The polymeric nano film with hydrophobic feature on the surface of Mg–Mn–Ce magnesium alloy was prepared through chemical reaction with synthesized organic monomer of the triazine dithiol monosodium reacted with magnesium alloy by self–developed technique of polymer plating. The reaction mechanism during polymer plating was investigated with selected characteristic points from the curves of cyclic voltammetry. The film properties polymer–plated on magnesium alloy surface were characterized by means of FT–IR spectrometer, X–ray photoelectron spectroscopy, spectroscopic ellipsometer and contact angle meter. The results showed that the process of polymer plating included the film formation through the electrochemical reaction and film thickening by polymerization reaction between film layers. The combination between magnesium alloy and the monomer of triazine dithiol monosodium were achieved by chemical bonds. Film thickness increased gradually from 9.14 nm to 64.51 nm during the reaction process of polymer plating, and then the stabilized nano–scale film formed. Contact angle of distilled water for polymer–plated magnesium alloy rose to 117.9o as compared with 45.8o for the substrate; therefore the conversion of functional performance was achieved from hydrophilic to hydrophobic.
Pr3+ doped SrAl2O4 : Eu2+、Dy3+ phosphor was synthesized by combustion method. The modification of optical properties of the sample has been investigated. X-ray diffraction pattern indicates that the samples possess a monoclinic crystal structure. The emission spectra shows a continuous luminescence band with a peak at 515nm and excitation spectra shows two peaks at 320 and 360 nm. The decay curves show that the initial intensity is three times before doping praseodymium. The morphology shows praseodymium has a great role in formating uniform grain size solid solution in SrAl2O4 : Eu2+, Dy3+, Pr3+ phosphor.
A non-contacting infrared thermometer was used to measure the temperature at the film surface in waving area for investigating dynamic mechanical properties of starch blend film and improving its performance, such as brittleness, hardness, and size shedding. Dynamic thermomechanical analysis(DMA) was conducted to investigating the dynamic mechanical properties of PVA and starch blend film and the starch was grafted by rheological phase method to improve the damping characteristic. The results showed that the temperature at the blend film surface in waving area ranged from 28.3oC to 35.1oC. In this temperature range, the damping characteristic of PVA blend film was much better than that of starch blend film, and the storage modulus (400–450 MPa) and loss modulus (25–30 MPa) of PVA were also higher than those of starch of which the storage modulus was less than 50 MPa and the loss modulus was less than 5 MPa. After grafted by rheological phase method, the storage modulus and loss modulus of graft starch blend film reached up to 500–520 MPa and 35–40 MPa respectively, increased by 900% and 600%. So through graft modification, the damping characteristic of starch blend film can be improved obviously.
Plasma graft polymerization of para–xylene (ppPX) on argon plasma–pretreated porous SiLK films coated Si(100) wafers (Si–SiLK) and retardation of copper diffusion on ppPX are investigated in the present work. The topography of the ppPX grafted Si–SiLK (Si–SiLK–g–ppPX) surfaces was analyzed by atomic force microscopy. X–ray photoelectron spectroscopy and fourier transform infrared spectroscopy results show that the benzene rings of ppPX can be retained to a large extent under a certain grow discharge conditions. Field emission scanning electron microscopy reveals the extent of copper diffusion into the pristine and graft–modified Si–SiLK substrates after thermal annealing. Since para–xylene monomers were introduced with argon (Ar) and nitrogen (N2), the different chemical structures of two kinds of ppPX are achieved and it is found that nitrogen could improve the adhesion between copper and the polymer film. Therefore, ppPX surface prepared on Si–SiLK wafers surface can serve a promising adhesion promotion layer and a diffusion barrier for copper.
As the absorber layer in CISe-based solar cell CIGSe thin film was prepared by precursorselenization method. The influences of selenization temperature on compositions, morphologies, phase structures and electronic properties of CIGSe thin films were investigated. The compositions, morphologies and phase structures of CIGSe by means of XRF, SEM, XRD and Raman, respectively were analyzed. Based on Hall Effect the resistivities and minority carrier mobilities of CIGSe were tested. The results show that there are no differences in morphologies and compositions of CIGSe films prepared at 520–560oC. Ordered defect compound (ODC) phase and Cu–Se phase increase with the increasing of selenization temperatures, which increases the concentrations of defect in CIGSes and causes the deterioration of electronic properties of thin film.
