Papers by Author: Xiao Min Chen

Abstract: Graphene, whose structure is composed of a single-atom-thick sheet of sp²-hybridized carbon atom, provides large specific surface area, excellent mechanical and chemical properties. In this paper, reduced graphene oxide/carbon nanotube (rGO/CNT) composite, which had superior electrochemical performance, was synthesized via a facile, handy and cheap method. Electrochemical tests showed that rGO/CNT composite that the weight ratio of graphene oxide (GO) to CNTs is 7.5 to 1 exhibited the specific capacitance was 346.84 F/g at the current density of 2 A/g in 1 M H₂SO₄. The good performance of rGO/CNT composite was ascribed to huge surface area of rGO and homogeneous distribution of CNT, which prevented the aggregation of rGO sheets, increased the path of electron circulation and speeded up the electrolyte penetrating into the materials. Therefore, rGO/CNT composite had great potential on supercapacitors.

Abstract: Platinum matrix composite is a new type of functional pottery material, which has excellent mechanical, electrical and optical properties. Due to the complexity of the synthesis method and the expensive equipment, the development of cermet material is extremely slow, so that the method to solve the problem is urgently needed. In view of the excellent performance of the Pt-C compounds, by hydrothermal method and high temperature roasting method, a new synthesis method for the composite is proposed using melamine and four platinum chloride at 60 °C by the polymerization reaction with a molar ratio of 20:1. The synthetic of Pt-C compounds provides a new synthesis method and new ideas and at the same time the Pt-C compounds has excellent performance, showing the excellent applications in machining.

Abstract: The compressive deformation experiments of 2124-T851 aluminum alloy were carried out over a wide range of temperature and strain rate. An artificial neural network (ANN) model is developed for the analysis and simulation of the correlation between the flow behaviors of hot compressed 2124-T851 aluminum alloy and working conditions. The input parameters of the model consist of strain rate, forming temperature and deformation degree whereas flow stress is the output. A three layer feed-forward network with 15 neurons in a single hidden layer and back propagation (BP) learning algorithm has been employed. Good performance of the ANN model is achieved. The predicted results are consistent with what is expected from fundamental theory of hot compression deformation, which indicates that the excellent capability of the developed ANN model to predict the flow stress level, the strain hardening and flow softening stages is well evidenced.

Abstract: The purpose of this paper is to investigate the possibility of rod-like Al2TiO5 / α-Al2O3 composites in situ formation via a mechanical activation process. A QM-ISP-4 Planetary Mill was employed to activate mechanically the mixtures of anatase and corundum in air at room temperature for different times. The milled powder mixtures were pressed into platelets and then sintered in air at 1300°C for 3 h. The XRD results showed that only Al2TiO5 and α-Al2O3 phases could be detected in the sintered samples when the activated time reached 30 hours. The SEM observations illustrated the unusual microstructure of Al2TiO5 / α-Al2O3 ceramic composite materials. Abnormal grains with longitudinal length ~10 μm23 transversal length ~1 μm and equiaxed matrix grains of ~3 μm on an average were observed. EDXA proved that the rod-like grains and the fine equiaxed matrix grains were composed of Al2TiO5 and α-Al2O3, separately. The roles of anisotropic grain growth caused by mechanical activation are discussed for the in situ formation of rod-like Al2TiO5 / α-Al2O3 ceramic composite materials.

Abstract: The purpose of this paper is to investigate the possibility of rod-like Al2TiO5 formation via a mechanical activation process. A QM-ISP-4 Planetary Mill was employed to activate mechanically the mixtures of anatase and corundum in air at room temperature for different times. The milled powder mixtures were then sintered in air at 1300°C for 1 h. The XRD results showed that the milled powder mixtures were completely transformed into Al2TiO5 after sintering, except the mixtures milled for 5 and 10 hours. The SEM observations showed the typical morphology of rod-like Al2TiO5 vary in the range: widths from 0.6 to 1.2 μm, and lengths from 3.0 to 6.0 μm. The rod-like Al2TiO5 formation was attributed to the positive effects caused by the mechanical activation.