排序方式: 共有39条查询结果,搜索用时 31 毫秒
1.
2.
3.
非晶态纳米Fe—W—B合金粉末的制备及结构 总被引:1,自引:0,他引:1
用KBH4化学还原FeSO4和Na2WO4制备了FeWB合金粉末。研究了改变溶液中的金属盐比例及KBH4浓度对制备的影响。X射线衍射及电镜分析表明,合金粉末为30~100nm球形粉末,结构为非晶态。实验表明,有些粉末中有明显的非晶氧化物存在。 相似文献
4.
Poly(N-vinylpyrrolidine)-silica hybrid shell coated cadmium selenide / cadmium sulphide and cadmium selenide / zinc sulfide nanoparticles were synthesized by combining the organometallic and single “step” modified Stober method. The synthesized nanoparticles were characterized by atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy, and a spectrofluorometer. Concluding, this report has provided important insights into the design of new water-soluble polymer silica hybrid shell coated quantum dots nanoparticles for biomedical, analytical and catalytic applications. 相似文献
5.
A novel route for the synthesis of metallic palladium consisting of nanosize particles has been reported. The synthesis is based on (a) the addition of tetramethylammonium hydroxide (TMAH) to the aqueous solution of PdCl2, and (b) autoclaving of this precipitation system at 160 °C. The distribution of the nanosize particles of metallic palladium has its mean value at about 18 nm. The mechanism of the metallic palladium formation is briefly discussed. 相似文献
6.
Meng Shang Wenzhong Wang Lin Zhou Songmei Sun Wenzong Yin 《Journal of hazardous materials》2009,172(1):338-344
Nanosized BiVO4 with high visible-light-induced photocatalytic activity was successfully synthesized via ultrasonic-assisted method with polyethylene glycol (PEG). The BiVO4 sample prepared under ultrasonic irradiation with 1 g PEG for 30 min was consisted of small nanoparticles with the size of ca. 60 nm. The effects of ultrasonic irradiation and surfactant were investigated. The nanosized BiVO4 exhibited excellent visible-light-driven photocatalytic efficiency for degrading organic dye, which was increased to nearly 12 times than that of the products prepared by traditional solid-state reaction. Besides decoloring, the reduction of chemical oxygen demand (COD) concentration was also observed in the degradation of organic dye, further demonstrating the photocatalytic performance of BiVO4. After five recycles, the catalyst did not exhibit any significant loss of photocatalytic activity, confirming the photocatalyst is essentially stable. Close investigation revealed that the crystal size, BET surface area, and appropriate band gap of the as-prepared BiVO4 could improve the photocatalytic activities. 相似文献
7.
Shuguang BIAN Xianggao LI Lei SHAO Jianfeng CHEN 《材料科学技术学报》2006,22(4):533-535
Functional phthalocyanine (Pc) compounds of H2Pc, TiOPc, FePc and CIAIPc were synthesized with a yield of 46.7%, 91.2%, 37.4% and 34.0%, respectively. Nanosized TiOPc was synthesized via a one-step sol-gel method and effects of surfactant doses, nucleation temperature on TiOPc particle size and photoconductivity were investigated. When re(PEG): m(TiOPc) was 0.1 and nucleation temperature was 0℃, the as-obtained TiOPc had the smallest particle size and largest specific surface area, which were 60 nm and 83m^2/g, respectively. TiOPc synthesized under these conditions also exhibits excellent photoconductivity with charging potential V0, dark decay speed Rd and energy for half-discharging of potential E1/2 being 1160 V, 30 V/s and 0.6 1x.s, respectively. 相似文献
8.
Using a non-transferred DC plasma spray torch, nanosized alumina particles were synthesized from micron-sized aluminium particles. Irregular-shaped micron-sized alumina particles were spheroidized using the plasma spray torch. The synthesized powder particles were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis, Fourier transform infra-red (FT-IR) spectroscopy and photoluminescence (PL) spectroscopy. The synthesized alumina nanoparticles appear spherical in shape, but mostly agglomerated in the size range 30-75 nm. It was identified that the main phase is γ-alumina with a small amount of δ-alumina. In the spheroidized alumina particles, the main phase is α-alumina with a small amount of γ-alumina. The mechanism of formation of alumina and its phase change are explained in detail. 相似文献
9.
The high temperature combustion of the mixture Ta2O5 + 5 Mg has been investigated using a microthermocouple in the medium MgO and molten NaCl. The effect of varying the amounts of these two inorganic agents (MgO and NaCl) was examined. It was shown that using MgO as the reaction medium produces the complex oxide MgxTayOz as an impurity in the Ta powder, whereas unagglomerated single-phase powder (particle size of 20-90 nm) of Ta was formed in the presence of NaCl. The approximate mechanism for forming the final product is discussed. The distributions of temperature, the rate of heat generation and degree of conversion in the combustion wave of the mixture Ta2O5 + 5Mg + NaCl were measured. The sizes of the combustion zones and the kinetics of reaction were derived. 相似文献
10.
In situ aluminium matrix composites were processed by the micropyretic reactions between the host aluminium matrix and powder containing nanodimensional Fe2O3 crystallites used as the precursor compound. Differential Scanning Calorimetric (DSC), studies have shown, use of nanosized Fe2O3 crystallites has decreased the initiation temperature of the in situ micropyretic reaction and the desirable reinforcements; iron-aluminide and alumina are formed during sintering. Microstructural features of the composite consist of well-dispersed reinforcements in the host Al matrix with size less than 1 µm. Wear tests performed on the composite samples have revealed coefficient of friction and wear volume can be reduced significantly by incorporating 20 vol% reinforcement. 相似文献