氧化石墨烯/氧化铕复合粉体的制备及性能研究

以氧化石墨烯和氧化铕为原材料,利用水热法合成了氧化石墨烯/氧化铕复合粉体。对不同氧化石墨烯加入量的复合粉体采用扫描电镜、差热分析、荧光分析等测试方法对其进行表征。结果表明:利用水热合成的方法成功制备了氧化石墨烯/氧化铕复合粉体;氧化铕包裹在氧化石墨烯表面,阻止了氧化石墨烯表面部分官能团的分解,复合粉体的稳定性较好;由荧光激发光谱可知复合粉体的荧光激发波长为435 nm;由荧光发射光谱可知,随着氧化石墨烯的质量分数从6%增大到10%时,复合粉体的荧光强度依次增强。     

化学还原法原位制备石墨烯/纳米银复合粉体及其导电性能

以水合肼为还原剂,PVP为分散剂,在反应温度为60℃,p H为6条件下同时还原氧化石墨烯和硝酸银,原位制备石墨烯/纳米银复合粉体。通过扫描电镜、X射线衍射、红外吸收光谱和拉曼光谱等手段研究溶液中硝酸银的质量浓度对石墨烯/纳米银复合粉体形貌与结构的影响。用石墨烯/纳米银复合粉体替代部分微米银粉制备低温固化导电浆料,对其导电性能进行研究。结果表明:银纳米粒子分布于石墨烯片层之间。当反应溶液中硝酸银的质量浓度为0.75 g/L,氧化石墨烯质量浓度为0.25 g/L时,获得分散性好,粒径均匀的石墨烯/纳米银复合粉体,且负载在石墨烯片层上的银纳米粒子的粒径集中在100 nm左右。用石墨烯/纳米银复合粉体替代4%微米银粉制备导电浆料,浆料的体积电阻率为1.8×10-5Ω·cm,与未添加石墨烯/纳米银复合粉体的导电浆料相比,电阻率降低61.7%。     

烧结温度对放电等离子烧结（SPS）制备氧化石墨烯/2024Al复合材料的微观组织和性能影响

以氧化石墨烯（Graphene Oxide）和2024Al粉末为原料，通过静电自组装+放电等离子烧结（SPS）的工艺，制备了含不同质量分数氧化石墨烯和不同烧结温度的氧化石墨烯/2024Al复合材料，并对烧结后材料的微观形貌和力学性能进行表征和测试。结果表明：复合粉体中氧化石墨烯均匀分布，包覆在Al颗粒表面。550℃烧结温度下含0.5%、1%和2%氧化石墨烯（GO）复合材料的压缩强度先提高后降低，分别提高到428.02 MPa和540 MPa，相比于基体提高了12.5%和42%     

氧化石墨烯在二水磷酸铁复合前驱体制备中的作用

以Fe(NO3)3·9H2O、NaH2PO4·2H2O、H3PO4为原料,添加氧化石墨烯(Graphene oxide,GO),采用均相沉淀法制备石墨烯/二水磷酸铁复合前驱体(Graphene/FePO4·2H2O),以期用于制备石墨烯/LiFePO4复合正极材料.结果发现,GO的添加可使FePO4·2H2O前驱体形貌由团聚的絮状转变为分散的类球状;对类球状粉体过滤浓缩后,再进行原料的滴加操作,使类球状粉体二次生长,产物为规则的球状粉体,且粒度分布均匀,分散性好,D50=4.220μm,振实密度达1.31 g/m3.粉体的XRD、FT-IR及Raman分析结果表明,前驱体制备中添加的GO在反应过程中已基本还原为石墨烯,这对于高密度球状石墨烯/磷酸铁复合前驱体的制备具有重要的应用价值.     

氧化石墨烯复合材料的制备及对铜离子吸附性能的研究

通过超声波和磁力搅拌法制备了氧化石墨烯-4A分子筛复合材料(GO-4A), 利用X射线衍射(X-ray diffraction, XRD)、傅里叶变换红外光谱(Fourier transform-infrared spectroscopy, FT-IR) 及扫描电子显微观察(scanning electron microscopy, SEM) 等多种手段对氧化石墨烯复合材料进行表征, 并研究了氧化石墨烯与4A分子筛在GO-4A复合材料中的质量比(复合比例) 对GO-4A吸附铜离子性能的影响。结果表明: 复合比例对GO-4A物相组成影响不大; 4A分子筛的加入会降低氧化石墨烯的团聚程度, 随着复合比例增大, 复合材料的热稳定性不断提高; 当氧化石墨烯和4A分子筛的复合比例为1:5时, 复合效果最佳, 在室温条件下, 溶液pH=6时, 对铜离子的去除效率可达到98.42%。     

