CaO-MgO-Al2O3-Fe2O3-B2O3-SiO2系微晶釉的制备

通过引入B2O3以降低烧成温度,利用赤泥中的Fe2O3为着色剂,在1150℃左右低温烧成制备了CaO-MgO-Al2O3-Fe2O3-B2O3-SiO2系微晶釉.赤泥的加入量为20;左右时,釉面具有良好的装饰效果和显微硬度.利用XRD、SEM研究了釉的物相及显微组织.结果表明,釉中析出的微晶是普通辉石,微晶的含量随MgO及CaO的含量增加而增加,而提高Al2O3含量则抑制微晶的析出.     

R2O-RO-SiO2-Al2O3-Fe2O3-P2O5系分相釉的研究

针对铁红分相釉的配方特点,采用L8(4 ×24)正交实验研究了钠长石、牛骨灰、滑石、方解石、石英加入量对R2O-RO-SiO2-Al2O3-Fe2O3-P2O5系统分相釉釉面效果的影响,采用扫描电子显微镜(SEM)和能谱分析(EDS)对釉层的微观结构进行了表征.研究发现:牛骨灰对釉面是否出现“柿红”效果影响最显著,而方解石影响最不明显.Si/P摩尔比对铁红色釉面的产生起关键作用,当Si/P摩尔比小于2O,出现铁红釉面效果的概率极高.随着滑石加入量从9份变化到18份,出现铁红色釉面的趋势反而降低.经SEM和EDS分析发现,“柿红色”、“酒红色”釉面效果的产生很大程度上是由于釉层液液分相促进Fe2O3富集或偏析造成,且特别容易在高钠、低镁、低铝处聚集,最终连成雪花状结晶.     

Yb2O3-Y2O3-Gd2O3-ZrO2热障涂层制备及性能研究

以Yb2O3、Y2O3 、Gd2O3稀土氧化物粉末和ZrOCl2·8H2O粉末为原料,采用化学共沉淀法制备了Yb2O3-Y2O3-Gd2O3-ZrO2 (YYGZO)热喷涂用粉末,采用大气等离子喷涂技术制备了YYGZO涂层,利用场发射扫描电镜(FESEM)、X射线衍射(XRD)研究了YYGZO粉末及涂层的微观组织形貌、相结构.结果表明,制备的热喷涂YYGZO粉末大部分呈规则实心球体状,且球形度良好,颗粒粒径均匀,大部分颗粒粒径分布为30～60μm,流动性能较好,满足大气等离子喷涂的要求.YYGZO涂层具有较好的高温相结构稳定性.所制备YYGZO热障涂层组织结构比较致密,涂层各个界面结合紧密,孔隙率约为9.23;,结合强度为35.2 MPa.     

CoC2O4·2H2O纳米晶形貌可控合成

通过简单调节反应介质热塑性酚醛树脂与乙二醇配比,选择性地制备了CoC2O4·2H2O纳米棒和纳米片晶体或其两种形貌晶体混合物.样品热重和差示扫描量热(TG-DSC)、X射线粉体衍射(XRD)、场发射扫描电镜( FESEM)实验表明:以热塑性酚醛树脂为反应介质得到了COC2O4·2H2O纳米棒;以乙二醇为反应介质得到了CoC2O4·2H2O纳米片;逐渐增大乙二醇和酚醛树脂质量比,实现了CoC2O4·2H2O形貌由纳米棒形貌转变为纳米片形貌.基于不同晶体形貌和实验结果,提出了棒状和片状COC2O4·2H2O可能的形成机理模型以解释两种形貌COC2O4·2H2O纳米晶的生长行为.     

Crystal structures of acid ethylenediaminetetraacetates [Cd(H2 Edta)(H2O)] · 2H2O and [Mn(H2O)4][Mn(HEdta)(H2O)]2 · 4H2O

The crystal structures of [Cd(H₂ Edta)(H₂O)] · 2H₂O (I) and [Mn(H₂O)₄][Mn(HEdta)(H₂O)]₂ · 4H₂O (II) are studied by X-ray diffraction [R ₁ = 0.0209 (0.0272), wR ₂ = 0.0571 (0.0730) for 2551 (4025) reflections with I > 2σ(I) in I (II), respectively]. Structure I contains mononuclear [Cd(H₂ Edta)(H₂O)] complexes with the C ₂ symmetry, and structure II contains centrosymmetric trinuclear [Mn(H₂O)₄][Mn(HEdta)(H₂O)]₂ complexes. In I and II, the protonated ligands are hexadentate (2N + 4O), and the water molecule increases the coordination number of the metal atom to seven. The acid protons participate in short intermolecular hydrogen bonds, which are symmetric in II and asymmetric in I.     

