钙铁硅微晶玻璃的晶相结构和性质进行了比较深入的研究,研究结果表明,在氧化性气氛下热处理的钙铁硅微晶玻璃以赤铁矿为主;必须在还原性气氛下热处理才能得到以磁铁矿为主要晶相的铁磁体微晶玻璃。     

用穆斯堡尔谱研究透明微晶玻璃的光吸收

用穆斯堡尔谱(Moessbauer Spectroscopy)研究了掺铁Li_2O-MgO-Al_2O_3-SiO_2系统微晶玻璃的光吸收。分析了穆斯堡尔谱(MB)的两个主要参数——同质异能位移(Isomer Shift)和四极分裂(Quadrupole Splitting)与光吸收的关系。结果指出,铁离子浓度(0～10重量%)和晶化时间(0～100小时)对铁在主晶相β-石英固溶体中的价态、配位状态和最邻近电子环境的不对称程度有直接的影响。     

钙铁硅铁磁体微晶玻璃晶化与核化的研究

铁磁体微晶玻璃是用于温热治疗肿瘤的一种热种子材料,使用XRD,DTA,SEM－EPMA,Moessbauer和VSM对添加了少量改善生物活性的P2O5和B2O3或Na2O的钙铁硅微晶玻璃在还原气氛下热处理的核化与晶化特性进行了研究。钙铁硅玻璃在还原气氛下热处理后其主要晶相是磁铁矿和硅灰石及少量赤铁矿。随着玻璃化学组成和热处理条件的不同,微晶玻璃中也会出现少量钙铁辉石,钙铁橄榄石等其它晶相。由于玻璃中存在很大的分相倾向,钙铁硅微晶玻璃中磁铁矿的核化是在成形冷却过程中完成的,核化速度很快。硅灰石的核化速度较慢,在重新加热进行热处理的过程中完成,添加少量P2O5和B2O3的钙铁硅玻璃的成核机理以整体成核为主,而添加少量P2O5和Na2O的钙铁硅玻璃以表面成核为主。经过1000℃,2h热处理的钙铁硅微晶玻璃中椭球形磁铁矿晶粒大小约250nm,硅灰石晶粒大小约150nm。所得微晶玻璃具有温热治疗所需的磁性和磁滞生热能力。     

穆斯堡尔谱学在磁记录材料中的应用

<正> 一、引言穆斯堡尔效应是原子核对γ射线的无反冲共振吸收现象。利用穆斯堡尔效应,可以测得 10~(-9)eV能级的变化,对不同的样品将会得到不同的谱线。所以有人将穆斯堡尔谱线位置视如“指纹”一样。因此,可用穆斯堡尔效应研究     

陶釉的穆斯堡尔谱研究

用穆斯堡尔谱研究了三种陶釉,其中含α-Fe_2O_3分别为15wt％金星釉、11％金(Ⅰ)和14％金(Ⅱ)。将生釉、在530℃保温5h及在860℃保温5h的生轴和熟釉的样品分别在室温和78K测穆斯堡尔谱。生釉中含有莫因转变(Morin transttion)和无莫因转变(non-Morin transition)的两种α-Fe_2O_3相,加热至530℃后仅金(Ⅰ)釉有莫因转变的α-Fe_2O_3含量增加,其他釉没有可观察到的变化。在860℃处理后,出现四极分裂的双线谱,无莫因转变的α-Fe_2O_3先开始转入玻璃态,Fe~(3+)进入四面体配位。熟釉中更多铁处于长程无序的玻璃态,四极分裂值和所占的面积都增大。重新析出的α-Fe_2O_3都是无莫因转变的和微晶态的。     

基于穆斯堡尔谱的煤气化渣中铁的析出机理

气化条件下,煤中含铁矿物被还原,气化渣中析出单质铁,影响熔渣的黏度.以铁含量较高的煤样为研究对象,借助XRD和穆斯堡尔谱分析煤中矿物尤其是含铁矿物的组成.利用高温管式炉模拟气化条件,制备不同温度不同气氛下的熔渣,采用穆斯堡尔谱定性和定量分析熔渣中的含铁物相,研究熔渣中含铁物相的生成与温度和气氛的关系,探讨单质铁的析出机...     

