• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.1
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• pp.17-22
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• 1999

Experiment was carried out to determine the agronomic characteristics, forage yield of silage corn(Zea mays L.) soil chemical characterictics and $NO_3-N$ level in infiltration water by different application rates of daily liquid manures. Four treatment consisting of chemical fetilizer, $200kg\;N\;ha^{-1}$, daily liquid manure $200kg\;N\;ha^{-1}$, $300kg\;N\;ha^{-1}$ and $400kg\;N\;ha^{-1}$ were arranged in a randonmized complete block design with three replicates. The results obtained at National Livestock Research Institute, RDA., in Suwon from 1996 to 1997 are summarized as follows; In plant height and crude protein content, it were appeared to highest by 264cm, 6.8% at the cattle slurry 150% plot(T3), respectively. but Dry matter yield(14.5MT/ha) and TDN(9.5MT/ha) production of chemical fertilizer plot(T1) were highest. Among daily liquid manure amount, dry matter yield(14.0MT/ha) and TDN yield(9.1MT/ha) of daily liquid manure 100% plot(T2) were resulted to 96% and 97% of chemical fertilizer plot(T1). End year's soil organic matter and phosphate content were appeared to high than those of beginning year in daily liquid manure plots, but it was not in proportioned to increase according to slurry amount. $NO_3-N$ level in infiltration water lower than 60cm of all plots were lowed than a permitted limit of cattle drinkable. As a result, it was appeared that the optimum application amount of dairy liquid manure was 200kg/ha by manure-N.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2000.04a
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• pp.9-10
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• 2000

An important business-field of world-wide steel-industry is the coating of thin metal-sheets with zinc, zinc-aluminum and aluminum based materials. These products mostly go into automotive industry. in particular for the car-body. into building and construction industry as well as household appliances. Due to mass-production, the processing is done in large continuously operating plants where the mostly cold-rolled metal-strip as the substrate is handled in coils up to 40 tons unwind before and rolled up again after passing the processing plant which includes cleaning, annealing, hot-dip galvanizing / aluminizing and chemical treatment. In the liquid Zn, Zn-AI, AI-Zn and AI-Si bathes a combined action of corrosion and wear under high temperature and high stress onto the transfer components (rolls) accounts for major economic losses. Most critical here are the bearing systems of these rolls operating in the liquid system. Rolls in liquid system can not be avoided as they are needed to transfer the steel-strip into and out of the crucible. Since several years, ceramic roller bearings are tested here [1.2], however, in particular due to uncontrollable Slag-impurities within the hot bath [3], slide bearings are still expected to be of a higher potential [4]. The today's state of the art is the application of slide bearings based on Stellite\ulcorneragainst Stellite which is in general a 50-60 wt% Co-matrix with incorporated Cr- and W-carbides and other composites. Indeed Stellite is used as the bearing-material as of it's chemical properties (does not go into solution), the physical properties in particular with poor lubricating properties are not satisfying at all. To increase the Sliding behavior in the bearing system, about 0.15-0.2 wt% of lead has been added into the hot-bath in the past. Due to environmental regulations. this had to be reduced dramatically_ This together with the heavily increasing production rates expressed by increased velocity of the substrate-steel-band up to 200 m/min and increased tractate power up to 10 tons in modern plants. leads to life times of the bearings of a few up to several days only. To improve this situation. the Mechanical Alloying (MA) TeChnique [5.6.7.8] is used to prOduce advanced Stellite-based bearing materials. A lubricating phase is introduced into Stellite-powder-material by MA, the composite-powder-particles are coated by High Energy Milling (HEM) in order to produce bearing-bushes of approximately 12 kg by Sintering, Liquid Phase Sintering (LPS) and Hot Isostatic Pressing (HIP). The chemical and physical behavior of samples as well as the bearing systems in the hot galvanizing / aluminizing plant are discussed. DependenCies like lubricant material and composite, LPS-binder and composite, particle shape and PM-route with respect to achievable density. (temperature--) shock-reSistibility and corrosive-wear behavior will be described. The materials are characterized by particle size analysis (laser diffraction), scanning electron microscopy and X-ray diffraction. corrosive-wear behavior is determined using a special cylinder-in-bush apparatus (CIBA) as well as field-test in real production condition. Part I of this work describes the initial testing phase where different sample materials are produced, characterized, consolidated and tested in the CIBA under a common AI-Zn-system. The results are discussed and the material-system for the large components to be produced for the field test in real production condition is decided. Outlook: Part II of this work will describe the field test in a hot-dip-galvanizing/aluminizing plant of the mechanically alloyed bearing bushes under aluminum-rich liquid metal. Alter testing, the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed. Part III of this project will describe a second initial testing phase where the won results of part 1+11 will be transferred to the AI-Si system. Part IV of this project will describe the field test in a hot-dip-aluminizing plant of the mechanically alloyed bearing bushes under aluminum liquid metal. After testing. the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed.

