Key Engineering Materials Vol. 501

Abstract: In order to obtain the composite coatings of abrasion resistance and anti-corrosion, experiments of Ni-P-Al2O3-SiO2 chemical composite plating were carried out by electroless composite plating technology, and then the added amount of composite particles influenced coatings performance were investigated. After experiments, the metallographic structure, the micro-hardness, bonding strength, thickness and anti-corrosion of composite coatings were characterized by using a XJZ-6A type metalloscope and a HVS1000 type micro-hardometer, respectively. The results show that the composite coatings have bright surface appearance and the properties of bath are stable. Besides having a higher hardness, a higher thickness and a lower porosity, composite coatings combine well with the matrix and the abrasion resistance is better when the amount of Al2O3-SiO2 composite particles were added correctly. These composite particles should be treated by ultrasonic vibration firstly.

Abstract: The alloy of Nylon6/Acrylonitrile-Butadiene-Styrene (ABS) with styrene-maleic anhydride (SMA) was prepared by melt blending as the compatilizer. Mechanical characteristics, dynamic mechanical analysis (DMA) and fracture appearances were determined. It was found that the impact and tensile strength firstly increased and then decreased along with the increase of the SMA content. The properties reached maximum values when the content of SMA was 2%. The results of DMA and scanning electron microscope (SEM) indicated that the addition of SMA can effectively enhance the compatibility of Nylon6 and ABS.

Abstract: Normal thermal conductivity of amorphous and crystalline SiO₂ nano-films is calculated by nonequilibrium molecular dynamics (NEMD) simulations in the temperature range from 100 to 700K and thicknesses from 2 to 6nm. The calculated temperature and thickness dependences of thermal conductivity are in good agreement with previous literatures. In the same thickness, higher thermal conductivity is obtained for crystalline SiO₂ nano-films. And more importantly, for amorphous SiO₂ nano-films, thickness can be any direction of x, y, z-axis without effect on the normal thermal conductivity, for crystalline SiO₂ nano-films, the different thickness directions obtain different thermal conductivity results. The different results of amorphous and crystalline SiO₂ nano-films simply show that film thickness and grain morphology will cause different effects on thermal conductivity.

Abstract: In this paper, the three-dimensional flow field and dynamic mixing processing in the continuous mixer have been studied using the professional polymer processing finite element analysis software package Polyflow. A quantitative evaluation system which consisted of dispersion mixing and distributive mixing was used to evaluate the mixing properties in simulation. Based on these numerical simulations, the influences of rotors’ phase angle and cross-section on mixing properties were analyzed. The results show that the main contribution of phase angles focus on distributive mixing and the main contribution of rotors’ cross-sections focus on dispersion mixing.

Abstract: The physical, mathematical and finite element models for the four-wing synchronous rotors and four-wing asynchronous rotors in internal mixer were established in this paper. By comparative analysis of the two types of processes involved in mixing process the pressure field, the velocity field and the concentration field, the viscosity field and the mixed exponential distribution on its 3D fluid field dynamic simulation were computed by the polyflow software. The results showed that the four-wing synchronous rotors were better than the four-wing asynchronous rotors in a number of performance parameters.

Abstract: This paper provides a concise description of the international development of the low-speed tire uniformity testing machine (TUTM). And particular emphasis is given to the developing history of YLJ series TUTM, researched and developed independently by MESNAC Co., Ltd. It is well known that data measurement and analysis are fundamental to a TUTM. However, very few studies of testing mechanism of tire uniformity have been reported. The primary subject of this paper is to describe operational principle, measurement of force, data measurement and analysis methods of YLJ series TUTM. It also shows the good property of YLJ series TUTM combined with the experimental data of a 215/70R15 97H tire repeated test 10 times.

Abstract: The heat conductive silicone rubber is prepared with methy1 viny1 silicone rubber as basic gum and SiCp (SiC particle), SiCp/SiCw (SiC whisker), graphite as heat conductive fillers. The effects of filler amount, filler shape, filler size and coupling agent on the thermal conductivity of silicone rubber have been studied in this article. The result shows that when the filling amount is increasing, the thermal conductivity of composite silicone rubber will increase too. There is no evident change for thermal conductivity with the small filling fraction, while the filling amount reaches a certain value, the thermal conductivity of composite increases obviously. Moreover, the thermal conductivity added with coupling agent (KH-602) is higher than that of composite without coupling agent addition.

Abstract: Galling is a known failure mechanism in sheet metal forming. It results in increased cost of die maintenance and scrap rate of products. For high strength steels, problems with galling are of major interest, since forming pressure is high as well as shear stress. In the last ten years, significant progress has been made on development and understanding of galling in sheet metal forming. In this paper, the main test apparatus and the methods used to reduce galling tendency are reported. And the galling mechanisms of galling are also analyzed.

Abstract: By blending homemade compatibilizer with carboxylic acid functional groups into the basic materials of PPO and PA66, through twin-screw extruder blending, the PPO/PA66 alloy was prepared. The micromorphological and mechanical properties of PPO/PA66 blends with different contents of the compatibilizer were studied by transmission electron microscope （TEM）, scanning electron microscope （SEM）, mechanical test and Molau test. The results showed that the homemade compatibilizer can improve the mechanical property. Besides showing good effect on the compatibility improvement for PPO/PA blends，it has an in-situ compatibilization for the PPO/PA66 alloy

Abstract: The new micro-nano lamination technology is developed to produce composite materials with alternating layers structure. After polymer melt enter into the unit passing the process of stream-reverse-superimposed, it produces functional composites with dozens or even thousands of alternating layers, it obtains barrier performance that general multi-layer co-extrusion can not compare with. Equipment cost is low and production process is simple in the barrier composite material production process.