钙硅比对钙铁硅铁磁体微晶玻璃核化与晶化的影响

为了研制用作温热治疗癌症的铁磁体微晶玻璃热种子材料,制备了一组化学组成为40Fe2O3xCaO(60-x)SiO23B2O33P2O5玻璃(x=20、25、30、35质量分数),用XRD、DTA、VSM对其核化与晶化过程进行了研究.研究发现,钙铁硅微晶玻璃在还原气氛下热处理后,除了磁铁矿和硅灰石及少量赤铁矿晶相外,还会出现钙铁辉石、方石英晶相.钙硅比较小的玻璃,热处理温度-时间相图中钙铁辉石相区范围较大;钙硅比较大的,钙铁辉石相区范围较小.另外,钙硅比不同,玻璃的成核机理、开始析出磁铁矿的温度也不同.     

钙硅比对钙铁硅铁磁体微晶玻璃核化与晶化的影响

为了研制用作温热治疗癌症的铁磁体微晶玻璃热种子材料,制备了一组化学组成为40Fe2O3xCaO(60-x)SiO23B2O33P2O5玻璃(x=20、25、30、35质量分数),用XRD、DTA、VSM对其核化与晶化过程进行了研究.研究发现,钙铁硅微晶玻璃在还原气氛下热处理后,除了磁铁矿和硅灰石及少量赤铁矿晶相外,还会出现钙铁辉石、方石英晶相.钙硅比较小的玻璃,热处理温度-时间相图中钙铁辉石相区范围较大;钙硅比较大的,钙铁辉石相区范围较小.另外,钙硅比不同,玻璃的成核机理、开始析出磁铁矿的温度也不同.     

穆斯堡尔谱在金属蛋白-铁蛋白结构研究中的应用

金属蛋白结构和功能关系的研究，是生物无机化学的一个重要研究课题。随着研究的深入，各种现代实验技术逐渐被应用这一领域中，穆斯堡尔谱作为一种吸引人的技术已经被广泛地应用。随着穆斯堡尔谱技术上的改进和发展，将会使其在此领域方面的应用更加广泛。本文着重介绍穆斯堡尔谱的一些重要参数以及其在金属蛋白尤其是在铁蛋白中应用的特点。     

Fe~(2 )、Fe~(3 )在玻璃中配位态的研究

本文用穆斯堡尔谱和分光光度计方法研究了Fe~(2 )、Fe~(3 )在硅酸盐玻璃、硼酸盐玻璃、磷酸盐玻璃中配位状态的变化并用特别方法控制了Fe~(2 )、Fe~(3 )的比值。得到较理想的光谱曲线为在0.8—1.1μm波段透过率<2％,而可见区透过率>80％。根据穆斯堡尔谱的两个主要参数——化学位移及四级劈裂的分析,算出Fe~(2 )、Fe~(3 )在玻璃中的比例,从而分析Fe~(2 )、Fe~(3 )在玻璃中的配位状态。 结果表明,Fe~(2 )在玻璃中主要以六配位形式存在,Fe~(3 )则主要以四配位形式存在。     

Tb3+掺杂钼酸盐玻璃陶瓷的制备及发光性能表征

采用熔融-晶化法制备了Tb3+掺杂的CaMoO4为主晶相的透明钼酸盐玻璃陶瓷。利用DSC、XRD、SEM确定了该体系玻璃样品的最佳热处理制度：715℃保温2.5 h;随着热处理时间的增加,玻璃陶瓷中的晶粒尺寸逐渐变大;利用UV-Vis-NIR得到样品玻璃陶瓷在可见光区的透过率可达80%;并利用荧光光谱讨论了在相同热处理条件下,不同Tb3+掺杂浓度对玻璃陶瓷样品发光性能的影响,研究表明Tb3+掺杂浓度为7.0mol%时样品的荧光强度最大。     

