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Zhao M.-L.,Hefei University of Technology | Luo L.-M.,Hefei University of Technology | Luo L.-M.,Laboratory of Nonferrous Metal Material and Processing Engineering of Anhui Province | Li H.,Hefei University of Technology | And 4 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2015

TiC powders were pretreated by chemical activation, and then Ni-W-coated TiC composite powders were synthesized by electroless plating process. The powders consist of 2%(mass fraction) Ni-W-coated TiC composite powders and pure W powders were pressed under different pressures and sintered to W-Ni/TiC bulk composites. The microstructure and compositions of the initial TiC powders, the pretreated TiC powders, the Ni-W-coated TiC powders and the W-Ni/TiC composites were analyzed by scanning electron microscopy (SEM) and energy dispersion spectrometry (EDS). The formation process of Ni-W-coated TiC powders and W-Ni/TiC composites, and the influence law of pressure on the sintered body were discussed. The results show that Ni-W coated TiC uniformly by electroless plating progress. W-Ni/TiC composites have higher density than that of pure W sintered body by the same process, and the higher pressure on compacts, the higher density of the composites can be obtained. ©, 2015, Editorial Office of Transactions of Materials and Heat Treatment. All right reserved. Source


Luo L.-M.,Hefei University of Technology | Luo L.-M.,Laboratory of Nonferrous Metal Material and Processing Engineering of Anhui Province | Chen J.-B.,Hefei University of Technology | Wang Z.-C.,Hefei University of Technology | And 5 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2014

Activitation treatment for PC plastic substrate by using nitric acid before electroless plating was carried out, then PC plastic substrate was successfully coated with a copper. The growth mechanism of copper layers and surface morphology of PC plastic before and after activated, and surface morphology of PC plastic after electroless plating for different time were analyzed by field emission scanning electron microscopy. The results show that the uniformly copper layers coated with PC substrate is successfully synthesized, which is activated by nitric acid. The dense, uniform distribution copper layers on PC are obtained. The growth mechanism of copper layers appears as follows: reactants in the plating solution are adsorbed on catalytic activity surfaces of PC surface and happened oxidation-reduction reaction. First deposited Cu particles grow in a linear way, the growth process is nano-Cu particle aggregation process, and repeated to form Cu particle physics reunion. Finally, the integration between the Cu particles, and form closely, evenly distributed copper layers. ©, 2014, Editorial Office of Transactions of Materials and Heat Treatment. All right reserved. Source


Lu Z.-L.,Hefei University of Technology | Luo L.-M.,Hefei University of Technology | Luo L.-M.,Laboratory of Nonferrous Metal Material and Processing Engineering of Anhui Province | Huang X.-M.,Hefei University of Technology | And 8 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2015

Copper (Cu)-coated titanium carbide (TiC) composite powders were synthesized by electroless plating with a simplified pretreatment. The surface morphology and composition of the initial TiC powders, pretreated TiC powders and Cu-coated TiC powders were analyzed by field emission scanning electron microscopy, and energy dispersion spectrometry. The growth mechanism of Cu layers was also discussed. The results show that uniform Cu-coated TiC composite powders are successfully synthesized without conventional sensitization and activation steps by ultrasonic electroless plating after a simple pretreatment. The growth mechanism of Cu layers appears as follows: the surfaces of pretreated TiC powders appear surface defects which act as activated sites. Nucleation and the growth of copper grains take place on the activated sites of the pretreated TiC powder, and the process repeats continuously on the lath particles with reticulate structure on the as-coated surfaces of previously deposited Cu-cells, finally Cu cells grow up and merge into a layer. ©, 2015, Editorial Office of Transactions of Materials and Heat Treatment. All right reserved. Source


Ding X.,Hefei University of Technology | Luo L.,Hefei University of Technology | Luo L.,Laboratory of Nonferrous Metal Material and Processing Engineering of Anhui Province | Huang L.,Hefei University of Technology | And 5 more authors.
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2015

With the demand for energy growing rapidly, fossil fuel and other traditional energy resources which bring about serious environmental problems will soon dry up in the foreseeable future. Producing fusion energy by light nuclear fusion reaction is an important potential way to solve the energy problem of human. Recent researches on fusion reactor have made significant progress, and the resulting material problem has become a realistic problem due to that the materials in the reactor will face harsh working environment. Tungsten (W) is considered to be the primary candidate for plasma facing materials like first wall in future fusion reactors owing to its superiority to other materials including high melting point, high thermal conductivity, high density, low thermal expansion coefficient, low vapor pressure, low tritium inventory, low sputtering yield and high energy threshold for physical sputtering, etc. However, there are still serious challenges of brittleness for W and W alloys in the future application for fusion reactors. Defects induced by irradiation often lead to embrittlement of the material, thus shortening the service life of components. The defects will also interact with precious fusion fuel (such as tritium), leading to serious retention and permeation. Therefore, it is very necessary to study the radiation damage of W and W-based materials and it will be of great significance to delay irradiation defects through designing material composition/structure/organization. In order to provide a reference to researchers devoted to irradiation damage, irradiation damage status and the latest research progress of commercial W and advanced W alloys were reviewed in the paper. © Editorial Board of Chinese Journal of Rare Metals. All right reserved. Source


Luo L.,Hefei University of Technology | Luo L.,Laboratory of Nonferrous Metal Material and Processing Engineering of Anhui Province | Lu Z.,Hefei University of Technology | Li H.,Hefei University of Technology | And 5 more authors.
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2013

Because of its high melting point, high strength, low vapor pressure, low sputter etching rate, good thermal stability and high strength ductility and excellent comprehensive properties, tungsten alloys were widely used in national defense, aerospace, metallurgy, electronics and other fields. However, tungsten alloys also existed a variety of problems, such as low recrystallized temperature, high ductile-brittle transition temperature (DBTT) and low temperature strength. Moreover, as the vitamin for metal, the rare earth elements with their unique properties could refine grain, effectively purify grain boundaries, and make the material improve to a great extent. Therefore, adding rare earth elements into tungsten alloys for improving mechanical properties of tungsten alloys became one of the hottest researches. This review introduced the function and the mechanism of the rare earth elements in tungsten alloys (W-Cu alloys, W-Ni-Fe (Cu) alloy, W-TiC alloy and the tungsten in the electrode) and came up with some problems on it and also pointed out how it developed in future. Source

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