• Journal of Welding and Joining
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• v.32 no.5
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• pp.65-71
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• 2014

Atmospheric plasma spraying (APS) is world-widely used process in the automotive industry as a method to provide wear resistance coatings for engine cylinder bore, using various materials. The weight of engine blocks can be considerably decreased by removing cast iron liners, which can finally result in the improvement of fuel efficiency. In this study, five kinds of powder materials, 1.2C steel powder and 1.2C steel powder mixed with 5, 10, 15, 20 wt.%. molybdenum powder, were deposited by atmospheric plasma spraying in order to investigate the effect of molybdenum on the wear resistance of coatings. Microstructural analysis showed that molybdenum splats were well distributed in 1.2C steel matrix with intimate bonding. The molybdenum added coatings showed better tribological properties than 1.2C steel coating. However, above the 15 wt.%. blending fraction, wear resistance was somewhat degraded with poor roughness of worn surface due to the brittle fracture occurred in molybdenum splats. Consequently, compared to conventional liner material, gray cast iron, 10 wt. pct. molybdenum blended 1.2C steel coating showed much better tribological properties and therefore it looks very feasible to replace gray cast iron liner.

• The Korean Journal of Ceramics
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• v.6 no.4
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• pp.396-400
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• 2000

Dielectric and piezoelectric properties of Pb$_0.9$La$_0.1$TiO$_3$ ceramics were investigated as a function of grain size. Sintering atmosphere was controlled with changing the kind of atmospheric powder and its amount. It was confirmed that dielectric and piezoelectric of Pb$_0.9$La$_0.1$TiO$_3$ were strongly influenced by the sintering atmosphere. Relative dielectric constant of Pb$_0.9$La$_0.1$TiO$_3$ which was sintered in PbO-deficient atmosphere made by Pb$_0.9$La$_0.1$TiO$_3$ powder, increased with the grain size. However, the dielectric constant of the samples sintered in the PbO-sufficient atmosphere made by PbZrO$_3$ powder was slightly decreased with the grain size. Piezoelectric d$_33$ constant of Pb$_0.9$La$_0.1$TiO$_3$ also showed a different trend, depending on the sintering atmosphere. It was almost constant in the range of grain size of 1.3~2.3 $\mu$m when the samples were sintered in the PbO-sufficient atmosphere, while it intensively decreased with the grain size in the case of the PbO-deficient condition.

• Resources Recycling
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• v.22 no.2
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• pp.18-21
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• 2013

In this study, surface modification of wood powder by atmospheric pressure plasma treatment was investigated. The composites were manufactured using wood powder and polypropylene(wood powder : PP = 55 wt% : 45 wt%). Atmospheric pressure plasma was treated as condition of 3KV, $17{\pm}1$KHz, 2 g/min. Helium was used as carrier gas and monomer such as hexamethyl-disiloxane(HMDSO) was used to modify surface property by plasma polymerization. The tensile strength of untreated waste wood powder(W3) and homogeneous wood powder(H3) were about 18.5 MPa, 21.5 MPa while the tensile strength of plasma treated waste wood powder(PW3) and homogeneous wood powder(PH3) were about 21.2 MPa, 23.4 MPa, respectively. And tensile strength of W3 and H3 were improved by 14.6% and 8.8%, respectively. From the results for mechanical property, morphological analysis, we obtained improved interfacial bonding of polypropylene and wood powder modified by plasma treatment.

• Journal of Powder Materials
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• v.11 no.3
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• pp.210-216
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• 2004

The possibility to decrease agglomeration of Cu nano powders and their separation during pulsed wire evaporation (PWE) process was investigated by controlling the working gas system, i.e., the design of the gas path, the type and pressure of the atmospheric gas. As a result, it was possible to choose the optimal design of the gas path providing large specific surface area and high degree of separation of the synthesized Cu nano powders. It was also shown that an Ar+10∼50$N_2$ mixture can be used in production of Cu nano powders, which do not react with nitrogen.