Characterization of New Categories of Bioactive Based Tellurite and Silicate Glasses

New types of tellurite glass ceramics were prepared and studied from the viewpoint of bioactivity. The obtained results were compared with those of silicate glass ceramics. The crystallization behaviors of both silicate and tellurite glass ceramics with equal ratio of CaO/P₂O₅ were investigated. The silicate glass samples were transformed to glass ceramics by a thermal treatment process. While the tellurite glass ceramics were directly obtained without any thermal treatment. The microstructure of these materials was characterized by X-ray diffraction (XRD), Fourier transform infrared absorption spectroscopy (FTIR) and a scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (SEM/EDX). The results revealed clear proof that TeO₂ promoted the nucleation and crystallization processes which led to the formation of different crystalline bio-phases. While the silicate glasses showed a much lower degree of crystallinity than that presented by the tellurite glass ceramics. The crystals of tellurite containing glass were needle- like morphology, which is attributed to the one-dimensional rapid growth of the apatite-tellurite phase. On the other hand, a particle-like morphology is shown in the silicate glass matrix. Bioactivity of the glasses in simulated body fluids (SBF) was investigated. Tellurite containing glass ceramics showed a better bioactivity during the in vitro test than that of the silicate one. This was attributed to a great analogous between the morphology of crystals of tellurite glass and the morphology of hydroxyapatite in human bone, since both possess a needle-like morphology.     

生理模拟液中的磷酸钙微晶玻璃的表面变化

应用玻璃结晶法制备了以磷酸钙为主体的多孔微晶玻璃载体材料。在一定的条件下对该药物载体材料进行了生理模拟液的浸泡实验,并用Fourier红外光谱和扫描电镜对其表面进行了表征分析。试验结果表明：经模拟液浸泡后,在材料的表面沉积了一定量的类骨磷灰石(碳酸羟基磷灰石),其形貌为球状颗粒,并证实了载体材料的粗糙表面有利于碳酸羟基磷灰石晶体的形成。研究结果有助于分析碳酸羟基磷灰石的形成机理及了解磷酸钙微晶玻璃载体材料在体内的骨诱导机理。     

Intriguing role of TiO2 in glass‐ceramics: Bioactive and magneto‐structural properties

We report on the structural, magnetic, and bioactive properties of TiO₂‐modified silicate glasses. Addition of TiO₂ and heat treatment, shows remarkable and distinguishable effect on the properties of the glasses. Growth of titania‐modified magnetic nanocrystals played effective role in the evolution of magnetic properties of the glass‐ceramics. Some of the samples exhibit superparamagnetic nature, while others are found to be antiferromagnetic. Interestingly, after heat treatment the magnetization trend of the samples reversed. The in vitro bioactivity of these glass‐ceramics was accessed by the formation of bone‐ like apatite structures on their surfaces after immersion in simulated body fluid. The magnetic properties along with the bioactivity of present glass‐ceramics indicate their usefulness in the magnetically induced hyperthermia treatment of cancer.     

Atomistic Structure of Calcium Silicate Intergranular Films in Alumina Studied by Molecular Dynamics Simulations

Molecular dynamics simulations of calcium silicate (CaSiO₃)intergranular films that were formed during the liquid-phase sintering of alumina (Al₂O₃)ceramics were conducted. A constant-pressure algorithm was used in the simulations to accommodate changes in the sample size during heat treatment and tensile tests. A model of the grain boundary that was wetted by glass was created by melting the silicate film between two Al₂O₃surfaces with the basal orientation. Samples with different film thicknesses and CaO contents were studied. The presence of an ordered interface in the atomistic structure of the mostly amorphous films was revealed. Calcium additives segregated preferentially into the ordered SiO₂/Al₂O₃interface regions. Increased addition of calcium further promoted the ordering and increased stability of the films. Tensile strength was evaluated and showed an increase with low calcium additions, followed by strength reduction at higher CaO additions. Two modes of fracture were observed in the simulations.     