石墨烯—铁掺杂二氧化钛复合物制备及其光催化性能

以氧化石墨烯溶液为底水,采用一步法热水解工业钛液制备石墨烯-铁掺杂二氧化钛复合光催化剂。以亚甲基蓝光催化降解为目标反应评价其光催化性能,考察了氧化石墨烯溶液浓度、加料速率、升温速率等因素对其光催化性能影响。采用XRD、SEM、FT-IR、UV-vis DRS及XPS等技术对其进行表征。研究结果表明:掺杂铁以Fe~(3+)形式进入TiO_2晶格形成杂质能级,提高复合物可见光响应范围。石墨烯有利于光生电子传输,实现光生电子-空穴对有效分离,提高光催化量子效率。最佳水解条件为:石墨烯溶液浓度为0.03 mg/mL、加料速率为8 mL/min、升温速率为1.0℃/min。在此条件下,紫外光下及可见光下光催化效率分别为94.15%和80.89%。     

氧化石墨烯二氧化钛复合材料的制备与表征

以氧化石墨烯和工业钛液为原料,采用水热合成方法制备了氧化石墨烯二氧化钛复合材料。复合材料的外观形貌用扫描电镜(SEM)进行分析。材料基团结构用红外光谱(IR)和X射线衍射(XRD)进行分析。光催化性能用紫外可见光谱(UV-vis)仪进行分析。结果发现氧化石墨烯加入使二氧化钛形态由球粒状变化为片层结构基础上带孔洞结构的球状颗粒。XRD分析表明氧化石墨烯加入有利于锐钛型二氧化钛生成。在一定范围内,随氧化石墨烯用量的增加,复合材料的光催化性能提升,表明氧化石墨烯的加入有利于光吸收。     

石墨烯增强WC-Co硬质合金的制备和力学性能研究

采用机械搅拌和静电吸附工艺制备了氧化石墨烯/WC-Co复合粉体,并对复合粉体的微观形貌进行了表征。利用放电等离子烧结(spark plasma sintering,SPS)技术制备了石墨烯/WCCo硬质合金,对复合材料的力学性能进行了测试分析。机械搅拌制备的氧化石墨烯/WC-Co复合粉体经过SPS烧结后得到的硬质合金横向断裂强度和维氏硬度为1 850 MPa,1 830,与不添加石墨烯的WC-Co硬质合金相比分别提高了3.9%,5.8%。静电吸附制备的氧化石墨烯/WC-Co复合粉体经过SPS烧结后得到的硬质合金横向断裂强度和维氏硬度为1 980 MPa,1 850,与不添加石墨烯的WC-Co硬质合金相比分别提高了11.2%,6.9%。     

基于数值模拟的Cu-Al复合粉体内氧化热力学与动力学研究

本文采用数值模拟研究了Cu-Al复合粉体的内氧化热力学和动力学过程,分析了时间、温度、粉体粒度和Al含量对内氧化动力学的影响。结果表明:Cu-Al复合粉体内氧化反应的氧分压要控制为低于上临界值,下限氧分压是一个极小量,对于内氧化控制无实际意义;Cu-Al粉体的内氧化反应主要在最初较短时间内完成,其内氧化程度、速率主要取决于温度、粉末粒度、Al含量和时间,在较高的温度下有利于提高内氧化的程度和速度。实验证明Cu-0.5%Al复合粉在900℃下、30 min内即可完成内氧化生成Cu-Al2O3复合粉体,与数值模拟的结果相一致。     

三元铜铁硫去除铬酸和罗丹明B的研究

以铜铁硫粉末为光催化材料,分析了铜铁硫分别去除含有六价铬离子的铬酸和罗丹明B的光催化性能,研究了光照时间、铬酸含量对去除铬酸,光照时间和铜铁硫含量对去除罗丹明B的影响。铜铁硫去除铬酸的结果表明在太阳光照射下,在10m L铬酸溶液中添加10mg铜铁硫、铬酸浓度为40mg L-1、光照30min后,可以完全去除铬酸。铜铁硫去除罗丹明B的分析表明在太阳光照射下,随着光照时间和铜铁硫用量的增加,罗丹明B的去除率增加,在10m L罗丹明B溶液中添加10mg铜铁硫、罗丹明B浓度为10mg L-1、光照90min后,可以完全去除罗丹明B。     

Enhanced photocatalytic performance of SrTiO_3 powder induced by europium dopants

In this work,Eu~(3+)doped SrTiO_3 powders were synthesized by sol-gel method and the influences of Eu~(3+)dopants on the crystalline structure,micro structure mo rphology,electronic band-gap and photocatalytic performance for degradation of o rganic pollutant were investigated in detail.Research results reveal that the incorporated Eu3+ions in SrTiO_3 lattice are preferable to substitute the Sr~(2+)-Ti4+ions pair by two Eu3+ions.The presence of Eu3+ions plays a significant role for the microstructure morphology of the S rTiO_3 powders,leading to the formation of smaller size nanoparticles with a higher specific surface area.The light absorption capability of the resulting materials is improved owing to the narrowing of the band-gap induced by Eu3+dopants.As a result,the enhanced photocatalytic activity application for photodegradation of Rhodamine B solution is demonstrated for the SrTiO_3 powders doped with Eu3+ions.     

