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2019年  第26卷  第9期

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Review on nanocomposites fabricated by mechanical alloying
Mohammed A. Taha, Rasha A. Youness, M. F. Zawrah
2019, 26(9): 1047-1058. doi: 10.1007/s12613-019-1827-4
摘要:

Composites are composed of multiphase materials, where each phase has specific properties that differ from those of the other phases which can effect on the whole properties of composite. Nanocomposites are class of materials that contain at least one phase in the nanometric size range and can be produced by any suitable technique for preparing nanomaterials. Composites are an interesting class of materials that have recently been used in numerous applications, including structural, biomedical, electronics, and environmental applications. In composites, reinforcements might be fibers, particulates, or whiskers. Mechanical alloying (MA) is a promising technique for producing nanocomposite materials that are difficult or impossible to prepare via conventional techniques. In this review, we provide an overview of nanocomposites prepared by the MA process. The mechanism of milling and other milling parameters are overviewed, and insights into sintering categories and parameters are also presented.

研究论文
Selective flotation separation of andalusite and quartz and its mechanism
Yan-ping Niu, Chuan-yao Sun, Wan-zhong Yin, Xing-rong Zhang, Hong-feng Xu, Xu Zhang
2019, 26(9): 1059-1068. doi: 10.1007/s12613-019-1842-5
摘要:
The separation of andalusite and quartz was investigated in the sodium oleate flotation system, and its mechanism was studied by solution chemical calculation, zeta-potential tests, Fourier transform infrared spectroscopic (FTIR), and X-ray photoelectron spectroscopic (XPS). The flotation tests results show that FeCl3·6H2O has a strong activation effect on andalusite and quartz and citric acid has a strong inhibitory effect on activated quartz, thus increasing the floatability difference between quartz and andalusite when the pulp pH is approximately 8. The FTIR, Zeta potential, and XPS analyses combined with the chemical calculation of flotation reagent solutions demonstrate that Fe forms hydroxide precipitates on the surface of andalusite and quartz and that oleate anions and metal ions adsorb onto the surface of the minerals. The elements Al and Fe can be chemically reacted. The anions in citric acid have different degrees of dissolution of Fe on the andalusite and quartz surfaces, thereby selectively eliminating the activation of the elemental Fe on andalusite and quartz and increasing the floatability of andalusite, leading to a better separation effect between andalusite and quartz.
研究论文
Mechanism of Mg2+ dissolution from olivine and serpentine: Implication for bioleaching of high-magnesium nickel sulfide ore at elevated pH
Jian-zhi Sun, Jian-kang Wen, Bo-wei Chen, Biao Wu
2019, 26(9): 1069-1079. doi: 10.1007/s12613-019-1823-8
摘要:
To inhibit the dissolution of Mg2+ during the bioleaching process of high-magnesium nickel sulfide ore, the effect of major bioleaching factors on the dissolution of Mg2+ from olivine and serpentine was investigated and kinetics studies were carried out. The results indicated that the dissolution rate-controlling steps are chemical reaction for olivine and internal diffusion for serpentine. The most influential factor on the dissolution of Mg2+ from olivine and serpentine was temperature, followed by pH and particle size. A novel method of bioleaching at elevated pH was used in the bioleaching of Jinchuan ore. The results showed that elevated pH could significantly reduce the dissolution of Mg2+ and acid consumption along with slightly influencing the leaching efficiencies of nickel and cobalt. A model was used to explain the leaching behaviors of high-magnesium nickel sulfide ore in different bioleaching systems. The model suggested that olivine will be depleted eventually, whereas serpentine will remain because of the difference in the rate-controlling steps. Bioleaching at elevated pH is a suitable method for treating high-magnesium nickel sulfide ores.
研究论文
Co-influencing mechanisms of physicochemical properties of blasting dust in iron mines on its wettability
Jian-guo Liu, Long-zhe Jin, Jia-ying Wang, Sheng-nan Ou, Tian-yang Wang
2019, 26(9): 1080-1091. doi: 10.1007/s12613-019-1874-x
摘要:
This study explores the key physicochemical factors affecting the hydrophilic characteristics of iron mine blasting dust (BD). The BD is separated into an unwetted part (UWBD, hydrophobic part) and a wetted part (WBD, hydrophilic part). Its particle size, true density (TD), pore parameters, mineral composition, and surface compounds are comprehensively characterized and compared. The results indicate that a smaller particle size and more developed pore parameters are two key factors responsible for the strong hydrophobicity of the BD. The mineral composition of the BD has no direct effect on its wetting properties; however, it indirectly influences the deposition characteristics of the BD in water by affecting its TD. Unlike coal dust, the surface organic composition of the BD does not affect its wettability and the peak area of C-C/C-H hydrophobic groups in the C 1s X-ray photoelectron spectrum of the UWBD (45.03%) is smaller than that in the C 1s spectrum of the WBD (68.30%). Thus, eleven co-influencing processes of physicochemical properties of the BD on its wettability are summarized. This research sheds light on the key factors affecting the wettability of the BD.
