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Authors: H.J. Oh, J.H. Lee, Y. Jeong, Su Jeong Suh, C.-S. Chi
Abstract: This study placed a focus on fabrication factors and surface morphology characteristics to obtain anodic alumina layers with ordered nanopore arrays using two-step anodization process. The regularity of nanopore arrangement in anodic alumina was prepared in oxalic acid at 40 V. The regular array was shown to be more strongly dependent on the time of first anodization than that of second anodization. The widening process of oxide surface in H3PO4 solution clearly exhibits that the nanopore diameter of the alumina layer subjected to widening time increased linearly at a rate of 0.6 nm/min at 30°C, and 0.8 nm/min at 40°C. The pore arrays in anodic alumina were analyzed by SEM.
Authors: Kyung Chul Lee, Nam Ho Kim, B.H. O, Hyoun Woo Kim
Abstract: We have investigated the effect of annealing temperature on the structural property of Au thin films deposited on Si(100) substrate using the radio frequency (RF) magnetron sputtering technique. X-ray diffraction revealed that the relative intensities and FWHM of (111), (200), and (311) peaks increased and decreased, respectively, after thermal annealing at 600°C. Scanning electron microscopy indicated that after annealing at 600-700°C, Au structures agglomerated on Si(100) surfaces. Energy dispersive x-ray spectrometry (EDX) revealed that the agglomerated structure was composed of pure Au.
Authors: Kee Sam Shin, Jung Hoon Yoo, Sung Hak Lee, Kenji Kaneko, Yoshitsugu Tomokiyo
Abstract: Because of its excellent process advantages such as high energy efficiency, short irradiation time and rapid heating, high energy electron beam (HEEB) irradiation is becoming of interest as a future surface modification technology. In this study, surface alloying of TiC, TiB2 and VC ceramic particles with a low carbon steel substrate was carried out using HEEB of 1.4 MeV. Surface alloyed layers of all the specimens were about 2 mm thick and consisted of a melted region, an interface region, a heat affected zone (HAZ) and the matrix. In all the specimens, the hardness at the surface was the highest, and then decreased sharply into the interior reaching the lowest values at the matrix. A remarkable increase in the mechanical properties was observed for the VC surface alloyed specimen. Vanadium carbides of large (~ 5 µm) and fine sizes (~ 20 nm) were formed uniformly, which resulted in an increase of hardness to 2-3 times of that of the matrix, and highest wear resistance.
Authors: Sang Baek Lee, Yung Keun Kim, Byung Il Kim
Abstract: The crystal structure, surface morphology and preferred orientation of copper electro-deposit were investigated by using sulfate bath with SiO2 suspension and the cathode substrate Au-sputtered. By addition of colloidal silica in copper electrolytic bath and Au pre-coating on substrate, the grains of deposits became fined and uniform and the number of grains were increased. Hardness of copper electrodeposits with colloidal silica increased about 15% in comparison with that of pure copper deposit film. The (111), (200) and (311) planes in the X-ray diffraction patterns were almost swept away, so preferred orientation of copper deposits change from (111) to (110) plane by co-deposit SiO2 and pre-coating the substrate.
Authors: M.W. Moon, T.Y. Kim, Kwang Real Lee, Kyu Hwan Oh
Abstract: The evaluation of elastic property for thin diamond-like carbon (DLC) films has been presented with buckle analysis of compressive stressed film on patterned substrate. When substrate has been patterned with adhesion release layer, the morphologies of buckle configuration on patterned layer has been controlled from straight sided (Euler) buckle to nonlinear telephone cord type buckle with respect to the pattern width. By using the simple equation for Euler buckle, the elastic modulus has been easily calculated, shown well consistent with the results by nano-indentation test.
Authors: Yuan Gao, Jin Yong Xu, Yan Ping Liu, Zhi Yong He, Zhong Xu
Abstract: Plasma surface alloying for low alloy high speed power hack saw blades was introduced.The bulk material of the blade is made of low alloy steel, while the teeth of which possess a composition of high speed steel like as a result of surface modification by a plasma surface alloying process.It is a solid diffusion process eliminating method avoids the formation of coarse primary carbides which is a major problem encountered in the production of smelting high speed steel. As a result the carbides in the layer of high speed steel are fine and well-distributed.Therefore,it has not only well wear-resistance but also toughness. Besides, the blade also has the advantages of ease manufacturing and low cost.
Authors: Wen Ji Xu, Jian Cheng Fang, F. Liu, Gui Bing Pang
Abstract: For the development of flexible forming using plasma arc (FFUPA), it is extremely necessary to investigate the forming rules of curvilinear scanning and multipath combined scanning. In this paper, the difference between circular scanning and linear scanning and the influence of sheet metal geometry on forming effect have been discussed. In the experiments, circle, ring and rectangle mild steel sheets with thickness of 0.8mm are taken as workpieces and the experimental results show that nonlinear prolonged surface can be obtained by curvilinear scanning and there exists the obvious difference between circular scanning and linear scanning. Afterwards, the reason of the difference mentioned above is concisely analyzed. Finally, some suggestions are presented for the future investigation.
Authors: Lin Qin, Yan Mei Qin, Xiao Ping Liu, Bin Tang, Zhong Xu
Abstract: Mo modified layers on Ti-6Al-4V alloy were obtained with plasma surface alloying technique. The properties of the Mo-diffusion layers were investigated in this paper. Results show that the Mo-diffusion layers obviously enhance the wear resistance of Ti alloys against a polished 2100 steel counterbody ball under ball-on-disc test condition. With a series of experimental results, a wear model of high wear resistance of modified layers is propounded. The noval wear behavior is a result of absolute elasticity characteristics on the subsurface of Mo modified layers.
Authors: Gao Hui Zhang, Zhi Yong He, Jun De Pan, Ping Ze Zhang, Zhong Xu
Abstract: By means of double glow plasma surface alloying process, Ti6Al4V surface was successively carbonitrided forming a layer with special physical and chemical properties. The depth profile of C and N elements showed a tendency of gradual decrease on the Ti6Al4V as well as the depth profile of its hardness. Friction and wear test indicate that the wear resistant property is increased greatly after carbonitriding the Ti6Al4V.
Authors: Jin Yong Xu, Yan Ping Liu, Yuan Gao, Zhong Xu
Abstract: The plasma surface alloying low-alloy high speed steel (HSS) is carried out in vacuum chamber where a source electrode (W-Mo) and a work piece are properly placed. By using the sputter of glow-discharge, under the common function of electric field and temperature field, ?????? the desired alloying elements (W- Mo) are sputtered from the source cathode, traveling toward the substrate. Subsequently the alloying elements deposit onto the surface of the substrate, forming alloy diffusion layer which the depth may vary from several micron to several hundreds micron. In the end a surface low-alloy HSS steel would be produced after ultra-saturation ion carbonization. The composition of the alloyed layer is equal or similar with it of low-alloy HSS. The carbonized layer, without coarse eutectic ledeburite structure, possesses high density of finely and dispersed alloy carbides with tungsten equivalent 10% above and a significant improvement in surface hardness and wear resistance. The principle of plasma surface alloying and its test results and commercial products application are introduced in this paper.

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