喷雾热解法制备掺锑二氧化锡薄膜及其性能表征

用喷雾热解法将掺杂锑的氯化亚锡溶液喷射到预先加热的玻璃管衬底上,制备了掺锑氧化锡透明导电薄膜.采用X射线衍射仪和扫描电镜分别对薄膜的结构和表面形貌进行了表征.研究了不同掺锑量对薄膜点电阻的影响及在可见光范围内与透光率之间的关系.结果表明,掺杂锑的薄膜呈四方金红石结构,薄膜比较致密,进行掺杂后的薄膜电阻变小,当锑锡原子比为0.04时点电阻最小,约为28 Ω/cm.镀膜玻璃管在可见光范围内透光率随锑掺杂量增多而减小.     

Microwave sintering of W-15Cu ultrafine composite powder prepared by spray drying &; calcining-continuous reduction technology

The effects of microwave sintering and conventional H2 sintering on the microstructure and properties of W-15Cu alloy using ultrafine W-15Cu composite powder fabricated by spray drying & calcining-continuous reduction technology were investigated.In comparison to the conventional H2 sintering processing,microwave sintering to W-15Cu can be achieved at lower sintering temperature and shorter sintering time.Furthermore,higher performances in microwave sintered compacts were obtained,but high microwave sintering temperature or long microwave sintering time could result in coarser microstructures.     

Morphology and microstructure characterization of 95W-3.5Ni-1.5Fe powder prepared by mechanical alloying

The mechanism of mechanical solid-state reactions for formation of tungsten heavy alloy powder was discussed. A highenergy ball mill operating at room temperature was used for preparing tungsten heavy alloy powders, starting from elemental tungsten （W）, nickel （Ni）, and iron （Fe） powders. X-ray diffraction （XRD）, particle size analyzer, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM） were used to follow the progress of the mechanical solid-state reaction of W, Ni, and Fe powders. These morphological studies revealed three stages in the milling process. In the first stage, the particle deformation changes the irregular structure of the as-received powder particles to flattened morphology, and the average particle size increases. In the second stage, the powder is sufficiently deformed and the tendency to fracture predominates over welding, and the particle size decreases. With continuous milling, the system reaches steady state, and relatively small and uniform particle size distribution is obtained after 20 h of milling.     

Fabrication and characterization of porous mullite ceramics from pyrolysis of alumina powders filled silicone resin

Porous mullite ceramics were fabricated from pyrolysis of nanometer alumina powders filled silicone resin. At 1573 K, the mixture of nanometer γ-Al2O3 and silicone resin can be entirely transformed to mullite in air. The effects of shaping pressure on microstructure and mechanical property were investigated. Increasing shaping pressure leads to decrease in open porosity and average pore size, narrower pore size distribution, and improvement in flexural strength. With a shaping pressure of 43 MPa, nanoporous mullite ceramics with an average pore size of 50 nm can be obtained, showing 33% in open porosity and 42 MPa in flexural strength. The microstructure of porous mullite ceramics consists of dense region and loose region.     

激光诱导制备纳米SiC粉体

以硅烷Sih4和乙炔C2H2为反应原料，采用激光诱导化学气相沉积制备(LICVD)理想纳米SIC粉体．用化学分析、X射线衍射(XRD)、透射电子显微镜(TEM)及比表面积(BET)等分析测试手段对粉体进行了表征，结果表明粉体中SiC含量高于98％，平均粒径为20nm，晶体结构为β—SiC粉体产率大于200g／h，粉体中含氧量低于1％。     

沉淀法制备纳米Al2O3粉末

以工业用NH4Al(SO4)2·12H2O和NH4HCO3为原料,采用均匀沉淀法制备纳米Al2O3粉末.研究了沉淀剂的滴加方式、表面活性剂等因素对粉体尺寸的影响.经检测,最佳工艺得到的Al2O3粉末的平均粒径小于15nm.     

