Papers by Author: Tong Xiang Fan

Abstract: Surface modification of activated carbon was performed using such chemical methods as nitric acid and H2O2.Oxidation of the ACs made samples with weakly acidic functional groups and the presence of other groups was confirmed by Fourier transform infra red (FTIR) spectroscopy. With different time for modification, the amount of elements of carbon and oxygen will change a lot and the results of these experiments show a stronger ability of HNO3 solution in oxidization. Furthermore the differences of face morphology between ACs and oxidized ACs can be observed clearly

Abstract: This article deals with the influence of processing parameters on the microstructure of (AlN+Mg2Si)/Mg composites. Parameters such as stirring impeller shape and pouring temperature are shown to control the distribution and size of reinforcements and the amount of “Chinese script” type Mg2Si.

Abstract: The bolt load retention (BLR) test fixtures and behaviors of Mg alloys by main research teams are reviewed. Parts of BLR test results are also presented. Since creep properties are relevant to BLR, an approach to predicting BLR behaviors from creep curves is briefly introduced. The BLR test fixtures and procedures in our study are also shown.

Abstract: TiB2 particulate reinforced magnesium matrix composites were successfully fabricated by adding a TiB2–Al master alloy processed via the flux-assisted synthesis (FAS) reaction into molten magnesium. X-ray diffraction (XRD) analysis and microstructural characterization of the TiB2–Al master alloy revealed the formation and uniform distribution of TiB2 reinforcements. By stirring, magnesium matrix composites with dispersed homogenously TiB2 particles can be obtained. Microstructural characterization of the TiB2/Mg composites revealed retention of hexagonal or rectangular TiB2 particulates with the size of about 1 μm.

Abstract: The effect of the alloying element additions on in-situ chemical reaction to synthesize particulate reinforced TiC/Mg composites was evaluated from the viewpoint of thermodynamics. The influences of alloying elements on the changes of the activity coefficient and the excess free energy in molten magnesium were calculated. The results show that additions, such as Nd, La, Ca, Cu and Zr can promote TiC formation, at the same time hinder the brittle TiAl3 phase formation.

Abstract: Alloying additions have an important effect on in-situ chemical reaction 4Al+Si3N4=4AlN+3Si to synthesis (AlN+Mg2Si)/Mg composites. Using the Wilson equation and an extended Miedema model, the activity in a multiple-component system can be calculated，and then the Gibbs free energy can be calculated. In final, the influence of alloying element additions on the in-situ chemical reaction at high temperature is investigated from a thermodynamic viewpoint.

Abstract: The (AlN+Mg2Si)/Mg metal matrix composite was successfully fabricated by adding Si3N4 into Mg-Al alloy. The formation mechanisms of AlN and Mg2Si were analyzed; the effects of synthesizing temperature and holding time were investigated as well.

Abstract: Bacterium have evolved a large variety of stunning morphologies controlled at the microor even nanoscopic level such as cocci, bacillus, vibrios and spirillum acting as templates can lead to the formation of corresponding hollow inorganic replicas. Here, cocci Streptococcus thermophilus has been used as a natural biotemplate to synthesize ZnO hollow spheres via a simple hydrothermal method, followed by calcination. The as-obtained products are characterized by techniques of TG, XRD, FESEM, TEM and N2 adsorption. A possible formation mechanism is proposed which has an effect on the bimodal pore structure of the products with pores in the mesoporous range. It has introduced a new concept to synthesize porous hollow spheres by using bacteria as a biotemplate and has opened up a new pathway to synthesize hollow nanospheres, nanotubes and other kinds of 3D hollow nanostructures with bacteria of different morphologies, dimensionalities and sizes as templates.

Abstract: In this paper, porous carbon was made from biomass derived carbonaceous mesophase and carbonaceous fillers, and further applied as the substrate for CVD grow of nano carbon materials. With the assistance of microwave plasma, the acetone gas was decomposed into carbon and grew on the surface of the porous carbon, which produce ballas diamonds, carbon tubes, nets, petal, and other structures.

Abstract: This work presents a thermodynamic model to theoretically predict the component activity in multicomponent liquid alloy based on the Wilson equation and an extended Miedema model. Using only the physical parameters of pure metals, the component activities can be theoretically calculated and the calculation results agree well with the measured data. The model should enable very useful predictions to be made for activities in multi-component liquid alloys, especially for the trend of the activity changes with increasing alloy content.