• Journal of Powder Materials
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• v.15 no.6
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• pp.503-508
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• 2008

Ti(C,N) solid solutions in hot-pressed Ti($C_{x}N_{1-x}$) (x=0.0, 0.3, 0.5, 0.7, 1.0) and 40TiC-40TiN-20Ni (in wt.%) cermet were characterized in this study. For hot-pressed Ti(C,N)s, the lattice parameters and hardness values of Ti(C,N) were determined by using XRD (X-Ray Diffraction) and nanoindentation. The properties of hot-pressed Ti(C,N) samples changed linearly with their carbon or nitrogen contents. For the TiC-TiN-Ni cermet, the hardness of the hard phase and binder phase were determined by nanoindentation in conjunction with microstructural observation. The measured hardness values were ${\sim}8.7$ GPa for the binder phase and ${\sim}28.7$ GPa for the hard phase, which was close to the hardness of hot-pressed Ti($C_{0.7}N_{0.3}$).

• Korean Journal of Materials Research
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• v.8 no.11
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• pp.1055-1060
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• 1998

Thermoelectric properties of ($Pb_{1-x}Sn_x$)Te ($0\leq{x}\leq{0.4}$) alloys, fabricated by mechanical alloying and hot pressing, were investigated with variation of the SnTe content. For the hot-pressed PbTe and ($Pb_{0.9}Sn_{0.1}$)Te. transition from p-type to n-type occurred at $200^{\circ}C$ and $300^{\circ}C$, respectively. However, the specimens containing SnTe more than 0.2mole exhibited p-type conduction up to 450'C. In extrinsic conduction region, the Seebeck coefficient and electrical resistivity of the hot-pressed ($Pb_{1-x}Sn_x$)Te decreased with increasing the SnTe content. The temperature at which the hot-pressed (Pbl-,Sn,)Te exhibited a maximum figure-of-merit was shifted to higher temperature with increasing the SnTe content The hot-pressed (Pbo ,Sno dTe exhibited a maximum figure-of-merit of $0.68\times10_{-3}/K$ at $200^{\circ}C$.

• Journal of the Korean Wood Science and Technology
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• v.30 no.1
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• pp.25-33
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• 2002

Improvement of density profile and sound absorption capability of particleboard was attempted. Three types of hot pressing methods examined ; flat-platen pressing method (A-type pressing), hot pressing in forming box (B-type pressing), and hot pressing set up jagged caul in forming box (C-type pressing). The raw materials were larch(Larix leptolepis (S, et. Z.) Gorden) shavings, phenol formaldehyde resin, and the particleboard perforated with stair type. The physical and mechanical properties such as specific gravity, bending strength (MOR), internal bonding strength (IB) and sound absorption coefficients were examined. The results are summarized as follows : 1) The MOR and internal bonding strength of the board pressed in forming box were higher than those of flat-platen pressed board. 2) The minimum density to average density ratio in thickness direction which pressed in forming box showed about 923%, in the case of 35 mm commercial particleboard and 50 mm flat-platen pressed board, its values showed about 66.4% and 865% respectively. 3) Sound absorption coefficients of the particleboard perforated with stair type were higher than those of flat-plated pressed board and commercial particleboard.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1994.04c
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• pp.42-43
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• 1994

• Journal of the Korean Physical Society
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• v.73 no.10
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• pp.1535-1540
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• 2018

In this study, we prepared and characterized Nb-doped $Li_7La_3Zr_{2-x}O_{12}$ (LLZNO) powder and pellets with a cubic garnet structure by using a modified sol-gel synthesis and hot pressing. LLZNO powder with a very small grain size and cubic structure without secondary phases could be obtained by using a synthesis method in which Li and La sources in a propanol solvent were mixed together with Zr and Nb sources in 2-methoxy ethanol. A pure cubic phase LLZNO pellet could be fabricated from the prepared LLZNO and an additional 6-wt% of $Li_2CO_3$ powder by hot pressing at $1050^{\circ}C$ and 15.8 MPa. The hot-pressed LLZNO pellet with a relative density of 99% exhibited a very dense surface morphology. The total Li ionic conductivity of the hot-pressed LLZNO was $7.4{\times}10^{-4}S/cm$ at room temperature, which is very high level compared to other reported values. The activation energy for ionic conduction was estimated to be 0.40 eV.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.4
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• pp.55-61
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• 2011

