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1.
采用EDTA络合溶胶.凝胶法制备出锂离子电池正极材料Li1-xKxCoO2,对Li1-xKxCoO2的成胶条件和形成过程进行了探讨,并分别应用XRD、SEM等技术对材料的晶相、形貌等进行了结构表征。结果表明,在焙烧温度达到700℃时能够形成单一相的Li0.98K0.02CoO2,焙烧12h制得的Li0.98K0.02CoO2粉体结晶良好,层状结构发育完善。充放电实验结果表明,在焙烧温度为800℃下制得的Li0.98K0.02CoO2材料具有较好的电化学性能。  相似文献   

2.
EDTA络合法制备锂离子电池正极材料Li1-xKxCoO2   总被引:1,自引:0,他引:1  
采用EDTA络合溶胶-凝胶法制备出锂离子电池正极材料Li1-xKxCoO2,对Li1-xKxCoO2的成胶条件和形成过程进行了探讨,并分别应用XRD、SEM等技术对材料的晶相、形貌等进行了结构表征.结果表明,在焙烧温度达到700℃时能够形成单一相的Li0.98K0.02CoO2,焙烧12 h制得的Li0.98K0.02CoO2粉体结晶良好,层状结构发育完善.充放电实验结果表明,在焙烧温度为800 ℃下制得的Li0.98K0.02CoO2材料具有较好的电化学性能.  相似文献   

3.
通过柠檬酸盐溶胶.凝胶法合成了ZnNb2O6陶瓷粉体,利用XRD、SEM等测试手段研究了合成工艺对粉体粒度的影响。XRD分析结果显示,当柠檬酸比例为1:2.5,煅烧温度为700℃时所合成的物相为单一铌铁矿相,Scherrer公式计算结果显示随着合成温度的升高,粉体晶粒尺寸有明显长大的趋势。SEM分析结果显示,随着溶液pH值的增大,合成的ZnNb2O6粉体晶粒尺寸明显减小。pH=9,700℃时合成的ZnNb2O6粉体晶粒尺寸为45nm。  相似文献   

4.
本文用Al作还原剂还原氮化TiO2制备了TiN—Al2O3复合粉体。通过对比不同温度下的含氮率和理论含氮率,可以判断反应进行的程度;通过XRD分析研究不同温度下的相变化;通过SEM、EDS分析观察晶粒的形貌和成分。研究结果发现,TiN在1100℃开始生成,1450℃TiN生成反应结束。SEM照片显示细小、不规则的TiN晶粒和多面体Al2O3晶粒相互交叉均匀分布,Al2O3晶粒尺寸10μm左右,TiN晶粒尺寸2μa左右。表明用此方法可以在比较低的温度下合成颗粒细小分散均匀的TiN-Al2O3复合粉体。  相似文献   

5.
以烷氧基金属化合物为原料,乙酸为催化剂,采用金属醇盐法制备了YAG前驱体粉体,在不同温度下焙烧,得到了YAG纳米粉体,并改变乙酸与水的用量以及醇盐溶液浓度,初步探讨了催化剂及醇盐溶液浓度对合成纯相YAG粉体的影响。主要采用X射线衍射(XRD)对这些粉体进行了物相分析,并利用透射电子显微镜(TEM)对粉体进行了形貌观察。结果表明,当钇、铝2种醇盐溶液浓度比为1:2、乙酸与水的摩尔比为10:1时,在1100℃焙烧得到了纯相YAG纳米粉体。粉体分散性较好,颗粒粒径在50~80nm,大致呈球状。  相似文献   

6.
蓝色荧光材料GdVO4:Tm的制备和性能   总被引:1,自引:0,他引:1  
采用溶胶-凝胶法合成了蓝色荧光纳米晶GdVO4:Tm粉体.通过XRD、荧光光谱和SEM分析了GdVO4:Tm粉体在不同焙烧温度、保温时间下的相结构、晶粒尺寸,形貌以及发光性能.结果表明:所得产物为单一的四方锆型GdVO4:Tm晶体,晶粒尺寸小于100 nm.GdVO4:Tm能够被200~320 nm的紫外光激发,在308 nm波长紫外光激发下发出波长为478 nm的明亮蓝光;焙烧温度为900 ℃,保温3 h得到的粉末发光性能最好.  相似文献   