• Korean Journal of Metals and Materials
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• v.48 no.6
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• pp.477-488
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• 2010

Zr-based amorphous alloy matrix composites reinforced with stainless steel (STS) and tantalum continuous fibers were fabricated without pores or defects by a liquid pressing process, and their quasi-static and dynamic deformation behaviors were investigated by using a universal testing machine and a Split Hopkinson pressure bar, respectively. The quasi-static compressive test results indicated that the fiberreinforced composites showed amaximum strength of about 1050~1300 MPa, and its strength maintained over 700 MPa until reaching astrain of 40%. Under dynamic loading, the maximum stresses of the composites were considerably higher than those under quasi-static loading because of the strain-rate hardening effect, whereas the fracture strains were considerably lower than those under quasi-static loading because of the decreased resistance to fracture. The STS-fiber-reinforced composite showed a greater compressive strength and ductility under dynamic loading than the tantalum-fiber-reinforced composite because of the excellent resistance to fracture of STS fibers.

• Korean Journal of Metals and Materials
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• v.48 no.2
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• pp.109-115
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• 2010

In the present study, a Zr-based amorphous alloy matrix composite reinforced with tungsten porous foam was fabricated without pores or defects by liquid pressing process, and its microstructures and mechanical properties were investigated. About 69 vol.% of tungsten foam was homogeneously distributed inside the amorphous matrix, although the matrix of the composite contained a small amount of crystalline phases. The compressive test results indicate that the composite was not fractured at one time after reaching the maximum compressive strength, but showed considerable plastic strain as the compressive load was sustained by tungsten foam. The tungsten foam greatly improved the strength (2764 MPa) and ductility (39.4%) of the composite by homogeneously dispersing the stress applied to the matrix. This was because the tungsten foam and matrix were simultaneously deformed without showing anisotropic deformation due to the excellent bonding of tungsten/matrix interfaces. These findings suggest that the liquid pressing process is useful for the development of amorphous matrix composites with improved strength and ductility.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.21-24
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• 2006

Based on the improvement in reinforcing SiC fibers and the utilization of very fine nano-SiC powders, the well known liquid phase sintering (LPS) process was drastically improved to become a new process called the Nano Infiltration and Transient Eutectic Phase (NITE) Process. Laboratory scale NITE-SiC/SiC composites demonstrated excellent mechanical properties, thermal conductivity, hermeticity and microstructure stability which made them attractive for not only energy application but many other industrial applications. For the real deployments of these materials, mass production system and evaluation methods, together with the design code and safety assurance systems are essential. The current efforts to establish these bases were introduced.

• Journal of the Korean Ceramic Society
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• v.32 no.7
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• pp.825-831
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• 1995

Reaction-bonded SiC-Si material was fabricated by infiltration of Si melt into a mixture of $\alpha$-SiC and carbon at 175$0^{\circ}C$ under the vacuum atmosphere. Wear properties were analyzed by ball-on-plate wear tester, changing loading weight, sliding speed, sliding time and atmosphere, Results showed that the friction coefficient was decreased with increasing load and sliding velocity. The lowest friction coefficient of 0.05 was obtained under an oil atmosphere. The analysis of the wear surface indicated that the areas wehre particles were pulled out and where free silicon particles worn out preferentially serve as liquid reservoirs to decrease the wear resistance.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1078-1079
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• 2006

The paper presents the possibilities of obtaining new composite materials based on sintered porous ceramics with particles and fibre of $Al_2O_3$ infiltrated by aluminum alloy. The EN AC - AlSi12 alloy features the matrix material, whereas the RF50AX-301 preform, of Saffil Automotive, was used as the reinforcement. Examinations of ceramics preforms permeability were made. Metallographic examination of composite materials made on light microscope and in scanning electron microscope show that aluminum alloys fill micropores in the matrix. New composite materials show twice higher value of hardness in comparison with matrix. Results indicate that it is possible to infiltrate porous ceramic with liquid aluminum alloy to obtain new composite materials were advantageous properties of each component are connected.

