Papers by Keyword: Composition

Abstract: Robot is a typical representative of high-tech research results. In a robot, the wisdom of human is applied throughout its whole structure, and also task commands are executed through an intelligent control system. Human society is always progressive and innovative. It is believed that great breakthroughs will be made to the future robots in structural combination, automatic control, working performance and so on. China is still a country in the developing stage, and therefore the research and manufacturing activities of robot products will be increasingly more. It is necessary for the research and development of robots at any period to give priority to "functional standards". On this basis, a study is made in this paper.

Abstract: In this research, marine clays has been studied its potential as a matrix composite materials that tend to be used as alternative materials to concrete. The study shows that marine clays which mixed with appropriate proportion of alkaline activator could have strength requirements for masonry cement. The alkaline activator that been used for the geopolymerisation reaction is sodium silicate and sodium hydroxide. Its compressive strength in early time reached 9-15 MPa.

Abstract: Polycrystalline Cr₂AlC was fabricated by a solid reaction synthesis of a mixture of Cr, Al and graphite powders in a flowing or the atmosphere in the temperature range of 700 to 1450 °C. The products for identification and analysis were characterized by X-ray diffraction (XRD). The effects of the composition of the initial elemental powders and temperature of purity and formation of Cr₂AlC were examined. It is found that the co-existence of Cr₇C₃ with Cr₂AlC is attributed to the surplus of carbon in the starting powders at 1350 °C, selecting the starting materials with a Cr: Al: C molar ratio of 2: (1.1-1.6): 1. For sample obtained from the starting elemental powders with the Cr: Al: C molar ratio of 2: 1.2: 0.94, no other phases but Cr₂AlC were detected. In addition, the effect of temperature on the formation of Cr₂AlC ceramic powders was carried out.

Abstract: We researched and developed the composite polymer materials and products from them, working in conjunction with raw-cotton. It is established that the production of friction pairs of working parts of machines (pegs) made of developed composite polymer materials increases their efficiency and durability to 2.0 -2.2 times.

Abstract: Seeking for reducing the cost of hydrogen energy fuel cells, one of the key points is reduce Pt loading in Pt/C catalytic electrode. Meanwhile, there is no negative impact about efficiency of electrode reactions. We manufactured PtCuCeO_x catalyst for fuel cell by Ion Beam Sputtering (IBS). In this paper, the electrodes were processed by different annealing temperature and acid treatment temperature for post-processing. An appropriate amount of Cu dopant can reduce the Pt loading, and the catalytic performance won't reduce. Doping CeO_x refined PtCu alloy crystal particle, active surface area of the electrode was improved. It had shown that Pt atoms accounted for 72%, Pt load 0.0618mg/cm2 by SEM + EDS and ICP-AES data. Performance of electrochemistry was increased by 40.5%. It showed the characteristics had low Pt loading with high performance of hydrogen evolution.

Abstract: Nickel-cobalt alloys have broad application prospect for their excellent properties (i.e. high microhardness, strength, abrasion, corrosion resistance and magnetic properties.etc). Nickel-rich Ni-Co coatings were produced on SUS304 substrates by pulse electrodeposition from sulfamate electrolytes with different average current density, pulse frequency, duty cycle and different bath temperature. It is clearly observed that the content of cobalt in the nickel-rich deposits gradually increases from 4.29 % to 25.47 % as the Co2+/Ni2+ concentration ratio increasing from 0.022 to 0.1(the current density applied was 2 A/dm2,bath temperature 25 °C). The Co content increases from 16.98 % to 25.47 % to 30.06 % when the duty cycle ranged from 20 % to 50 % to 60 %.The Co content seems to hardly change when pulse frequency changed from 500 Hz to 1000 Hz. The cobalt content decreases as the growth of the current density. The formation of good Ni-Co deposits with high cobalt content and smooth morphologies can be obtained by reducing current density, increasing bath temperature and pulse duty cycle.

Abstract: Laboratory researches of cooling rate influence on matrix structure, composition and quantity of nonmetallic inclusions in iron-aluminum alloys, containing 25-33%Al, are conducted. Thermodynamic modeling of composition and quantity of phases, which were formed in alloy system, containing Fe-Al-Si-C-O, for equilibrium conditions by means of the program complex ASTRA-4 (TERRA) is carried out. It is established, that irrespective of cooling rate the matrix has structure of intermetallic Fe-Al, and nonmetallic inclusions have platelet shape and composite of iron and aluminum oxy-carbides. It is confirmed, that ferroalloy with the optimal structure, necessary for receiving the high heat-resistance cast iron, should be cooled after smelting with the highest speed in these condition.

Abstract: The structure and properties of a kind of domestic continuous basalt fiber is analyzed in the paper. Chemical composition, crystal structure, thermal properties, flammability, mechanical properties and morphology of the fiber are investigated. Element analysis experiment shows that the basalt fiber is a kind of aluminosilicate fiber which mainly composed of the oxides of such elements as Fe, Si, Ca, Al, K, Mo, Ti, Ba and so on. X-ray diffraction indicates that the bulk structure of the fiber is non-crystal with short range order. SEM observation finds that basalt fiber is circular in cross-section and smooth in longitudinal direction. Solubility experiment reveals the superior resistance of the fiber to acids, alkaline and organic solvents. DGA demonstrates there are three weight loss stages in the process of elevating temperature. There are, respectively, evaporation of moisture in the fiber at about 100°C, decomposition of the residual carbonate minerals between 480°C and 630°C, and decomposition of newly generated carbonates between 850°C~995°C. In heatflow curve, there are also three endothermic peaks in which the first and the second correspond to the last two stages of weight loss and the third corresponds to melting process of the fiber and it onsets from 1122.14°C, comes to its peak value at 1194.96°C and ends at 1380°C. The tensile strength of the basalt fiber is better than S-glass fiber, worse than carbon fiber. Flammability of the fiber is also analyzed.

Abstract: The self-lubrication Ni-P/PTFE co-coatings were obtained by chemical plating. The tribological properties of the co-coating were carried on by the MM-200 type abrasion, and the microstructure and compounds of this composition and surface morphology were described by using X-ray diffraction and scanning electron microscope separately. The Ni-P/PTFE co-coating still had a low friction coefficient and good wear resistance. This was due to the PTFE material structure with the twisted chain, helical characteristics of carbon nanotubes, and the hexagonal structure in connection with many unusual mechanical and chemical properties.

Abstract: Heterogeneity of composition and microstructure in cast large sized 3104 aluminium alloy slab were studied using AES-ICP, OM, SEM, etc. The results show that the cooling rate on the cross section of 3104 slab is different, macro-segregation is found in the different section in the slab .The content of Ti decreases gradually from the surface to about 1/4 thickness of the slab, then increases rapidly to the center of slab; other elements content increases gradually from the surface to the about 1/4 thickness and then decreases rapidly to the center; the grain size on the surface area is fine, and the grain size at the center is coarse , segregation of Mg is found within the grains; great amount compound is found to be of presence on the grain boundary, with chemical compositions of Al 87（FeMn）13 and Al83（FeMn）12Si5; The compound size at the surface area is comparatively smaller, and coarser at the centre of slab.