研究论文
Gas-liquid mass transfer and flow phenomena in a peirce-smith converter: A numerical model study
Hong-liang Zhao, Xing Zhao, Liang-zhao Mu, Li-feng Zhang, Li-qiang Yang
2019, 26(9): 1092-1104. doi: 10.1007/s12613-019-1831-8
摘要:
A numerical model was established to simulate the flow field in a Peirce-Smith converter bath, which is extensively adopted in copper making. The mean phase and velocity distribution, circular area, and mean wall shear stress were calculated to determine the optimal operation parameter of the converter. The results showed that the slag phase gathered substantially in the dead zone. The circular flow was promoted by increasing the gas flow rate, Q, and decreasing the nozzle height, h. However, these operations significantly aggravate the wall shear stress. Reducing the nozzle diameter, d, increases the injection velocity, which may accelerate the flow field. However, when the nozzle diameter has an interval design, the bubble behaviors cannot be combined, thus, weakening the injection efficiency. Considering the balance between the circular flow and wall shear stress in this model, the optimal operation parameters were Q=30000-35000 m3/h, h=425-525 mm, and d=40 & 50 mm.
研究论文
Complete stabilization of severely As-contaminated soil by a simple H2O2 pre-oxidation method combined with non-toxic TMT-15 and FeCl3·6H2O
Chang-sheng Yue, Ben Peng, Wei Tian, Guang-hua Lu, Gui-bo Qiu, Mei Zhang
2019, 26(9): 1105-1112. doi: 10.1007/s12613-019-1819-4
摘要:
The stabilization of severely As-polluted soil has been a challenge, especially for the extremely toxic As(Ⅲ) contaminants. In this study, soil with a high As concentration (26084 mg/kg) was availably stabilized by a H2O2 pre-oxidation assisted TMT-15 (Na3S3C3N3 solution with a mass fraction of 15%) and FeCl3·6H2O stabilization method. The results showed that the combination of the two stabilizers (i.e., TMT-15 and FeCl3·6H2O) presented a better stabilization behavior than either stabilizer used individually. The use of the H2O2 pre-oxidation assisted TMT-15 and FeCl3·6H2O stabilization approach not only converted the As(Ⅲ) to As(V) but also reduced the toxic leaching concentration of As to 1.61 mg/L, which is a safe level, when the additions of TMT-15 and FeCl3·6H2O were 2 mL and 0.20 g, respectively. Thus, using only a simple H2O2 pre-oxidation to combine clean stabilization with non-toxic stabilizers TMT-15 and FeCl3·6H2O could render the severely As-contaminated soil safe for disposal in a landfill.
研究论文
Effect of Fe2O3 on the size and components of spinel crystals in the CaO-SiO2-MgO-Al2O3-Cr2O3 system
Qi-qiang Mou, Jian-li Li, Qiang Zeng, Hang-yu Zhu
2019, 26(9): 1113-1119. doi: 10.1007/s12613-019-1822-9
摘要:
size of spinel crystals in the CaO-SiO2-MgO-Al2O3-Cr2O3 system was investigated using lab experiments carried out in a carbon tube furnace. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) and X-ray diffraction (XRD) were used to analyze the microstructure, components, and the mineral phases of synthetic slags. FactSage 7.1 was used to calculate the crystallization process of the molten slag. The results showed that the addition of Fe2O3 promoted the precipitation of spinel crystals and inhibited the formation of dicalcium silicate. The size of spinel crystals increased from 2.74 to 8.10 μm and the contents of chromium and iron in the spinel varied as the Fe2O3 addition was increased from 0 to 20wt%. Fe2O3 thermodynamically provided the spinel-forming components to enhance the formation of FeCr2O4, MgFe2O4, and Fe3O4. The addition of Fe2O3 increased the fraction of liquid phase in a certain temperature range and promoted diffusion by decreasing the slag's viscosity. Therefore, Fe2O3 is beneficial to the growth of spinel crystals in stainless steel slag.
