Y_2O_3-SnO_2常温气敏薄膜的Sol-Gel制备及性能研究

以无机盐ＳｎＣｌ２·２Ｈ２Ｏ,Ｙ（ＮＯ３）３·６Ｈ２Ｏ为原料,无水乙醇为溶剂,采用溶胶－凝胶工艺制备了Ｙ２Ｏ３掺杂的ＳｎＯ２薄膜．采用差热－失重分析研究了Ｙ２Ｏ３掺杂的ＳｎＯ２干凝胶粉末的热分解、晶化过程．研究了Ｙ２Ｏ３－ＳｎＯ２薄膜的电学和气敏性能．从实验中得到了Ｙ２Ｏ３掺杂份量对ＳｎＯ２薄膜电学及气敏性能的影响．实验表明Ｙ２Ｏ３掺杂的ＳｎＯ２薄膜在常温下对ＮＯｘ具有较好的灵敏度和选择性,并具有较好的响应恢复性能;在常温下对Ｈ２Ｓ气体也具有一定的灵敏度．     

制备金属氧化物纳米粉的液雾燃烧工艺研究

将金属熔融并过热到一定的温度，然后由高压纯氧将其雾化并立即于燃烧塔内进行直接氧化燃烧，可快速制得金属氧化物纳米粉体。应用该工艺不仅制备出了Ｂｉ２Ｏ３、ＳｎＯ２、Ｉｎ２Ｏ３粉末，同时对Ｓｎ－Ｉｎ合金熔体进行液雾燃烧时，获得复合的ＳｎＯ２／Ｉｎ２Ｏ３金属氧化物纳米粉体，粉末的最大粒径为２５ｎｍ，金属雾滴燃烧时的强烈挥发，高速飞行过程中的再雾化以及表面氧化膜的快速剥离是使得燃烧产物达到纳米级粉体的基本原     

ZnO／SnO2,SnO2／ZnOUPF复合膜的制备及气敏特性研究

用直流气体放电活化反应蒸发沉积技术在普通玻璃基片上制备了ＺｎＯ／ＳｎＯ２及ＳｎＯ２／ＺｎＯ超微粒子（ＵＰＦ）双层复合薄膜。样品经扫描电子显微镜（ＳＥＭ）和Ｘ射线衍仪分析，结论为超微凿子的复合薄。同时提出了最佳制备工艺。气敏测试结果表明：ＺｎＯ／ＳｎＯ２及ＳｎＯ２／ＺｎＯ ＵＰＦ复合膜较单层ＺｎＯ及ＳｎＯ２ＵＰＦ表现出优良的选择性，其灵敏度和最佳工作温度也得到相应的改善。     

MSnO_3和MSn_（0．5）Zr_（0．5）O_3（M＝Sr，Ba）的水热合

本文利用水热合成方法对ＭＳｎＯ３和ＭＳｎ（０．５）Ｚｒ（０．５）Ｏ３（Ｍ＝Ｓｒ，Ｂａ）的合成进行了研究，并采用ＸＲＤ、ＳＥＭ和ＩＣＰ等方法对产物进行了表征，结果表明：在Ｍ（ＯＨ）２－ＳｎＯ２（或ＳｎＯ２＋ＺｒＯ２）－ＫＯＨ体系中，当ＫＯＨ／Ｓｎ和ＫＯＨ／（Ｓｎ＋Ｚｒ）≥３０时，２６０℃下晶化５～７天，可获得ＭＳｎＯ３和ＭＳｎ（０．５）Ｚｒ（０．５）Ｏ３纯相，在Ｍ（ＯＨ）２－（ＳｎＯ２＋ＺｒＯ２）－ＫＯＨ－Ｈ２Ｏ体系中，可通过控制介质碱度来获得ＭＳｎＯ３＋ＭＺｒＯ３混合物和ＭＳｎ（０．５）Ｚｒ（０．５）Ｏ３，并根据合成规律初步探讨了反应过程．     

SnO2／Fe2O3纳米复合粉的制备与表征

用共沉淀法制备了ＳｎＯ２／ＦｅＯ３纳米复合粉体,用Ｘ射线衍射（ＸＲＤ）、Ｍｏｅｓｓｂａｕｅｒ谱研究了它的物相,晶粒度及变化过程。结果表明,煅烧温度在７００℃以下时,它可能是以四方ＳｎＯ２纳米晶为主体（其平均粒径为３．０ｎｍ）,α－Ｆｅ２Ｏ３纳米晶包裹在ＳｎＯ２晶界的复合相,其中α－Ｆｅ２Ｏ３结晶很不充分,５４．７％聚集于晶界。这种复合相的结构阻碍了ＳｎＯ２晶粒的长大,有利于煅烧后保持纳米晶结构。     

