Advanced Materials Research Vols. 503-504

Abstract: Nano-TiO2 powders were synthesized by a sol-gel method using tetrabutyl titanate as the precursor, and then the composites of ACF(activated carbon fiber) supported nano-TiO2 was prepared by impregnating method. Tests of the amount of loaded TiO2 showed that three impregnating times was adequate. The Nano-TiO2 powders and composites were characterized by XRD, SEM, and BET surface area method. XRD tests showed that nano-TiO2 powders prepared by this way are anatase phase, and the mean size of the particles is about 11.5nm, when the calcination temperature is 673K. BET results showed that compared with original ACF, the surface area of the composites decreased slightly, indicating the impregnating process did not change the porous structure of original ACF. SEM result indicated that most of the nano-TiO2 particles as the size of 10-20nm were homogeneously dispersed on the surface of ACF.

Abstract: Froth images are pre-processed, which are acquired at the flotation laboratory. Digital image analysis techniques are used to analysize these froth images and their grey histogram and to extract statistical texture features of those froth images. Finally, the relation model for statistical texture features of those froth images and flotation index is established by RBF neural networks. A simulation showed that the relation model is higher precise

Abstract: The simultaneous desulphurization and dephosphorization of molten steel with CaO-based slag containing BaO for vacuum treatment, and inclusion in steel and microstructure of steel are carried out separately. These results show that desulfurization rate exceed 92% and dephosphorization rate exceed 50% , final [S] content and [P] content in molten steel are less than 0.0024% and 0.020% respectively for all heats, and the lowest final [S] content and [P] content are 0.0012% and 0.010% respectively, they satisfy the demand of ultra-low S steels and low P steels; Comparing a grade 1.5 of inclusion level of the compared sample without vacuum treatment, inclusion level of these treated samples with vacuum is all less than grade 1.0 and that is less than grade 0.5 for 78% of treated samples; And micro-structure of the compared sample is ferrite + pearlite in steel base, but micro-structure of these treated samples is all needle-like ferrite + pearlite + netted ferrite in steel base and netted ferrite + pearlite in local area. This kind of fiber structure which comes from netted ferrite + needle-like ferrite and grade 0.5 of inclusion level can make steel possess better mechanical properties.

Abstract: Na-bentonite/poly AMPS composite were prepared as an adsorbent for the removal of Pb (Ⅱ) from aqueous solutions. Pb (Ⅱ) adsorption experiments show the optimum pH and the bentonite content are pH 4.0 and 5g Na-bentonite /10g AMPS, respectively. Experimental data were described by Langmuir and Freundlih isotherms, and the correlation coefficient (R2) shows that the adsorption follows the Freundlich adsorption model.

Abstract: Adding small Ir element into Procelain Fusing Metal alloy can produce finer grains of PFM. Mechanical properties and dispersion of metal oxide can be improved by grain refining. In order to understand the effect of grain refining and mechanical properties by adding Ir into Au70.1-Ag12.4-Cu10.3-Pd6.2-Pt1-IrX alloy, series of experiments are carried out. There is an obvious effect of grain refining when adding 0.1wt% Ir into alloy. More than 0.1wt% Ir addition will no longer change the grain size obviously. Yield strength and Ultimate tensile strength are getting higher after adding more than 0.1wt% Ir. We found that these two mechanical properties will reach the maxima when 0.3wt% Ir added. And there is a little descent on mechanical properties when 0.5wt%, 0.7wt% of Ir existed in alloys.

Abstract: The RCF (Rolling Contact Fatigue) life of bearing balls is a main method, to evaluate the performance of bearing materials and their production technology. In general, The RCF life of ceramic balls is a reliable technique to asses whether or not they are suitable to be used in rolling bearings. The RCF life of ceramic balls is depend on contact stresses chiefly. It applies the finite element analysis to calculate the surface stresses and subsurface stresses, including 1st principal tensile stresses and shear stresses. The theory results are compared with the finite element solutions. Very good agreement is observed. The finite element results in this paper have an important applied value. The results provided theoretical basis for rolling contact fatigue life prediction of the ceramic balls.

Abstract: As a starting point of the subject, the basic performances of Jutecell fiber and yarn were studied, the fiber cross-sectional shape, composition and mechanical properties of Jutecell fiber were first tested and analyzed systematically. In process of evaluating the quality of the yarn , its fineness , evenness, twist, strength, moisture content , hairiness properties were taken for the important reference parameters to carry on test and analysis. The blended yarn of Jutecell fiber and cotton fiber[1], with the blended rate of 50/50, Yarn fineness of 22.6tex, Fiber specification of 1.33dtex*38mm, were used in the research of the subject.

Abstract: A black trivalent chromium conversion coating (CCC) was obtained on Zn deposit in chromium trichloride solution at 55 °C. The formation process of trivalent CCC on Zn deposit were thoroughly investigated by using X-ray fluorescence spectrometer and X-ray photoelectron spectroscopy in combination with atomic force microscopy surface analysis. The trivalent CCC on Zn deposit is consisted of Zn, Cr, O, Ni, Co, P and N elements, with visible micro-cracks on the film’s surface. The growth rate, the surface color and the morphology of this conversion coating vary with the dipping time.

Abstract: For many problems and defects in 20Cr2Ni4 steel application, through the analysis of mining machinery gear working condition, comparative study in cutting, forging, carburizing layer performance, heat treatment process, heat treatment deformation, mechanical properties, deformation resistance and abrasion resistance of overload capacity of 20CrNi2Mo and 20Cr2Ni4 steel respectively. The results show that, using 20CrNi2Mo steel instead of 20Cr2Ni4 steel in the mining machinery heavy-duty gear is feasible.

Abstract: The crystal structure of alloyed austenite distorted after Ni and Co replaced Fe. The crystal type of austenite changed from cubic structure to tetragon or orthorhombic structure due to the influence of Co and Ni. The ratio (B/G) for γ-Fe (C) is equal to 2.841, which is higher than that for other alloyed austenite with Co and Ni. The workability of alloyed austenite with Co and Ni are poorer than γ-Fe (C). The formation of alloyed austenite needs more energy than γ-Fe (C) at ambient conditions.