研究论文
Effects of the continuous cooling process conditions on the crystallization and liberation characteristics of anosovite in Ti-bearing titanomagnetite smelting slag
Zhen Wang, Hao-yan Sun, Qing-shan Zhu
2019, 26(9): 1120-1128. doi: 10.1007/s12613-019-1830-9
摘要:
This study involved the investigation of the effects of the continuous cooling process conditions on the crystallization and liberation characteristics of anosovite in Ti-bearing titanomagnetite smelting slag. The samples were heated until melting and then the temperature was held at 1650℃ for nearly 0.5 h; subsequently, the samples were cooled at different cooling rates to different temperatures and water-quenched after being held for different times at these temperatures. Last, the obtained crystallized samples were used to analyze the crystallization and liberation characteristics. It was found that, during the continuous cooling process, anosovite particles were found to initially precipitate in the slag at a relatively high crystallization temperature, showing the characteristics of euhedral crystal. The precipitation and growth of anosovite grain is strong and the morphology of anosovite was basically not affected by the continuous cooling conditions. From the morphology perspective, the formed anosovite is an excellent Ti-rich phase to be selective separated. The formation of spinel and diopside is negative for the liberation and selective separation of the anosovite phase. The crystallization diagrams of TiO2-MgO-CaO-SiO2-Al2O3-FeO slag undergoing different continuous cooling processes were constructed to help to determine the optimal continuous cooling-quenching condition for selective separation of anosovite. Moreover, the addition of B2O3 can enlarge the range of the optimal continuous cooling-quenching conditions for selective separation of anosovite.
研究论文
Solid solution evolution during mechanical alloying in Cu-Nb-Al compounds
Kaouther Zaara, Mahmoud Chemingui, Virgil Optasanu, Mohamed Khitouni
2019, 26(9): 1129-1139. doi: 10.1007/s12613-019-1820-y
摘要:
This work concerns the structural evolution of Cu70Nb20Al10 (at%) alloy processed by mechanical alloying using a planetary ball mill in air atmosphere for different times (4 to 200 h). The morphological, structural, microstructural, and thermal behaviors of the alloy were investigated by scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, and differential scanning calorimetry. X-ray diffraction patterns were examined using the Rietveld refinement technique with the help of the MAUD software. A disordered FCC-Cu(Nb,Al) solid solution was formed after 8 h of milling. The crystallite size, microstrain, and lattice parameter were determined by the Rietveld method. With increasing milling time, the crystallite size of the final product-ternary-phase FCC-Cu(Nb,Al)-is refined to the nanometer scale, reaching 12 nm after 200 h. This crystallographic structure combines good mechanical strength and good ductility. An increase in microstrain and partial oxidation were also observed with increasing milling time.
研究论文
Effect of thermal deformation parameters on the microstructure, texture, and microhardness of 5754 aluminum alloy
Chang-qing Huang, Jia-xing Liu, Xiao-dong Jia
2019, 26(9): 1140-1150. doi: 10.1007/s12613-019-1852-3
摘要:
The evolution of the microstructure, texture, and microhardness of 5754 aluminum alloy subjected to high-temperature plastic deformation under different deformation conditions was studied on the basis of thermal simulations and electron-backscattered diffraction and Vickers microhardness experiments. The results of a misorientation angle study show that an increase in the deformation temperature and strain rate promoted the transformation of low-angle grain boundaries to high-angle grain boundaries, which contributed to dynamic recrystallization. The effect of the deformation parameters on the texture and its evolution during the recrystallization process was explored on the basis of the orientation distribution function. The results demonstrate that the deformed samples mainly exhibited the features of type A, B, and B textures. The formation and growth of the recrystallized grains clearly affected the texture evolution. The microhardness results show that the variation of the microhardness was closely related to the temperature, strain rate, and dynamic recrystallization.
研究论文
New high-strength Ti-Al-V-Mo alloy: from high-throughput composition design to mechanical properties
Di Wu, Wan-lin Wang, Li-gang Zhang, Zhen-yu Wang, Ke-chao Zhou, Li-bin Liu
2019, 26(9): 1151-1165. doi: 10.1007/s12613-019-1854-1
摘要:
The high-throughput diffusion-multiple technique and thermodynamics databases were used to design new high-strength Ti alloys. The composition-microstructure-property relationships of the Ti64-xMo alloys were obtained. The phase fraction and composition of the α and β phases of the Ti64-xMo alloys were calculated using the Thermo-Calc software. After aging at 600℃, the Ti64-6Mo alloy precipitated ultrafine α phases. This phenomenon was explained on the basis of the pseudo-spinodal mechanism by calculating the Gibbs energy curves of the α and β phases of the Ti64-xMo alloys at 600℃. Bulk forged Ti64-6Mo alloy exhibited high strength and moderate plasticity after α/β-phase-field solution treatment plus aging. The tensile properties of the alloy were determined by the size and morphology of the primary and secondary α phases and by the β grain size.
