Er_2O_3掺杂对Y_2O_3-Ta_2O_5-ZrO_2陶瓷相结构及相稳定性的影响

采用固相合成法制备了Er_2O_3掺杂Y_2O_3-Ta_2O_5-ZrO_2体系热障涂层陶瓷材料,利用XRD对材料的物相组成进行分析。结果表明,Er_2O_3掺杂Y_2O_3-Ta_2O_5-ZrO_2体系热障涂层陶瓷材料为单一的四方相结构,无单斜相和立方相出现。在低温200℃处理450 h及高温1 500℃处理310 h后仍为单一的四方相结构,说明Er2O_3-Y_2O_3-Ta_2O_5-ZrO_2体系陶瓷具有良好的相稳定性。     

烧结助剂Al_2O_3与Y_2O_3对固态锂离子电解质LLZO的锂离子电导率的影响

以Li_2CO_3,La_2O_3和ZrO_2为原料,分别添加Al_2O_3和Y_2O_3作为烧结助剂,制备锂离子固态电解质xAl_2O_3-Li_7La_3Zr_2O_(12)和xY_2O_3-Li_7La_3Zr_2O_(12)(分别简称为xAl_2O_3-LLZO和xY_2O_3-LLZO。x为摩尔分数,x=0,0.1,0.2,0.3,0.4和0.5),研究Al_2O_3和Y_2O_3的添加量对LLZO的结构与锂离子电导率的影响。结果表明,在1 150℃烧结15 h时,Al_2O_3和Y_2O_3这2种烧结助剂都能稳定立方相石榴石结构LLZO。当Al_2O_3过量时,产生LaAlO_3杂相,当Y_2O_3过量时,产生Li_2ZrO_3和YO_(1.458)杂相。0.2Y_2O_3-LLZO在1100~1200℃范围内能形成稳定的立方相石榴石结构LLZO,并且在1 150℃烧结27 h不发生分解反应;LLZO的致密度和锂离子电导率都随烧结助剂含量增加而先增加后减小,Al_2O_3和Y_2O_3的最佳添加量x分别为0.2和0.3,所得0.2Al_2O_3-LLZO的致密度与离子电导率分别为94%和1.78×10~(-4)S/cm,0.3Y_2O_3-Li_7La_3Zr_2O_(12)的致密度与离子电导率分别为96%和5.23×10~(-4)S/cm。     

Na_3AlF_6—Al_2O_3—Y_2O_3—MgF_2熔盐体系密度的研究

采用气泡最大压力法测定了2.7NaF·AlF_3(+6wt%MgF_2)～Al_2O_3—Y_2O_3熔盐体系的密度。研究了Al_20_3含量,Y_2O_3含量及温度三变量对体系密度的影响。Y_2O_3与Al_2O_3含量对体系密度的影响,表现出不同的规律,随Y_2O_3含量增加。体系的密度增加;而随Al_2O_3含量增加,体的密度反而下降。随温度的升高,体系的密度非线性地下降。     

二元碱度和Al_2O_3对CaO-SiO_2-FeO-Fe_2O_3-P_2O_5-Al_2O_3-MgO-MnO钢渣中磷酸盐富集的影响

以八元CaO-SiO_2-FeO-Fe_2O_3-P_2O_5-Al_2O_3-MgO-MnO钢渣体系为研究对象,结合热力学计算和实验检测,分析了二元碱度B和Al_2O_3含量对八元钢渣系中磷酸盐富集行为的影响。结果表明:钢渣二元碱度和Al_2O_3含量直接影响钢渣中f-C2S的生成量,进而影响磷酸盐富集相nC_2S-C_3P内P_2O_5的含量。随着二元碱度从1.3提高至2.5,磷酸盐富集率增大,磷酸盐富集相nC2S-C3P中的P_2O_5含量呈现先迅速增大(B从1.3至1.7),然后逐渐减小(B从1.8至2.5)的趋势。当二元碱度和Al_2O_3质量分数分别控制在1.7和12%时,即当满足四元碱度R为1.23时,此八元钢渣体系有较好的磷酸盐富集效果,磷酸盐富集相nC_2S-C_3P内的P_2O_5的质量分数可以达到24.23%。     