Preparation of Incompact Strontium Aluminate Phosphors

The incompact long afterglow pigment SrAl2O4: Eu, Dy was synthesized by ceramics technology.The agglomerated starting raw material had little effect on the synthesis of SrA12O4 matrix through solid-state reaction method,but the shrinkage and densification was retarded greatly by the agglomerated powder by the formation of large and extensive pore network.The sintering mechanism is surface diffusion ( without flux B2O3 ) and grain boundary diffusion (with B2O3 as flux)respectively, and the as-prepared long afterglow pigment glows in the dark for over 4000 min.     

Preparation and characterization of Y3Al5O12:Ln（Ln=Eu,Ce） phosphor powders by ultrasonic atomization and co-precipitation process

A novel technique for YAG:Ln(Ln=Eu,Ce) phosphor powder synthesis with a nanocrystalline structure was developed.Nanocrystalline YAG:Ln powder was prepared by an ultrasonic atomization and co-precipitation method using a mixture solution of ammonium hydroxide(NH3·H2O) and ammonium hydrogen carbonate(NH4HCO3) as precipitant.The as-prepared nano-powders were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),and fluorescence spectrometer.The obtained phosphor powders were homogenous and in size of 50-70 nm.The results demonstrated that by using ultrasonic atomization and co-precipitation process,we could synthesize a good quality YAG:Ln(Ln=Eu,Ce) phosphor powder that had many potential applications.     

Luminescent properties of MMgP_2O_7：Eu~（3＋）（M=Ca,Sr,Ba） phosphor

A series of red phosphors Eu3+-doped MMgP2O7(M=Ca,Sr,Ba) were synthesized by solid-state reaction method.X-ray powder diffraction(XRD) analysis confirmed the formation of pure CaMgP2O7,SrMgP2O7 and BaMgP2O7 phase.Photoluminescence spectra of MMgP2O7(M=Ca,Sr,Ba):Eu3+ phosphors showed a strong excitation peak at around 400 nm,which was coupled with the characteristic emission(350-400 nm) from UV light-emitting diode.The CaMgP2O7:Eu3+,SrMgP2O7:Eu3+ and BaMgP2O7:Eu3+ phosphors showed strong emission bands peaking at 612,593 and 587 nm,respectively.Due to the difference of the ion sizes between Ba2+(0.142 nm),Sr2+(0.126 nm),Ca2+(0.112 nm),Mg2+(0.072 nm) and Eu3+(0.107 nm),Eu3+ ions were expected to substitute for different sites in CaMgP2O7,SrMgP2O7 and BaMgP2O7 lattice.     

水热法制备Y2O3：Eu及其发光性能的研究

利用水热法制备立方相Y2O3：Eu红色荧光粉.在不同掺杂浓度、不同溶液pH值的系列样品中,均观测到Eu3＋离子的特征发射.荧光强度与Eu3＋离子掺杂浓度关系研究表明：在不同掺杂浓度中,Eu3＋离子掺杂浓度为9%时其相对发射强度最强.在不同溶液pH值所获得的样品中,以溶液pH等于6制备的样品发光效果最好.此外通过与商用Y2O3：Eu红色荧光粉比较,发现其荧光强度相当.因此,与传统高温固相法相比,水热法合成Y2O3：Eu红色荧光粉是简单易行方案.     

Vibrational Spectrum and Luminescence Properties of CaAl_2B_2O_7∶Eu~(3 )

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Effect of Al2O3 on Structure and Wearability of Composite Coating

Asasurface strengtheningtechnology ,thether malsprayhasevolvedfromearlynormal protectivecoatingtocurrentfunctionalcoating .Thedevelopmentofcompositepowderisanimportantbreakthroughinthisfield .Particularly ,thenewlydevelopedmetal basedceramiccoatings ,such…     

Preparation and characterization of Y3Al5O12:Ln (Ln=Eu,Ce) phosphor powders by ultrasonic atomization and co-precipitation process

A novel technique for YAG:Ln (Ln=Eu, Ce) phosphor powder synthesis with a nanocrystalline structure was developed. Nanocrystalline YAG:Ln powder was prepared by an ultrasonic atomization and co-precipitation method using a mixture solution of ammonium hydroxide(NH₃·H₂O) and ammonium hydrogen carbonate(NH₄HCO₃) as precipitant. The as-prepared nano-powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and fluorescence spectrometer. The obtained phosphor powders were homogenous and in size of 50-70 nm. The results demonstrated that by using ultrasonic atomization and co-precipitation process, we could synthesize a good quality YAG:Ln (Ln=Eu, Ce) phosphor powder that had many potential applications.     

掺杂Eu3+离子的YPO4的合成及其发光特性

用BPO4和稀土氧化物为原料，采用固相反应法合成了掺杂Eu^3 离子的YPO4，并用X射线粉末衍射对其结构进行了表征，X射线粉末衍射实验结果表明，YPO4属四方晶系，晶胞参数α=0.6894nm,c=0.6020nm，属I41/αmd(No.141)空间群，测定了其激发光谱和发射光谱，探讨了掺杂Eu^3 离子的YPO4的发光特性。