制备金属氧化物纳米粉的液雾燃烧工艺研究

将金属熔融并过热到一定的温度，然后由高压纯氧将其雾化并立即于燃烧塔内进行直接氧化燃烧，可快速制得金属氧化物纳米粉体。应用该工艺不仅制备出了Ｂｉ２Ｏ３、ＳｎＯ２、Ｉｎ２Ｏ３粉末，同时对Ｓｎ－Ｉｎ合金熔体进行液雾燃烧时，获得了复合的ＳｎＯ２／Ｉｎ２Ｏ３金属氧化物纳米粉体，粉末的最大粒径为２５ｎｍ。金属雾滴燃烧时的强烈挥发、高速飞行过程中的再雾化以及表面氧化膜的快速剥离是使得燃烧产物达到纳米级粉体的基本原因。     

用于深油井超声探测换能器的PT－PSN系压电陶瓷

如果在ＰｂＴｉＯ３（ＰＴ）粉末中添加适量的Ｐｂ（Ｓｎ１／３Ｎｂ２／３）Ｏ３（ＰＳＮ）粉末，可以制成高温ＰＴ－ＰＳＮ系陶瓷，并可以把此种陶瓷用于制作深油井超声探测换能器。本文主要报导ＰＴ－ＰＳＮ系压电陶瓷的制备工艺、性能参数和试验结果。     

用于深油井超声探测换能器的PT—PSN系压电陶瓷

如果在ＰｂＴｉＯ３（ＰＴ）粉末中添加适量的Ｐｂ（Ｓｎ１／３Ｎｂ２／３）Ｏ３（ＰＳＮ）粉末，可以制成高温ＰＴ－ＰＳＮ系陶瓷，并可以此种陶瓷用于制作深油井超声探测换能器，本文主要报导ＰＴ－ＰＳＮ系压电陶瓷的制备工艺，性能参数和试验结果。     

MSnO3和MSn0.5Zr0.5O3（M=Sr,Ba）的水热合成

本文利用水热合成方法对ＭＳｎＯ３和ＭＳｎ０．５Ｚｒ０．５（Ｍ＝Ｓｒ，Ｂａ）的合成进行了研究，并采用ＸＲＤ、ＳＥ几ＩＣＰ等进行产物进行了表征，结果表明：在Ｍ（ＯＨ）２．ＳｎＯ２（呈ＳｎＯ２＋ＺｒＯ２）－ＫＯＨ体系中，当ＫＯＨ／Ｓｎ和ＫＯＨ（Ｓｎ＋Ｚｒ）≥３０时，２６０℃下晶化５－７天，可获得ＭＳｎＯ３和ＭＳｎ０．５Ｏ３纯相，在Ｍ（ＯＨ）３－（ＳｎＯ２＋ＺｒＯ３）－ＫＯＨ－Ｈ２Ｏ体系中，可通过控制介质     

纳米ZrO2/(1-n)SiO2-nAl2O3介孔复合作的制备与光致发光

采用溶胶－凝胶法和超临界干燥技术制备了（１－ｎ）ＳｉＯ２－ｎＡｌ２Ｏ３（ｎ＝０、０．０１、０．１）混合气凝胶体系，并以此作为载体，成功地将纳米ＺｒＯ２粒子组装到（１－ｎ）ＳｉＯ２－ｎＡｌ２Ｏ３介孔体系中，而形成纳米ＺｒＯ２／（１－ｎ）ＳｉＯ２－ｎＡｌ２Ｏ３介孔复合材料。光致发光光谱研究表明，室温下以３１６ｎｍ（３．９２ｅＶ）波长激发时，纳米ＺｒＯ２粒子５４０ｎｍ（２．３０ｅＶ）荧光峰，在介孔复合体     

稀土氧化物掺杂对SnO2基气体传感器材料性能的影响

采用化学共沉淀法制备Ｙ２Ｏ３、ＺｒＯ２,Ｅｒ２Ｏ３和Ｓｂ２Ｏ２基气体传感器。结果表明掺杂后的材料经煅烧后,平均晶粒尺寸均小于３０ｎｍ,比未经掺杂的材料小,中掺杂体系不同成分材料制备成厚膜传感器,进行了对ＣＯ气体敏感度性能测试,发现掺杂稀土氧化物的气体敏感度较纯ＳｎＯ２厚膜传感器高。其中掺杂Ｅｒ２Ｏ３材料性能最好。     

