• Journal of the Korean Ceramic Society
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• v.43 no.12 s.295
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• pp.859-864
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• 2006

For the pressure compaction process of the ceramic powder, the green density is very different with both the ceramic body shape and the processing conditions. The density difference cause non-uniform shrinkages and deformations, and make cracks in the sintered ceramics. In this paper, Material properties of the alumina powder mixed with binder and the friction coefficient between the powder and the tool set were determined through the simple compaction experiments: Also the powder flow characteristics were simulated and the green density was analyzed during the powder compaction process with Finite Element Method (FEM). The results show that the density distributions of the green body were improved at the optimized processing condition and both the possibility of the farming crack generation and rho deformation of the sintered Alumina body were reduced.

• Journal of Biomedical Engineering Research
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• v.16 no.1
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• pp.57-60
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• 1995

To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed and produced a composite that is consisted of calcium phosphate and collagen. Human umbilical cord origin pepsin treated type I atelocollagen was used as the structural matrix, by which sintered or non-sintered carbonate apatite was encapsulated to form an inorganic-organic composite. With cross linking atelocollagen by UV ray irradiation, the resistance to both compressive and tensile strength was increased. Collagen degradation by the collagenase induced collagenolysis was also decreased.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.339-345
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• 2006

This these was conducted to investigate tile characteristics of a frozen start up for a VCHP which has water as a working fluid and Nitrogen as a non-condensible gas. The tested heat pipe was made of a copper tube with the outer diameter of 12.7 mm, the length of 340 mm, and the sintered metal wick had the thickness of 0.7 mm. This experiment was conflicted under the thermal load, inclined angle and cooling conditions.

• Korean Journal of Materials Research
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• v.30 no.6
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• pp.301-307
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• 2020

In this study, factors considered to be causes of promotion of densification of sintered pellets identified during phase change are reviewed. As a result, conclusions shown below are obtained for each factor. In order for MA powder to soften, a temperature of 1,000 K or higher is required. In order to confirm the temporary increase in density throughout the sintered pellet, the temperature rise due to heat during phase change was found not to have a significant effect. While examining the thermal expansion using the compressed powder, which stopped densification at a temperature below the MA powder itself, and the phase change temperature, no shrinkage phenomenon contributing to the promotion of densification is observed. The two types of powder made of Ti-silicide through heat treatment are densified only in the high temperature region of 1,000 K or more; it can be estimated that this is the effect of fine grain superplasticity. In the densification of the amorphous powder, the dependence of sintering pressure and the rate of temperature increase are shown. It is thought that the specific densification behavior identified during the phase change of the Ti-37.5 mol.%Si composition MA powder reviewed in this study is the result of the acceleration of the powder deformation by the phase change from non-equilibrium phase to equilibrium phase.

• Transactions of the Korean hydrogen and new energy society
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• v.7 no.2
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• pp.157-164
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• 1996

The AB5-type metal hydride electrodes using $(LM)Ni_{4.49}Co_{0.1}Mn_{0.205}Al_{0.205}$(LM : Lanthaniumrich Mischmetal) alloy powders(${\leq}200$mesh) which were coated with 25wt% copper in an acidic bath were prepared with or without addition of 10wt% PTFE as a binder. Prior to electrochemical measurements, the electrodes were sintered at $40^{\circ}C$ for 1 and 2hrs in vacuum with Mm(mischmetal) and sponge type Ti getters. The properties such as maximum capacity, cycle life and mechanical strength of the negative electrode have been investigated. The surface analysis of the electrode was also obtained before and after charge-discharge cycling using scanning electron microscope(SEM). From the observations of electrochemical behavior, it was found that the sintered electrode shows a lower maximum discharge capacity compared with non-sintered electrode but it shows a better cycle life. For the both electrodes with or without addition of PTFE binder, the values of mechanical strength were obtained, and their values increased with increasing sintering time. However, there is little difference of discharge capacity for both electrodes.