• Transactions of Materials Processing
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• v.18 no.3
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• pp.262-267
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• 2009

Selective laser sintering is a kind of rapid prototyping process whereby a three-dimensional part is built layer wise by laser scanning the powder. This process is highly influenced by powder and laser parameters such as laser power, scan rate, fill spacing and layer thickness. Therefore a study on fabricating Fe-Ni-Cr powder by selective laser sintering has been performed. In this study, fabrication was performed by experimental facilities consisting of a 200W fiber laser which can be focused to 0.08mm and atmospheric chamber which can control atmospheric pressure with argon. With power increase or energy density decrease, line width was decreased and line surface quality was improved with energy density increase. Surface quality of quadrangle structure was improved with fill spacing optimization.

• Journal of Powder Materials
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• v.30 no.5
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• pp.424-430
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• 2023

YAG phosphor powders were fabricated by the atmospheric plasma spraying method with the spray-dried spherical YAG precursor. The YAG precursor slurry for the spray drying process was prepared by the PVA solution chemical processing utilizing a domestic easy-sintered aluminum oxide (Al₂O₃) powder as a seed. The homogenous and viscous slurry resulted in dense granules, not hollow or porous particles. The synthesized phosphor powders demonstrated a stable YAG phase, and excellent fluorescence properties of approximately 115% compared with commercial YAG:Ce³⁺ powder. The microstructure of the phosphor powder had a perfect spherical shape and an average particle size of approx imately 30 ㎛. As a result of the PKG test of the YAG phosphor powder, the synthesized phosphor powders exhibited an outstanding luminous intensity, and a peak wavelength was observed at 531 nm.

• Korean Journal of Agricultural Science
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• v.45 no.3
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• pp.475-484
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• 2018

Nitrite is an essential additive for the manufacture of cured meat products. This study was conducted to investigate the curing effect of the plasma treated juice of red Perilla in meat batter. The nitrite content in the juice of red Perilla was increased by the indirect treatment of atmospheric pressure plasma, and the lyophilized powder of red Perilla juice contained 9,133 ppm of nitrite. A meat batter without a nitrite source was prepared as a negative control (NC), and the meat batters cured with sodium nitrite (PC), celery powder (CP), and the lyophilized powder of red Perilla juice treated with atmospheric pressure plasma (PTP) at 70 ppm level of nitrite were prepared. The PTP showed the highest pH and the lowest cooking loss among the treatments. There were no significant differences in the nitrosyl-hemochrome content in the cooked meat batters of the PC, CP and PTC. However, the PTP had a lower CIE $a^*$-value compared to the PC and CP. The malondialdehyde content in the cooked meat batters was significantly lower in the CP and PTP than in the NC while there was no significant difference between the NC and PC. Based on the results of this study, the plasma treated juice of red Perilla can be used as a new natural nitrite source for cured meat products.

• Journal of the Korean institute of surface engineering
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• v.41 no.5
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• pp.220-225
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• 2008

In this study, two kinds of Fe-based bulk metallic glasses (BMG) powder were built-up through atmospheric plasma spray (APS) technique. The microstructure of two coatings was analyzed through X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Crystallization and oxidation in coatings were affected by chemical composition and initial powder size. Then, both of them influenced the tribological property.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.157-162
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• 2012

The basic study for combustion characteristics of micron-sized aluminum powder with water suspension was carried out. Under atmospheric pressure, the combustion characteristics of aluminum powder with water suspension was studied by adjust the equivalent ratio and the density of a mixture which effect on burning rate. Based on atmospheric pressure's result, the device for the combustion characteristics of aluminum powder with water suspension under high-pressure environment was developed. In the pressure range from 2 to 50 atm the effect of pressure to burning rate was same as the case of nano-aluminum with water suspension, but the pressure range from 50 to 70 atm the sharp increase in burning rate was observed. In the experiment of varying the equivalence ratio, the combustion did not proceed in the condition of excess oxidizer (eq = 1.5).

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.99-102
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• 2005

Plasma surface coating is applied to the wood powder to improve its bonding and dispersion with the polypropylene(PP). Some mechanical test results and visual inspection indicates the good compatibility between the wood powder and the PP, and relatively good interfacial adhesion between wood powder and PP matrix was seen. Also, this method is considered as a non-toxic process as compared to other direct chemical method.