柠檬酸-凝胶燃烧法制备钇铝石榴石(Y_3Al_5O_(12))纳米粉体的研究

透明YAG多晶陶瓷具有优良的光学、力学与化学性能,逐渐成为新一代固体激光基质材料。分散均匀、团聚轻的纳米粉体有利于制备出高度透明的激光陶瓷。以Y2O3、Al(NO3)3·9H2O和柠檬酸为原料,采用柠檬酸凝胶燃烧法制备出黑色粉体,经1100℃烧结出尺寸小于50nm的YAG粉体。采用TG-DTA、XRD、FT-IR和TEM测试手段对YAG纳米粉体进行表征,采用谢莱公式计算出不同烧结温度下的晶粒尺寸。研究结果表明:YAG的析晶温度范围为850～900℃,烧结过程中出现赝YAG相物质,1050℃转变成纯YAG相,随着热处理温度的升高,晶粒呈线性增长,纳米粉体的TEM尺寸和采用谢莱公式计算的结果相一致。     

Fabrication and Magnetic Property of One-dimensional SrTiO3/SrFe12O19 Composite Nanofibers by Electrospinning

The composite nanofibers of SrTiO3/SrFe12O19 with a molar ratio of 1:1 and diameter about 120 nm were prepared by electrospinning. Effects of calcination temperature on the formation, crystallite size, morphology and magnetic property were studied by infrared spectroscopy, X-ray diffraction, scanning electron microscopy and vibrating sample magnetometer. The binary phase of strontium ferrite and titanate was formed after being calcined at 900℃ for 2 h and the composite nanofibers were fabricated from nanograins of SrTiO3 about 24 nm and SrFe12O19 around 33 nm. The crystallite sizes for the nanofibers increase with increasing calcination temperature and the addition of SrTiO3 has an obvious suppression effect on SrFe12O19 grain growth. The specific saturation magnetization and remanence tend to increase with the crystallite size. With increasing calcination temperature from 900 to 1050℃, the coercivity increases initially, achieving a maximum value of 520.2 kA·m-1 at 950℃, and then shows a reduction tendency.     

复合纳米纤维静电纺丝法的制备及其磁性

以聚乙烯吡咯烷酮（PVP）和金属盐为原料,利用静电纺丝法成功制备出了摩尔比为1：1的SrTiO3-SrFe12O19磁电复合纳米纤维。并通过FT-IR,XRD,SEM和VSM等技术对纤维前驱体及其产物的结构、热处理产物的物相、形貌及磁性能进行了表征。结果表明,样品经900℃焙烧2h后,即可得到纯的SrTiO3和SrFe...     

Synthesis of nanocrystalline carbonated hydroxyapatite powder via nonalkoxide sol–gel method

Nanocrystalline hydroxyapatite powder was synthesized via nonalkoxide sol–gel method. Ca(NO₃)₂·4H₂O and P₂O₅ were mixed in ethanol, which led to a stable sol. STA, XRD and FTIR were used to characterize the calcined powders. The degrees of crystallinity and crystallite sizes were thereafter calculated from XRD patterns. The microscopic observations of the powder were performed using SEM and TEM. Results showed that a nanocrystalline hydroxyapatite powder was obtained after being heated at 450 °C for 6 h. Furthermore, increasing the calcining temperature caused both the formation of carbonate bonds and the increase in the crystallite sizes, and the degree of crystallinity.     

硬脂酸凝胶法制备CeO2纳米粉体

采用硬脂酸凝胶法制备了CeO2纳米晶。XRD分析表明,当焙烧温度为450～900℃时,所合成的CeO2纳米晶均属于单相立方晶系,空间群为O5H-FM3M;计算表明,随焙烧温度的升高,平均晶粒度增大,而平均晶格畸变率则随平均晶粒度的增大而减小,表明粒子越小,晶格畸变越大,晶粒发育越不完整。TEM分析表明,CeO2纳米晶呈球形,粒度随焙烧温度的增加而增大。热失重分析表明,当焙烧温度高于750℃时,CeO2中的杂质基本挥发完毕。相对密度分析表明,随CeO2纳米晶粒度的增大,粉末的密度增加。,CeO2 nanocrystalline particulates of different sizes were prepared by stearic acid gel method.XRD patterns showed that the synthesized CeO2 was cubic in structure with single-phase when calcination temperature was 450-900℃,space group was O5H-FM3M.Calcination revealed that the mean crystalline size increased with the increase of calcinstion temperature,but average crystal lattice distortion rate decreased with the increasing in the average crystalline size.This indicated that the smaller the particle size,the bigger crystal lattice distortion,the worse the crystal growed.TEM photos revealed that CeO2 particles were spherical in shape,and the mean sizes of the C eO2 particles increased with the increase of calcination temperatures.Weight loss analysis indicated that the impurity in CeO2 completely volatilized when calcination temperature was above 750℃.The density of nanocrystalline CeO2 powders analysis showed that the density of CeO2 nanocrystalline powders increased with the increasing in CeO2 particles sizes.     

