Using cetyltrimethyl ammonium bromide (CTAB) as a template agent, a facile grinding sol-gel process was adopted to prepare earthworm-like LaVO4: Eu3+ mesoporous material with La(NO3)3·6H2O, Eu(NO3)36H2O and NH4VO3 as raw materials. The as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron energy spectrum (XPS), transmission electron microscopy (TEM), the BET specific surface area, infrared spectra (IR) and fluorescence spectra (FL). It is found that the as-prepared LaVO4: Eu3+ annealed at 673 K is a typical mesoporous materal with zircon structure of tetragonal phase (t). The specific surface areas and the average pore diameter of the sample is about 179.5 m2/g and 2.56 nm, respectively, and its pore volume and grain size is 0.115 m3/g and 6.40 nm, respectively. The fluorescence results show that the mesoporous LaVO4: Eu3+ exhibits a strong red emission (5D0→7F2), and a suitable range of annealing temperature can improve its fluorescence properties, but more high annealing temperature (≥1273 K) can rapidly decrease its fluorescence intensity due to demolishing the mesoporous structure of LaVO4: Eu3+.
A honeycomblike porous film has been fabricated from a homogeneous solution of tadpole POSS acrylate block copolymer (POSS-PMMA-b-PS), which was made via atom transfer radial polymerization (ATRP) polymerization in one pot, using the static breath figures method. Taking into account of the formation mechanism of the pore, the influencing factors, such as the kind of solvent, the concentration of the solution and relative humidity for the formation of self-assembled block copolymer membrane, have been evaluated, and especially, the effects of interfaces, including air/glass wafer, air/water and air/ice interfaces, were investigated. The results show that cycloidal bubble arrays can be prepared when chloroform was chosen as solvent, concentration of POSS-PMMA-b-PS was 20 mgmL-1, relative humidity was 80%, and the solution was cast on the air/glass wafer interface; well-patterned membrane can also be prepared when the solution was cast on air/water and air/ice interfaces in the same condition; nevertheless, the pore size and hole spacing of the latter was much smaller. The result of static contact angle with water analysis shows that this porous film has good hydrophobic performance, and the contact angle increases with the decrease of pore size; the porous film shows excellent resistance to acid, alkaline and heat.
The antibacterial performance of 17-4PH stainless steel by different heat treatments was investigated. The results show that aging at 482℃ after cryogenic treatment at liquid nitrogen can effectively improve the antibacterial rate and hardness of 17-4PH steel, and the antibacterial rate increased with the increase of both aging temperature and aging time, but the hardness declined. The cryogenic treatment can promote the decomposition of the martensite, and then the dislocation density in 17-4PH steel become larger, which could increase the Cu-rich precipitations in the steel matrix and improve the antibacterial performance of the steel. An optimal antibacterial heat treatment procedure for 17-4 PH steel is recommended as solution treatment at 1040℃/0.5 h+cryogenic treatment/0.5h+aging at 482℃/6 h.
Different galvanized coatings on hot stamping steel was obtained by using hot dip galvanizing simulation experiment device dipping in zinc baths with four different Al contents. The effect of Al content on the microstructure of galvanized was investigated using SEM/EDS and glow discharge optical emission spectrometer (GDOES).The results show that press-hardened steel has good reactive wetting in different Al content zinc bath. The Al content (mass fraction) in zinc bath has a significant influence on coating/steel interface composition, morphology and light property. Enrichment of Mn, Si elements occurred in the steel surface during bright annealing process, and the Mn-Si oxides react (redox reaction) with Al in zinc bath. For 0.11% dissolved Al bath, continuous ζ phases formed at the coating/steel interface. For 0.17% dissolved Al bath, the coating/steel interface consist of ζ phases and Fe-Al phases. A continuous Fe2Al5 inhibition layer achieved in baths with Al content 0.25% and 0.43%, and the morphology of interface layer became coarser when Al content in zinc bath was 0.25%. In addition, with the increase of Al content in zinc bath, the light property of zinc coatings gradually became worse.
Combined Miedema’s model with experimental data provided by Kleppa, the parameters of oxygen and sulfur which were satisfied with Miedema’s model were derived: Oxgen: electronegativity 7.04, electronic density 6.03, molar volume 4.59; Sulfur: electronegativity 5.8, electronic density 3.24, and molar volume 6.97. In comparison with results from literature, those parameters had been turned out to be highly reasonable to Miedema’s model. The mean absolute percentage error of enthalpies of formation of binary alloying oxides and sulfides were 36.8%, 34.2% respectively. Combining Ding’s model, the activities and interaction coefficients between oxygen and other elements of Fe-based alloying melt in 1873 K were derived and further compared with available experimental data. Calculated results were confirmed to be in good agreement with available experimental data, except some special cases. Therefore the long-term problem related with the parameters of oxygen and sulfur for Miedema’s model has been resolved successfully by this method. In particular, the special cases Nb, Pt, Ag-their electronegativities(4.05, 5.65, 4.35) were revised to be 4.31, 5.57 and 4.17, respectively, and the revised parameters were much more reasonable than the original parameters.