The n-type $Bi_2(Te_{0.9}Se_{0.1})_3$ powers were fabricated by mechanical alloying, mixed with tungsten(W) powders, and hot-pressed at $550^{\circ}C$ for 30 minutes. Thermoelectric properties of the hot-pressed $Bi_2(Te_{0.9}Se_{0.1})_3$ were characterized as a function of the volume percent of tungsten-powder addition. The power factor of the hot-pressed $Bi_2(Te_{0.9}Se_{0.1})_3$ was $21.9{\times}10^{-4}$ $W/m-K^2$, and was improved to $30.5{\times}10^{-4}$ $W/m-K^2$ by dispersion of 1 vol% W powders. While the dimensionless figure-of-merit of the $Bi_2(Te_{0.9}Se_{0.1})_3$ hot-pressed without dispersion of W powders was measured as 0.52 at room temperature, it became substantially enhanced to 0.95 with addition of 1 vol% W powders.

• Journal of the Korean Ceramic Society
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• v.31 no.12
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• pp.1513-1520
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• 1994

Mechanical properties of hot-pressed SiC whisker/Al2O3 composites were strongly dependent on the granular characteristics of mixed powder, which were controlled by co-dispersion condition, the existence of steric barrier on whisker surface, and granulating method, etc. Heat-treatment of SiC whiskers at $700^{\circ}C$ for 1 hr in air was very effective both for achieving dispersion stability of whiskers with PVA adsorption and for obtaining excellent mechanical properties of resulting composites. It is believed from the fractography of composites prepared with various whisker dispersion conditions that the most common fracture origin of Al2O3 agglomerate could be attributed to whisker clusters arising due to flocculation. Further improvement of mechanical properties of composites were achieved by hot pressing green tapes prepared by Doctor-blade process, which promoted two-dimensional random alignment of whiskers.

• The Korean Journal of Ceramics
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• v.4 no.3
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• pp.227-230
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• 1998

Alumina($Al_2O_3$)-Titanium Diboride($TiB_2) particulate composites were fabricated by hot pressing of the powder mixture that was prepared from Self-propagating High Temperature Synthesis (SHS) product and commercial powders. Their propeties were examined in order to find feasibility of using SHS for making the high performance ceramic composite. $TiB_2 particles obtained by grinding the SHS product were finer than the commercial powders. Hot pressed sample containing the SHS products exhibited higher strength than the one prepared from the commercial powders.

• Journal of the Korean Ceramic Society
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• v.32 no.8
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• pp.865-872
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• 1995

Ultra-fine $\beta$-SiC powders were fabricated by self-propagating high temperature synthesis process (SHS) using microwave oven. The flexural strength, fracture toughness, and hardness of hot pressed sample at 200$0^{\circ}C$ for 60 min using synthesized SiC powders, which had 2 wt% of Al2O3 and 2.5 wt% of B4C content, showed 438 MPa, 4.15MPa.m1/2 and 28 GPa, respectively. The highest strength, fracture toughness, and hardness of composites containing 4wt% of Al2O3, which had highest relative density of 99.9%, showed 458 MPa, 4.6MPa.m1/2 and 36.2 GPa, respectively.

• Journal of the Korean Ceramic Society
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• v.37 no.2
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• pp.158-163
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• 2000

Six different SiC ceramics with SiO2-Re2O3 (Re=Yb, Er, Y, Dy, Gd, Sm) as sintering additives have been fabricated by hot-pressing the SiC-Re2Si2O7 compositions at 1850$^{\circ}C$ for 2 hr under a pressure of 25 MPa. The room temperature strneth and the fracture toughness of the hot-pressed ceramics were characterized and compared with those of the ceramics sintered with YAG (Y3Al5O12). Five SiC ceramics (Re=Yb, Er, Y, Dy, Gd) investigated herein showed sintered densities higher than 94% of theoretical. Tthe SiC-Re2Si2O7 compositions showed lower strength and comparable toughness to those from SiC-YAG composition, owing to the chemical reaction between SiO2 and SiC during sintering. SiC ceramics fabricated from a SiC-Y2Si2O7 composition showed the best mechanical properties of 490 MPa and 4.8 MPa$.$m1/2 among the compositions investigated herein.