退火处理对非晶态Ni-P合金超细粉结构及磁性能的影响

采用液相脉冲放电技术,在NiSO4溶液中用NaH2PO2为还原剂,制备出了Ni-P合金超细粉体材料。将Ni-P合金粉在200～450℃下退火处理,并通过X射线衍射(XRD)、透射电镜(TEM)和场发射扫描电镜(FESEM)对退火前后Ni-P合金粉的结构、形貌进行了分析。用振动样品磁强计(VSM)对Ni-P合金粉进行了磁性能分析。结果表明所制备的超细Ni-P合金粉为非晶结构,颗粒直径在300～500nm之间,颗粒之间紧密结合成链枝状形貌。Ni-P合金粉在250～280℃退火后具有良好的软磁性能,250℃退火后矫顽力降低至0.437×10-4T。     

Factors affecting CO oxidation over nanosized Fe2O3

Nanocrystallite iron oxide powders with different crystallite sizes were prepared by co-precipitation route. The prepared powders with crystallite size 75, 100 and 150 nm together with commercial iron oxide (250 nm) were tested for the catalytic oxidation of CO to CO₂. The influence of different factors as crystallite size, catalytic temperature and weight of catalyst on the rate of catalytic reaction was investigated using advanced quadrupole mass gas analyzer system. It can be reported that the rate of conversion of CO to CO₂ increased by increasing catalytic temperature and decreasing crystallite size of the prepared powders. The experimental results show that nanocrystallite iron oxide powders with crystallite size 75 nm can be recommended as a promising catalyst for CO oxidation at 500 °C where 98% of CO is converted to CO₂. The mechanism of the catalytic oxidation reaction was investigated by comparing the CO catalytic oxidation data in the absence and presence of oxygen. The reaction which was found to be first order with respect to CO is probably proceeded by adsorption mechanism where the reactants are adsorbed on the surface of the catalyst with breaking OO bonds, then CO pick up the dissociated O atom forming CO₂.     

氧化镍掺杂酚醛树脂热解炭的结构及抗氧化性

在普通酚醛树脂中直接掺杂氧化镍粉末,研究氧化镍掺量和炭化处理温度对树脂热解炭的结构与氧化过程的影响,用X射线衍射仪、拉曼光谱分析仪、扫描电镜和综合差热分析仪等对掺杂改性树脂热解炭的石墨化度、显微结构及氧化过程分析表征,结果表明,在埋炭条件下掺杂改性树脂在450-750℃的炭化处理中三氧化二镍被逐级还原为一氧化镍和单质镍后,碳原子在镍颗粒上沉积生长,形成晶须、片状或块状结构的热解炭,热解炭石墨化程度取决于炭化温度和氧化镍掺杂量,在高于1050℃炭化处理的热解炭中出现明显的石墨化炭峰,随着掺杂量增加,热解炭石墨化程度大大增加,氧化温度比普通树脂明显提高,且以3~5%的掺杂量为佳。     

马氏体时效不锈钢热处理工艺优化

利用热力学计算软件Thermo-Calc,研究了马氏体时效不锈钢Fe-13Cr-7Ni-4Mo-4Co-2W在不同温度下的基体组织和析出相的变化.通过TEM、SADP法分析研究了马氏体时效不锈钢在固溶处理与时效处理过程中显微组织与析出行为.热力学计算与实验研究结果一致表明,马氏体时效不锈钢高温析出Laves-Fe2Mo相,固溶温度超过1050℃,Laves-Fe2Mo相全部溶解;时效析出R相,其含量在8%左右.根据计算结果优化了相应的热处理工艺,力学性能研究结果表明,用所确定的时效工艺进行热处理后,马氏体时效不锈钢的强韧性最好.