Carbon aerogel (CA) as the catalyst support was synthesized via a sol-gel process. Pt/CA catalysts were prepared by intermittent microwave-assisted polyol process. The content of Pt was measured by inductively coupled plasma (ICP). The results of X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements show that the catalyst particles distributed homogeneously. The mean particle size of Pt/CA is about 4 nm. The chemical contents of the catalysts were analyzed using energy diffraction X-ray(EDX)spectroscopy. The electrochemical property of carbon aerogel supported Pt catalyst for methanol oxidation was evaluated by cyclic voltammetry (CV), linear-sweep voltammetry (LSV), and chronoamperometry. The results of electrochemical measurements show that the activity of Pt/CA catalyst is better than that of Pt/C catalyst.
Thermal stability of Ti3AlC2 at static high pressure was dealt with in this paper. It was found that the lowest reaction temperatures of Ti3AlC2 were all between 700 and 800oC at pressures of 2, 3, 4 and 5 GPa, respectively, and the final products mostly were Al3Ti and TiC. The decomposition reaction processes depended on the pressure.
Purification mechanism of impurity aluminum in multicrystalline silicon ingot made from metallurgical-grade silicon was investigated by composition analysis and theoretical analysis of vacuum induction melting and directional solidification. The results showed that the content of impurity aluminum was significantly decreased due to the obviously evaporation in the stage of thermal insulation (T ≥1723 K). The segregation of impurity aluminum plays an important role in the distribution of aluminum in subsequent directional solidification process, but a little amount aluminum evaporation still happened. A new theoretical model including segregation phenomenon and evaporation mechanism was developed to simulate the distribution of aluminum in multicrystalline silicon. The result of simulation was well consistent with the measured distribution of aluminum in the obtained ingot.
A massive porous Ti–24Nb–4Zr–8Sn(%, mass fraction, Ti2448)alloy was prepared by cold rolling forming and vacuum sintering process. The effect of rolling reduction (20%–40%) and sintering temperature (1100 ℃ –1300 ℃) on porosity, mean pore size, compressive strength and Young's modulus of porous Ti2448 alloy were investigated. The results show that porosity and mean pore size both decrease with increasing rolling reduction under the same sintering temperature, but compressive strength and elastic modulus increase linearly with increasing rolling reduction. The effect of sintering temperature on porosity and pore size of porous material is not obvious. The porous Ti2448 alloy excels porous pure Titanium in the ratio of compressive strength and elastic modulus for the same porosity.
The corrosion resistance in the simulated body fluid of Mg–1.0%Ca–1.0%Zn (mass fraction) magnesium alloy with Titanium ion implantation of 1.5×1017cm−2 was investigated. The implantation element content, distribution of elements into the alloy surface were obtained via X-ray energy dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS); The surface hardness and modulus of the alloy, the polarization curve and the morphology in the SBF were characterized by nano snick, three electrode system and scanning electron microscope respectively. The results show that the implantation element content was improved with the ion implantation dose increases. TiO2 formed at the surface of Mg–1.0%Ca–1.0%Zn magnesium alloy. Hardness and modulus were improved after the implantation of Titanium ions, the maximum of surface hardness was achevied at a depth of 100 nm below the alloy surface. Meanwhile, the polarization resistance was strengthened and consequently the corrosion resistance of the alloy was improved.