• Composites Research
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• v.26 no.5
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• pp.322-327
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• 2013

Carbon fiber-reinforced SiC matrix composites have good oxidation resistance and thermal shock resistance. These properties have allowed the composites to be applied to high-temperature structures. In this study, $C_f/SiC$ composites were fabricated via precursor infiltration and pyrolysis (PIP) process, including liquid phase infiltration and chemical vapor curing using cyclohexene. The final $C_f/SiC$ composites, which have gone through the PIP process five times, showed a density of $1.79g/cm^3$, as compared to a density of $0.43g/cm^3$ for pre-densified bare carbon fiber preform. As for the oxidation resistance characteristics, the weight of $C_f/SiC$ composite was maintained at 81% at $1400^{\circ}C$ in air for 6 hours. Chemical vapor curing (CVC) using cyclohexene has shown to be an effective method to achieve high densification, leading to increased oxidation resistance.

• Korean Journal of Metals and Materials
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• v.50 no.9
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• pp.697-702
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• 2012

In this study, unidirectional and plain woven carbon fiber reinforced magnesium matrix composite laminates were fabricated by the liquid pressing infiltration process, and evolutions of the microstructure and compressive strength of the composite laminates under corrosion were investigated by static immersion tests. In the case of the unidirectional composite laminate, the main microstructural damage during immersion appeared as a form of corrosion induced cracks, which were formed at both CF/Mg interfaces and the interfaces between layers. On the otherhand, wrap/fill interface cracks were mainly formed in the plain woven composite laminate, without any cracks at the CF/Mg interface. The formation of these cracks was considered to be associated with internal thermal residual stress, which was generated during cooling after the fabrication process of these materials. As a consequence of the corrosion induced cracks, the thickness of both laminates increased in directions vertical to the fibers with increasing immersion time. With increasing immersion time, the compressive strengths of both composite laminates also decreased continuously. It was found that the plain woven composite laminates have superior corrosion resistance and stability under a corrosive condition than unidirectional laminates.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.3
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• pp.203-210
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• 1999

Of all the nutrients in liquid manure, N has the greatest potential both for the environment and for increasing forage yields. This experiment was carried out to determine the effect of different types and N rates of liquid manure on mineral content and nitrate-N of oats(Avena sativa L.), soil chemical characteristics in Suweon. Seven treatments consisting of chemical fertilizer $120kg\;N\;ha^{-1}$, liquid cattle manure 120, 240 and $360kg\;N\;ha^{-1}$, liquid swine manure 120, 240 and $360kg\;N\;ha^{-1}$ were arranged in a randomized complete block design with three replications. Compared with the plot of chemical fertilizer, increasing liquid manure N rates increased mineral contents of oats. Nitrate-N contents of oats were ranged from 1,881 to $2,605mg\;kg^{-1}$ in all treatments, which was orderly ranked as chemical fertilizer>liquid cattle manure $360kg\;N\;ha^{-1}$> liquid swine manure $240kg\;N\;ha^{-1}$. Contents of exchangeable cation of the soil were appeared to be higher with increasing liquid manure N rates. Amount of total-N and inorganic-N in soil affected by increasing liquid manure N rates, and there was the highest at liquid swine manure $360kg\;N\;ha^{-1}$ among the treatments. Nitrate-N concentration in infiltration water was not remarkably variable during the experimental period. Based on the results of this experiment, it is suggested that the amount of nitrogen in soil was orderly ranked as liquid swine manure $360kg\;N\;ha^{-1}$, followed by liquid swine manure $240kg\;N\;ha^{-1}$.