Sc_2O_3对ZrO_2电解质烧结和电导率的影响研究

ZrO基电解质由于导电性良好、机械性能高而备受在注,目前广泛使用的YSZ电解质使用温度高,电导率偏低,Sc~(3+)与Zr~(4+)的半径最为相近,用其掺杂能提高ZrO_2基电解质电导率。研究了Sc~(3+)掺杂量为5%~10%mol的ZrO_2基电解质的物相、烧结性能和电导率,结果发现,当Sc~(3+)的掺杂量低于8%时,ZrO_2以大量单斜相和少量四方相存在,Sc~(3+)的掺杂量为8%时,ZrO_2以少量的单斜相和四方相存在,当Sc~(3+)的掺杂量为9%或10%时,ZrO_2全部以四方相存在。增加ZrO_2电解质的Sc~(3+)掺杂量可以降低ZrO_2电解质的烧结温度,当掺杂量为9%或10%时1550℃可以烧结致密,掺杂量为8%时1600℃下才能烧结致密。随Sc~(3+)掺杂量的增加ZrO_2电解质的电导率增大,同样烧结和测试条件下,ScSZ电解质电导率是YSZ电解质电导率的2.7~3.2倍。     

Al_2O_3对Mo-W-Co高温合金力学性能的影响

通过改变Mo-W-Co高温合金中Al_2O_3的含量,研究Al_2O_3对Mo-W-Co高温合金硬度和耐磨性能的影响.采用球磨、压制成形和真空烧结等工艺制备Mo-W-Co-Al_2O_3高温合金,利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和金相显微镜(OM)对制备好的合金的相结构、形貌和粒度进行分析,并测试合金的硬度和耐磨性能.结果表明:添加Al_2O_3能提高Mo-W-Co高温合金的硬度和耐磨性能,当wAl_2O_3为5%时,Mo-W-Co高温合金的硬度和耐磨性能达到最佳效果;在真空烧结时,Al_2O_3在合金中形成了γ-Al_2O_3相,是影响合金组织和性能的关键相.     

Al_2O_3-CaO-CaF_2渣系性能的研究

对Al_2O_3-CaO-CaF_2渣系的初晶温度、电导率以及物相组成进行了研究。研究结果表明:向CaO-Al_2O_3二元系中分别添加10%、15%以及20%的CaF_2时,Al_2O_3-CaO-CaF_2系的渣样电导率随着CaF_2含量的增加而增大,初晶温度不断降低;随着渣系的温度升高,该渣样的电导率也不断增大,当添加20%CaF_2时,Al_2O_3-CaO-CaF_2渣的初晶温度为1 468℃。A_2O_3-CaO-CaF_2渣系中主要物相组成为CaAl_2O_4、Ca_2Al_3O_6F、Ca_2AlF_7以及AlF_3。CaF_2添加量为10%时,熔渣中有大量的CaAl_2O_4物质,随着CaF_2添加量的增加,CaAl_2O_4物质越来越少,而Ca_2Al_3O_6F和Ca_2AlF_7物质越来越多。     

Al_2O_3/WO_3/ZrO_2催化剂的制备及在酯交换反应中的研究

以松木为模板,采用模板法将不同含量的Al_2O_3添加到WO_3/ZrO_2复合氧化物中,采用X射线衍射、BET比表面积分析、拉曼光谱和NH_3等温吸附测试等手段对其进行表征,以评估其改进结果。将Al_2O_3/WO_3/ZrO_2催化剂应用到甲醇与乌桕油(非食用油)的酯交换反应中,在其他反应条件相同,Al_2O_3质量分数为3%时,生物柴油最高产率达到83.1%。结果表明:添加Al_2O_3稳定了ZrO_2的四方相结构,使得催化剂比表面积更大、孔数量增加;模板法制备的催化剂孔径分布均匀,WO_3呈高度分散无定型状态;引入Al_2O_3增加了WO_3/ZrO_2催化剂的中强酸性,对弱酸性和强酸性无明显改变。     

氧化锆基系的相变和稳定化作用的研究

本研究通过对不稳定ZrO_2和稳定ZrO_2的差热分析和X衍射分析,探讨了氧化锆系的相变化和稳定剂的固溶机理及稳定作用。证实了相变是在一个温度范围内进行。添加稳定剂类型和数量对稳定相系起着直接的影响,它是与阳离子半径和晶格参数变化有关的。比较Y_2O_3、CaO、MgO三种稳定剂,Y_2O_3稳定的效果最好。     