Synthesis of [Mn(O2CCH2CH2CO2)(2,2′-bipyridyl) (H2O)2]n·H2O

The title compound exists as a 1D coordination polymer consisting of succinate anions, manganese cations and 2,2-bipyridyl molecules. Twelve water molecules are present in the unit cell and are part of a hydrogen bonding system. Some of these waters are binding to manganese cations while others are only participating in hydrogen bonding. The structure has a monoclinic space group P2₁/c with a = 8.2750(3) Å, b = 11.5104(3) Å and c = 16.9113(6) Å, = 95.2727(16); V = 1603.96(9) ų and Z = 4.     

Glass forming region and physical properties in the system P2O5-Na2O–Fe2O3

The glass forming region of the system P₂O₅–Na₂O–Fe₂O₃ was determined, using phosphate salts as precursor materials. The glasses were produced in non-wetting gold/platinum crucibles in order to avoid contamination. Glass formation was confirmed using XRD and the final composition determined using EDX. The glass forming region was found to be relatively short at 50% P₂O₅ content in comparison to both lower and higher P₂O₅ content. As expected, the inclusion of Fe₂O₃ had a significant effect on both glass transition temperature and density with a peak seen at around 30 mol% Fe₂O₃. This coincides with previously reported abrupt structural changes in the glass. The inclusion of Na₂O has little effect on the glass transition temperature but causes a small increase in density.     

Magnetite nanoparticles prepared by the crystallization of Na2O–Fe2O3–B2O3–SiO2 glasses

A glass with the composition of 35Na₂O–24Fe₂O₃–20B₂O₃–20SiO₂–1ZnO (mol%) was melted, quenched, using a twin roller technique, and subsequently heat treated in the range 485–750 °C for 1–2 h. This led to the crystallization of magnetite as the sole or the major crystalline phase.Heat treatment at lower temperatures resulted in the crystallization of magnetite crystals 7–20 nm in diameter, whereas heat treatment at higher temperatures produced higher quantities of magnetite and much larger crystals. The room temperature magnetization and coercive force values were in the range of 6–57 emu g^? 1 and 0–120 Oe, respectively for the heat treated glasses.     

TiO2烧结助剂对纳米η-Al2 O3制备Al2 O3-Cr2 O3固溶体的影响研究

以纳米η-Al₂O₃粉和工业铬绿为原料,以摩尔比1:1配比制备Al₂O₃-Cr₂O₃固溶体,以TiO₂为烧结助剂,在还原气氛下经1400 ℃、1500 ℃和1600 ℃固相烧结.研究了TiO₂的加入对纳米η-Al₂O₃制备Al₂O₃-Cr₂O₃固溶体的致密度、线收缩率、相组成、晶胞参数、互扩散程度和微观结构的影响.结果表明:TiO₂的加入能促进Al₂O₃-Cr₂O₃固溶体的致密化;当温度为1600 ℃,TiO₂的添加量为2wt;时,试样的体积密度最大为4.57 g·cm^-3,线收缩率为19.8;;TiO₂的加入能使Al₂O₃-Cr₂O₃固溶体中Al³⁺和Cr³⁺的互扩散程度增加;微观结构表明,TiO₂的加入能使Al₂O₃-Cr₂O₃固溶体晶粒之间结合更紧密,实验温度范围内,随着TiO₂添加量的增加晶粒从沿晶断裂向穿晶断裂转变,只在晶间和晶内存在极少量气孔,当温度为1600 ℃,TiO₂的添加量为2wt;时,晶粒大小较均匀,平均晶粒尺寸约10μm.     

ZnO/B2O3对R2O-RO-B2O3-Al2O3-SiO2系统低温分相釉乳浊效果的影响

以K2O-CaO-Al2O3-SiO2系统为基础,通过添加氧化锌和硼酸钙,制备出了1120℃烧成的高白度无锆低硼低温分相乳浊釉,并借助TEM、XRD、FTIR和白度仪等测试手段研究了ZnO/B2 O3对乳浊釉分相结构和白度的影响,探讨了其乳浊机理.结果表明:随着ZnO/B2 O3的增大,釉面白度呈先增后降趋势,当ZnO/B2 O3为4.04时达最大值为80.5;.随着ZnO/B2 O3的增大,分相粒子尺寸逐渐减小,数量逐渐增多.ZnO/B2 O3过高,分相粒子尺寸太小,远小于可见光波长,不利于乳浊度的提高.     

