Papers by Keyword: Modification

Abstract: In order to settle the environmental pollution and improve the excellent rate of products, ZL109 piston alloy modified by Al9Fe3P master alloy was prepared in factory. The microstructures and mechanical properties of ZL109 piston alloy were invested respectively. The technological parameters and modifying effect of using Al9Fe3P alloy were researched too. Experiments show that high quality of ZL109 pistons can be produced by adding 0.4~0. 5wt% Al9Fe3P master alloy at 760-770°C.The maxim and average grain size of primary Si decrease largely, less than 66μm and 40μm respectively, and the mechanical properties were improved accordingly. It was proved that Al-Fe-P master alloys have advantages such as no pollution, no reaction slag, shorter modifying time and saving energy, which would reduce the total cost of piston products. So Al-Fe-P master alloy is a promising modifier to refine ZL109 piston alloys.

Abstract: Effect of RE and V on microstructure and mechanical properties of high chromium cast iron were investigated by optical microscopy, scanning electron microscopy, X-ray diffraction, impact test and wear test. The results show that proper modification using RE combined with V makes the alloy present a more refined and homogenous austenite matrix, and makes the morphology of carbide changing from thick lath to thin lath, and rosette-like. Modification can also increase hardness, wear resistance and impact toughness of high chromium cast iron.

Abstract: A kind of austempered boron alloyed high silicon cast alloy was developed though modification with Ti and controlling austempering temperature, the impact toughness of which increases to 20.7 J/cm², which is more than triple that of the previous work. The alloy with modification exhibits obvious grain refining both in matrix and boride, improved the morphology of boride into discontinuous network and small particles. The phenomenon and mechanism are discussed in the article, it proved TiC is possible to act as the nuclei of eutectic boride and Ti can be an effective modifier.

Abstract: The modification of CaCO₃ powder was studied by the composite modifier in n-butanol and water solution. Aluminate coupling agent (ACA) and stearic acid (SA) were added as the composite modifier. The characters of modified CaCO₃ were investigated by the contact angles and infrared spectroscopy (IR). It was found that the contact angles/water of modified CaCO₃ powder increased with the increase of SA/ACA weight ratio, and showed a maximum when ratio was 0.8:1. The contact angles/water of modified CaCO₃ powder obtained in optimum conditions was 136.5°. The results indicated that the surface character of CaCO₃ powder exhibited hydrophobic properties. When adding the active CaCO₃ into PE (the weight ratio of CaCO₃/PE about (20:100), the mechanical properties of PE were remarkably improved.

Abstract: Selecting effective xenon adsorbents is important for preventing significant global nuclear proliferation. The adsorption capacity of coconut shell activated carbons (SAC),zeolite 10X,zeolite 5A, zeolite 13X were researched and the Xenon adsorption of the coconut shell activated carbon modified by KOH(SAC/KOH-1 and SAC/KOH-2) were compared in this paper. The factors of temperature and flow rate that influenced the dynamic adsorption of xenon by 10X were discussed. The order of the Xenon adsorption capacity is as follows: zeolite 10X, SAC/KOH-2, SAC/KOH-1, SAC, zeolite 13X, zeolite 5A.

Abstract: Antibacterial activity of zinc oxide (ZnO) or strengthening of hydroxylapatite whisker (HAPw) had been studied and applied widely. However, antibacterial property of ZnO-HAPw was scarcely researched nowadays. The aim of this study was to further investigate several kinds of morphologies of ZnO-HAPw prepared by sol-gel technology at different pondus hydrogenii (pH) value and temperature. Four kinds of morphologies of ZnO-HAPw were granule, triangle, short rod and gongs nail at 70°C and pH=6.4, 37°C and pH=6.6, 70°C and pH=6.6, 70°C and pH=6.6. The SEM images of HAPw and ZnO-HAPw samples showed that the HAPw surface was smooth and no difference after annealing treatment. In addition, different shapes of nanoZnO fused uniformly on the HAPw surface. The EDS indicates nanoZnO fuses on HAPw surface.

Abstract: Manganese oxides supported palygorskite (MnOx/PG) catalysts used for low-temperature selective catalytic reduction of NO with NH₃ was modified by doping cerium oxide as additive for enhancement of its performance. The effects of doped cerium content on catalysts' activity were investigated. It was found that the NO removal efficiency of Mn8Ce5/PG catalyst was remarkably higher than Mn8/PG catalyst especially at low temperatures, revealing that the addition of cerium oxide effectively enhanced the catalysts' SCR activity. Catalysts were characterized by BET, XRD, XPS to explore the relation between structural properties and increasing in SCR activity via modification. Results showed that the doping of cerium oxide has improved the dispersion of manganese oxides as active species. And furthermore, the stability of surface MnO₂ was also improved which was suggested to be the main reason for the enhancement of catalysts' activity.

Abstract: Coal fly ashes are a coal combustion product at high temperature. With a certain porous structure and large specific surface area, they have certain adsorption capacities and can be used as the materials for watewater treatment.But limited by the adsorption properties, the raw coal fly ashes have a very low pollutant removal efficiency, and can not meet the practical requirements of wastewater treatment. Therefore, researches now focus on the coal coal fly ashes modification, including increasing the active components in them, enlarging the specific surface area to improve their performance, and to enhance their wastewater treatment effects.Aiming at providing some references of their integrated utilization in wastewater treatment, the modification methods and application status of the coal coal fly ashes are summarized.

Abstract: The coal fly ash (CFA)/coal fly ash modified by sulfuric acid (MCFA)-conditioned sludge dewaterability was investigated in this study. Specific resistance of filtration (SRF) was used to assess the sludge dewaterability. Extracellular polymeric substance (EPS) was determined in attempt to explain sludge conditioning process. The results showed that SRF of the sludge significantly decreased with coal fly ash addition, and the MCFA showed much stronger conditioning capacity than the raw coal fly ash. Under a MCFA dosage of 36g.L^-1, the SRF of the sludge decreased from 1.18×10¹² to 6.47×10¹⁰ m.kg¹, and EPS concentration of the sludge decreased from 32.64 to 17.55mg.L^-1. The sludge conditioning mechanisms with MCFA mainly included improving adsorption bridging and providing the water transmitting passages by skeleton builder.

Abstract: Photocatalyst of Fe-Sm-Yb modified TiO₂ loaded on clay brick was prepared for degradation of NH₃-N in coking water. The influence factors of NH₃-N degradation rates were discussed by single factor experiment and orthogonal experiment. The optimum process conditions of photocatalytic degradation NH₃-N in coking water were confirmed. The results show that NH₃-N degradation rates 82.23% were highest in the conditions of pH 6.5, photocatalyst charge of 1.4 g, illumination for 6h, reaction at 55°C, calcination at 500°C.