Na_3AlF_6-AlF_3-LiF-MgF_2-La_2O_3-Al_2O_3熔盐体系密度的研究

采用阿基米德法研究温度、单一或混合添加La_2O_3与Al_2O_3对Na_3AlF_6-AlF_3-LiF-MgF_2熔盐体系密度的影响,并用最小二乘法建立了密度数学模型,确定了熔盐密度与温度、 La_2O_3与Al_2O_3加入量之间关系的回归方程,为了使熔盐与所制备的La-Al中间合金液的有效分离,从熔盐密度的角度分析了电解制备La-Al中间合金时的合理电解温度与氧化物加入量。研究结果表明:熔盐密度随温度的上升或Al_2O_3加入量的增加呈现线性降低的趋势,却随着La_2O_3加入量的递增而线性增加;当(质量分数)w_(La_2O_3)∶w_(Al_2O_3)=1∶9时,熔盐密度随La_2O_3-Al_2O_3混合氧化物加入量的增加而线性下降,当w_(La_2O_3)∶w_(Al_2O_3)=3∶7, 1∶1或7∶3时,密度却随La_2O_3-Al_2O_3混合氧化物加入量的增加而线性增加;在温度为905～1055℃, La_2O_3与Al_2O_3加入量分别为0%～5%, 0%～10%(质量分数)的研究范围内,熔盐密度(ρ)与温度(t), La_2O_3, Al_2O_3含量之间的关系为:ρ=3.0231-0.0011t+0.0260w_(La_2O_3)-0.0053w_(Al_2O_3),从而可以确定电解制取La-Al中间合金较为理想的Na_3AlF_6-AlF_3-LiF-MgF_2-La_2O_3-Al_2O_3熔融体系温度应控制在965～995℃之间,氧化物的加入量应满足条件w_(La_2O_3)+w_(Al_2O_3)9%,w_(La_2O_3)∶w_(Al_2O_3)1。     

Study of Bi_2O_3-based Rare Earth Solid Electrolyte Used in Fuel Cell

ＳｔｕｄｙｏｆＢｉ_２Ｏ_３－ｂａｓｅｄＲａｒｅＥａｒｔｈＳｏｌｉｄＥｌｅｃｔｒｏｌｙｔｅＵｓｅｄｉｎＦｕｅｌＣｅｌｌ￥ＨｅＬａｎｙｉｎｇ；ＣｈｅｎＧｕａｎｇｙｕ；ＬｉｕＪｉａｎｇ；ＳｕＷｅｎｈｕｉ（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓ，ＪｉｌｉｎＵ...     

Y2O3与MgO复合掺杂ZrO2材料的电性能研究

利用交流复阻抗分析技术对Y2O3与 MgO复合掺杂ZrO2材料的电性能进行了研究.发现随着Y2O3掺入量的增加,参与跃迁的氧空位增多,并促进烧结体的密度提高,气孔率降低,使得晶粒边界的电阻减少,导致(ZrO2)1-x-y(YO1.5)x(MgO)y陶瓷电导率增大.烧结温度的提高也是增加 (ZrO2 )1-x-y(YO1.5)x(MgO)y陶瓷电导率的重要因素之一.     

反相微乳液碳吸附耦合法制备氧化钇稳定四方氧化锆纳米粉体及表征

采用反相微乳液和碳吸附法制备了氧化钇稳定四方氧化锆纳米粉体,探讨了碳黑的加入量对粉体比表面积的影响,得到最佳的碳黑量。分别采用XRD、TEM、BET和TG分析了不同温度下煅烧所得粉体的物相、颗粒度和比表面积以及前驱体热分解特性。实验结果表明,经700℃焙烧后制得了分散性好的四方相ZrO2纳米粉体,比表面积为97.4m2/g,平均粒径为9nm。     

合金粉末预氧化法制备Ag-SnO2-Y2O3电接触材料的研究

Ag-SnO2是各国电接触材料研究人员近年来新开发的一种无镉新型触头材料,它具有较好的导电导热性,优良的耐热性、抗电弧烧蚀性和抗熔焊性,是目前代替Ag-CdO的最理想材料。本文通过合金粉末预氧化法、复合粉体改性处理技术来制备Ag-SnO2-Y2O3电接触材料,添加稀土后合金粉末容易氧化,氧化粉体经改性处理后可有效改善氧化物颗粒与银基体间的润湿性、改善材料的后续加工性能,并且所制备的Ag-SnO2-Y2O3材料密度高、组织均匀、不存在宏观偏析,SnO2和Y2O3颗粒在材料中弥散均匀分布。     

Optical performance study of Sr_2ZnSi_2O_7:Eu~(2+),Dy~(3+), SrAl_2O_4:Eu~(2+),Dy~(3+) and Y_2O_2S:Eu~(3+),Mg~(2+),Ti~(4+) ternary luminous fiber