• Journal of the Korea Concrete Institute
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• v.13 no.2
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• pp.114-122
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• 2001

The purpose of this study was to manufacture sintered lightweight aggregate using paper sludge ash and to evaluate the qualities of the aggregate according to various mix proportions, conditions of pelletization and sintering. The paper sludge ash alone, due to its mineral and chemical compositions could not gain suitable expansion and strength. Hence, it was essential to add mineral additives such as clay, fly ash etc. The optimum muting ratio range determined in this study is as follows , paper sludge ash 30∼50 %, clay 30∼50 %, fay ash 0∼40 %, Paper sludge 0∼10% and hematite 2∼3 %(for manufacturing lightweight aggregate both for non-structural and structural concrete). It was possible to manufacture various lightweight aggregate whose dry specific gravity ranged about from 0.6 to 1.4 by using this optimum mixing ratio. From the test results of the qualities of aggregate, it showed that the 10% granules crushing value test and water absorption percentage ranged about 5∼10 ton and 10∼20%. Thus, it was favorably comparable to those of the imported aggregate. The manufactured lightweight aggregate could be used for structural concrete and non-structural concrete.

• Journal of Powder Materials
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• v.28 no.3
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• pp.221-226
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• 2021

We fabricate the non-equiatomic high-entropy alloy (NE-HEA) Fe_49.5Mn₃₀Co₁₀Cr₁₀C_0.5 (at.%) using spark plasma sintering under various sintering conditions. Each elemental pure powder is milled by high-energy ball milling to prepare NE-HEA powder. The microstructure and mechanical properties of the sintered samples are investigated using various methods. We use the X-ray diffraction (XRD) method to investigate the microstructural characteristics. Quantitative phase analysis is performed by direct comparison of the XRD results. A tensile test is used to compare the mechanical properties of small samples. Next, electron backscatter diffraction analysis is performed to analyze the phase fraction, and the results are compared to those of XRD analysis. By combining different sintering durations and temperature conditions, we attempt to identify suitable spark plasma sintering conditions that yield mechanical properties comparable with previously reported values. The samples sintered at 900 and 1000℃ with no holding time have a tensile strength of over 1000 MPa.

• Journal of the Korea Institute of Building Construction
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• v.18 no.2
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• pp.185-193
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• 2018

In this study, using Granulated Blast Furnace Slag (GBFS), an industrial byproduct, and Phosphogypsum (PG), and Waste Lime (WL) as activator, non-sintering binder (NSB) which does not require a sintering process was produced, and the chemical penetration resistance was evaluated through a seawater resistance experiment. The result of the experiment showed that the inside of NSB mortar saw almost no influence from the ions in seawater due to its dense structure. Also, as it appears that only the surface reacts with ions in seawater while spreading inward is suppressed, the high seawater resistance of NSB could be confirmed.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.619-624
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• 2002

The purpose of this study is to manufacture sintered lightweight aggregate for non-structural concrete using sewage sludge, organic waste matter is produced to a sewage treatment plant. It is tested for basic property and strength of artificial aggregate according to addition ratio of sewage sludge, and the results are compared with imported aggregate from Spain. As the results of experiment, the manufactured lightweight aggregate could be used for non-structural concrete. Also, it was favorably comparable to those of the imported aggregate. When it is manufactured with aggregate, it is safe environmentally because of protecting elution of harmful heavy metals.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.33-36
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• 2006

This Study is based on manufacture non-sintering cement(NSC) by adding phosphogysum and waste lime to GBFS as sulfate and alkali activators. This study also investigates the basic physical properties and duality of NSC, and evaluates its reusing possibility as construction materials. Therefore, we design 40MPa and 60MPa for compressive strength using OPC and NSC by binder. And There is a purpose to present fundamental data, applying in field and analyzing quality control of concrete using NSC according to rate of replace between OPC and NSC.