Li2O-Al2O3-SiO2高强度半透光微晶玻璃晶化及机械性能研究

设计玻璃组成及晶化工艺提高Li₂O-Al₂O₃-SiO₂微晶玻璃的强度是当前亟需解决的问题。本文通过熔融浇铸法制备了具有特定组成的Li₂O-Al₂O₃-SiO₂玻璃,通过两步热处理方法制备了高强度半透光微晶玻璃。差示扫描热分析结果显示玻璃的转变温度为532 ℃,且有多个析晶峰。热处理后,X射线衍射证明了玻璃中析出以Li₂Si₂O₅、LiAlSi₃O₈、LiAlSi₄O₁₀为主晶相的晶体,且随着热处理温度的上升或时间延长,透锂长石逐渐转变为锂辉石晶相,晶粒尺寸也从70 nm(热处理条件为:750 ℃,0.5 h和780 ℃,10 h)生长至340 nm(热处理条件为:820 ℃,0.5 h和850 ℃,4 h),微晶玻璃从半透光转变为完全乳浊。微晶玻璃具有优异的机械性能,维氏硬度最大可达9.15 GPa,环上环的最大负载可达1 335 N,最大整机跌落高度可达162 cm。此微晶玻璃可用于手机等电子器件的背板保护玻璃。     

钙铁硅铁磁体微晶玻璃生物活性的模拟体液研究

为了研究用作温热治疗肿瘤热种子材料的钙铁硅铁磁体微晶玻璃的生物活性，试样在模拟体液中浸泡以后，用ＳＥＭ、俄昂扬电子能谱、ＦＴ－ＩＲ对其表面生成的江膜进行观察和分析，研究结果表明，试样表面的硅胶层上生成物活性。     

Rare-earth Cerium Additives for Sinterability of Anorthite-Diopside Ceramics

Anorthite-diopside ceramics were prepared by sintering iron ore tailings,calcium carbonate,and silicon dioxide. Rare-earth cerium nitrate was evaluated as a sintering additive for the ceramics,whose mass percentage was 3%,5%,7%,9%,and 11%,respectively.The sinterability of anorthite-diopside ceramics during heat treatment was confirmed by X-ray diffraction,transmission/scanning electron microscopy,thermogravimetric analysis-differential thermal analysis,and hotstage microscopy,respectively. The obtained results show that the density of ceramics gradually increases,while the sintering temperature and sintering activation energy of anorthite-diopside ceramics are notably decreased with the increasing cerium content. Rare-earth cerium not only is beneficial to the complete reaction of raw materials,but also can accelerate the mass transfer process through forming eutectic phase with aluminum.     

Distribution of the main inorganic elements of Kaa-Khem coals in ash-and-slag waste from the Kyzyl heat and power plant

Comparative silicate analysis data on the distribution of the main ash-forming elements of Kaa-Khem coals in fly ash and slag from the Kyzyl heat and power plant in 1989?C2009 heating seasons are presented. The degree of binding of SO₂ from industrial smoke emissions increased in this two-decade time interval. The distribution of six main ash-forming elements between slag and fly ash is uneven: silicon, iron, manganese, and sulfur are concentrated in the slag. Fly ash is enriched in aluminum, titanium, and unburned carbon. The concentrations of alkali metals and calcium in the slag and fly ash are almost the same. The lowsulfur ash-and-slag waste of the Kyzyl heat and power plant with high silicon, aluminum, iron, calcium, and unburned carbon contents can be recommended as a raw material in the production of building materials, wall ceramics, and porous fillers, for road building, etc. The ash dump is of practical interest in terms of the extraction of valuable ferromagnetic materials (magnetite and ferrosilicon) and aluminosilicate microspheres.