研究论文
Graphite addition for SiC formation in diamond/SiC/Si composite preparation
Wei Zheng, Xin-bo He, Mao Wu, Xuan-hui Qu, Rong-jun Liu, Dan-dan Guan
2019, 26(9): 1166-1176. doi: 10.1007/s12613-019-1808-7
摘要:
Herein, graphite was used in the Si-vapor reactive infiltration of diamond/SiC/Si composites to produce composites with various SiC contents. X-ray diffraction was used to determine the phases of the composite, whereas scanning electron microscopy was used to confirm the Si-C reaction between the silicon, graphite, and diamond and to observe the SiC morphology. Various SiC contents in the composite were observed with graphite addition. Furthermore, the reaction between silicon and graphite (diamond) produced coarse (fine) SiC particles. The generation of a 10-μm-diameter Si-C area on the surface of the diamond was observed. The thermal conductivity (TC) and coefficient of thermal expansion (CTE) of the composite was investigated, where the TC varied from 317-426 W·m-1·K-1 with the increase of the SiC volume fraction from 38% to 76% and the corresponding CTE increased from 1.7×10-6 to 3.7×10-6 K-1, respectively. Furthermore, a critical point for the CTE was found to exist at approximately 250℃, where the composite was under a hydrostatic condition. Finally, the bending strength was found to range from 241 to 341 MPa.
研究论文
Novelty phase synthesis mechanism and morphology in resin-bonded Al-Al2O3-TiO2 composites at high temperatures under flowing N2
Yang Sun, Yong Li, Li-xin Zhang, Shi-ming Li, Ming-wei Yan, Jia-lin Sun
2019, 26(9): 1177-1185. doi: 10.1007/s12613-019-1829-2
摘要:
An Al-AlN core-shell structure is beneficial to the performance of Al-Al2O3 composites. In this paper, the phase evolution and microstructure of Al-Al2O3-TiO2 composites at high temperatures in flowing N2 were investigated after the Al-AlN core-shell structure was created at 853 K for 8 h. The results show that TiO2 can convert Al into Al3Ti (~1685 K), which reduces the content of metal Al and rearranges the structure of the composite. Under N2 conditions, Al3Ti is further transformed into a novelty non-oxide phase, TiCN. The transformation process can be expressed as follows:Al3Ti reacts with C and other carbides (Al4C3 and Al4O4C) to form TiCx (x < 1). As the firing temperature increases, Al3Ti transforms into a liquid phase and produces Ti(g) and TiO(g). Finally, Ti(g) and TiO(g) are nitrided and solid-dissolved into the TiCx crystals to form a TiCN solid solution.
研究论文
Effect of annealing temperature on the microstructure and optoelectrical properties of ZnO thin films and their application in self-powered accelerometers
Xiao-zhou Zhang, Yan-ping Xia, Xing Liu, Yi-ming Zhong, Hai-bo Zhao, Pei-hong Wang
2019, 26(9): 1186-1193. doi: 10.1007/s12613-019-1828-3
摘要:
This paper reports a piezoelectric nanogenerator (NG) with a thickness of approximately 80 μm for miniaturized self-powered acceleration sensors. To deposit the piezoelectric zinc oxide (ZnO) thin film, a magnetron sputtering machine was used. Polymethyl methacrylate (PMMA) and aluminum-doped zinc oxide (AZO) were used as the insulating layer and the top electrode of the NG, respectively. The experimental results show that the ZnO thin films annealed at 150℃ exhibited the highest crystallinity among the prepared films and an optical band gap of 3.24 eV. The NG fabricated with an AZO/PMMA/ZnO/stainless steel configuration exhibited a higher output voltage than the device with an AZO/ZnO/PMMA/stainless steel configuration. In addition, the annealing temperature affected the open-circuit voltage of the NGs; the output voltage reached 3.81 V when the annealing temperature was 150℃. The open-circuit voltage of the prepared self-powered accelerometer increased linearly with acceleration. In addition, the small NG-based accelerometer, which exhibited excellent fatigue resistance, can be used for acceleration measurements of small and lightweight devices.