纳米级SnO2气敏材料制备及结构分析

制备敏感元件的原材料粉粒越细越好．介绍了以明胶作分散介质用溶胶－明胶法制备纳米级ＳｎＯ２敏感材料的工艺方法．制备的ＳｎＯ２材料粒径小于１０ｎｍ．实验研究了热处理的温度和时间对ＳｎＯ２材料粒径的影响,并进行了理论上的解释．对制备的ＳｎＯ２材料进行了透射电子显微镜、比表面积测试和Ｘ射线衍射等方法的测试分析,给出了测试分析结果．     

熔盐合成法制备CaTiO3粉体的研究

以TiO2及CaCO3为原料，CaCl2为反应介质，对熔盐合成法制备CaTiO3粉体进行研究，并与固相合成法进行比较。结果表明，熔盐合成法可将纯相CaTiO3的合成温度从固相合成法所需的1400℃降至800℃，熔盐法合成的CaTiO3粉末粒度较小（〈0．5μm），分布均匀，且具有很高的分散性。在熔盐合成法中由于Ca—CO3及TiO2在熔融CaCl2中有较高的溶解度，两者可在其中通过“溶解析出”机理进行反应，从而在较低的温度下生成单一相的CaTiO3。     

水热法制备钛酸锶纳米粉体的性能

以Sr(NO₃)₂和Ti(OC₄H₉)₄为主要原料,以NaOH为矿化剂,在175℃下反应60min,水热合成了颗粒大小均匀,粒度约在100nm的SrTiO₃纳米粉体.将Ti(OC₄H₉)₄先溶于无水乙醇中,再与NaOH反应生成前驱物TiO(OH)₂,在80℃下热处理2h,可以大大减少产物中的杂质相,得到纯度较高的SrTiO₃粉体.由XRD图谱分析发现,在合成过程中加入机械搅拌得到的粉体,晶化更完全.由此粉体制备的SrTiO₃压敏陶瓷材料经电性能测试,其压敏电压为18?V,非线性系数为46,介电损耗为0．078,相对介电常数ε=2．7×10^4.     

电镀法制备Ni-W合金镀层的耐盐雾腐蚀性能

利用电镀法在N80钢表面制备了Ni-W合金镀层,用SEM、EDS分析了镀层表面与界面形貌以及化学元素的分布,通过XRD测试了镀层物相的组成。在5% NaCl溶液中测试了镀层盐雾腐蚀能力,分析了Ni-W镀层抗盐雾腐蚀机理。试验结果表明,镀层厚度约40m,主相为Ni-W,Ni和W以金属形式存在于镀层中;经过高温热处理后,镀层与基体发生了化学元素扩散现象,形成冶金结合;盐雾腐蚀后镀层表面腐蚀物为Fe的氧化物和氯化物,基体无腐蚀现象发生。     

化学沉淀法制备HA粉体过程中水中分散效果的试验研究

选用聚乙二醇2000、六偏磷酸钠和BK Giulini公司提供的粉体分散剂LoponR 885对化学沉淀法制备的HA进行水中分散性试验研究. 用粒度分布仪、X射线衍射仪（XRD）和透射电子显微镜（TEM）对分散体系进行粒度分布、形貌和物相分析. 对粉末HA颗粒的团聚及分散机理进行了探讨. 结果表明,采用这种方法得到的粉体的组成相以羟基磷灰石（HA）为主,且颗粒具有近似球形的微观形貌. (NaPO3)6和LoponR 885对HA颗粒团聚的消弱作用明显. 可以认为合理选用分散剂是在不影响HA粉体品质前提下消除HA颗粒团聚现象的有效方法.     

燃烧法制备NaYF_4:Er~(3+),Yb~(3+)纳米发光粉

采用低温燃烧法制备了NaYF4:Er3+,Yb3+上转换纳米发光粉。确定最佳工艺参数为:尿素用量为200%stio,烧结温度为600℃,反应时间为8min。通过X射线衍射和透射电镜分析了晶粒尺寸和粉体粒径,粒径为30～35nm。结构为六方晶相。NaYF4:Er3+,Yb3+样品对980nm附近的波长具有上转换发光效应,上转换发射光谱5个发光峰分别为380、408、522、540和658nm。拟合材料发光强度与泵浦功率之间的关系说明,380、408nm紫光发射属于三光子过程,526、540和652nm发射均属于双光子过程。     

