Advanced Materials Research Vol. 413

Abstract: Cu₂O thin films is preparated through electrodeposition with conductive glass of coating indium tin oxide as work electrode.The effects of various factor upon Cu₂O film morphology are investigated.The best conditions of electrodeposition Cu₂O film are discussed.The deposition potential is determined by Linear sweep voltammetry.The results indicate that when pH is 5.50~ 6.00, the concentrations of Cu (CH₃COO)₂ is 0.015 ~ 0.04 mol/L,and the deposition potential is-0.075 ~ 0.225 V (vs SCE),Cu₂O thin films morphology is dendritic crystal.

Abstract: The homogeneous rare earth IR/NR blend applied in tread compound of all-steel TBR tire was investigated,and compare to Russian SKI-3, SKI-5/NR blends and NR.The results showed homogeneous rare earth IR/NR blend had similar vulcanization characteristics, dynamic mechanical properties and heat-aging resistance or even better. It was inspected that the appearance, balance, air bubbles, X-ray and homogeneity inspection test of the tires produced by homogeneous rare earth IR/NR blend by the tire factory,all the indicators were qualified. The tires passed the China National Quality Supervision and Inspection Center of rubber tire certification. The tires met the requirements of all-steel TBR tire.The homogeneous rare earth IR prepared by Petro China Jilin Petrochemical Company could 40 phr instead of NR using in tread compound of all-steel TBR tire,which could extend tire life and reduce tire material costs.

Abstract: This article with the electrochemistry workstation, electrochemical noise, SEM, X-ray diffraction and atomic absorption spectrophotometer (AAS) has studied the corrosion behavior of Cl^- which destroys the surface passivation film of T23 materials in supercritical water tubes. According to the experimental results and analysis, it can be concluded as followed: material was immersed in passivation solution for 7200S electrochemistry noise (ECN) testing, after 6000S, the potential and current tended to be stable. To unify ECN, Tafel curve and electrochemical impedance spectroscopy (EIS), it was considered that the material surface had formed passivation film. But the first 1500S noise potential and current fell rapidly in the 7200S erosion process, Tafel curve passivation area and EIS second arc disappeared, the potential and current was stable after 1500S. So the passivation film of material surface was destroyed, and Fe₃O₄ product gradually formed on the surface, finally the material corrosion entered into stable state.

Abstract: The commercialisation of Silicon Carbide devices and circuits require high performance, miniaturised devices which are energy efficient and can function on the limited power resources available in harsh environments. The high temperature Technology Computer Aided Design (TCAD) simulation model has been used to design and optimise a potential commercial device to meet the current challenges faced by Silicon Carbide technology. In this paper we report a new methodology to optimise the design of high temperature four terminal enhancement mode n-and p-JFETs for Complementary JFET (CJFET) logic.

Abstract: Currently, an environmental reduction factor (ERF) is incorporated in design codes/guidelines of Fiber Reinforced-Polymer (FRP) in reinforced concrete (RC) structures to account for the FRP long-term durability. Due to the lack of real time durability data, justification of the ERF is still necessitated. This paper presents a calibration of ERF for GFRP bar to be used in China on the basis of the prediction of GFRP long-term performance with monthly average temperature records from 32 major cities. Research results show that the ERF values vary from 0.49 to 0.58 at 100% R.H. exposure, while ERFs are greater than 0.70 for all cases being studied when R.H. is below 90%. On the basis of this study, ERF can be recommended as of 0.70 and 0.50 for application with R.H. <90% and moisture saturated exposures, respectively.

Abstract: This paper demonstrates the attempt to identify a reasonable chain pillar width in the condition of large mining height, along with a case study at the gateway of No.1103 panel with large mining height in Suancigou Mine. Theoretical calculation and numerical simulation were employed as the main approaches during the research to figure out the rational width of entry protection coal-pillar, which was then proved to be capable for engineering practice. The results that derived from our research can offer technical support for spot production, and serve as references for future investigation upon chain pillar design under large mining height.

