材料的腐蚀与防护实践教学探索

材料的腐蚀与防护是一门理论与实践紧密结合的学科．理论教学往往达不到良好的效果,必须与实践教学相结合。本文论述了此门课程的理论教学与多种方式的实践相结合,激发学生们的学习兴趣,培养学生们的技术应用能力．提高学生们分析问题和解决目愿的能力．     

Ni–Zn铁氧体的掺杂研究与磁相互作用分析

通过化学共沉淀法并经过后续不同温度烧结制备了系列Ni1-xZnxFe2O4(x=0,0.1,0.2,0.3,0.4,0.5,0.7和1)铁氧体粉末样品。用X射线衍射(XRD)、傅里叶红外光谱(IR)以及超导量子干涉仪(SQUID)对样品的结构及磁性进行研究。结果表明,x=0.4时,样品的比饱和磁化强度最大,σs=60.6 A·m2·kg-1;并研究了不同烧结温度下x=0.4样品中的磁相互作用行为,讨论了相关机理。     

Li含量、沉淀时间以及溶液浓度对Y2O3:Eu(5％),Li(x％) 薄膜的形貌和光学性质影响

利用电化学沉积法制备Li掺杂的Y₂O₃:Eu(5％)荧光薄膜,并且研究了Li含量,沉积时间和溶液浓度对样品的表面形貌和发光强度的影响。结果表明,所制备的Y₂O₃:Eu(5％), Li(x％) 荧光发光薄膜具有立方晶体结构,当x=15时候,形貌和发光强度表现为最佳。     

VO43-在R2V2O7:Eu3+（R=Sr,Ca,Ba）的宽带发射（英文）

R2V2O7:Eu3+(R=Ca,Sr,Ba)样品由溶胶凝胶法制备。研究了样品的发光性能。随着R离子半径的增加,样品的发射光谱出现了一个450～750nm宽的发射宽带。发射谱在617nm的发射峰来自于Eu3+的5D0-7Fj的跃迁,除此之外,在510nm出现了另一最强发射峰,归因于VO43-离子团的本质的发射。另外,可以改变R离子半径来控制蓝绿光和红光强度的比例,这可能是一个很好的应用。     

Thermoelectric properties of Sr0.9La0.1TiO3 and Sr2.7La0.3Ti2O7 with 15%Ag addition

15%Ag-added cubic perovskites Sr0.9La0.1TiO3 and Ruddlesden-Popper （RP） phases Sr2.7La0.3Ti2O7 were fabricated via hydrothermal synthesis, cold pressing and high-temperature sintering. The structure and thermoelectric properties were also investi-gated for all samples. The results indicated that Ag precipitated as a second phase. Ag addition made electrical conductivity and ab-solute Seebeck coefficient enhanced, as a result, the ZT values were enhanced both for two series. Compared with cubic perovskite, RP phase was subjected to smaller impact by Ag addition. The reasons for enhancing ZT value and the different impact for two series by Ag addition were also discussed.     

Photoluminescence properties and effect of Bi~（3＋） dopant of Eu~（3＋） and Dy~（3＋） co-doped Sr_3V_2O_8

Photoluminescence properties of Sr 2.5 Dy 1/3-x Eu x V 2 O 8(x=0,0.06,0.12,0.18,0.24,0.33) were investigated.The excitation spectra included a broad band in the short wavelength region and several sharp lines in the longer wavelength region,and the spectral origin were discussed.The emission spectra were measured in two different exciting ways,i.e.,exciting the VO 4 group at 270 nm and the Eu 3+ ion at 398 nm,respectively,and the energy transferring process was reasonably suggested.Furthermore,multi-color emission could be achieved in Sr 2.5 Dy 1/3-x Eu x V 2 O 8,indicating that the studied samples had potential applications in the white light emitting diodes.Further investigation showed that reducing the concentration of Eu 3+ and Dy 3+ and introducing Bi 3+ as a sensitizer ion greatly enhanced the emission intensity.     

共沉淀法制备的锶铁氧体磁粉的结构、形貌及磁性能

采用共沉淀法按照n(Fe)∶n(Sr)=10∶1合成M型锶铁氧体.通过把样品在不同的温度下退火,研究了退火温度对晶体结构、形貌和磁性能的影响.所制备的样品用FTIR、XRD、SEM和VSM进行表征.结果表明,当退火温度为1000℃时样品颗粒分布规则且比饱和磁化强度达最大值,为77.87emu/g.当退火温度为1100℃时样品颗粒变成球形且矫顽力最小,为1601Oe.此外,通过控制退火温度可使矫顽力在1601～4591Oe范围内变化.     

溶胶-凝胶自燃烧合成法制备SrFe12O19及其磁性能研究

本文采用溶胶-凝胶自燃烧合成法制备了SrFe12 O19.研究了柠檬酸配比对SrFe12O19的物相组成、形貌及磁性能的影响.当柠檬酸与金属离子摩尔比为3:1时,矫顽力为6518 Oe (518.83kA/m),比饱和磁化强度σs为84.45 A·m2/kg.通过对经过预烧和不经过预烧所制备出的两种样品的研究,发现不经...     

Eu3+和Ce3+共掺Ba3V2O8的发光性质

用固相法制备Ba3(0.92-y)Ce0.16Eu2yV2O8(0≤y≤0.1)系列样品。发射光谱的检测结果表明,Ba3(0.92-y)Ce0.16Eu2yV2O8能同时发出Ce3+的紫光、蓝光和Eu3+的红光,说明基质吸收的能量可以分别传递给Ce3+和Eu3+。而且,Ce3+的发光强度随Eu3+的浓度增减变化不大,而Eu3+的浓度能在很大程度上改变红光的强度。因此,可通过Eu3+的浓度变化调节蓝光和红光的强度比获得白光。     

Dy3+ activated LaVO4 films synthesized by precursors with different solution concentrations

Using different-solution-concentration precursors with citric acid as chelating agent and polyvinyl alcohol as dispersing media, Dy3+ activated LaVO4 films were deposited on indium tin oxide (ITO) substrates. The scanning electronic microscope (SEM) showed that the compact and crack-free LaVO4:Dy3+ film could be obtained at a suitable solution concentration. The deposited films could absorb the ultra-violet light below 400 nm and were transparent in the visible and infrared region as evidenced by the transmission spectra, and the photolumines-cence spectra exhibited the characteristic emissions of Dy3+ peaking at 484 (blue) and 576 (yellow) nm due to the transitions of 4F9/2→6H15/2 and 4F9/2→6H13/2, respectively. The potential application of LaVO4:Dy3+ film in the dye-sensitized solar cell (DSSC) was also discussed.