In this study, down-conversion fluorescent powder of Sr_2ZnSi_2O_7:Eu~(2+),Dy~(3+), SrAl_2O_4:Eu~(2+),Dy~(3+) and Y_2O_2S:Eu~(3+),Mg~(2+),Ti~(4+), which were the common three primary colors materials with long afterglow, were synthesized by high temperature solid state method. The blends of rare earth(RE) luminescent materials have been of interest to reinvest the luminescent characteristics of polyethylene terephtahalate(PET) luminous fiber. The scanning electron microscopy(SEM) and an inversion fluorescence microscope were used to characterize the surface morphology and the dispersion of inclusion. Through analysis of microcosmic morphology, three typical dispersions of luminescent particles were summarized. The X-ray diffraction indicated that the phase structure of fiber samples and crystal structure of luminescence materials kept complete after prilling and spinning. From the fluorescence spectra and CIE 1931 coordinates, it could be found that different combinations of luminous fibers were desired to obtain divers colors emission luminous fiber. And the fiber samples were a light sensation which could induct different excitation wavelengths and convert it down to different colors. The afterglow decay curve and its differential curve were summarized indicating the three decay stages. The decay curve and decay rate curve showed that the contents of Sr_2ZnSi_2O_7:Eu~(2+),Dy~(3+), SrAl_2O_4:Eu~(2+),Dy~(3+) and Y_2O_2S:Eu~(3+),Mg~(2+),Ti~(4+) had obvious influence on the afterglow of fiber samples.     

电子束激发氧化锆马氏体相变的研究

用JEM-2000FX分析型透射电镜研究了以Al_2O_3为基体、ZrO_2为第二相的氧化锆增韧氧化铝(ZTA)陶瓷。发现马氏体条在ZrO_2/Al_2O_3界面上产生,长大极快,止于ZrO_2/Al_2O_3及ZrO_2/ZrO_2界面,薄膜表面或晶粒内其它马氏体表面上。增强电子束,马氏体条就可穿过ZrO_2/ZrO_2界面,使相邻晶粒中产生马氏体相变。含Y高的ZrO_2相变困难。少数t-ZrO_2,在强电子束照射下不发生相变。     

自蔓延高温合成Al2O3＋ZrO2＋Cr复合材料

自蔓延高温合成是制备材料的一种新工艺。通过热力学和显微结构分析研究了Ａｌ－Ｃｒ２Ｏ３－ＺｒＯ２系统，结果表明：在Ａｌ：Ｃｒ２Ｏ３：ＺｒＯ２＝１：２．８：１．４３（ｗｔ）时，可以自蔓延高温合成Ａｌ２Ｏ３－ＺｒＯ２－Ｃｒ复合材料，ＺｒＯ２不与Ａｌ发生反应，产物孔隙度达３５％－４５％。     

Microstructure and high-temperature properties of Fe-Ti-Cr-Mo-B-C-Y_2O_3 laser cladding coating

Fe-based composite coatings were fabricated on 5 CrNiMo die steel by laser beam melting a precursor mixture of ferrotitanium,ferrochromium,ferromolybdenum,B4 C and Y_2 O_3 powders.Micro structure and properties of the coatings were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive spectrometer(EDS),resistance furnace and high-temperature tribometer.The results show that(Ti,Mo)C particles with flower-like and(Ti,Mo)B_2 with block-like shapes are in situ formed during laser cladding.Volume faction of multiple ceramic particles increases with the increasing of Y_2 O_3.The cumulative oxidation mass of the coating with 2 wt% Y_2 O_3 is decreased by one-third than that of the coating without Y_2 O_3.The oxidation layer of the coating with Y_2 O_3 is getting smooth.Meanwhile,high temperature wear volume loss of the coating with 2 wt% Y_2 O_3 is about 40% that of the coating without Y_2 O_3.The coating with 2 wt% Y_2 O_3 shows a smoother wear scar and few flat grooves are observed after high temperature wear test.     

Bi-and Eu-Doped Y_2O_3 Phosphors for Ultraviolet Light Emitting Diodes

Bi-and Eu-Doped Y_2O_3 Phosphors for Ultraviolet Light Emitting Diodes     

Experimental study and thermodynamic calculation of Lu_2O_3-SiO_2 binary system

As a binary system of BaO-Lu_2O_3-SiO_2 ternary system, Lu_2O_3-SiO_2 system was optimized and calculated by CALPHAD approach based on available phase diagram and relevant thermodynamic data of RE_2O_3-SiO_2(RE=Lu,Yb,Y) binary systems as well as our experimental data of Lu_2O_3-SiO_2 system obtained by quenching experiment. The Gibbs free energy of high temperature solution was described by an ionic two-sublattice model as(Lu~(3+))P(O~(2-), SiO_2~0)Q. The calculated phase diagram below 1873 K was in good agreement with experimental data at 1573, 1773 and 1873 K. The calculated Gibbs energies of two intermediate phases Lu_2SiO_5 and Lu_2Si_2O_7, the activity of Lu_2O_3 and SiO_2 and specific heat capacities of intermediate phases agreed well with experimental results of Y_2O_3-SiO_2 system. This tentative study will offer help for the research of single-phase phosphor and related metallurgical slags, refractories, high-temperature superconductivity material systems.