Ferro-based friction material was fabricated by reaction sintering technology, using Fe and Ti elements containing in vanadium and titanium iron concentrate as main raw materials, adding other ingredient on the basic of composition of ferro-based friction material, synthesis and sintering were accomplished unanimously in vacuum resistance furnace. Thermodynamic of the reduction of vanadium and titanium iron concentrate was calculated and studied, and the mass change of the reduction was studied by TG–DSC. The results show that the reduction temperature of Fe and Ti oxides is above 979 K, in the reduction process of vanadium and titanium iron concentrate, Fe3O4 is reduced by carbon firstly, and then titanomagnetite and ilmenite are reduced into Fe and Ti oxides, and finally different valent titanium oxides are reduced into TiC.Good interface bonding and compact structure have been got in experimental research by making reasonable process route.
The transformation of undercooling austenite in a X100 pipeline steel was investigated by means of thermal simulation test. Based on the obtained results, a thermo-mechanical control process (TMCP) by which a mixed microstructure mainly consisted of granular bainite and lath bainite can be obtained has been proposed and effects of finish rolling deformation amount, cooling rate and final cooling temperature on microstructure have been analyzed. The results show that the microstructure of tested steel gradually refines and the volume fraction of lath bainite decreases with the increase of deformation amount. With the increase of cooling rate and the decrease of final cooling temperature, microstructure refines and volume fraction of lath bainite increases obviously. High volume fraction of lath bainite in microstructure is good for high strength. However, excessively high volume fraction of lath bainite and M/A islands with the shape of acicular have harmful influences on toughness.
The mix proportion design of reactive powder concrete (RPC) with circulating fluidized bed combustion (CFBC) fly ash was done through orthogonal design. The effect of curing system on strength and shrinkage property of RPC with CFBC fly ash, and the effect of CFBC fly ash on shrinkage property of RPC were investigated. The results show that RPC which could have flexural strength of 26 MPa and compressive strength of 140 MPa was prepared by using CFBC fly ash, silica fume, superplasticizer, intermediate quartz sand, PO42.5R and hydrothermal curing treatment; Hydrothermal curing can promote the hydration of RPC with CFBC fly ash and form a relatively dense structure, so its early strength was higher than that of standard curing about 30 MPa, but high temperature made early-formed AFt transform into AFm, so later strength was decreased; Compared to standard curing, Hydrothermal curing promoted the early shrinkage of RPC with CFBC fly ash, reduced the late drying shrinkage, but its overall shrinkage rate was still greater than that of standard curing; The expansibility characteristics of CFBC fly ash can effectively reduce the large self-shrinkage of RPC.
The surface grain boundary distribution characteristics and microtopography of hot rolled and heat treated 10CrNi5Mo high strength steel were tested by EBSD technology and AFM. The corrosion behavior of 10CrNi5Mo high strength steel was investigated by full immersion tests and electrochemical impedance spectroscopy (EIS) in simulated seawater environment. The results show that there is higher proportion of low angle grain boundaries on the surface of hot rolled 10CrNi5Mo high strength steel than that of the heat treated specimen. The corrosion of the heat treated specimen is more uniform and the roughness is less than that of the hot rolled specimen after nital corrosion. In the full immersion tests in simulated seawater environment, the hot rolled 10CrNi5Mo high strength steel presents a better corrosion resistance. The impedance increased in the mid-stage of immersion tests. The integration of corrosion products on the surface and matrix metal is closer so that the corrosion products can prevent the electrochemical reaction between the matrix metal and solution.
The styrene-acrylic emulsion was synthesized by pre-emulsified semi-continuous seeded emulsion polymerization, with styrene (St) and 2-ethylhexyl acrylate (2-EHA) as main monomers. The particle size distributions were characterized by laser particle size analyzer, the glass transition temperatures were measured by DSC, and the rheological behaviors were analyzed by rheometer. The effects of monomer-proportion, the amount of cross-linking agent and emulsifiers on particle sizes, emulsion stabilities, rheological behaviors and bonding properties were investigated. The results show that styrene-acrylic emulsion is a pseudoplastic fluid, and the viscosity enhanced with the increase of the ratio of 2-EHA/St, the amount of cross-linking agent or emulsifiers. The emulsions stabilize with the increment of emulsifiers, while destabilize with the increment of cross-linking agent. The shear bond strength enhances with the increment of cross-linking agent or the ratio of 2-EHA/St. The particle size of emulsions decreases with the increment of emulsifiers, while increases with the increment of cross-linking agent.