Abstract: With the oxygen-acetylene flame spray technology, the high aluminum copper alloy coating (Cu-14Al-X) was precasted in surface of steel 45#. Then, the coating was remelted by using the high frequency induction heating technology. Using the optical microscope, EPMA,the coating organization, interface combination and interface element diffusion was analysised. The results showed that the high frequency induction remelting process can prepare metallurgicalbonding interface, get good rid of the oxide residue of coating, and get compact structure coating. From this investigation, The conclusion can get that high frequency induction remelting process has the ability of the preparation of non-self-fluxing coating of copper-based alloy, and there was a good interface combination attribute the success to interdiffusion of the coating elements and substrate elements.

Abstract: Theoretical calculation equation of meshing efficiency of globoidal indexing cam mechanism with steel ball is derived by analyzing the motion of steel ball and power loss of the mechanism. Based on the features of loads, meshing efficiency and influencing factors are analyzed. Calculation and analysis show that meshing efficiency varies with cam angle, friction coefficient and sliding velocity are major influencing factors, with the increase of them, meshing efficiency increase. Pretightening force, contact ratio factor and cam motion rule are minor influencing factors, meshing efficiency increases with the increase of pretightening force, the contact ratio factor affects meshing efficiency and the distribution of losing power, cam motion rule affects meshing efficiency by mean of it’s influence on inertia load of the mechanism, this research has guiding significance for design and manufacture of the mechanism.

Abstract: The B₄C/BN composites were fabricated by hot-pressing process. The B₄C/BN composites included the B₄C/BN microcomposites and the B₄C/BN nanocomposites. The B₄C/BN microcomposites were fabricated by hot-pressing process, and the B₄C/BN nanocomposites were fabricated by chemical reaction and hot-pressing process. In this research, the phase composition, microstructure, machinability and machinable mechanism of the B₄C/BN microcomposites and the B₄C/BN nanocomposites were investigated. The microstructure of the B₄C/BN composites was investigated by SEM and TEM. The SEM micrographs showed that the B₄C/BN microcomposites and the B₄C/BN nanocomposites exhibited the homogenous and compact microstructure, and the h-BN particles were homogenously distributed in the B₄C matrix. The TEM micrographs of the B₄C/BN composites showed that there existed the weak interface between B₄C matrix grains and h-BN particles as well as the microcracks within the laminate structured h-BN particles. The machinability of the B₄C/BN microcomposites and the B₄C/BN nanocomposites increased gradually with the increase of h-BN content. The drilling rates and materials removal rates of the B₄C/BN composites increased gradually with the increase of h-BN content. The surface roughness of drilled specimens of the B₄C/BN composites decreased gradually with the increase of h-BN content. The relationship between the microstructure and machinable mechanism of the B₄C/BN composites was analyzed and discussed. The phase composition and microstructure of drilled debris of drilled specimens of the B₄C/BN composites were investigated by XRD and TEM. The microstructure of drilled surface of drilled specimens of the B₄C/BN composites was observed and analyzed by SEM.

Abstract: In this study, the commercial VANADIS 4 (V-4) tool steel powders with sifting classification below 25 μm to be the matrix with fine titanium carbide (TiC) powder to produce a new material with high hardness and wear resistance, via powder metallurgy, sintering and HIP (Hot Isostatic Pressing) process. Experimental results showed that the TRS of original V-4 steel powder was 678.5 MPa, but below 25 μm of V-4 steel powder adding 35 wt% TiC enhanced to 868.6 MPa through 1673 K sintered. Beside, the hardness increased to HRA 86.2, TRS reached 1059.3 MPa, and porosity decreased to 1.0% of the V-4 steel powders (below 25 μm) added 35 wt% TiC after 1673 K sintered and heat treatments. Furthermore, HIP treatment can improve the microstructure and mechanical properties of V-4 composite material. TRS of V-4 composite steel increased to 1180.4 MPa and hardness was HRA 87.4 (HRC 71.7), porosity decreased to 0.71% after 1673 K sintered and HIP (1523 K, 150 MPa, 1 hour) treatments.