3%C-Cu机械球磨复合粉末的烧结

为了给后续的致密化工序（如热挤压）提供较高质量的烧结坯,用扫描电镜和光学显微镜分析了3%C-Cu机械球磨复合粉末所制备烧结坯的显微组织,并研究了工艺参数对其相对致密度的影响规律。结果表明,烧结温度对未机械球磨混合粉烧结行为的影响很大,而机械球磨复合粉对烧结温度不敏感。真空热压烧结可以明显地促进致密化过程。提高烧结温度、延长烧结保温时间或增加热压压强,均有助于提高烧结坯的相对致密度。在相同条件下,烧结坯的相对致密度随着复合粉末机械球磨时间的延长而降低。     

Characterization of ultrafine copper powder prepared by novel electrodeposition method

The auto-evolved ultrafine copper powders were synthesized via a novel electrodeposition route performed by ultrasonic dispersion of the electrolyte. The properties of the samples obtained were characterized by X-ray powder diffractometry (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and laser size distribution analyzer (SL) respectively. The formation mechanisms of the powders and the efficiency of the elctrodeposition were discussed. The results show that the as-prepared powders are high-purity copper nanoparticles with the fcc structure taking a mixture of fishbone-like and irregular shapes. When the concentration of Cu²⁺ increases from 0.03 to 0.09 mol/L, the average size of copper particles increases from 0.92 to 1.80 μm, and current efficiency of electrodeposition linearly changes from 66.5% to 91.3%.     

化学沉淀法制备纳米HAP粉体的工艺优化

用化学沉淀法制备出了纳米级的HAP粉体 ,讨论了不同工艺参数对化学沉淀法制备的HAP粉体性能的影响 .用X射线衍射、红外光谱以及TEM对所制粉体进行了分析 .测定结果表明 :煅烧后粉体的结晶程度明显提高 ,在进行煅烧时以 90 0～ 10 0 0℃煅烧 1h以下为宜 .反应温度及保温时间的影响较小     

High-performance spherical LiVPO4F/C cathode enabled by facile spray pyrolysis

Science China Technological Sciences - LiVPO4F suffers problems of difficulty in synthesis and poor conductivity. To solve these, herein sub-micro spherical LiVPO4F/C is synthesized from a...     

ZnO films on transferable and low thermal resistance graphite substrate grown by ultrasonic spray pyrolysis

ZnO thin films were deposited on graphite substrates by ultrasonic spray pyrolysis method with Zn(CH 3 COO) 2 ·2H 2 O aqueous solution as precursor. The crystalline structure, morphology, and optical properties of the as-grown ZnO films were investigated systematically as a function of deposition temperature and growth time. Near-band edge ultraviolet(UV) emission was observed in room temperature photoluminescence spectra for the optimized samples, yet the usually observed defect related deep level emissions were nearly undetectable, indicating that high optical quality ZnO thin fi lms could be achieved via this ultrasonic spray pyrolysis method. Considering the features of transferable and low thermal resistance of the graphite substrates, the achievement will be of special interest for the development of high-power semiconductor devices with suffi cient power durability.     

Direct spray pyrolysis of aluminum chloride solution for alumina preparation

The effects of pyrolysis mode and pyrolysis parameters on Cl content in alumina were investigated, and the alumina products were characterized by XRD, SEM and ASAP. The experimental results indicate that the spray pyrolysis efficiency is higher than that of static pyrolysis process, and the reaction and evaporation process lead to a multi-plot state of the alumina products by spray pyrolysis. Aluminum phase starts to transform into γ-Al2O3 at spray pyrolysis temperature of 600 °C, which is about 200 °C lower than that of static pyrolysis process. The primary particle size of γ-Al2O3 product is 27.62 nm, and Cl content in alumina products is 0.38% at 800 °C for 20 min.     

纳米ZnO粒子的溶胶凝胶制备及抗菌活性研究

采用溶胶凝胶法制备了纳米ZnO粒子,通过XRD、SEM对所制备粉体颗粒的物相组成以及表面形貌进行表征,并且通过K-B纸片扩散法研究了抗菌性能,并对比了紫外光照前后的抗菌性能.结果表明,所制备的ZnO纳米粒子粒径约为200nm左右,显示优良的抗菌活性,未经紫外光照对大肠杆菌(Escherichia coli)和金黄色葡萄球菌(Staphylococcus aureus)的抑菌圈达到18～22mm,并对其机理做了初步探讨.