Advanced Materials Research Vols. 463-464

Abstract: Geomagnetically induced current (GIC) relates to factors such as magnetic amplitude, geotecture and structure of power grid. On the basis of geotecture, according to the geomagnetic storm data of Dec 2006, employing the plan wave method, this paper finish the calculation of GIC level of 2012 Beijing planning power gird, and compare the result to the measure data of Shanghe substation, in Yanghuai transmission system. The comparison shows that power grid is much more affected by geotecture, direction and length of transmission line, grid topology and electrical parameters in mid-low latitude area

Abstract: Material properties of L80 oil tube were tested by means of chemical composition analysis, hardness testing and metallographic examination. Micro-morphology and corrosion production analysis of inner surface were carried out by SEM, EDS and XRD. The results showed that the material properties accorded to API SPEC 5CT. The main reason of inner wall corrosion and thinning for tube sample was solid erosion of multiphase fluid.

Abstract: Ti-6Al-4V alloy was subjected to surface mechanical attrition treatment (SMAT) by using SAE 52100 steel balls of 5 mm diameter for two treatment durations (30 and 60 min). SMAT resulted in the formation of nanostructured material on the surface and near surface regions, increased hardness, increased surface roughness and compressive residual stress on the surface. Treated samples exhibited lower tangential force coefficient (TFC) compared to untreated samples. Samples treated for 60 min exhibited higher grain refinement, higher hardness, lower surface roughness and higher TFC compared to the samples treated for 30 min. Fretting wear resistance of the samples treated for 30 min was higher than that of untreated samples and the samples treated for 60 min. Due to very high hardness and presumably reduced ductility, the fretting wear resistance of the samples treated for 60 min was lower than that of the untreated samples and samples treated for 30 min.

Abstract: Chemical mechanical polishing (CMP) is the best global planarization technology of GLSI process. After CMP process, there may appear large roughness, micro scratch, dishing pit, erosion pit, with-in-wafer-non-uniformity (WIWNU), organic contamination, particles and metal ions pollution on wafer with copper interconnects. Surface measurement of CMP process on the wafer mainly involves the test of roughness, defects and the contaminations. Atomic force profiler (AFP) combined with the resolution of the AFM and long-range-scan ability of the steps instrument (100 mm), is suitable for CMP process which needs to measure both the planarization of long-range scanning and tungsten plug and copper interconnects with high resolution imaging. Optical detection technology combined with the advantages of dark and bright view detection is suitable for detection of particles, crystal originated pits (COP), defects, etc. The time-of-flight static secondary ion mass spectrometry (TOF-SIMS) and total reflection X-ray fluorescence (TXRF) are applicable to detect metal ions. The selection and use of advanced data analysis theory and method can help to improve the speed of analysis and to find the main factors of influence surface quality. Pareto diagram analysis is very beneficial for study polishing effects and the main reason of the surface state for Cu-CMP wafer. Nine sampling method and five sampling method fit to analysis the uniform surface distribution, on the contrast isometric sampling can reflect the distribution of the surface state along the radius difference.

Abstract: The preparation and characterization of a novel mixed metal complex of europium (III) and terbium (III) of a tripodal heptadentate Schiff-base ligand N [CH2CH2N=CH (2-OH-3-MeC6H3)]3 (H3L1) have been studied. The complex was prepared by the reaction of [EuL1] and [TbL1] in N, N-dimethylformamide. The ratio of europium (III) to terbium (III) in the mixed metal complex was found to be 3 to 7. The molecular structure of [Eu0.3Tb0.7L1] was determined by X-ray crystallography. The crystal structure analysis revealed that the Schiff-base behaves as a tri-deprotonated heptadentate ligand encapsulating the each metal ion within the N4O3 cavity. Under the excitation of UV light, the solid state of the complex exhibited red emission corresponding to europium (III) ion. The emission bands of 5D0 → 7Fj (j = 2, 3, 4) were observed at 609, 652, and 706 nm, respectively. On the other hand, the green emission corresponding to terbium (III) ion was not observed.

Abstract: In this paper, a static electromagnetic field problem will be solved. The method to solve the problem is Finite Difference Method ( FDM ). The software MATLAB is the main environment used to finish the numerical computing. Finally, we found using Finite Difference Method to solve a static electromagnetic field problem is quite convenient. We also can draw the two-dimension and three-dimension graph of the distribution of the electromagnetic field. Furthermore, we discuss the advantages of using FDM to solve the problem, and the disadvantages still exist in this method.

Abstract: In this article, the sliding frictional contact problem for a half-plane which is graded in two dimensions is studied. The effect of medium properties gradient and coefficient of friction in contact mechanics of two dimensional (2D) graded materials which is loaded by a flat stamp have been investigated by developing two Finite Element (FE) models, in macro and micro scales. Discretizing the graded half- plane by quadrants for whose material properties are specified at the centroids by Mori-Tanaka method in both directions has been used to model the 2D FGM in macro scale. In micro scale, the ideal solid quadrant particles which are spatially distributed in a homogeneous matrix used to model the FGM structure. Also, boundary conditions and loading of both models are the same. The study is focused on determining the contact stress distributions on contact surface. The contact mechanic problem of 2D graded materials has been solved and the results are presented for various combinations of friction coefficient and material non-homogeneity constant parameters Analyses and comparison of the results showed that micro and macro scale results are in a very good agreement.

Abstract: Fretting is now fully identified as a small amplitude oscillatory motion which induces a harmonic tangential force between two surfaces in contact. It is related to three main loadings, i.e. fretting-wear, fretting-fatigue and fretting corrosion. Fretting regimes were first mapped by Vingsbo. In a similar way, three fretting regimes will be considered: stick regime, slip regime and mixed regime. The mixed regime was made up of initial gross slip followed by partial slip condition after a few hundred cycles. Obviously the partial slip transition develops the highest stress levels which can induce fatigue crack nucleation depending on the fatigue properties of the two contacting first bodies. Therefore prediction of the frontier between partial slip and gross slip is required.

Abstract: Superhydrophobic surfaces have been a hot topic during the last decade owing to their great potential in widely application. In this work, we report on a facile and low-cost two-step method to fabricate superhydrophobic surface on steel substrates. The as-obtained surface shows an interesting hierarchical structure composed of microscale flowerlike cluster and nanoscale particles, which is similar to that of a lotus leaf. After further modification with stearic acid, the resultant surface exhibits remarkable superhydrophobic properties. The water contact angle is as high as 155°. Moreover, the superhydrophobic properties are long-term stable.

Abstract: The low-cost production and performance of 6061-aluminium alloy matrices reinforced with coated silicon carbide particulate has been studied. The micro-wave vacuum sintering was adopted to prepare the composite in order that the loss ignition is very small. The effect of copper coated silicon carbide has proved beneficial to interfacial bonding and improved the mechanical properties. Differences in the fracture characteristics of specimens containing coated and non-coated particles were observed. The particulates size has much influence on mechanical properties.