7.
将质量比为1:4的TiCl4和NaN。放入不锈钢反应釜内,以二甲苯为溶剂,填充率为60%,用溶剂热方法,在温度340℃,保温24h,制得粉体。粉体分别经二甲苯,无水乙醇、蒸馏水洗涤,105℃干燥和直接经700℃煅烧2h,XRD测试表明:制备出的氮化钛粉体为纳米立方相粉体,晶格常数a=0.4241nm,平均粒径为11.04nm,700℃煅烧后全部转化为TiO2和Ti的混合物;IR测试表明在619cm^-1的吸收峰归属为Ti—N键,表面吸附了一些有机溶剂,有C=C弯曲振动峰;SEM测试表明其晶粒有立方状、圆粒状,长柱状和内部有中孔的圆环状晶粒,表面存在毛绒状的细小晶须,形成网状包裹在晶粒表面。  相似文献   

8.
采用柠檬酸溶胶-凝胶法,以Sm_2O_3和ZrO(NO_3)_2·2H_2O为原料,柠檬酸为螯合剂,合成了单相的Sm_2Zr_2O_7粉体。果用TG/DSC、XRD和SEM对制备的粉体进行了表征,利用TG/DSC对干凝胶粉的热分解过程进行了分析。研究了煅烧温度对粉体物相及晶粒大小的影响,以及柠檬酸含量对粉体相组成和粉体分散性的影响。结果表明,干凝胶粉的热分解主要分为两个放热阶段进行,500℃左右干凝胶粉的热分解基本完成。Sm_2Zr_22O_7的结晶约在450℃左右开始发生,950℃保温2 h可以得到结晶良好的具有纳米晶粒Sm_2Zr_2O_2粉体,粉体晶粒为10~20 nm;柠檬酸与金属离子的螯合作用提高了结晶产物的纯度,随着柠檬酸含量的增加,粉体团聚程度先减小后增加,在CA/M=0.5时粉体分散性最好,粉体粒度为100~200 nm。  相似文献   

9.
以柠檬酸及金属盐为原料,采用有机凝胶.热分解法制备了Mn0.5zn0.5Fe2O4铁氧体陶瓷纤维.通过FTIR、TG/DSC、XRD、SEM分别对前驱体凝胶的结构、热分解过程及热处理产物的物相和形貌进行了表征,用VSM对纤维的磁性能进行了检测.结果显示所得Mn0.5zn0.5Fe2O4铁氧体陶瓷纤维由9.7~12 nm晶粒组成,直径从1μm到20μm,长径比可达1×103.纤维的晶粒大小在400~580℃范围内随焙烧温度的升高而增大.这些铁氧体纤维显示出了超顺磁性,超顺磁程度与组成纤维的晶粒大小有关.  相似文献   

10.
溶胶-凝胶法制备氧化锆粉体   总被引:2,自引:0,他引:2  
以正丙醇锆为锆源,采用溶胶-凝胶法制备了ZrO2粉体。研究了硝酸含量对凝胶时间及热处理温度对ZrO2晶型的影响规律。通过控制硝酸含量可以有效改变凝胶时间;通过锆醇盐水解缩聚制备的ZrO2干凝胶,在低温下热处理首先形成ZrO2四方相,在较高温度热处理后才转变为单斜相;锆醇盐水解缩聚制备的氧化锆粉体在1200℃以后烧结过程明显加快。  相似文献   

11.
In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.  相似文献   

12.
After nearly two years' tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry (SRIF), located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.  相似文献   

13.
The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.  相似文献   

14.
On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes' collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.  相似文献   

15.
An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.  相似文献   

16.
A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.  相似文献   

17.
吴玉梅  熊晓云  靳蓉  孙敬民  杨林  罗晓星 《金属学报》2005,10(10):1100-1103
目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。  相似文献   

18.
On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.  相似文献   

19.
During the slab continuous casting process, the flow field of molten steel in the mold plays a decisive role in the quality of the slab. In this paper, electromagnetic swirling flow in nozzle technology is proposed to control the flow field in mold.This technology can drive molten steel to rotate inside the submerged entry nozzle by electromagnetic force, thereby controlling the flow field. This research shows that it can reduce the impact of molten steel on the bottom of nozzle and partly reduce the negative pressure at the upper part of nozzle outlet which is even eliminated by optimizing the structure and angle of nozzle. The area of heat flux of the mold wall becomes larger, and the crest value of heat flux gets lower than that without swirling in nozzle and any nozzle optimization. The meniscus fluctuates smoothly, and the flow velocity at the top surface is within a reasonable range. The temperature field distribution in the mold is uniform which was beneficial to the growth of equiaxed crystal and decreased element segregation.  相似文献   

20.
The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).  相似文献   

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