10?#20?#30?#40? and 50? in-plane rotation models of SrTiO3 (STO) films on GaN(0001) substrates with different interface structure were designed. The total energies of different epitaxial models of STO/GaN magnetoelectric films were theoretically explored by the plane wave ultra soft pseudo-potential model based on density functional theory. The simulated results show that STO films grown on GaN (0001) substrates with the ideal (with the lowest lattice mismatch) epitaxial relation of [1–10]SrTiO3//[10–10]GaN have the highest energy, indicating this unstable configuration. The total energies become lower quickly with the rotation of STO[1–10] along GaN[10–10] direction, showing the lowest energy at the 30? rotation, which are the most stable structures. The epitaxial orientation relations are [1–10]SrTiO3//[11–20] GaN by this 30? rotation in the in-plane direction of the STO epilayer on GaN(0001) substrates, which are in agreement with experimental observation. Calculation results also reveal that the STO/GaN magnetelectric film is favor in forming STO-Ti-GaN interface structure.
A light brown ceramic coating was obtained on TA2 pure titanium substrate by micro–arc oxidation in the H3PO4–K2ZrF6 electrolyte system containing Cu(CH3COO)2 and Mg(CH3COO)2. The XRD, SEM, EDS methods were employed to investigate the phase constitutes, element compositions and morphologies of the coatings. The color of coatings were tested by spectrophotometer, the adhesion strength of the coatings to substrate were investigated by thermal impact and three–point bending method. The results show that with increasing oxidation time, the content of copper and magnesium element were added and the color of the coatings changed too, and bonding strength was reduced. After thermal shock the coating and the substrate remains a high bonging strength.
Fe/Al2O3 graded coatings on steel substrate was prepared by spraying and sol-gel, while the mixed powders FeAl and FeAlNi were used as two different transitional layers, and the combined properties of the coatings were analyzed. The results show that the adhesive strength of Fe/Al2O3 graded coatings with the FeAl and FeAlNi transitional layers reach the highest, 21.2 MPa and 25.3 MPa, respectively, when the sintering temperature is 1220℃ . Two kind of coating composed respectively of α–Al2O3, AlFeO3, Al2Fe2O6, Al3Fe5O12 and α–Al2O3, AlFeO3, NiFe2O4. It can be seen that the Fe/Al2O3 graded coatings with FeAlNi transitional layer are much denser than the coatings with FeAl transitional layer, and there is not obvious hole and macroscopic interface, while some organization , which similar to the branch appeared in the coatings, increase the combined properties of Fe/Al2O3 graded coatings.
The abradability of two NiCrW–BN seal coatings processed by different heat treatments were observed by pin–disk, single–pass scratching, and high–speed wear tests. The results show that seal coating abradability is different from its wear– resistance, i.e. measuring of wear loss, wear–resistance, specific energy consumption and hardness, can not be used as abradability criterion. Coating abradability evaluation should be composed of extensive information, such as coating and blade wear loss, friction coefficient, wear topography. Seal coating abradability is obviously influenced by test condition, while high–speed rubbing test can simulate working variables of seal coating, such as rub linear speed, incursion velocity, probably reproduce its wear phenomena. Therefore the adoption of high–speed test to evaluate seal coating abradability is more reasonable.
Effects of Sulfate Reducing Bacteria (SRB) on corrosion of pure zinc anode in marine sediment was investigated by using electrochemical impedance spectroscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The macrocell corrosion of the coupons with or without SRB in marine sediment was also studied. The results show that the passive film of pure zinc in marine sediment is quickly destroyed by SRB, and the corrosion rate of the coupons is increased. The corrosion of samples in the marine sediment with SRB is accelerated as the anode of macrocell, but the corrosion of samples in the marine sediment without SRB is inhibited as the cathode of macrocell.
Structurally ordered ethane-bridged periodic mesoporous organosilicas (PMOs) have been facilely prepared with the assistance of ZrOCl2–NaCl salt pair using nonionic P123 (EO20PO70EO20) as the structure-directing agent, and was thoroughly characterized by advanced techniques as such SAXS, HRTEM, N2–adsorption/desorption isotherms and solid state 13C CP/29Si CP MAS NMR etc.. The results indicated that the present material possess highly ordered hexagonal structure and organic-inorganic hybrid network, and thus illustrating the effective function of salt pair in the assembly of PMO material under the studied synthesis system.
