• 세라미스트
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• 제9권6호
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• pp.42-48
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• 2006

The structural ceramic, such as $A1_2O_3,\;ZrO_2\;and\;Si_3N_4$ have applied as several parts of precision machines, automotives and instruments for semiconductor. The mechanical properties depended on purity, morphology and microstructure of the ceramic and its fabrication process. High purity and fine starting powder for the structural ceramic was prepared mainly by wet process and powder processing such as milling, mixing, drying and granulating strongly influenced on the fabrication process. Powder processing included powder synthesis technology is essential for ceramic manufacture. Also, the advanced mechanical treat[neat in powder processing to create nano composite powder was developed to improve several properties of ceramic materials. Innovation of powder processing will lead to improve mechanical and functional properties of the ceramics.

• 한국재료학회지
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• 제23권4호
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• pp.250-254
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• 2013

In order to increase the toughness of ZTA(zirconia toughened alumina) ceramics, the present study focused on rearrangement and densification of particles according to the particle size of the parent material. When rough alumina was used for production of ZTA, densification behavior was observed in the specimen sintered at a temperature over $1550^{\circ}C$. However, it was found that the densification behavior was occurred in the specimen sintered at $1450^{\circ}C$ when fine alumina powder was used. High relative density exceeding 98% was obtained when fine alumina powder was mixed with 15 wt% of 3Y-TZP and sintered at $1600^{\circ}C$. Also, a hardness of 1820.2 Hv was obtained when a specimen containing 10 wt% of 3Y-TZP was sintered at $1600^{\circ}C$. In the case of 3Y-TZP containing rough alumina powder that had been sintered the hardness value was around 1720.3 Hv. It was predicted that an improved toughening effect in ZTA could be achieved by using finer alumina powder as the parent material.

• 한국분말재료학회지
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• 제12권3호
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• pp.174-178
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• 2005

This paper deals with the fabrication of titanium carbide using fine titanium hydride. The ratio of $TiH_2$ and C (Activated carbon) was 1:1 (mol) and milled in a planetary ball mill at a ball-to-powder weight ratio of 20:1. Thereafter, TGA was performed at $1400^{\circ}C$ to observe change of weight with milling time. Titanium carbide was obtained by using tempering the milled powders at $1100-1500^{\circ}C$. The microstructures of titanium carbide as well as the change of the lattice parameters and particle size have been studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM).

• 한국분말재료학회지
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• 제16권3호
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• pp.209-216
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• 2009

A composite of rapidly solidified Al-6061 alloy powder with graphite particle reinforcements was prepared by ball milling and subsequent hot extrusion. The microstructure and mechanical properties of these composites were investigated as a function of milling time. With increasing milling time, the gas atomized initially and spherical powders became elongated with a maximum aspect ratio after milling for 30 h. Then, refinement and spheroidization were achieved by further milling to 70 h with a homogeneous and fine dispersion of graphite particles forming between the matrix alloy layers. The best compression and wear properties were obtained in the powder milled for 70 h, associated with the increased fine and homogeneous distribution of graphite particles in the aluminum alloy matrix.

• 한국분말재료학회지
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• 제13권2호
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• pp.129-137
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• 2006

In this study, high purity fine $BaTiO_3$ powders were prepared by SHS (Self-propagating High-temperature Synthesis). We would examinate the study of sintering properties and characteristics as a function of temperature with various additives (binder, sintering agent). In separately binder addition, the green and sintered density of specimen were increased as binder content increases. The increased porosity resulted in fine grain size due to the inhibition of grain boundary moving. The $Al_{2}O_{3},\;TiO_{2}$ and MgO playa role of increasing dielectric constants at room temperature. These values were decreased at curie temperature. In case of $SiO_2$, the Curie temperature was decreased. In this study, a high dielectric ceramic capacitor material with temperature stability was synthesized by using various additives.

• 한국식품조리과학회지
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• 제31권4호
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• pp.405-412
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• 2015

To develop a color stable and fine bamboo leaf powder (BLP) as a functional green biomaterial, bamboo leaf (BL) purchased from Sasa borealis and cultivated in Damyang, Jeonnam was treated with different conditions and BLP was evaluated. The four treatments comprised of boiling in water, in zinc chloride, sodium bicarbonate, and vinegar solutions, BLP4 was treated with 2% $ZnCl_2$ for 1 h, BLP5 was treated with 1% $ZnCl_2$ for 2 h, and BLP6 was treated with 1% $ZnCl_2+10%$ NaCl for 1 h. The particle size distribution, ash content, water binding capacity, and color change after heating in acidic solution were compared to commercial fine green tea (GTP) and bamboo leaf powders (CBLP). The particle size (cumulative 90%) of BLP was finest in BLP4 followed by BLP6 < BLP5 < GTP < CBLP. The water binding capacity of GTP was the highest and that of BLP was negatively correlated with particle size. After heating in acidic solution, the color of commercial GTP and CBLP changed from bright green to olive green, but the treated BLPs remained bright green. Especially, the -a (greenness) values for the commercial powders decreased from 11.2-13.6 to 3.1-3.8, while those of the treated BLPs did not change.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2004년도 International Symposium on Powder Materials and Processing
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• pp.44-45
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• 2004

• 한국재료학회:학술대회논문집
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• 한국재료학회 1998년도 추계학술발표강연 및 논문개요집
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• pp.22-22
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• 1998

• 한국세라믹학회지
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• 제25권6호
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• pp.655-664
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• 1988

As a part of study to establish the industrial process for manufacturing high purity alumina powder which is largely used as fine ceramics, an adsorption method using a silica-containing material which can absorb to eliminate a major impurity, Na in aluminum hydroxide as a raw material has been studied. It is confirmed that the primary property of powder such as the particle size of raw material and that of silica-containing material plays a great important role in the purification process.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.203-204
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• 2006

There is an increasing demand for PM-processes with the capability to produce parts of higher complexity than with conventional press and sinter technology in high production numbers. Warm-flow-compaction (WFC) makes use of improved flowability of powders when blended in an appropriate ratio with fine powder fractions and lubricating binders. Here the process is shown with examples of PM-Steels. General features possible with the process like pressing of undercuts and threaded bores are shown.