BaBPO5和(H3O)Zn(H2O)2BP2O8·H2O的低温溶剂热合成及表征

以乙醇为溶剂,在低温条件下合成出了两种手性硼磷酸盐化合物BaBPO5(1)(T=120℃,t=5d)和(H3O)Zn(H2O)2BP2O8·H2O (2)(T=80℃,t=5d).XRD单晶衍射仪测定了化合物的结构,结果表明:(1)属三方晶系,P3221空间群,a=b=7.1162(3)(A),c=6.9979(6),(A)=3,该晶体含有一维线性链状阴离子结构;(2)属六方晶系,P6122空间群,a=b =9.513(2)(A),c=15.906(8),(A)=6.该晶体具有三维骨架结构.实验结果表明使用乙醇作溶剂可以极大降低硼磷酸盐的合成温度,进而有助于获得手性硼磷酸盐化合物,这为手性硼磷酸盐的合成提供了一种新思路.     

Characteristics and biocompatibility of Na2O–K2O–CaO–MgO–SrO–B2O3–P2O5 borophosphate glass fibers

A novel Na₂O–K₂O–CaO–MgO–SrO–B₂O₃–P₂O₅ borophosphate glass fiber is prepared. The thermal properties including differential thermal analysis (DTA) and viscosity measurement of the glass were presented. The tensile strength of the glass fiber is measured. The reaction of the glass fibers in the SBF solution is characterized by XRD, FTIR and SEM. XRD and FTIR indicate that the carbonate hydroxyapatite has formed rapidly on the glass. Cell attachment, spreading and proliferation on the glass are determined by MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] assay method using Human osteosarcoma MG-63 cells. The bioactivity and biocompatibility of the glass fiber make it a good potential prospect in the field of tissue engineering.     

Crystallization behavior during cooling and glass-forming ability of Al2O3-poor Li2O–Al2O3–SiO2 melts

The influence of K₂O/(MgO + K₂O) on some melt properties, including crystallization during cooling of melts and glass-forming ability, was investigated in the Li₂O–Al₂O₃–SiO₂ system with low Al₂O₃ content. The dependence of viscosity on K₂O/(MgO + K₂O) above 1000 °C showed a monotonic decrease due to the reduction of [MgO₄] concentration and the conductivity also decreased due to the larger ion radius of K. The temperature dependence of conductivity for all melts showed an abrupt change at one temperature due to crystallization in which temperature of crystallization decreases with increase of K₂O. The crystallization behavior near liquidus temperature was studied quantitatively by calculating the crystal volume fraction from apparent viscosity value. The glass-forming ability of the melts was discussed by using data related with viscosity and crystallization. Finally, it was suggested that the melts with K₂O/(MgO + K₂O) ? 0.75 have a good glass-forming ability.     

Fe2O3-CO3O4共掺杂MgO-Al2O3-SiO2体系的红外辐射性能研究

采用固相反应法制备Fe2O3-Co3O4共掺杂MgO-Al2O3-SiO2体系的复合陶瓷材料,并通过XRD、SEM、XPS以及红外辐射测试等方法研究了样品的结晶行为与红外辐射性能.结果表明:Fe2 O3和Co3 O4共掺杂MgO-Al2 O3-SiO2体系后离子分布改变并生成混合尖晶石,从而引起品格畸变,从而有效提高材料的红外辐射性能.材料的红外发射率与其晶格畸变程度具有相同的变化趋势,并随Fe2 O3与Co3O4质量之比(R)的增加呈非线性变化.当R=3∶2时,材料在8 ～ 14 μm波段的辐射率可达0.92.     

区熔法制备Al2O3/MgAl2O4共晶陶瓷

利用感应区熔法制备了Al2O3/MgAl2O4共晶陶瓷.当坩埚壁温为2150℃、行走速度为5 mm/h时,获得了φ10 mm×104 mm表面光滑的圆棒.结果表明共晶陶瓷由Al2O3相和MgAl2O4相组成,分别按照(110)(311)晶面生长;Al2O3相为基体相,MgAl2O4相以非连续的片状均匀地分布在基体相之中.定向凝固共晶陶瓷的密度是理论值的99;;硬度和断裂韧性分别达到18.7 GPa和3.74 MPa·m1/2,约是预烧结体的2倍.气孔和界面非晶相的消失以及以单晶形态存在的Al2O3基体相,有效提高了材料的硬度和断裂韧性.     