Titanate nanotubes have been synthesized by a hydrothermal method using tetrabutyl as titanium source. The prepared sodium titanate nanotubes were applied in the adsorption of uranium ions. The determination of the structure of the materials by TEM and XRD showed that titanate nanotubes compose of Na2Ti3O7 and H3Ti3O7 with external diameter of 8 nm, tube length up to 2 μm. The investigation of adsorption of uranium ions demonstrated that adsorption capacity growed gradually with the increase of temperature and shock time, and achieved maximum adsorption capacity at pH 5.5. The adsorption isotherm accorded with Langmuir and Freundlich matrix. Thermodynamic studies showed that the adsorption is endothermic spontaneous process. The recovery studies showed that the recovery graduately decrease with the increasing of uranium content. N2 adsorption/desorption tests found that the surface area of titanate nanotubes adsorbed uranium ions were smaller than previous.
The different effect of Sn and Te substitution for Sb on thermoelectric properties of CrSb2 was investigated. The results show that the effect of lattice distortion after doping leads to the increase in the electron concentration of CrSb2. The substitution of Sn and Te for Sb can be regarded as p–doping and n–doping, respectively, the electron concentration of CrSb1.99Sn0.01 is smaller than that of CrSb1.99Te0.01 due to the compensation effect, leading to lesser decrease of resistivity and the absolute value of thermopower |S| for Sn doping than that of Te doping. Thermal conductivity of CrSb1.99Sn0.01 and CrSb1.99Te0.01 decreased after doping, which can be attributed to the enhancement of the phonon scattering by impurity (Sn and Te, respectively) atoms, the atomic mass of Te is greater than that of Sn, the phonon scattering by impurity atoms is stronger, resulting in the more decrease of thermal conductivity for Te doping. As a result, the thermoelectric properties of CrSb2 was improved by Te doping, however, Sn doping did not meet the purpose of improving the performance of CrSb2. In addition, the Neel temperature does not change much after doping, which can be attributable to non-magnetic feature with full 3d orbits for Sn and Te.
Mechanical properties and deformation mechanics at small scales of the bulk nanostructured Al–10Zn–2.8Mg–1.8Cu alloys before and after heat treatment were investigated by nanoindentation. The results showed that no clear change was found in the Yong's modulus (E) but the hardness (H) increased remarkably of the nanostructured alloys after T6 heat treatment. Obvious room temperature creep and notable shear bands were observed in the as–SPSed samples. In addition, room temperature creep became obvious and shear bands diminished with the increase of the strain rates. However, it was difficult to observe room temperature creep and shear bands in the as T6 treated samples. This phenomenon resulted from the changes of the distribution and morphology of second phase particles conducted by theT6 heat treatment.
The Al/Al2O3 (AAO) template with about 100 nm porous diameter was prepared by secondary anodic oxidation. The effects of concentration of sulphuric-oxalic acid, electrolysis temperature and anodic voltage on porous diameter of AAO template were investigated. The surface morphology of alumina films was characterized by scanning electron micrograph (SEM). Silicon nanotubes with 60–80 nm porous diameter were prepared with AAO template by sol-gel method and the surface morphology was observed by transmission electron microscope (TEM) and SEM. The results show that the porous diameter increases with increasing of concentration of sulphuric-oxalic acid, electrolysis temperature and anodic voltage, respectively. There is important relationship between the formation of silicon nanotubes and the method of embedding of silane sol, drying temperature and the formation time of silane gelatin.
The effects of Li2CO3–V2O5 (LV) co-doped on the sinterability, phase compositions and microwave dielectric properties of 0.6Mg4Nb2O9– 0.4SrTiO3 composite ceramics were investigated. It is found that the densification sintering temperature of 0.6Mg4Nb2O9–0.4SrTiO3 is lowed to 1175℃ with an amount LV addtion. The second phases Sr(NbTi)O3+δ and MgO were confirmed by the XRD and EDX spectrum analysis. The specimens with 1.5% LV sintered at 1175℃ for 5 h shows excellent dielectric propertis: εr=20.1, Q · f=10240 GHz (at 8.5 GHz), τf=0.15 ppm/.