Studies of ternary Li2SO4–Li2O–P2O5 glasses

Glasses in a wide range of compositions in the ternary system xLi₂SO₄–yLi₂O–zP₂O₅ where x ranges from 0 to 30 mol%, y ranges from 35 to 55 mol% and z ranges from 25 to 50 mol% have been prepared and their properties measured using infra-red, Raman, and ³¹P magic angle spinning nuclear magnetic resonance spectroscopic techniques. We conclude that a random close packing of phosphate and sulphate ions which also leads to formation of connected voids in the structure is consistent with our data. There is also evidence for formation of condensed sulphate–phosphate species in the liquid which may be retained in the glass structure.     

Performance investigation of Li2O–Al2O3–4SiO2 based glass–ceramics with B2O3, Na3AlF6 and Na2O fluxes

Influence of single fluxes (10 wt.% B₂O₃), bi-component fluxes (4 wt.% B₂O₃ + 6 wt.% Na₃AlF₆), and complex fluxes (4 wt.% B₂O₃ + 4 wt.% Na₃AlF₆ + 2 wt.% Na₂O) on the thermal kinetic parameters, microstructure, flexural strength and coefficient of thermal expansion (CTE) of Li₂O–Al₂O₃–4SiO₂ (LAS) glass–ceramics was investigated through differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscope (SEM). The results showed that complex fluxes could efficiently decrease transition temperature (T_g) and crystallization temperature (T_p), and accelerate the formation of needle-like β-spodumene crystals which benefit high flexural strength. The homogeneous LAS glass–ceramic (sample C₃) which has a high strength of 132.4 MPa and low CTE (100–650 °C) of 2.74 × 10^? 6/°C is obtained by doping of the initial LAS glass by complex fluxes of 4 wt.% B₂O₃, 4 wt.% Na₃AlF₆, and 2 wt.% Na₂O, nucleating at 630 °C/120 min and then crystallized at 780 °C/120 min. It is worthy of further investigation as a bonder of diamond composite material due to its outstanding prosperities.     

O2/(O2+Ar)流量比对ZnO-0.25mol; V2O5薄膜缺陷类型的影响

利用射频磁控溅射技术在玻璃衬底上沉积ZnO-0.25mol; V2O5(ZnO∶V)薄膜,研究了O2/(O2+Ar)流量比(0;~87.5;)对ZnO∶V薄膜中缺陷的影响.研究结果表明:沉积的ZnO∶V薄膜为具有c轴取向的纤锌矿结构,V以五价和四价形式共存其中.ZnO∶V薄膜中的缺陷态为氧空位(VO)和间隙锌(Zni)杂化形成的复合体,两者比例随O2/(O2+Ar)流量比而变化.     

Effect of alumina on the structure and properties of Li2O–B2O3–P2O5 glasses

The structure of glasses within the system Li₂O–Al₂O₃–B₂O₃–P₂O₅ has been studied through ³¹P, ¹¹B and ²⁷Al Nuclear Magnetic Resonance, and the effect of Al₂O₃ substitution by B₂O₃ and P₂O₅ network formers on the structure and properties investigated for a constant Li₂O content. Multinuclear NMR results reveal that substitution of Al₂O₃ for B₂O₃ and P₂O₅ network formers in a glass with composition 50Li₂O·15B₂O₃·35P₂O₅ produces a change in boron environment from four-fold to three-fold coordination. Meanwhile aluminum can be present in four-, five- and six-fold coordinations a higher amount of Al(IV) groups is found for increasing alumina contents. The behavior of the glass transition temperature and electrical conductivity of the glasses has been interpreted as a function of the structural changes induced in the glass network when alumina is substituted for B₂O₃, P₂O₅ or both. Small additions of alumina produce a drastic increase in glass transition temperature, while it does not change for [Al₂O₃] greater than 3 mol.%. However, the electrical conductivity shows very different behavior depending on the type of substitution; it can remain constant when B₂O₃ content decreases or sharply decrease when P₂O₅ is substituted by Al₂O₃, which is attributed to a higher amount of BO₃ and phase separation.